Sound Performance Lab 2595 Stereo Amplifier User Manual
Contents
1. Manual No 39 Output amp Sound Performance Lab Passive Equalizer 120V Gain Stages e Boost MEN Model 2595 asseq Model 2595 Passive Equalizer with 120 V Makeup Amplifiers Manual Passeq Model 2595 Version 1 0 7 2006 Designer Wolfgang Neumann This user s guide contains a description of the product It in no way represents a guarantee of particular characteristics or results of use The information in this document has been care fully compiled and verified and unless otherwise stated or agreed upon correctly describes the product at the time of packaging with this document Sound Performance Lab SPL continuously strives to improve its products and reserves the right to modify the product described in this manual at any time without prior notice This document is the property of SPL and may not be copied or reproduced in any manner in part or fully without prior authorization by SPL SPL electronics GmbH Sohlweg 80 41372 Niederkruechten Germany Tel 49 0 2163 983 40 Fax 49 0 2163 983 420 Email info soundperformancelab com Web www soundperformancelab com CE Declaration of Conformity Manufacturer SPL electronics GmbH C Type of Equipment Audio Signal Processor Product Passeq Model 2595 Compliance Engineer Wolfgang Neumann Test Basis EN50081 1 1992 EN50082 1 1992 EN60065 1993 EN61000 3 3 1995 EN60065 2002 EN55013 2001 EN55020 2002 EN61000 3 22. Peak Filters A peak filter boosts or cuts a chosen frequency s energy with a maximum amplitude and a definable frequency range around this frequency with a fall off of up to 3dB to both sides The chosen frequency with the maximum amplitude is called center frequency it takes place in the middle at the peak of the response curve The response curve forms a bell thus peak filters are also often referred to as bell filters Bandwidth The width of a frequency range or band is musically defined in octaves The technical coun terpart to this is the Quality of a filter and the abbreviated Q is the most common value for the bandwidth of a filter A high Q value means a narrow bandwidth while a smaller Q factor corresponds to a wider one Bandwidth 2 Octaven 0 7 Q Bandwidth 11 3 Octaven 1Q Bandwidth 1 Octave 1 4 Q Bandwidth 1 2 Octave 2 8 Q 22 Passeq The Basics of Frequency Filtering Equalizer In our context here an EQ is in effect a network of frequency filters which changes its output characteristics depending on frequencies The common recording studio concept for sound shaping or correction is the amplitude based EQ But owing to the large number of filter combinations there are practically too many existing formulations of this design concept to count Nonetheless it is sensible to make some general observations that categorize the most important technical differences among these design concepts Passive
3. on page 5 Passeq Schematic of a passive frequency filter Block diagram of passive filter set flat Block diagramm of a passive filter at 18 dB boost 23 The Basics of Frequency Filtering Active EQs The filters of an active network require external power which allows for an integration of amplifying elements that allow for both boost and cut functions Active EQs dominate the market and perhaps a good part of this is due to their user friendly capacity to combine both boost and cut features into single controls Avery good active filter designs can often offer very responsive characteristics with relatively little signal coloration or alteration But the operative word here is can the sonic result of filtering comes under the influences of so many parameters that it is almost impossible to fullfill any such claims made categorically Parametric EQs With a fully parametric EQ all filter parameters are adjustable The frequency amplitude and bandwidth of each filter can be adjusted by a user The fully parametric EQ is therefore ideally suited to working very specific or in very narrow limits at any desired frequency There is also the case of semi or half parametric filters whose bandwidth is fixed usually at around two octaves Graphic EQs For working with the entire audible frequency range there are available certain fixed frequency and bandwidth active filters One can only alter the amplitude of each fil
4. 2000 73 23 EWG 93 68 EWG We herewith declare that the construction of the Passeq Model 2595 is in compliance with the standards and regulations mentioned above Notes on environmental protection At the end of its operating life this product must not be disposed of with regular household waste but must be returned to a collection point for the recycling of electrical and electronic equipment The wheelie bin symbol on the product user s manual and packaging indicates that The materials can be re used in accordance with their markings Through re use recycling of raw materials eee or other forms of recycling of old products you are making an important contribution to the protection of our environment Your local administrative office can advise you of the respon sible waste disposal point WEEE Registration 97334988 2008 SPL electronics GmbH All rights reserved Names of other companies and their products are trademarks of their respective owners Passeq Important Safety Information ccc cece cence ee ee cence III meme 4 HOOKUP pre 5 duipnindini MEET 6 Unique Features Special Features 1 socer tren a re EnA TEE ETRE TUE 6 Advantages of Passive Filtering 72 passive Filters with 120 V Makeup Amplifiers Filter Types Single Core Coils Peak and Shelving Filters 7 120V Makeup Amplifiers SPLSUPRAOp Amps 8 Lundahl Tra
5. 230 or 115 volts before using the unit Before connecting any equipment make sure that any machine to be connected is turned off on the Passeq rear panel the power switch must be pushed down An AC power cord is included for connection to the standard 3 prong IEC connector The trans ELE former power cord and IEC connector are VDE UL and CSA approved The AC fuse is rated at UH 500mA for 220 240 V and 1A for 110 120 V gy Ey sat Operation Power The Passeq is turned on and off with the rear Power switch The blue LED in the center of the front indicates operating status Passive Equalizer 120V Gain Stages Channel Switches Two illuminated switches in the center of the front activate or bypass the left or right channel Layout of Operational Elements nitially one might be struck by the circular arrangement of the Passeq s control elements As unusualas this first appears the more understandable and clearer this layout becomes when one looks closer Along with the fact that we simply like this design from an aesthetical view this layout makes even more sense with respect to the idea of the passive EQ concept itself In a passive design filters for boosting and cutting a frequency range are physically separated from each other Reflecting this fact the elements left of the central output control perform level cuts while controls to the right of this central regulator serve as signal boost
6. MF MHF cut band overlaps the LF LMF cut band by approximately an octave with its lowest frequency extending from 1kHz The LF boost and LMF MHF boost bands are set up in a similar fashion with the lowest LMF MHF boost band frequency set at 220 Hz and thereby 1 1 2 octaves under the highest LF boost band frequency The maximum values of the MF MHF cut and LMF MHF boost band extend from 11 5 dB to 10 dB The overlapping band characteristics give a good idea of the available degree of precision in frequency adjustment For example one can boost in the LMF MHF boost band at 220 Hz while in the LF boost band 240Hz can be followed by 320Hz in the LMF MHF boost band The next step could be at 380Hz in the LF boost band followed by 460 Hz in the LMF MHF boost band and 55oHz in the LF boost band 14 Passeq Operational Elements MHF HF Cut and HF Boost Passeq s high frequency bands have a different layout for the cut and boost ranges The MHF HF cut band exhibits a wide band shelving characteristic while the HF boost band exhibits a variable Q peak filter characteristic As seen above one can also note and intensification in choice of frequencies in the high range Here the same reasons apply as in prior cases Individually designed and constructed coil condenser resistor configurations result in slightly differing sonic characteristics Thus beginning at 10 kHz there are seven additional switchable frequencies The available variable
7. of In producing a tone the distribution of energy within the frequency spectrum is further and decisively influenced by the acoustic environment through the mixing of direct and reflected sound The energy relationship between fundamentals and harmonics is different between direct sound and that which is reflected for example harmonics of a reflected frequency spectrum may have measurable more energy and this can change a tone s perceived sound Later when a musician has the impression that a recording is not true to the original that he or she has either played or sung an important consideration to make is to examine the resul tant frequency spectrum Sound Correction and Sound Design Along with acoustic influences of a recording ambience it should also be understood and accepted that to say the least there are definite technical limits to recording and playback that may strongly influence an end result In the first decades of electronic recording the principle influence on the quality of such recordings centered on the choice and placement of microphones The first Equalzers were used to combat technical and acoustical problems such as insufficient frequency response from microphones and loudspeakers or even inad equate relationships in room acoustics that needed to be corrected or brought into balance The goal was always to bring into balance as much as possible and maintain the correct frequency spectrum of an originating to
8. of the above described frequency range separation and processing through complementary signal filtering In the process specific frequencies of one instrument should be reduced with narrow bandwidths while increasing the same frequencies of other instruments This involves boot and cut values between ca 3 6 dB Classic conflicts of this type happen for example between kick drum and bass or between lead and background vocals and these are perfect circumstances for applying complemen tary filtering to avoid masking problems e Kick Drum Bass A reduction of the kick drum between 350 and 400 Hz and an increase in the same bass frequencies will reduce the cardboard sound of the kick drum while lending the bass more presence e Lead Background Vocals A cut between 3 and 4 kHz in the background voices gives them a needed airy quality while boosting the same lead vocal range allows it to come through with more clarity 18 Passeq Recommendations on using Equalizers An overview of frequencies and examples for possible processing Here we provide approximate values which may expand to adjacent areas 50 Hz cut Reduces boominess in all lower instruments basses kick drums toms whose function also implicitly increases the relative level of harmonics and improves the presence of bass lines 50 Hz boost Fuller sonic qualities for all lower frequency instruments 100 Hz cut Limits boominess greatly increased guitar clarity and limits
9. sustain with Toms 100Hz boost Firmer bass sound for all low frequency instruments adds more warmth to piano and horns 200 Hz cut Less muddiness with voices and middle instruments while helping to elim inate the gong resonance with cymbals 200Hz boost Fuller sound for voices snare drums and guitars 400 Hz cut Limits hollower sound qualities in lower drums 400Hz boost Clearer bass lines 800Hz cut Diminishes the cheap sound of some guitars 8ooHz boost Noticeably clearer punchier bass lines 1 5 kHz cut Reduces an uninteresting sound in guitar tracks 1 5kHz boost Clearer cleaner basses 3kHz cut Hides badly tuned guitars or other problems with poor intonation 3kHz boost Better bass guitar attacks more attack with electric and acoustic guitars snares and other percussion as well as lower piano parts more voice clarity 5 kHz cut Softens thinner or tiny sounding guitars 5 kHz boost Improves voice presence and brightens guitars gives more attack to low frequency drums piano and acoustic guitars 7 kHz cut Reduces sibilants 7 kHz boost Provides more attack with percussive instruments 10 kHz cut Also reduces sibilants iokHz boost Brightens voices similarly brightens guitar piano and harder cymbals 15 kHz Boosts in this range brighten most sounds but be careful with hidden dangers such as emphasizing noise hiss and or creating excessive sibi lance The ru
10. 116 dB signal to noise ratio and 34dB of head room the SUPRA OPs offer a stunning 150 dB dynamic range placing them in an unsurpassed leadership position in either analog or digital signal processing The tremendously fast SUPRA slew rate of 200V ms allows for a highest possible precision in filter output signals particularly in the all important arena of transient response These amplifiers effortlessly and without coloration or degradation transmit all the desired filter characteristics and sonic results an engineer has sought out and in the process pushing beyond the limits of what has been technically possible to now SPL SUPRA Op Amps The specially designed and for audio optimized SUPRA OPs are constructed in three stages with high performance extremely low noise transistors from the HF technology sector Input Stages of the SUPRA Components The development of the SUPRA components focused on high loop amplification extremely low phase shifting and THD combined with maximum amplification and a frequency response up to 100 kHz A main and obvious advantage of the discrete SUPRA components is the exclusion of parts often found in industrially manufactured standard components that are not necessary for audio processing The SUPRA input stages are designed as balanced differential stages and comprise six matched high voltage transistors switched in parallel The concept ofthe input stage is based on the established principle that curr
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12. EQs The filters in a passive network employ no intrinsic amplification elements and therefore need no external power which means in effect that they can really only cut the energy of a chosen frequency In order to expand this capability to include boosting the energy of a bandwidth that is to be able to boost and cut frequencies the overall filter input signal level is reduced Based on this overall reduction and relative to the original input signal one can achieve a further cut or boost in the form of a return to that original signal level Thus a passive filter is always followed by an amplifier which is responsible to regain the initial energy reduction and restore level balance between the input and output signal levels dB o oV A nut signal level 2 Bass boost at 5o Hz by 18 dB 20 Filter output level when set for flat response Bass cut at 50 Hz by 18 dB 36 U 50 Hz 20 kHz o dBu Filter flat 20 dBu Amp o dBu Input gt sao dB 220 dB Output Filter 18 dB Amp boost 20 dBu Passive filters react differently than active filters mostly due to the saturation and loading characteristics of its coils and condensers The characteristics of passive filters often are very advantageous in their ability to create a musically pleasing sonic result they sound comparably very smooth and harmonious please see Introduction Advantages of Passive Filter s
13. HAZARDS FROM FIRE DANGEROUS ELECTRICAL SHOCK OR MACHINE DAMAGE DO NOT OPEN THE MACHINE THE LIGHTNING SYMBOL WITHIN A TRIANGLE WARNS YOU ABOUT UNINSULATED HIGH VOLTAGE INSIDE THE TRANSDUCER AND THE POTENTIAL FOR DANGEROUS ELECTRICAL SHOCKS WHICH CAN ALSO OCCUR EVEN AFTER THE MACHINE HAS BEEN DISCONNECTED FROM A POWER SOURCE Symbols and Notes ALSO IN THIS MANUAL A LIGHTNING SYMBOL WITHIN A TRIANGLE WARNS YOU ABOUT THE POTENTIAL FOR DANGEROUS ELECTRICAL SHOCKS WHICH CAN ALSO OCCUR EVEN AFTER THE MACHINE HAS BEEN DISCONNECTED FROM A POWER SOURCE AN EXCLAMATION MARK WITHIN A TRIANGLE IS INTENDED TO MAKE YOU AWARE OF IMPORTANT OPERATIONAL ADVICE AND OR WARNINGS THAT MUST BE FOLLOWED BE ESPECIALLY ATTENTIVE TO THESE AND ALWAYS FOLLOW THE ADVICE THEY GIVE The symbol of a lamp directs your attention to explanations of important functions or applica tions Attention Do not attempt any alterations to this machine without the approval or supervision of SPL electronics GmbH Doing so could nullify completely any and all of your warranty guarantee rights and claims to user support Passeq Hook Up CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN AVIS RISQUE DE CHOC ELECTRIQUE NE PAS OUVRIR A A Introduction SPL Passeq the most powerful passive Equalizer ever made Unique Features The most powerful passive EQ ever made 72 passive filters per channel in one EQ 120V makeup amplifiers based upon SPL SUPRA O
14. I O electrical interference they offer transformers also introduce their own element of sonic warmth that is today too often inadequately attributed solely to tube circuitry The sonic quality from Passeq s Lundahl transformers may be described in comparison to straight electronic O circuitry as Bass and fundamentals are rounder fuller and exhibit more punch while higher frequencies and harmonics sound silkier and more present yet without leaving the impression of being overly emphasized or singled out Moreover they add the subtle impression that mix elements are better localized The reasons for this are the tendency of transformers to reduce uneven harmonics which often give the impression of harshness in a sonic canvas and to act with some latency compared to electronically balanced stages In particular fundamentals and low frequencies benefit from this Other Features XLR contacts from Switchcraft serve as In and Output connections while controls and switches are from the manufacturers Elma and ALPS including ALPS Big Blue with 41 steps The internal fully analog power supply features a generously proportioned toroidal transformer that offers switchable 110 120 Volt 60 Hz or 220 240Volt 50 Hz functions Conclusion The Passeq represents the most powerful passive EQ system to date and fulfills the highest expectations in all areas of audio processing from recording through mixing to mastering Passeq
15. Introduction Rear Panel p1022 1ou z QNO t S 20S Y1X SUHIM Uld yauuey Y T Jeuuey 34514 ndul yndjno Output Left Channel Right Channel PIOD Uld JOH Z Uld OND T Uld SUMIM Uid YIX ANVW3I39 NI 3dVW uoo qeje ueuuojiedpunos MMM ueunas ue3upnanypiepelN qeq e ueuuojiad punos TIITA e8ed x u y uo s ou y 0 1 J 1 SL d 10729 S 980 0A pue Q2 IMS 19MOd 2H 09 AOzE AOLE ZH OS A ObZ A OTZ 220 V 240 V 50 Hz 110V 120V 60 Hz uwop u 1IMs pe1eAn2eep aq PINOYS 1J GND eui jensn Suiuuinu doo punoj ejeuluiie 0 punoJ sisseyd Ul0JJ puno4 eu49 UI soje1edas u21IMS YI QN9 9u 1 G3H13V3 38 LSNW LNIWdINDI SIHL 783A02 ONIAOW3Y 330338 SNIVW 123NNOOSIG JUNLSIOW YO NIVY OL LINN SIHL3SOdX3 LON OQ 320HS 21412313 30 3314 30 NSIY 320033 OL Suyjey asny mols VI ZH 09 AOZT A OTL M0 S vuigos zH OS A OYZ A 0ZZ Fuse Rating jnduj suew 3Y D AC Mains Input MIMANO SVd IN 3001312313 20H2 30 300 SI SIAV N3dO LON OG JDOHS2RIL3T3 40 Shi NOI1nV5 CEEI ZH 09 AOZE AOTT ZH 0S A0tZ AOZ 220V 240 V 50Hz 110V 120 V 60 Hz Voltage Selector j y _ g Q S Connections Power and Signal Connections Be very careful to check that the rear chassis power selection switch is set to the correct local line voltage position either
16. LF Boost The low cut frequency range extends from 3o Hz to 1 9 kHz and will be referred to in this text as LF LMF Low to Low Mid frequencies In contrast the low boost LF Boost band encom passes a range of 10 Hz to 550 Hz The maximum available increase in this LF boost band is 317 dB while the maximum reduction of the LF LMF cut band is 22 dB Optically these filter bands may be represented as having a shelving characteristic with an 6dB slope Passive filters do not allow for direct alteration ofthe slope gradient because this quality is pre determined by component selection and not as with active filters by a vari able value The lowest frequencies begin here with 10 Hz then follow with 15 18 26 40Hz and so on At this point one might think that such a lavish set of frequency choice in this range might be a bit overdone as there is acoustically a rather limited amount of audio material of any real significance below 26 Hz However these choices are anything but arbitrary These frequen cies represent a consistent 3 dB point of a sloping down response curve That is the gentle 6 dB slope also allows frequencies above 10 Hz to be processed As mentioned in other parts of this text special condenser coil resistor filter networks have been designed for each frequency range The choice of one or the other inductances produces differences in sonic coloration even when limited differences between frequencies such as 10 Hz or 15 Hz
17. Ps with 150dB dynamic rage and 200V ms slew rate e Individual coils per filter Single core coils which means that every one is wound individually on its own dedicated core This excludes sonic degradation from mutual influences while at the same time improving THD values Special Features Individual design and component specificity for each filter Custom made coils for critical mid frequency ranges Boost and cut crossovers mesh perfectly so that with the high number of frequencies one can dependably command the most elaborate set of response curves that to date any passive EQ has offered Transformers from Lundahl with perfectly matched sonic characteristics provide for balanced I O stages Passeq Advantages of Passive Filtering e Typically coil inductance in virtually all active filters is achieved through simulation True passive coil filters on the contrary can only deliver the genuine characteristic sound asso ciated with inductive components e Inherent distortion elements of active filters are ruled out by passive filter design For any number of reasons stemming from design and component advantages over active filters passive filters achieve a very natural aural quality and through their harmonic treat ment THD distortion phase response etc offering at the very least a clear sonic alter native which our ears often perceive as an extremely attractive one All passive filter components variab
18. Q ranging from Q o 1 to Q 1 0 allows the engineer access to an enormously flexible range in high frequency boost options HF Boost Q Settings with the Proportional Q Principle With the proportional or variable Q principle boost control settings would apply only if the HF boost Q were to be set at Q 1 0 control set fully clockwise Were the value to be reduced thus increasing the bandwidth the boost would also be reduced This can lead to a situ ation wherein for example a HF boost Q setting of o 1 and a boost of 3dB would result in effectively no audible boost in the chosen frequency at this value the Q value resides at about o 3 dB With this Q value don t hesitate to turn turn up the HF band boost control to its full 12 5 dB setting this results in an actual overall increase of around 3 5 dB Narrower Q settings for example to o 6 result in further level boosts again The advantage of proportional Q as compared to constant Q designs rests with the musi cally superior way it functions The wave energy which resides below the bell curve remains essentially the same and in the process retains the balance of high frequencies in relation to the entire frequency spectrum as one experiments with varying Q values While itis true that one must think independently of the scaled HF boost dB values in such cases because these only apply to a value of 1 the result is a simpler more musically sensible and worthwhile way to work that does n
19. ble is sonically tuned to its intended frequency range Thus each filter has its own musically sensible audio color appropriate to its own frequency In turn each coil is also wound on its own separate core to avoid mutual and degrading influ ences which stem from past designs where multiple coils were wound on a single core Not the least the construction of each filter on its own particularly core also provides for excel lent THD values Allocation of Frequencies One of the greatest Passeq design challenges was in determining the choice of frequencies which in contrast to parametric EQ designs are fixed or nonadjustable One could accept standardized values from such as the so called ISO frequencies but such measurements stem too much either from conventional measurement standards or those from room correc tions rather than choices of what may be musically more sensible In assigning the Passeq s frequencies it was inevitable that we would rely on the nearly 30 years of experience of SPL s chief developer audio engineer and musician Wolfgang Neumann To enhance further our achieving this musical objective many audio experts and musicians were consulted regarding their favored frequencies Among the many David Reitzas Michael Wagener Bob Ludwig Ronald Prent and Peter Schmidt offered valuable advice From this point of departure we managed to determine that there is definite agreement among profes sionals about their preferred musica
20. ce possible unwanted coloration of the signal Reducing bleed from other instruments or noise outside an instru ment s frequency range Wide band filters setups should be chosen with threshold frequencies in ranges from one to two octaves above or below the highest or deepest instrument s frequency Example To eliminate cymbal bleeding in a kick drum recording one should try a setting from about 10 kHz with a 10 15 dB cut Reducing bleed within an instrument s frequency range The main frequencies of the bleeding instrument should be reduced as far as possible while avoiding to alter the natural sound of the main instrument in an unnatural way Boosting harmonic frequency levels Harmonic enhancement is one of the foremost techniques for increasing the clarity and defi nition of an instrument The following is an overview for three typical instruments Bass 400 Hz Bass lines will be accented Bass 1500 Hz More clarity and attack sounds Guitar 3 kHz Clearer attacks Guitar 5 kHz Brighter more brilliance Vocals 5 kHz More presence Vocals 10 kHz Brighten up Note that each instrument will have at least two frequencies where EQ can achieve a greater clarity or brilliance Boosting fundamental levels Inexperienced audio engineers will often first try to make corrections by boosting fundamen tals something which in fact should be the last thing one considers Boosting fundamentals typically lowers clarity a
21. controls Cut and boost switches are positioned next to the appropriate frequency band selector and frequency bands are arranged from low to high from the standpoint of both physical and frequency range layout all in all a clear overall functional picture though without much in the way of boring routine The most powerful passive EQ system ever made The Passeq is the first passive EQ which provides three separate frequency ranges for both boost and cut stages One famous if not the most famous passive design was the Pulteq EQ from the decades of the 1950 s and 60 s This EQ sported two frequency bands low and high frequencies or LF and HF and had only a few switchable frequencies to offer In contrast the Passeq has 12 switchable frequencies per band totaling 36 boost and 36 cut frequencies Boost and cut frequencies are NOT identical thus the resultant 72 frequencies per channel offer an enormous choice for the most elaborate EQ curves please refer to the next chapter Frequency Layout The Passeq offers for the first time passive filter control possibilities extending throughout the relevant audio frequency range and that with an unheard of abundance of filter choices Passeq 11 Operation 12 One Coil per Filter one Core per Coil Each Passeq filter is individually constructed for its intended frequency that is each coil condenser and variable resistor var resistor boost or cut control ensem
22. ents of not correlated noise sources in shunt circuits add up which decreases the overall noise of the input circuitry The input stages are free of coupling capacitors to exclude additional capacitor noise The balanced operational voltage of 60V is delivered from a linear 8o dB high voltage power supply Intermediate Stages of the SUPRA Components The audio signal is further routed to a differential stage and from there through further processing stages to the Class A output stage All passive components have been tested to yield the highest possible fidelity Output Stages of the SUPRA Components Extremely low noise high voltage output transistors are set up with a high quiescent current and excess heat is dissipated via special cooling plates Passeq Lundahl Transformers The Swedish firm of Lundahl is recognized world wide for the superior sonic qualities of its hand made transformers SPL has used Lundahl transformers for many years typically for optional in and output stages of various products In the case of the Passeq there is no question of whether solid state or transformer based input and output stages are the better choice Because of their excellent and similar sonic qualities Lundahl transformers are a clear choice to complement to the Passeq s EQ circuitry I O transformers are classical analog components in many vintage machines In addition to increased operational safety due to the isolation from incidental
23. ertz Hz Lower tones produce longer waves and higher waves of shorter length and the higher the frequency the higher the tone The higher the amplitude of a wave the higher its energy level and in turn the louder it is perceived Tone and Sound In the area of music a sound event is referred to as a tone Such a tone is complex it is comprised of different frequencies each at a different energy level In analyzing the components of a naturally produced tone such as those created by a real instrument or voice we see the following ingredients A natural tone is comprised of a lowest pitch or fundamental along with many additional higher components called harmonics The arrangement of these pitches is called the harmonic series which includes the entire group of frequencies from fundamental to higher harmonics and is called the frequency spectrum of atone As the lowest pitch a fundamental determines the basic frequency and its perceived pitch The frequencies of the harmonics are multiples of the fundamental frequency and determine the specific sound of a tone that is whether it sounds like an instrument voice etc Should one wish by electronic means to record process and play back a given tone it is crucial to maintain the accuracy of the frequency spectrum if one wishes to be able to recog nize it later as the original Just as important is the aspect of maintaining the original energy levels of all frequencies it is composed
24. h the machine has not been subjected to any of these unusual circumstances but still is not functioning normally or its perfor mance is substantially altered In cases of damage to the power cord or its plug first consider turning off the main circuit breaker before unplugging the power cord Operate the controls and switches only as described in the manual Incorrect adjustments outside safe parameters can lead to damage and unnecessary repair costs Never use the switches or level controls to effect excessive or extreme changes Replacement Substitute Parts Be sure that any service technician uses original replacement parts or those with identical specifications as the originals Incorrectly substituted parts can lead to fire electrical shock or other dangers including further equipment damage Safety inspection Be sure always to ask a service technician to conduct a thorough safety check and ensure that the state of the repaired machine is in all respects up to factory stan dards Cleaning In cleaning do NOT use any solvents as these can damage the chassis finish Use a clean dry cloth if necessary with an acid free cleaning oil Disconnect the machine from your power source before cleaning Passeq Be very careful to check that the rear chassis power selection switch is set to the correct local line voltage position before using the unit 230V position 220 240V 115 V position 110 120 V When in doubt about a source contac
25. ible range and tonally appealing sound color palette from any passive EQ Filter Types The Passeq employs two distinct filter types One of these functions much like traditional shelving filters while the other as a peak filter and together they provide the combined char acteristics of wide band control in low and high ranges with more specific frequency range control in mids This selection minimizes mutual influences between low mid and high bands while providing a more selective control in the mids is often useful Single Core Coils Until now design approaches have involved individually wound coils but multiple coils have nonetheless been placed on a single core The Passeq design places each coil on separate cores This eliminates any possible unwanted mutual influence transmitted through common core windings and thus among other improvements results in better THD values Peak and Shelving Filters Mid boost and cut as well as HF boost filers have been set up in a peak bell configuration while the hi cut low cut and low boost filters function in a shelving configuration The HF boost band offers variable values from Q 1 to 0 1 Passeq Introduction Introduction 120 Volt Makeup Amplifiers With passive filtering comes an unavoidable drop in signal level that requires makeup ampli fication and with the Passeq here SPL s extraordinary Supra OPs with their unique analog 120 volt technology come into play With a
26. l frequencies and these differ clearly from the standard ISO choices The results also showed that the closely meshed boost and cut frequencies are important and sensible Through them one can on the one hand focus more precisely on a certain frequency and on the other offer the option of influencing the Q factor which is typically rather small in passive designs by creating so called S curves An Example Assume you wish to boost in the mids around 320 Hz an instrument or voice level while at the same time avoiding a boost to the frequency range below it due to the small Q factor high bandwidth of the filter and perhaps even lower it In this case let s say you choose the LMF MHF boost band and increase the chosen 320 Hz frequency range by about 3 dB At the same time you chose a 4dB reduction in the LF LMF cut band The close proximity of the chosen frequencies allows you achieve an increase in the slope between the two This is S slope EQ ing at its best and in this discipline the Passeq is a world champion in both options and results Frequency Table per Band LF LF LMF LMF MHF MF MHF MHF HF HF Boost Cut Boost Cut Boost Boost E EM E PB m E 1k2 mo e me Fen w e CNN CNN RN CN Dus e a fe T z j Passeq Table Allocation of Frequencies Operation Cut LF LMF Cut MF MHF Cut MHF HF BoostLF B LMF MHF Boost HF IEEE Unica ee ee i Paks S J 9 Operational Elements LF LMF Cut and
27. le always applies Before reaching for the knob to boost levels first try cutting frequencies elsewhere for accentuations Passeq 19 Recommendations on using Equalizers 20 Classical instruments and their frequencies A symphony orchestra presents a kind of ideal paradigm of a balanced wide spectrum instrumental sound canvas It is therefore only sensible to consider its sound as an orienta tion point also for other musical genres it will definitely not harm a Rock or Pop production to employ such an orientation to achieve a comparable balance and proper distribution of mix elements in the latter Fundamental Frequencies Em Harmonics 20 50 100 150 300 500 1 1 5 3 5 10 15 Hz Hz Hz Hz Hz Hz kHz kHz kHz kHz kHz kHz Piano Pipe Organ Bass Viola Violin Strings Cello Contra Bassoon Bassoon Clarinet Oboe Flute Woodwinds Piccolo Bass Tuba French Horn Brass Trombone Trumpet Tympani Snare Drum Percussion Cymbals Male Voice Voice Female Voice 20 50 100 150 300 500 1 1 5 3 5 10 15 Hz Hz Hz Hz Hz Hz kHz kHz kHz kHz kHz kHz Passeq The Basics of Frequency Filtering Frequency and Energy In general a frequency prescribes a number of events ina time interval The per second cycle of a wave form is given in H
28. le resistor capacitor and coil work in concert to produce this beautiful sonic result An important part of this process is played by coil and condenser loading and saturation characteristics The resulting difference in latency from characteristically extremely fast reaction of active filters provides for more pleasant musical sonic qualities We tend to perceive these attributes in terms of an increased suppleness and transparency with perceptibly improved silky highs and robust basses 72 passive Filters with 120 Volt Makeup Amplifiers With 72 passive filters 36 x boost 36 x cut per channel the Passeq surpasses all previous designs of this type by a wide margin Each channel is divided into three cut and three boost bands each offering 12 switchable frequency ranges The cut and boost ranges are not iden tical crossovers are designed to work with like a precise mechanic cogwheel so as to allow the engineer access to the largest possible number of optimal wide band S curves with variable slopes A further noteworthy Passeq feature is its individual sonic adaptation of each induc tive filter through separate coil condenser resistor combinations In stark contrast to earlier filter design and construction each Passeq filter is optimized for the frequency assigned To insure the best possible signal warmth richness and musicality in processing coils for critical voice frequencies are custom made for the Passeq This achieves the widest poss
29. machine Be doubly careful to note and follow the warn ings and special safety notices Connections Only use the connections as described Other connections can lead to health risks and equipment damage Water and Humidity Do NOT use this machine anywhere near water for example near a wash basin or bath in a damp cellar near swimming pools or the like In such cases there is an extremely high risk of fatal electrical shocks Insertion of Foreign Objects or Fluids NEVER allow a foreign object through any of the machine s chassis openings You can easily come into contact with dangerous voltage or cause a damaging short circuit NEVER allow any fluids to be spilled or sprayed on the machine Such actions can lead to dangerous electrical shocks or fire Opening the Machine Do NOT open the machine housing as there is great risk you will damage the machine or even after being disconnected you may receive a dangerous elec trical shock Electrical Power Run this machine ONLY from sources which can provide proper power at the prescribed rating When in doubt about a source contact your dealer or a professional electri cian To be sure you have isolated the machine do so by disconnecting the power cord from your wall connection Be sure that the power cord plug is always accessible When not using the machine for a longer period make sure to unplug it from your wall power socket Power Cord Protection Make sure that your powe
30. nd produces a muddy sound If two instruments are playing the same part and thereby produce the same fundamental raising these levels will lead to a decrease in the sonic difference between them i e will make the two instruments sound more alike and lower their intelligibility in the mix This is also true when two instruments play similar parts in the same key Exception When an instrument sounds thin or small boosting the fundamental can help Or perhaps a microphone was poorly placed or the harmonics had been raised excessively through EQ Finally increasing fundamental levels can also play a constructive role when instruments play alone or as soloists with others in the background Passeq 17 Recommendations on using Equalizers Cutting fundamental levels Cutting fundamental frequencies provides for a perceived increase in harmonics and is therefore an effective alternative to boosting harmonic levels This is a common practice in Rock Pop productions that can be effective in all musical recording genre An example Bass Reduction at 40 Hz may limit boominess and increase presence Guitar Reduction at 100 Hz may limit boominess and increase clarity Voice Reduction at 200 Hz limits muddiness in the sound Emphasis of an instrument s main frequencies For this purpose a bandwidth of 1 and 1 3 octaves is generally a very good starting point in other words this range best encompasses that of most instruments frequency spect
31. ne source The introduction of multi track recording in the 1960 s brought a fundamental change in the way recording was done Instruments intended for one production could be recorded in sepa rate sessions and at different times The mix from many individual recordings at first in only four tracks nonetheless added a new problem of offering ways to add further sonic quality through further processing of individual tracks because with each copy a track s quality was reduced This introduced an entirely new function for EQ for example the emphasizing of partic ular instruments in their tracks to prevent them from being lost in a mix by altering certain parts of their frequency ranges Along with this ability to emphasize specific tonal qualities appeared the added capacity to indulge in even more creative work through much stronger or even exaggerrated processing of a sound and thereby lend it even more presence in mixes Without a doubt the increasing popularity of electronic tone production has played a large part in the further development of EQ filtering as a creative element in audio production Passeq 21 The Basics of Frequency Filtering Frequency Filters As a rule almost everyone of us has first made an aquaintance with frequency filtering through our listening to home stereos Such elementary kinds of filters are simple ampli tude based filters When one turns a bass control clockwise one hears a general or overall increa
32. nsformers Other Features Conclusion 9 Rear Panel 4 nade i inis eM Den MAREM UN ted nite tach MER UU EPUM RUE 10 Rear Panel XLRPin WINE lt a sews e EXE ER A ERE RPAET EU NO QPRR EU v E CHE AT ERES 10 Connections uuu her e ya Deme dili des dee Dess whualule tete xis eode Erro dA 11 Power and Signal Connections nivesccevaeecsadoseetseencdds outs asad OE EEE EEES 11 Operation sospendono non ean aE E aayqa E EEDE EEE 11 Power Channel Switches Layout of Operational Elements The most powerful passive EQ system ever made sssssscresosissrsssserecsesessssseesasss 11 One Coil per Filter one Core per Coil Allocation of Frequencies Frequency Table per Band esee rro serena eerte e ERN EE ER AEE EERTSE 12 Table Allocation of Freq encles saa ehe hte r ret anre Er RR YR Rr eh in 13 LF LMF Cut and LF Boost MF MHF Cut and LMF MHF Boost 14 MHF HF Cut and HF Boost HF Boost Q Settings with the Proportional Q Principle MHF HE Cut Output Control escsas e roto proe rre bu RR OS E EA S IPLE EEERES 15 Recommendations on using Equalizers ccc eeceeeee cence eect eee eeeaeeeaeeeaes 16 Basic Approaches and Working Techniques EQ Yin amp Yang 16 First control levels then apply EQ First cut then boost Reducing bleed from other instruments or noise outside an instrument s frequency range Reducing bleed within an Instrume
33. nt s frequency range Boosting harmonic frequency levels Boosting fundamentallevels 17 Cutting fundamental levels Emphasis of an instrument s main frequencies In the mix or not Splitting frequency bands to reduce masking effects Complementary filtering 4 sientan yh nnn n EE RREPER sacs EEEE OaE EEEE 18 An overview of frequencies and examples for possible processing 19 Classical instruments and theirfrequencies uuu cc cece ccc cece cece enneeeeeeeeeeeeeeens 20 The Basics of Frequency Filtering cesses 21 Frequency and Energy Tone and Sound Sound Correction and Sound Design 21 Frequency Filters Filter Types Shelf Filters Peak Filters 22 Bandwidth Equalizer Passive EQs Schematic and block diagrams on passive filters 23 Active EQs Parametric EQS Graphic EOS s lt ccccscceiethisiads maeswded taea EET GEENE 24 Power SUpDly cisco ree keinuei ERR RE OE ERE C aaaiiees ETE RRE EE KEEPS 25 Specifications srono ronron neare T aychaq shay PRAE divs oh was EEEN EEE EEE DECR 25 Guarantee amp Product Registration 26 Copy Master Recall Settings sssssssse Hh 27 Passeq Contents Important Safety Information Please note and retain this information Carefully read and follow all of the safety and oper ating instructions before you use the
34. o consider always such implied repercussions of work in one frequency for example that in working to enhance warmth that one might want to avoid losing presence Harshness in the upper middle to lower high range can be countered with more than one approach A harsh trumpet section may be improved through a reduction around 6 8kHz oder with an increase at around 250 Hz Both of these measures result in a warmer sound but the decision of which to use should depend on which of the two also works best in the entire mix Moreover one should never forget how easy it is while working intensely with isolated elements of a mix to fall into the trap of forgetting how such elements can influence for better or worse the rest of the mix Passeq Recommendations on using Equalizers First control levels then apply EQ Badly adjusted levels often induce us to misuse EQ in misguided efforts to correct them As soon as one has the feeling that he or she needs more that 6dB in EQ boost one should investigate thoroughly whether or not initial levels have been set properly First cut then boost The ear is more used to energy reductions in a frequency range thus boosts attract more attention That is a 6 dB boost is perceived to be similar in amount to a 9 dB cut Therefore when wishing to emphasize one frequency it is typically better first to consider a reduc tion in others The result will bring more transparency and clarity as well as redu
35. ot require continual additional corrections MHF HF Cut The MHF HF cut band is similar to a shelving filter that can reduce higher frequencies in a wide bandwidth It is appropriately wide beginning with 580 Hz and extending to 19 5 kHz a range of over 5 octaves and overlapping the lowest LF LMF cut band by just about two octaves With it one can lower a very wide bandwidth and with the peak mid range filters further reduce or raise specific ranges The process can result in the creation of very interesting curves Here the maximum cut is 14 5 dB while the maximum boost reaches 12 5 dB The Passeq is not limited to any one particular kind of application and for example is also especially well suited to processing individual instruments in recording sessions In such cases the wide downward reaching MHF HF cut band may be play an exceptional role Individual instruments can easily be cut upwards either to give them a more compact sound or when higher frequencies might be supplied from different microphone or because the mix simply suggests it Output Control The Output control serves as output level regulator If boosts increase levels at the output they can be reduced again to the input level s value compare the block diagram passive filter at 18 dB boost on page 21 The proven Big Blue potentiometer from ALPS with 41 steps is employed here to ensure precise control and minimum tolerances over both channels Pa
36. play a subordinate role Along with this differing phase relationships may come into play and affect tonal color Because modern productions often demand a definite number of choices in an engineer s options for achieving an optimal result in bass emphasis the Passeq has been designed with a very complete set of low frequency options to insure realizing these goals MF MHF Cut and LMF MHF Boost The midrange bands elevate the Passeq to a complete combination of filter options that classic passive designs do not offer Both midrange bands exhibit peak filter characteris tics that is when viewed from the boost band the frequency curve appears as bell shaped slopes above and below the chosen frequency range The slope or Q value is again not variable but attuned through the choice and configuration of the passive filter s compo nents for a maximum in musical efficiency relying in the Passeq on its developer Wolfgang Neumann s years of musical experience The middle bands peak structure is chosen for a clean separation of LF and HF bands Were the choice here to be for a shelving filter design f MH ETS ve C too many neighboring frequencies would be processed with resulting undesirable influ ences extending into LF and HF bands Along with this is the simple fact that a midrange peak filter characteristic is accompanied by a more easily focused center point processing of critical voice and instrument fundamental frequencies The
37. r cord is arranged to avoid being stepped on or any kind of crimping and damage related to such event Do not allow any equipment or furniture to crimp this power cord Power Connection Overloads Avoid any kind of overload in connections to wall sockets extension or splitter power cords Always keep manufacturer warnings and instructions in mind Overloads create fire hazards and risk of dangerous shocks Lightning Before thunderstorms or other severe weather disconnect the machine from wall power but to avoid life threatening lightning strikes not during a storm Similarly before any severe weather disconnect ALL the power connections of other machines and antenna and phone internet cables which may be interconnected so that no lightning damage or over load results from such secondary connections Air Circulation Chassis openings offer ventilation and serve to protect the machine from overheating NEVER cover or otherwise close off these openings NEVER place the machine on a soft surface carpet sofa etc Make sure to provide for a mounting space of 4 5 cm 2 inches when mounting the machine in racks or cabinets Repairs Unplug the machine and immediately contact a qualified technician when you think repairs are needed or when moisture or foreign objects may accidentally have gotten in to the housing or in cases when the machine may have fallen and shows any sign of having been damaged This also applies to any situation in whic
38. rum This can be somewhat narrower with percussion instruments while it is recommendable to consider a wider bandwidth for melody instruments such as voice or bowed strings The boost value should remain between 3 and 6 dB In the mix or not The more an instrument is placed outside a mix resp above or in front of a mix the more natural its sound should remain When already embedded in a mix main frequencies should on the other hand be processed with a higher dB value but lower bandwidth An example A boost of 3dB at 5 kHz may serve to make a voice track clearer and much more present in front of a mix while when embedded in the mix a 6dB boost with less bandwidth may be more useful Splitting frequency bands to reduce masking effects In order to separate two instruments whose sound lies in the same range one may choose to process frequencies that are a half an octave from each other With a bandwidth of a half octave and 3dB boost one can achieve clarity and instrument differentiation The higher frequency should by applied to the instrument which sounds brighter or more brilliant Complementary filtering One of the most difficult problems in mixing instruments is the masking effect Loud instru ments cover others when their frequencies lie in the same range It can be very frustrating to discover that a terrific sounding instrument track suddenly sounds boring when added to a mix Of great help here can be an application
39. se in bass frequency energy But with the explanation above on the composition of a complex natural tone it is clear that such a low frequency control does not only influence the energy of the fundamental frequency but also always the sound of a tone the relationship between energy of the fundamental and harmonics frequencies is changed Typically amplitude based frequency filtering boosts or cuts the energy of a specific audio frequency band In such processes it is possible to employ filters with design and function that are very different from each other Depending upon the technical construction such filters may for example process only high or low frequencies in certain way Filter Types There are two types of filters used in the Passeq wide band filters which are comparable to shelf filter characteristics and bell formed peak filters with narrower bandwidths Shelf Filters A shelf filter increases or decreases the energy of all frequencies above or below a chosen frequency Depending upon the direction of processing one refers to high frequency HF or low frequency LF shelf filters Beginning with the threshold frequency the frequency band is boosted or cut much like a shelf The maximum boost or cut achieved at the point furthest from the threshold frequency The threshold frequency is usually about 3dB less with the overall increase set to maximum This gives the typical rising form of the shelf filter s response curve
40. sseq 39 o Output de Recommendations on using Equalizers 16 In the arenas of recording and mixing one can generally distinguish between two main goals in applying EQ The first is sound correction or sound design through processing of indi vidual channels while the second may be improving their separation or presence in the mix In the overall recording process there may be deficiencies due to technical problems for example noise or bleeding of neighboring instrument sounds that detract from the natural quality of the desired instrument Through frequency response characteristics of a microphone or phase shifts due to reflec tions energy at certain frequencies can be reduced or get lost denigrating the original sound quality of an instrument EQ is probably the most important tool to combat these problem areas Moreover an instrument s sound can also be accentuated or emphasized to the point that this becomes in its own right a creative sonic activity with a production made only possible by the employment of EQs and their special characteristics Basic Approaches and Working Techniques While we would never assume that in creative and artistic work there should be absolute rules and this also applies to work with EQ There is no such thing as The Voice or The Kick Drum or The Piano The following is thus offered strictly as a basic orientation or starting point for such work and should no
41. t be misconstrued as dogma or any other kind of absolute Nonetheless in order to achieve sometimes hard to define goals when applying EQ it really is important to be aware of and be able to use a few accepted basic musical and technical guidelines EQ Yin amp Yang This section on EQ Yin amp Yang reproduces thoughts and verbalizations by Bob Katz whose superb Focal Press book based ona series of lectures entitled Mastering audio the art and the science we highly recommend In Chinese philosophy Yin and Yang describe unconditionally bound opposites within some kind of unity which in turn both complement and conflict with one other This idea also provides an insightful analogy to the understanding of the connection between music harmony fundamentals and harmonics please see also Basics of frequency filtering Tone and Sound beginning on page 19 This mutual bond and interaction between such oppo sites creates inevitable and mutual reactions and repercussions in the other whenever some thing occurs to one Here are a few examples e A small reduction in the lower middle range around 250Hz can have a similar effect as an increase in the presence region of 5 kHz e Added energy in the very high region of 15 20 kHz can create the impression of having made the bass and lower mids thinner Adding warmth to a voice will reduce its mix presence Working with EQ and this Yin and Yang principal means ideally t
42. t your dealer or a professional electrician Before connecting any equipment make sure that any machine to be connected is turned off rear panel power switch Follow all safety instructions on page 4 Place the unit on a level and stable surface The unit s enclosure is EMC safe and effectively shielded against HF interference Nonetheless you should carefully consider where you place the unit to avoid electrical disturbances It should be positioned so that you can easily reach it butthere are other considerations Try notto place it near heat sources or in direct sunlight and avoid exposure to vibrations dust heat cold or moisture It should also be kept away from transformers motors power amplifiers and digital processors Always ensure sufficient air circulation by keeping a distance of 4 5 cm 2 inches to other units and to the sides of the unit Rack Mounting Be sure that both above and below the machine you maintain a distance of 1U 44mm 1 5 2 inches in order to eliminate electromagnetic or high frequency interference from other equipment Moreover this will ensure adequate air circulation to prevent overheating Do NOT locate other machines that produce excessive heat below the Transducer The rear side of the machine should be properly supported especially when transport is involved Warnings DO NOT PLACE THE MACHINE IN SUCH A WAY THAT IT MIGHT COME INTO CONTACT WITH OR SIT ON ANY FLUIDS AVOIDING SUCH CONTACT WILL AVOID
43. ter Because the designs of such machines originally employed fader controls and often continue to do so these adjusted faders represent in a graphic curve the frequencies and amount of alteration and thus earned the name graphic EQ Passeq Power Supply The power supply was carefully engineered to provide clean and consistent currenttttan important prerequisite for excellent audio Built around a toroidal transformer the power supply generates a minimal electromagnetic field with no hum or mechanical noise The output side is filtered by an RC circuit to extract noise and hums inherent in commercial AC power All audio related components are fed by two separate voltage regulators to minimize distur bance from other components An AC power cord is included for connection to the standard 3 prong IEC connector The trans former power cord and IEC connector are VDE UL and CSA approved The AC fuse is rated at 500 mA 230V version or 1A 115 V version Inputs and Outputs Indul sureW 3V AC Mains Input Specifications Instrumentational amplifier transformer balanced Nominal Input Level Input Impedance Output Impedance Max Input Level Max Output Level Measurements Frequency Range CMRR THD amp N o dBu Input Level S N A weighted Crosstalk L R 8 1kHz Dynamic Range Power Supply Toroidal Transformer Fuses Voltage Selector Power Consumption Dimensions Standard EIA 19 Inch Ho
44. using 4U Weight Notes odBu 0 775 V Subject to change without notice Passeq 4dBu 22kOhm 6000hm 28dBu 32dBu 20Hz 50 kHz linear 50 kHz 100 kHz 3 dB gt 70dBu 1kHz gt 110 dBu 115 dBu gt 85 dBu 143 dB 48 VA 500mA 230V 1A 115 V 230 50 Hz o 115 V 60 Hz 40W 482 x 176 x 390mm ca 19 x 7 X 15 6 inches 11 8kg 25 96 lb Guarantee amp Product Registration 26 All SPL products come with a two year manufacturer s guarantee against defects in material or assembly from the date of purchase Tubes have a guarantee of three months End users are supported in the two year guarantee through their distributor In such cases please contact your dealer for full guarantee conditions and service Direct SPL product support requires product registration Please fill out the guarantee card enclosed in the package legibly in printed letters and send it directly to SPL Or use the online registration form that may be reached at www soundperformancelab com international clients or www spl usa com US clients Passeq S6Sz japow qeq e ueuiojjad punos ep 1nd no seSejs ure AOZT Jezijenb3 9AISSed 2 a S 2 Ey lv IP 5008 Qi A SP 35008 JHW 3S SH N WK 3k ak 5k kg D od aE E sro amp O s009 38 x sgog 9Jeq OL sdno19 s yoe4L ungqjv 199U18U7 SIV je sSuines e2ey 1e1sew Ado Manual Passeq
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