Apex dBG-8 - User manual
Contents
1. INTRODUCTION Thank you for buying the Apex dBG 8 The Apex dBG 8 is part of the Apex dB series of professional audio equipment offering unprecedented quality for money The dBG 8 offers 8 channels of gating in an ultra compact package but without compromising quality If you are used to working with noise gates you will immediately find your way about the dBG 8 However if you would like to make the best use of the dBG 8 or would like to know more about nois gates in general we invite you to read this manual UNPACKING AND SAFETY i Follow all warnings and instructions Install in accordance with the manufacturer s instructions Power Source This product is intended to operate from a regular 220V AC outlet Grounding The chassis of this product is grounded through the power cord To avoid electric shock plug the power cord into a properly wired receptacle before making any con nections to the product A protective ground connection by way of the grounding conductor in the power cord is essential for safe opera tion Do not defeat the safety purpose of the grounding plug The grounding plug has two blades and a third grounding prong The third prong is provided for your safety When the provided plug does not fit your outlet consult an electrician for replacement of the obsolete outlet Danger from loss of ground If the protective ground connection is lost all accessible conductive parts including knobs a2. User s Manual dB SERIES EIGHT CHANNEL GATE WITH SIDE CHAIN EQ User s Manual version 1 0 0 APEX NV Schoebroekstraat 62 3583 Beringen Paal BELGIUM Tel 32 0 11 28 61 91 Fax 32 0 11 25 56 38 email info apex audio be website www apex audio be Environmental precaution EU Directive 2002 96 EC Remark This notice applies only to countries within the European Union EU and Norway Electrical and electronic equipment may contain hazardous substances for humans and their environment The crossed out wheelie bin symbol present on the device and represen ted above is there to remind one of the obligation of selective collection of waste This label is applied to various products to indicate that the product is not to be thrown away as unsorted municipal waste At the end of life dispose of this product by returning it to the point of sale or to your local municipal collection point for recycling of electric and electronic devices Customer participation is important to minimize the potential affects on the environment and human health that can result from hazardous substances that may be contained in this product Please dispose of this product and its packaging in accordance with local and national disposal regulations including those governing the recovery and recycling of waste electrical and electronic equipment Contact your local waste administration waste collection company or dealer
3. how small or how large the bandpass filter will be This will not alter the sound of the signal path unless you active the LISTEN 4 button 7 BYPASS activating this switch will connect the input to the output of that channel thus bypassing the gate function The green LED indicates the bypass function is active so the gate is not in the signal path Sound passes unaltered 8 GATE LED s The green LED indicates that the gate is open and sound will pass trough The red LED indicates that the input level is below the threshold the gate is closed and sound will not pass REAR PANEL d B G 8 SHOCK HAZARD DO NOT REMOVE COVER 100 230 v 50 60 hZ APEX N V BELGIUM j FUSE Serial nr T 500 mA H 250V CLASS 1 EQUIPMENT WARNING THIS EQUIPMENT MUST BE EARTHED 1 POWER INLET please connect the supplied power chord to this inlet The power supply of the dBG 8 is auto sensing and accepts between 100V and 230V 50 60Hz Do never connect a broken or damaged power chord or when not sure what the voltage is 2 POWER SWITCH turns the unit on or off 3 FUSE do not replace with another value other that that mentioned 4 CH IN channel input use standard TRS Jack for balanced connection 5 CH OUT channel output use standard TRS Jack for balanced connection 9 CONNECTING i Cable connections Most of the time a gate is connected to the insert point of a mixing desk H
4. it even if there are a lot of people talking around you As long as the ambient noise is not too loud you will be able to follow the discussion Microphones are not intelligent they are stupid they cannot discern what they should pick up and what not For example you are miking a drumset In the ideal world the mic on the snare drum should only pick up the sound of the snare drum when it is hit but as you already know it will also pick up the sound of the bass drum the Hi Hat the cymbals some of the tom s and even the farting of the drummer depending on the drummer of course The same is of course true for the mic of the bass drum and the ones on the toms the Hi Hat etc This means that the sound of the snare drum will be captured by almost all microphones on the drum set We are now facing a major problem the sound of the snare will not arrive at all these microphones at the same time since they APEX are not at the same distance from the snare drum On the other hand all these micropho nes will be mixed together on the mixing desk On top of that not all these microphones will be identical so will not have the same frequency response and the applied EQ on each input channel on the mixing console will also be different The result is that the one original sound of the snare drum will be spread out with different delays and different EQ and different levels over a number of channels on the mixing console This phenomenon is also
5. of frequencies around that centre frequency In other words you select the frequency of the snare drum and then try to cut off the lower and higher end frequencies What now happens is that if the kick drum is hit the filter does cut off most of its energy so that the level detector measures a much lower value which is under the threshold and so that the gate stays closed It sounds much more complex than it is to do this make the drummer play activate the EQ on the snare drum channel of the dBG 8 and activate the listen button You will now hear the effect of the EQ on the side chain channel Play with the Frequency and Q controls and try to isolate the snare drum and cut off most of the base drum hi hat or other sounds It might be easier if you solo the snare drum channel on the mixing console Once you are satisfied release the listen function Keep your atten tion to the snare drum sound if you are missing snare drum hits or parts of the sound go over your controls again first the threshold than the Q control than the release time Use the listen function to verify if you have correctly set the Frequency If you are new to using gates please take the time to experiment and find out how the con trols work and the effect they have You will quickly discover how easy it is to operate the Apex dBG 8 and how it can help you getting a better sound Good Luck AS _ APEX Technical Specifications 7 Line Inputs Eight balance
6. the threshold the gate will stay close This will have the same effect as muting a channel 2 RELEASE variable between 20ms and 5s When the gate is open and the input level drops again under the threshold the gate will close will reach the maximum attenuation of 60dBu With this control you can alter how fast the gate will close 3 EQ IN this switches the EQ into the side chain path of the gate As long as you do not activate the LISTEN 4 switch the EQ is not audible on the output of the gate and does not affect the input signal It is only used to fine trim the detection circuit of the gate 4 LISTEN this switches the side chain path of the gate to the output so that you can listen to changes effectuated by the FREQ 5 and Q 6 potentiometers Activating this button will remove the gate from the signal path AS APEX 5 FREQ variable between 80Hz and 10kHz Used in conjunction with the EQ IN 3 switch You can now select the centre frequency of the band pass filter A band pass filter is a filter which is passing a certain frequency range look at it as a high pass filter on the low end and a low pass filter on the high end The gate will become more sensible to this frequency band This will not alter the sound of the signal path unless you active the LISTEN 4 button 6 Q variable between wide and narrow Used in conjunction with the EQ IN 3 switch Permits you to select the bandwidth of the filter This will decide
7. will use an example Let s consider the mic on the snare drum To avoid other drum sounds especially base drum and hi hat to leak into this mike you will put a gate in the signal path However since the base drum and the Hi Hat are near and can produce some very loud levels you will not be able to avoid the gate on the snare drum channel to open when the base drum or hi hat are hit Since they will be hit a lot of times the gate might become almost useless since it might be open all the time Raising the threshold is not a solution since you might cut out some snare drum hits First of all Using the EQ on the dBG 8 will not alter the sound of the signal Unless you activate the Listen switch The signal through the dBG 8 channel is split and send to a detector circuit who is calcu lating it s level necessary to know when it exceeds the threshold level and when it drops under it again This is called the side chain path When you activate the EQ you activate a band pass filter in the side chain path As you all know we hope the sound from a snare drum is quiet different from that of a base drum or a hi hat The base drum has much more low frequency energy while the hi hat has much more high frequency energy APEX When you activate the EQ you can centre it around the fundamental frequency of the snare drum the frequency which appears to you as the loudest With the Q control you can then set a more or less smaller band
8. alanced line connect the output or send signal of the console or line to the input of the dBG 8 and connect the output of the gate to the Return or input connection of the console or line BALANCED CONNECTION SEND gt INPUT CH SEND INPUT OUTPUT at a GND INSERT RETURN GND ORT l ono a Grounds Connecting a number of equipment via inputs and outputs especially when going from one piece of equipment to another and returning can cause hum generated by ground loops Connections to the safety earth via the power chord can participate to this hum problem DO NEVER CUT THE EARTHING of equipment which is meant to be earthed In case of persisting hum problems you can try to lift the ground on the dBG 8 respective input s This is done via a jumper on the circuit board Removing this jumper will disconnect the electrical circuit ground from the chassis of the dBG 8 This requires opening up the equipment and should only be done by qualified technicians AS APEX WHAT IS THE USE OF A GATE AND HOW TO USE IT i In this chapter we will briefly try to explain why the gate was invented and how it is used But whatever we are telling you please feel free to experiment and make creative use of the dBG 8 just remember that all tricks explained in this manual are normally done by trained professionals The gate originally was known as Noise gate As long as we humans hear an acoustic s
9. d high impedance line level inputs 10 KOhms on 1 4 TRS jack connector Maximum Input Level 20 dBu Line Outputs Eight electronically balanced low impedance outputs lt 600 Ohms Maximum Output Level 20 dBu into 600 Ohms Output noise lt 90 dBu 22 Hz 22 kHz Gate attenuation lt 90 dBu 22 Hz 22 kHz Threshold Continuously variable between 60 dBu and 15 dBu Side chain filter Continuously variable between 80 Hz and 10 kHz centre frequencies Attack Fixed internally Release Continuously variable from 5 mS to 5 S Crosstalk Better than 80 dB THD 0 dB lt 0 05 20 Hz 20 kHz Frequency response _ 0 5 dB 20 Hz 20 kHz Metering Gate open close led indicators Power supply Auto detect 100 230 V 50 60 Hz switching power supply power switch and fuse on the back panel Dimension H x W x D 1U rack Case x 483mm 19 inch x 44 mm 1 75 inch Weight 2 Kgs A APEX EE amp RoHS Compliance Certificate For Apex dBG 8 Eight Channel Gate Code Number 80 00 20 000110 01 06 2006 Apex NV Schoebroekstraat 62 3583 Paal Beringen Belgium WEEE Apex shall be WEEE compliant based on EU regulation 2002 96 EC On 01 07 2006 All our products will have the WEEE directive label placed on the case So the products can be returned to Apex if the product have reached the end of use at the end of the life cycle RoHS Based on information provided by our suppliers Ape
10. e gate opens when it should Be careful however sound levels during rehearsal or sound check may be different than those during the live act In general musi cians will play louder during the live performance Also don t forget that there might be songs or passages where some of the musicians play subtle and with low levels The threshold is the function you will adjust the most during set up and even live performance If the threshold is set too low it will be like there was no gate at all if on the other hand the threshold is set too high you will cut out certain sounds Attack Time As already explained the attack time is the time it takes the gate to open when a sound exceeds the threshold level One might think that this should be set to instantaneous but this might lead to clicks On the dBG 8 the value is fixed This is a rather fast time so that the gates opens up quickly enough not to eat away part of the sound when the singer starts to sing or when the drummer hits the snare drum We recognize different instruments by the spectral content the balance between the funda mental frequency and the level of the different harmonic frequencies but also although often overlooked by their envelope shape the attack decay sustain and release of the sound If the attack time of the gate would be too slow you would kind of cut off the attack of the sound and in certain cases make it very confusing for the listener to recognize the ins
11. e of 4000Hz This all led to the use of the logarithmic scale of the decibel dBu when using decibels we are thus expressing ratio s And when expressing ratio s we have to use a reference value In the case of dBu this reference is 0 775 Volt Do not confound with dBU or dBV where the reference is 1 Volt RMS the rms value is the square root of the mean of the sum of the squares of the root mean square Electrical power is proportional to the square of the RMS voltage and acoustic power is pro portional to the square of the RMS sound pressure In more common words this is the mean value compared to the peak or sometimes called program value Attack Time The time it takes for a processor to alter between two states For example in the case of a gate the time it takes for the gate to change between the maximum attenuation and a linear transfer state Or the time it takes for the gate to open when the sound has exceeded the threshold level On the dBG 8 the attack time is fixed and can not be altered by the user Hold Time The time it takes the processor to start altering its state For example in the case of a gate the time the gate will stay open even when the sound level has dropped under the threshold level In other words the gate will stay open for a little while duration of the hold time even when the input level has dropped under the threshold Release Time The time it takes the processor to reverse its state For examp
12. ignal music speech we can focus on that signal and forget annoying side effects like noise The moment there is a pause in that relevant signal all annoying side effects like noise and other signals become more apparent In the dark ages when digital was not yet invented all audio was recorded on analog carriers like tape vinyl discs mini cassette etc These carriers and the equipment needed to read and amplify the audio from them also carried and amplified some noise inherent to the medium So someone invented the simple noise gate when the audio signal dropped under a certain level the threshold it was considered as non relevant and the signal was attenuated in the case of the dBG 8 60dB The moment the signal rises again above the threshold the gate will open and audio will pass So here is the first use of a gate attenuating the existing noise during pauses in the program material Another issue occurs when multiple microphones are on a stage and amplified All microp hones how elaborated there design may be are still very stupid electro acoustic trans ducers And even the most expensive digital mixing console or multi Fx processor is not much more than a good calculator Most of us humans have a brain there will always be exceptions and the human brain is still much more advanced than whatever equipment we are able to design When you are at a cocktail party you have no problem following a nearby discussion when you focus on
13. ion is of course to tell the band you only have 4 microphones So another reason to use a gate is to keep the number of open microphones at any given times as small as possible The Mute button on your mixing console does the same of course but in case of the 15 headed folk band you will have to choose if you want to be a sound mixer or a piano player Setting the gates correctly will prevent that the backing vocal microphones are open all the time thus reducing your gain before feedback The same goes of course if you have to mix a debate or conference with 15 speakers And in the event they all start shouting at the same time you better turn off the sound system and go have lunch since nobody will be listening ZN _ APEX PARAMETER SETTING j What is the effect of the different parameters and how to correctly set a gate Not all parameters on the dBG 8 are accessible to the user To be able to fit 8 channels in 1 Rack Unit Height some of them are fixed and can not be altered We will however describe them all to give you a better understanding Threshold This is quiet an easy parameter when the level of the signal stays under the threshold the gate is closed and no sound passes When the level of the signal exceeds the threshold the gate opens and sound passes through So the first parameter to set is the threshold level Move the potentiometer while the intended signal is passing through the channel and make sure th
14. ker and some of that sound is again picked up by that same microphone amplified etc When a certain gain is applied between the microphone and the loudspeaker the circuit will start to oscillate and produce what we call Feedback Larsen effect Nobody likes feedback as far as know not human beings not amplifiers and definitely not spea kers and if more definitely not speaker tweeters With only one microphone on stage and open one can via rather complex mathematics calculate the possible gain before feedback will occur In other words this will decide how loud you can go before you get feedback Based on this there is the rule of NOM Number of Open Microphones If we have 2 microphones on stage open and with the same gain we will have to reduce the overall gain by 3dB to avoid feedback compared with one open microphone If more microphones are open you can use the following formula NOM in dB 10 log NOM APEX If you have 6 microphones open on stage all having the same gain this means 7dB 10 log 5 mic s So we will lose 7dB of Gain Before Feedback So when that folk band arrives with 15 musicians and they say that 10 of them will do some backing vocals at some time or another and you are in a small hall with lousy acoustics and you don t have some Apex dBG 8 s you know you are in deep trouble since all the audience will ask to get it louder and that dreadful feedback monster is smiling in your face The cheap solut
15. known under the name of phase shift The result is that the original sound is smeared out you loose definition impact and imaging Since everybody is still waiting on the microphone manufacturers to develop an intelligent microphone which can dis tinguish between snare drum and other drum sounds you can still buy an Apex dBG 8 to clean up your sound Using the gate in a right way we can try to minimize the effects of phase shift If the gate is set in a correct way it will only let the sound of the snare drum pass when it is hit in the intermediate pauses the gate will be closed and will not let other drum sounds through This goes of course for the other drum mics to This only works of course if the intended source is clear and distinguished from the others That is why there are normally no gates on the overhead microphones these tend to pick up the sound of the cymbals but also the overall sound of the complete drumkit Thus this now means that you can only use gates on drum mics No not at all Let s consider the backing vocals This leads us to another problem of multiple open microphones Feedback When a microphone is picking up sound the signal is amplified and fed to a loudspeaker we have a complex electro acoustic circuit A tiny sound is picked up by the microphone is amplified and fed to the loudspeaker But some of the sound coming from the loudspea ker is picked up by that same microphone amplified and fed to the same loudspea
16. l probably at a certain point descend under the threshold level although the sound has not died out yet To avoid that the gate is cutting off the tail of your sounds the hold time sets the time it will take the gate to start closing after the level has dropped under the threshold If the fixed hold time of the dBG 8 does not suffice for your specific applications you might also consider setting the release time to a higher value Please see below Release Time As explained this is the time it will take the gate to close completely attenuate the sound by 60dB when the level drops under the threshold and after staying open for the duration of the hold time see above Again if the release is set to fast it might cut off the tail of your sound While listening to the signal adjust the release time so the sound dies out naturally before the gate is closed Too short a release time might also lead to artifacts or an unnatu ral feeling Humans do not like it when ambience or reverberations suddenly disappear so adjust the release time to keep a very natural feel and to avoid that the audience is hearing the gate function EQ or side chain Filter INPUT GAIN CONTROL VCA ATTENUATION CALCULATOR 0 20 mS 5S 60 15 THRESHOLD dB RELEASE I detection in this area I Frequency As explained before microphones are not intelligent devices To describe the function of the Side Chain EQ and how to set it we
17. le in the case of a gate the time it will take the gate to reach the maximum attenuation when the input level drops under the threshold and after holding on during the hold time On the dBG 8 the hold time is fixed and can not be altered by the user If really necessary the hold time can be adjusted by a trim control on the circuit board of the dBG 8 This requires opening up the equipment and should only be done by a qualified technician APEX PRODUCT HIGHLIGHTS The dBG 8 offers 8 individual gates in an extremely compact package The user controls are extre mely straightforward and intuitive Connections are balanced on TRS Jacks The dB8 offers profes sional sound quality with user friendly controls in a compact housing APPLICATIONS Applications include live sound PA gating of multiple mic s to clean up the mix and to prevent smearing out of sound conferencing reducing the number of open microphones to obtain a higher gain before feedback recording creative use to alter the characteristics of sounds ONLINE REGISTRATION i FRONT AND REAR PANEL DESCRIPTION j All 8 channels being equal only one channel is described FRONT PANEL mom Po fe ORQ 6 l 7 THRESHOLD dB RELEASE O THRESHOLD dB RELEASE 1 THRESHOLD variable between 60 dBu and 15dBu When the input level reaches the level set by this control the gate will open and let the sound pass When the sound level at the input stays under
18. n or moisture does not operate normally or has been dropped Equipment markings The lightning flash with arrowhead symbol within an equi lateral triangle is intended to alert the user of the presence of uninsulated dangerous voltage within the product s enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons The exclamation point within an equilateral triangle is intended to alert the user of the presence of important operating and maintenance servicing instructions in the literature accompanying the product i e this user guide CAUTION To prevent electric shock do not use the polarized plug supplied with the unit with any extension cord receptacle or other outlet unless the prongs can be fully inserted WARNING TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE A APEX ABBREVIATIONS AND DEFINITIONS OF TERMS dB the decibel is not a unit but expresses a ratio The range of numbers associated with sound is related to the sensitivity of the human ear which is quiet enormous The threshold of hearing occurs at approximately 20 uPa micro Pascal while the threshold of pain is situated above 100 Pa This means that the range is quiet enormous We perceive frequencies from around 20Hz to 20kHz and we experience the interval between 400Hz and 800Hz range of 400Hz as equal to the interval between 4kHz and 8kHz rang
19. nd controls that may appear to be insulated can render an electric shock Proper power cord Use only the power cord and connector specified for the product and your operating locale Use only a cord that is in good condition Protect the power cord from being walked on or pinched particularly at the plug conve nience receptacle and the point where the cord exits from the apparatus Operating location Do not operate this equipment under any of the following conditions explosive atmospheres in wet locations in inclement weather improper or unknown AC mains vol tage or if improperly fused Do not install near any heat source such as radiators heat registers stoves or other apparatus including amplifiers that produce heat Unplug this apparatus during lightning storms or when unused for long periods of time Stay out of the box To avoid personal injury or worse do not remove the product covers or panels Do not operate the product without the covers and panels properly installed Only use accessories specified by the manufacturer Clean only with a damp cloth User serviceable parts There are no user serviceable parts inside the dBG 8 In case of failure refer all servicing to the factory Servicing is required when the dBG 8 has been damaged in any way such as when a power supply cord or plug is damaged liquid has been spilled or objects have fallen into the apparatus the apparatus has been exposed to rai
20. owever nothing prevents you to insert the gate elsewhere in the signal path but do remember that the gate does expect a line level input Mic level signals may be used but you will find that they have too low a level to be controlled precisely The dBG 8 is a professional piece of equipment and has balanced in and outputs where Tip is Ring is and Sleeve is Ground When your console has an unbalanced insert point mostly in the form of a single TRS chas sis connector please verify which part of the TRS jack carries the send and return signal Most consoles have the send signal on the TIP of the connector and the return signal on the RING of the connector The ground of both signals is shared on the SLEEVE of the con nector Connect the Send signal to the Input of the dBG 8 and the Output of the dBG 8 to the Return signal TIP when by accident you exchange the in and out put connections on the dBG 8 the gate will not function Sound will not pass through the dBG 8 UNLESS you hit the bypass function Bypass will connect the input to the output and sound will pass even when you reverse input and output This may lead you to think that one or more channels of the dBG 8 are malfunctioning So please always verify your connections MIXING CONSOLE UNBALANCED CONNECTION INSERT INPUT OUTPUT Connection could vary amp send from console manufacturer When you have a balanced insert point or are inserting the gate in a b
21. trument If you have an editing software try cutting off the attack of a clean electric guitar the resemblance with an organ will become obvious But why would you need a longer attack time This is only necessary in very specific appli cations and mostly only on program material If you would have digital silences between APEX parts of music that start with some background noise it might be handy to have a longer attack time to avoid the sudden transition between absolute silence and background noise The value of the attack time of the dBG 8 was chosen after hours of experimenting so that the final value chosen would suit almost all real live applications Hold Time As explained this is the time it will take the gate to start closing when the level drops under the threshold This parameter is also fixed and cannot be altered from the front panel There is a trim control inside the equipment which lets you trim this hold time In normal use you should not attempt to alter the factory setting Again the value of the hold time was chosen after hours of experimenting in the factory and should suit most applications Please do not open the equipment if you are not a qualified technician Again this has to do with the envelop shape of sounds and music Some sounds have a rather long tail and decay rather slowly for example floor toms It can take quiet some time before a hit on a floor tom has died out completely The decay of the sound wil
22. x indicates the dBG 8 as RoHS compliant for orders placed on or after the date of this certificate RoHS compliant means that e Our supplier has confirmed that the product concerned is RoHS compliant e We apply rigorous and persistent processes to confirm and document this Wherever applicable we perform material content tests Soldering Apex only uses Lead Free Soldering Techniques See norm IEC 61760 Lead free wave soldering PCB Apex only use RoHS Compliant and compatible PCB s Lead free finishes amp lead free laminate requirements Component Checking We assembly and purchased components with RoHS Compliant certification For these purposes the maximum concentration values of the limited substances as to weight in homogeneous materials are as follows Lead 0 1 Mercury 0 1 Hexavalent Chromium 0 1 Polybroombifenylen 0 1 Polybroomdifenylethers 0 1 Cadmium 0 1 Apex takes all possible steps to document the supplier statement This document is made for the distributors of Apex products see above product Document 90 44 20 000110
Download Pdf Manuals
Related Search