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1. Troubleshooting No Output e Check that all your system components are turned on e Check that the master power switch adjacent to the AC receptacle is set to On e Check that the power switch on the subwoofer is set to either Auto or On Check your wires and connections Check all interconnecting cables Make sure the level control is not turned down Turn off and unplug the Grotto i and check the fuse near the AC power cord receptacle on the back If the fuse has blown replace the bad fuse with a matching T4 H 250V fuse T 2 L H 250V if you are in a region using 230v 240v current e Ifthe problem persists contact your dealer Muddy Bass e Check placement Try moving the subwoofer closer to the front and side walls e Check the type of feet that are being used Try installing the ETC spikes e Decrease the level e Check your processor setup e If the problem persists contact your dealer Hums or Unusual Sounds e Turn the subwoofer off unplug all signal inputs turn the subwoofer back on and turn up the level If the problem disappears the hum is originating elsewhere in your system e Connect the subwoofer s AC connection to the same AC circuit as the pre amp e Ifthe problem persists contact your dealer Frequently Asked Questions amp Troubleshooting 19 DIMENSIONAL DRAWINGS Plan View Top 13 8 35cm Front Elevation 18 6 47 3cm Side Flevation aa2. complained that the movie was too real The following list and descriptions will give you only a brief outline of the responsibilities and demands placed on each speaker Front Left and Front Right If these speakers will be the same two used for your stereo playback they should be of very high quality and able to play loudly over 102 dB and reproduce bass below 80 Hz Center Channel This is the most important speaker in a home theater system as almost all of the dialogue and a large portion of the front speaker information is reproduced by the center channel It is important that the center speaker be extremely accurate and mate well with the front speaker and that it is recommended for use as a center speaker This is not the place to cut corners Surround Speakers We recommend along with the film industry that the sur round speakers play down to at least 80 Hz Surround speakers contain the information that makes it appear that planes are flying over your head Some may suggest that this is the place to save money and purchase small inexpensive speakers If you choose to do so be prepared to upgrade in the future as discrete multi channel digital encoding is proliferating rapidly and the demands on surround speak ers have increased Subwoofer With any good surround system you will need one or more high quality subwoofers the 1 in a 5 1 6 1 or 7 1 channel surround system Most movie soundtracks contain large amounts
3. priate technical analysis to alleviate the situation WARNING e Hazardous voltages exist inside do not remove cover e Refer servicing to a qualified technician e To prevent fire or shock hazard do not expose this module to moisture e Turn amplifier off and unplug subwoofer should any abnormal conditions occur e The power cord should not be installed removed or left detached from the speaker while the other end is connected to an AC power source e The main power switch near the AC inlet shall remain readily operable e No candles or other sources of open flame should be placed on the speaker e No liquids either in glasses or vases should be placed on speaker e Speaker should not be exposed to dripping or splashing liquids e The terminals marked with the lightning bolt symbol should be connected by an instructed person or by way of ready made terminals e The power cord should remain readily oper able should any abnormal conditions occur Step 1 Unpacking Remove your new subwoofer from its packing Note Retain original packing materials for future use Step 2 Placement Ideally place the subwoofer in a corner near the front of the room Please see the Placement section page 16 for more details Step 3 Signal Connection Use the best cables you can High quality cables available from your specialty dealer are recommended and will give you superior performance Attach your preamplifier processo
4. Additional sub on left GROTTO GROTTO Left Out 70Hz High INO Ye Left Out 70Hz High INO YS fics MO 3N NQC EA oul Right Out Right Out Line Level Out Sub Out Line Level Out Sub Out u EP z 5 EC i fe EF 05 S m Er Z ES LFE In LFE In ul 1 11 el In In O O J Line Level In Left In TETEZI U 2437 our Right In ENC a TEEN Figure 11 Using multiple Grotto i Right Left option Primary sub on right Additional sub on left Controls and Connections 13 AC Power Connection WARNING The power cord should not be A N installed removed or left detached from the subwoofer while the other end is connected to an AC power source The IEC cord should be firmly inserted into the AC power receptacle on the rear connection panel of the subwoofer then to any convenient AC wall outlet Directly adjacent to the AC power receptacle on the rear connection panel of the subwoofer is a master power switch This switch is wired directly to the AC main and turns on off all power going to the subwoofer The Grotto i also integrates a sig nal sensing power supply that will go to Standby mode after a few minutes of no music signal if the front panel power switch is set to Auto Your subwoofer is wired for the power service supplied in the country of original consumer sale The AC power
5. attempts to drive the speaker beyond its rated frequency range This warning also applies to products from other manufacturers Right Out b Level Out u c E z EF 03 4 uj 441 MENEN Line Level In TETESI Ul 2437 our It is recommended to run center and effects type speakers in limited or narrow mode Figure 5 Signal connection for multi channel mode Recommended Control Settings 1 With multi channel source material playing adjust the Level control to your preferred level 2 Try the phase control in different settings until the best blending is obtained If you are using the subwoofer to augment other MartinLogan products we suggest start ing with the phase set at 90 3 If you have completed steps 1 2 and still have weak or boomy bass adjust the 25Hz Level knob to com pensate for these anomalies Increase and decrease to controls and listen to the effects Try to find a position that sounds correct to you Experiment by changing the Level control while adjusting these knobs Find a position that gives you deep extended bass and good blending with your main speakers 4 Follow the bass management setup instructions in your processor manual to fine tune the subwoofer level Controls and Connections 9 2 Channel Multi Channel Mode This setup is recommended if your subwoofer will a be used in both 2 channel ade and as a LFE chan PROC
6. be accessed at www martinlogan com or by emailing info martinlogan com Thank you to you the MartinLogan owner for loving what we do and for making it possible for us to do what we love CONTENTS amp INTRODUCTION Contents amp Introduction ccccceeees Installation in Brief ccc cece cece eee Controls and Connections 0eeee00 ConttOl AA edd phe eed CONNETTO e 4 xa na Naa Mp stan SKNLA 2 Channel Mode 0 00 e cence eee ee Multi Channel Mode 2 Channel Multi Channel Mode 2 Channel Mode Using Speaker Level Inputs 2 Channel Mode With 2 Channel Output Why the Filters Are Not Equal Sub Out Using Multiple Subwoofers AC Power Connection a Replacing the Fuse Break In Placement sawsawan awww saaan Listening Position Installing In A Cabinet Ask Your Dealer Enjoy Yourself Room ACOUSTICS 2 0 c cece cece aaa asaan Your Room Terminology Solid Footing Home Theatet sicccsscesswesesiceistasasecs MartinLogan Exclusives saa Servo Controlled Dynamic Drivers Proprietary Switching Amplifier 25Hz Level Control Frequently Asked Questions amp Troubleshooting Dimensioned Drawings 0eeeeeeeees General Information ccccecececees Specifications Warranty and Registration Serial Number Service Glossary of Audio Terms 00eee0e CE 4 Contents 8 Introdu
7. few subwoofers A room especially when small can greatly exaggerate bass in the 20 60Hz range The Grotto i s 25Hz Level control knob increases or decreases lower bass to compensate for these room anomalies and allows increased deep bass if you desire a subsonic sense of energy at the lowest frequencies FREQUENTLY ASKED QUESTIONS amp TROUBLESHOOTING Frequently Asked Questions How do I clean my subwoofer Use a dust free cloth or a soft brush to clean your subwoofer We recommend a specialty cloth available through the Xtatic shop at www martinlogan com that cleans better than anything else we have tried Is it safe to set things on my subwoofer While your subwoofer is designed with a durable stain resistant surface we advise you not to set anything on your subwoofer especially containers holding liquids Is there likely to be any interaction between my subwoofer and the CRT television in my Audio Video system Yes The subwoofer doesn t use a shielded driver We recommend 3 feet between the subwoofer and video components that are susceptible to magnetic fields Will my electric bill go sky high by leaving my subwoofer plugged in all the time No The subwoofer when the power switch is set to Auto or Standby will draw about 15 watts when idle Should I unplug my subwoofer during a thunderstorm Yes or before It s a good idea to disconnect all of your audio video components during stormy weather
8. i Example Filter Settings and Frequency Response for a Bookshelf Loudspeaker With A Low End of 56Hz Why the Filters Are Not Equal Io You may have noticed the recommended setting proce dure does not advise setting the Low Pass Filter and High 2 1 Pass Filter Out to the same frequency Between 20Hz and 100Hz as the subwoofers output decreases the loud O nag al le speakers output increases For a seamless crossover of 0 5 Filter 40Hz PEA ka Ni these two slopes the summation of their two values at 4 any given frequency should add to maintain a level out BN parang put By correctly setting your Low Pass filter this result can oe pa pr a 460 easily be achieved see figure 9 Frequency Hz mmm System Response Sub Output Speaker Output senna Sub Response Low Pass Filter set to 40Hz Speaker Response 70Hz High Pass Out Figure 9 12 Controls and Connections Sub Out Using Multiple Subwoofers Using Sub Out offers an easy way to implement multiple subwoofers in your audio video system Note Additional subwoofers must run as either dedicated 2 channel stereo or multi channel LFE subwoofers but not both Signal Connection 1 Connect the first subwoofer to your system using one of the five modes previously described Connect the Sub Out of the first subwoofer to either the LFE In or the Right or Left In of the next subwoofer Use quality RCA interconnects Connecting to the LFE In allo
9. we would like to notify you that this product may contain regulated materials which upon 13AUG2005 disposal according to the WEEE directive require spe cial reuse and recycling processing For this reason MartinLogan has arranged with our distrib utors in European Union member nations to collect and recycle this product at no cost to you To find your local distributor please contact the dealer from whom you pur chased this product email info martinlogan com or visit the distributor locator at www martinlogan com Please note only this product itself falls under the WEEE directive When disposing of packaging and other related shipping materials we encourage you to recycle these items through the normal channels INSTALLATION IN BRIEF We know you are eager to hear your new MartinLogan subwoofer so this section is provided to allow fast and easy set up Once you have your subwoofer operation al please take the time to read in Grotto the rest of the information in this manual It will give you perspective on how to attain the greatest possible performance from this most exacting woofer system If you should experience any difficulties in the setup or operation of your MartinLogan subwoofer please refer to the Room Acoustics and Placement sections of the this manual Should you encounter a persistent problem that cannot be resolved please contact your authorized MartinLogan dealer They will provide you with the appro
10. ESSOR GRO ITO nel in a multi channel system By following this setup you will allow your processor to handle most of the bass management while running in multi channel mode and relinquish control of the low pass filter to LFE 0 1 Out O the subwoofer when running in a 2 channel mode Left Out 70Hz High INO YT VA Pass NG Right Out Signal Connection see figure 6 MESS KO S 1 Connect the left and right out of your preamplifier to the subwoofer s Left In Right In Use quality RCA interconnects If your preamplifier only has one set of oO Eh 05 e 4 UKOR U outputs you need to obtain Y adapters from your dealer PREAMP T 2 Connect the LFE output of the processor to the sub RECEIVER a2 woofer s LFE In Use quality RCA interconnects as o Left O Recommended Control Settings al amp 1 1 Set your front speakers for wide large or full mode in Peroni C your processor Set the center and effects type speakers in limited or narrow mode see the warning on page 10 Figure 6 Signal connection for 2 channel multi channel mode 2 Calculate the number equal to 70 of your main loud speaker s lowest frequency rating Set the Low Pass Filter switch to the closest setting below the resulting number 3 While playing familiar music with bass content turn the level control up until the music has deep bass that is not overwhelming 4 Try the phase control in different settin
11. GROTTO I Serial Number Record your serial numbers here for easy reference You will need this information when filling out your warranty registration Grotto i s serial number is located near the bottom of the backplate and also on the shipping container Grotto i Settings Level 25Hz Level Phase Low Pass Filter A V Processor Bass Management Settings Main Speaker Size The lightning bolt flash with arrowhead symbol within large recommended for full range speakers an equilateral triangle is intended to alert the user to Center Speaker Size the presence of uninsulated dangerous voltage within small recommended the product s enclosure that may be of sufficient mag Surround Speaker Size nitude to constitute a risk of electric shock small recommended Level The exclamation point within an equilateral triangle is intended to alert the user to the presence of important High Pass operating and maintenance servicing instructions in the literature accompanying the appliance Low Pass WARNING Do not use your Grotto i loudspeakers outside of the country of original sale voltage requirements vary by country Improper voltage can cause damage that will be potentially expensive to repair The Grotto i is shipped to authorized MartinLogan distributors with the correct power supply for use in the country of intended sale A list of authorized distributors can
12. MartinLogan distributor for any given country is responsible for warranty servicing only on units distributed by or through it in that country in accordance with its applicable warranty 2 Should a MartinLogan product require servicing in a country other than the one in which it was originally purchased the end user may seek to have repairs performed by the nearest MartinLogan distrib utor subject to that distributor s local servicing policies All cost of repairs parts labor transportation must be born by the owner of the MartinLogan product 3 If after owning your MartinLogan product for six months you relo cate to a country other than the one in which it was purchased your warranty may be transferable Contact MartinLogan for details General Information 21 GLOSSARY OF AUDIO TERMS AC Abbreviation for alternating current Active crossover Uses active devices transistors IC s tubes and some form of power supply to operate Amplitude The extreme range of a signal Usually measured from the average to the extreme Arc The visible sparks generated by an electrical discharge Bass The lowest frequencies of sound Bi Amplification Uses an electronic crossover or line level passive crossover and separate power amplifiers for the high and low frequency loudspeaker drivers Capacitance That property of a capacitor which determines how much charge can be stored in it for a given potential difference between
13. Sensitivity The volume of sound delivered for a given electrical input Stator The fixed part forming the reference for the moving diaphragm in a planar speaker THD The abbreviation for total harmonic distortion See Distortion TIM The abbreviation for transient intermodulation distortion Transducer Any of various devices that transmit energy from one system to another sometimes one that converts the energy in form Loudspeaker transducers convert elec trical energy into mechanical motion Transient Applies to that which lasts or stays but a short time A change from one steady state condition to another Tweeter A small drive unit designed to reproduce only high frequencies Wavelength The distance measured in the direction of progression of a wave from any given point characterized by the same phase White noise A random noise used in measurements as it has the same amount of energy at each frequency Woofer A drive unit operating in the bass frequencies only Drive units in two way systems are not true woofers but are more accurately described as being mid bass drivers Glossary of Audio Terms 23 vary by country Improper voltage can cause damage that will be potentially expensive to repair The Grotto i is shipped to authorized MartinLogan distributors with the correct power supply for use in the country of intended sale A list of authorized distributors can be accessed at www martinlogan com or by email
14. artinlogan com MartinLogan may not honor warranty service claims unless we have a completed Warranty Registration card on file If you did not receive a Certificate of Registration with your new subwoofer you cannot be assured of having received a new unit If this is the case please contact your authorized MartinLogan dealer Serial Number Grotto i s serial number is located near the bottom of the backplate Each individual unit has a unique serial number Service In the rare event that your MartinLogan product should require service please contact the dealer from whom the product was purchased In most cases your dealer will be able to assist you in troubleshooting and resolving the issue If the dealer is unable resolve the issue or if there is no local dealer in your area contact MartinLogan customer service directly by using the service request form at www martinlogan com or by calling 785 749 0133 Before returning any product to MartinLogan for service first contact the service department for an RMA number Incoming shipments will only be accepted if labeled with a MartinLogan issued RMA number Before returning this product to MartinLogan for service first contact the service department to receive a shipping kit which will include packing straps and packing instructions Should you be using a MartinLogan product in a country other than the one in which it was originally purchased please note the following 1 The appointed
15. ction 15 16 wea LZ 18 19 20 21 22 Congratulations You have invested in one of the world s premier subwoofers The MartinLogan Grotto i represents the culmination of an intensive dedicated research program directed toward creating a world class reference subwoofer using advanced technologies and without compromising dura bility reliability craftsmanship or aesthetics The Grotto i subwoofer uses a custom 10 inch high excursion driver to deliver deep tight well defined bass Servo control woofer technology minimizes distortion A proprietary digital amplifier drives the output stage with precision and extremely high efficiency Low pass filtering and phase control have been designed to make integrat ing the Grotto i subwoofer with both MartinLogan and non MartinLogan products both seamless and simple The materials in your new Grotto i subwoofer are of the high est quality and will provide years of enduring enjoyment and deepening respect The cabinetry is constructed from the highest quality composite material for acoustical integrity This User s Manual will explain in detail the operation of your Grotto i subwoofer and the philosophy applied to its design A clear understanding will help you obtain maxi mum performance and pleasure from this most exacting subwoofer system In accordance with the European Union WEEE Waste Electrical and Electronic Equipment directive effective August 13 2005
16. dependent on the size and configuration of your listening environment the placement of the unit and your seating arrangement Due to the way bass sound waves develop in dif ferent rooms there is no rule of thumb for setting phase For instance if your room has a peak at the subwoofer crossover area you may wish to set the phase so the actual acoustic outputs of the subwoofer and main speakers are out of phase Experiment try dif ferent settings and be patient 25Hz Level The 25Hz Level knob signifi cantly adjusts frequencies where peaks and dips of different ampli tudes often manifest in real world environments The ideal setting is dependent on room size and construction system configura tion and personal preference 15dB 410dB 1088 Pa 10dB 280aaa 5dB NS im OdB 25Hz ire eee geese 5dB 10dB fame 15dB 20Hz 50Hz 100Hz 200Hz Figure 2 Graph demonstrating the fre quencies effected by the 25Hz Level controls Connections Right Out Left Out _ Should only be used if con necting this sub between a pre amp and amplifier Connect to the Left In Right In on the amplifier The High Pass Out control filters the output from these connections Sub Out For systems utilizing multiple subwoofers Connect Sub Out to the LFE Input or Right In Left In on additional sub s LFE In Connect to LFE Out on your A V processor The sub
17. en the Grotto i is connected in multi channel mode via its LFE input the low pass filter is not active and your processor handles the bass management When connected in 2 channel mode via its speaker or line level left right input the low pass fil ter is active As a general rule the Low Pass Filter should be set at the option approximately equal to or below 70 of your main speaker s low est frequency response Example The MartinLogan Vista s low est frequency response is 43Hz 70 of 43Hz equals 30 1 so you should set the Grotto i s low pass filter to 30Hz Remember this is a general rule We advise that once you try the recommended set ting using the formula above you should try the surrounding settings to see which sounds best Optionally an internal module in the Grotto i can be upgraded with a custom tailored Low Pass Filter setting for use with the MartinLogan CLX loudspeaker When this upgrade is imple mented the 30 Hz setting on the Grotto i becomes the CLX Low Pass Filter setting 6 Controls and Connections MARTIN LOGAN i ESL N GROTTO i Low Pass Filter Hz ag ft a LFEIn Sub Out Rigi uj ad INO qns mowy INO YET Left In Up eT I 5 ie a gt a al v 7 gt a al v u paa ur IMNO pa Ur Right In upy3y 10dB Speaker Level In Figure 1 Connection and control panel ng 10dB Phase Control The phase control is entirely
18. er to the left and right speaker level high level inputs of the subwoofer and run an additional set of cables from your subwoofer to the speakers SPEAKER OR SPEAKER OR Recommended Control Settings AMPLIFIER AMPLIFIER 1 Set the controls as recommended on page 9 Figure 7 Signal connection for 2 channel mode using speaker level inputs Controls and Connections 11 2 Channel Mode With 2 Channel Output This setup is recommended if your subwoofer will be used in a 2 channel only system AMPLIFIER GRO ITO Signal Connection see figure 8 1 Connect the left out right out from your preamplifier to a the Left In Right In of the subwoofer Use quality RCA reece G g 5 interconnects e Right 5 3 A 2 Connect the Left Out Right Out of your subwoofer to Go C 2 8 the left in right in of your amplifier Use quality RCA interconnects 7 E 7 Recommended Control Settings 1 Set the controls as recommended on page 9 PREAMP o TF 5 2 At this time the Low Pass Filter should be set to g o 3 oT approximately 70 of your main loudspeakers lowest S 28 o frequency response paran i If your Low Pass Filter setting is less than 55Hz change B the setting to 55Hz ROL CT The Low Pass Filter should be set to 55Hz or 7096 of your Figure 8 Signal connection for 2 channel mode with 2 channel output main loudspeakers lowest frequency response which ever is greater
19. eted steps 1 3 and still have weak or boomy bass adjust the 25Hz Level knobs to compen sate for these anomalies Experiment with the controls and listen to the effects Try to find a position that sounds correct to you Experiment by changing the Level control while adjusting these knobs Find a position that gives you deep extended bass and good blending with your main speakers 8 Controls and Connections Left Out 70Hz High 0000 SubOut Right Out PREAMP RECEIVER Left Out Right Out Figure 4 Signal connection for 2 channel mode L 5 ie E gt b nad m T E gt Ino qng moy ING YET ul eT ul 441 uy sry U 437 BUTT ING 243 OUT Multi Channel Mode This setup is recommended if you will use your subwoofer NG in a dedicated home theater or multi channel system When PROCESSOR G ROTTO I a signal is connected to the subwoofer s LFE In the Low Pass Filter control is NOT active Your processor handles most of the bass management Left Out 70Hz High VA Pass INO Ye LFE 0 1 Out Signal Connection see figure 5 1 Connect the LFE out of the processor to the LFE In WARNING A Based on the performance of most processors it is recommended that MartinLogan center and effects type speakers i e Stage Cinema Theater and Script i not be run in large wide or full range mode Doing so may potentially dam age the speaker if the processor
20. gs until the best blending is obtained If you are augmenting MartinLogan loudspeakers we suggest you start with Phase set at 90 5 Use the bass management section of your processor s speaker setup to set the subwoofer level at an appro priate level Follow the instructions in your processor s manual to fine tune the subwoofer level 6 If your processor offers the option to setup crossovers for a subwoofer we recommend that you start with the fol lowing settings Crossover 70Hz High Pass 12dB and Low Pass 24dB The optimal setting for these options may vary depending on your room and listen ing preferences 10 Controls and Connections 2 Channel Mode Using Speaker Level Inputs This setup is recommended if your subwoofer will be used in a 2 channel only system with full range front loudspeakers mg When a signal is connected to the subwoofer s Left In Right G ROTTO In subwoofer s Low Pass Filter control is active Speaker Level In Signal Connection see figure 7 1 Connect the left and right outputs of your amplifier to the subwoofer s high level Speaker Level In Left In Right In binding posts Use quality speaker cable If your amplifier only has one set of outputs you may connect your amplifier to your speakers as normal and run an additional set of cables from your speakers to the subwoofer s Speaker Level In binding posts It is also possible to connect the left and right outputs of your amplifi
21. ing info martinlogan com i WARNING Do not use your Grotto i loudspeakers outside of the country of original sale voltage requirements MARTIN LOGAN Lawrence Kansas USA tel 785 749 0133 fax 785 749 5320 www martinlogan com 2007 MartinLogan All rights reserved Rev 111609
22. is initializing This also indicates if the subwoofer temperature has exceeded nominal operating range If the subwoofer overheats please allow it to cool and reset it by unplugging the unit and plugging it back in AC Power Connection amp Fuse Controls and Connections 7 2 Channel Mode WARNING Turn the Master Power switch Off iN and unplug it before making or breaking any signal connections This setup is recommended if your subwoofer will be used in a 2 channel only system When a signal is connected to the subwoofers Left In Right In the Low Pass Filter control is active Signal Connection see figure 4 1 Connect the left out right out from your preamp receiver to the Left In Right In of the subwoofer Use quality RCA interconnects If your preamp receiver only has one set of outputs you need to obtain Y adapters from your dealer Recommended Control Settings 1 Calculate the number equal to 70 of your main loud speaker s lowest frequency rating Set the Low Pass Filter switch to the closest setting below the resulting number 2 Play familiar music with bass content Increase the Level control until the music has deep extended bass Be careful to avoid levels that become overwhelming 3 Try the phase control in different settings until the best blending is obtained If you are using the subwoofer to augment other MartinLogan products we suggest start ing with the phase set at 90 4 If you have compl
23. its terminals measured in farads by the ratio of the charge stored to the potential difference Capacitor A device consisting of two or more conducting plates separated from one another by an insulating material and used for storing an electrical charge Sometimes called a condenser Clipping Distortion of a signal by its being chopped off An overload problem caused by pushing an amplifier beyond its capabilities The flat topped signal has high levels of har monic distortion which creates heat in a loudspeaker and is the major cause of loudspeaker component failure CLS The abbreviation for curvilinear linesource Crossover An electrical circuit that divides a full band width signal into the desired frequency bands for the loudspeaker components dB decibel A numerical expression of the relative loud ness of a sound The difference in decibels between two sounds is ten times the Base 10 logarithm of the ratio of their power levels 22 Glossary of Audio Terms DC Abbreviation for direct current Diffraction The breaking up of a sound wave caused by some type of mechanical interference such as a cabinet edge grill frame or other similar object Diaphragm A thin flexible membrane or cone that vibrates in response to electrical signals to produce sound waves Distortion Usually referred to in terms of total harmonic distortion THD which is the percentage of unwanted harmonics of the drive signal present with the
24. n 13 8 35cm 20 Dimensional Drawings GENERAL INFORMATION Specifications System Frequency Response 22 120 Hz 3 dB Anechoic through the LFE effects input Low Pass Filter Frequencies 30 35 45 55 65 80Hz High Pass Filter Frequencies 70Hz Phase 0 90 180 270 25Hz Level 10dB Power On Auto Standby Components 10 25 4cm high excursion aluminum cone with extended throw driver assembly sealed non resonant asymmetrical chamber format Amplifier 300W at lt 0 5 THD 900W peak Inputs Left Right RCA Line Level RCA LFE Speaker Level Output RCA Sub Out all inputs summed RCA Left Right with High Pass Filter Input Impedance 20 000 Ohms Power Draw Max 250 Watts Idle 15 Watts Standby 10 Watts Weight 51 Ibs each 23 2 kg Size 18 6 inches H x 15 2 inches W x 13 8 inches D 47 3cm H x 38 6cm W x 35cm H Specifications are subject to change without notice Warranty and Registration Your subwoofer is provided with an automatic Limited 90 Day Warranty coverage You have the option at no additional charge to receive Limited 3 Year Warranty coverage To obtain the Limited 3 Year Warranty coverage you need to complete and return the Certificate of Registration included with your subwoofer and provide a copy of your dealer receipt to MartinLogan within 30 days of purchase For your convenience MartinLogan also offers online warranty registra tion at www m
25. nearity The extent to which any signal handling process is accomplished without amplitude distortion Midrange The middle frequencies where the ear is the most sensitive Passive crossover Uses no active components transistors IC s tubes and needs no power supply AC DC battery to operate The crossover in a typical loudspeaker is of the passive variety Passive crossovers consist of capacitors inductors and resistors Phase The amount by which one sine wave leads or lags a second wave of the same frequency The difference is described by the term phase angle Sine waves in phase reinforce each other those out of phase cancel Pink noise A random noise used in measurements as it has the same amount of energy in each octave Polarity The condition of being positive or negative with respect to some reference point or object RMS Abbreviation for root mean square The effective value of a given waveform is its RMS value Acoustic power is proportional to the square of the RMS sound pressure Resistance That property of a conductor by which it opposes the flow of electric current resulting in the generation of heat in the conducting material usually expressed in ohms Resistor A device used in a circuit to provide resistance Resonance The effect produced when the natural vibra tion frequency of a body is greatly amplified by reinforcing vibrations at the same or nearly the same frequency from another body
26. ntil you find the optimal relationship between your room settings and subwoofer that gives to you the best results Your efforts will be rewarded 9 Figure 13 Grotto i Subwoofers as the LFE effects channels MartinLogan Vista speakers as front channels and MartinLogan Motif as the center and surround effects channels Note the corner placement of the Grotto i at the front of the listening room Cabinet Front 3 inches Cabinet Back Figure 14 Placing the Grotto in a cabinet requires a minimum of three inches of open space on the front left and right Placement 15 Room ACOUSTICS Your Room Your room is actually a component and an important part of your system This component is a large variable and can dramatically add to or subtract from a great sonic experience All sound is composed of waves Each frequency has its own wave size with the lower or bass frequencies liter ally encompassing from 10 feet to as much as 40 feet Your room participates in this wave experience like a swimming pool with waves reflecting and becoming enhanced depend ing on the size and shape of the room and the types of surfaces in the room Remember that your audio system can actually generate all of the information required to recreate a sonic event in time space and tonal balance Acoustically the role of an ideal room would be to neither delete nor contribute to that information Ho
27. of bass information as part of the special effects Good subwoofers will provide a founda tion for the rest of the system Figure 16 Vista speakers as front channels the Motif as the center and surround channels and the Grotto i subwoofers as 0 1 effects channel Home Theater 17 MIARTINLOGAN EXCLUSIVES Servo Controlled Dynamic Drivers All dynamic drivers generate distortion caused by spider and surround nonlinearities as well as voice coil inductive disturbances and variant motor strength during massive woofer excursions These challenges plague all subwoofer designers The result Induced harmonic and intermodulated distortions causing dramatic disturbances at high excursions This occurs significantly in almost all non servo controlled subwoofers MartinLogan s advanced servo system uses a sophisticated monitoring and control circuit to detect and instantaneous ly correct any deviation between acoustical output and electrical input The result A reduction in distortion for the purest possible low frequency reproduction 18 MartinLogan Exclusives Proprietary Switching Amplifier The Grotto i incorporates a proprietary switching ampli fier that allows for an incredible amount of woofer control resulting in tighter better defined bass and while keeping distortion at the lowest possible levels 25Hz Level Control The Grotto i 25Hz Level controls allows custom sound tailoring capabilities found in
28. r outputs through cables to the signal input area located on the subwoofer s rear panel Please see the Controls and Connections section pages 6 15 for more details If you plan to connect your subwoofer using Speaker Level high level inputs please refer to the 2 Channel Mode Using Speaker Level Inputs section page 12 for more details Step 4 Power Connection AC see warning Set your subwoofers power switch to Standby Make sure the level knob is set at O Plug the subwoofer into a wall outlet Review the AC Power Connection section page 15 of this manual for more details Step 5 Setting the Controls Set the Level knob to 3 or 4 Set the Power switch to Auto Set the 25Hz Level knob to 0 Set the Phase to 90 Set the Low Pass Filter to the closest setting below the low end frequency response of your main speakers These settings are only a beginning point Your subwoofer will need proper setup to optimize performance Please see the Controls and Connections section pages 6 15 for more details Step 6 Listen and Enjoy Installation in Brief 5 CONTROLS AND CONNECTIONS Controls Level Setting the level too high will cause the bass to seem bloated and is the single most common cause of bad sounding subwoofers A rule of thumb is that the subwoofer should not draw attention to itself but should simply make the system s low end seem more extended and accurate Low Pass Filter Wh
29. rat ing applicable to a particular unit is specified both on the packing carton and on the serial number plate attached to the subwoofer If you remove your subwoofer from the country of original sale be certain that AC power supplied in any subsequent location is suitable before connecting and operating the subwoofer Substantially impaired performance or severe damage may occur to the subwoofer if opera tion is attempted from an incorrect AC power source 14 Controls and Connections Replacing the Fuse If the fuse in your subwoofer should require changing turn your subwoofer off and unplug it before removing the fuse Replace the bad fuse figure 12 with a matching T 4H 250V T 2 LH 250V if you are in a region using 230v mains voltage Break In Our custom made woofers require approximately 50 hours of break in at moderate listening levels before their optimal performance occurs This will factor in on any critical listening and judgment ac power maximum current draw is 4A 100V 120V 4Amp Slow Blow T 4 H 250V 230V 2Amp Slow Blow T 2 H 250V Figure 12 Grotto i s Fuse and AC Power receptacle PLACEMENT Listening Position Generally subwoofers have the most output when placed in the corner of a room However this can also exagger ate the subwoofers output making blending difficult We recommend starting by placing the subwoofer in a corner It should be placed in such a way that there are 2 inches bet
30. rs that create their own standing waves and can drum their own one note sounds Solid Footing After living and experimenting with your subwoofer you may want to use ETC energy transfer coupler spikes sup plied with the subwoofer see figure 15 With the use of these spikes the subwoofer will become more firmly planted on the floor and consequently bass will tighten and imaging will become more coherent and detailed It is best not to implement the spikes however until you are secure in the positioning as the spikes can damage the floor if the speaker is moved The feet that attach to the bottom of the Grotto i use a common 3 8 16 thread Spike Installation Instructions 1 Ona soft padded surface carefully lay your subwoofer on its side to gain access to the bottom 2 Remove existing feet or spikes Thread new spikes into holes and screw them in all of the way If the subwoofer does not sit level loosen one spike until level is achieved 3 By hand tighten the jam nut snugly against the cabinet Do not over tighten the nut 4 Right the speaker Caution Make sure your hands and any cabling are clear of the spikes Do not slide subwoofer as spikes are sharp and can damage your floor or carpet 5 Adjust to level by rotating spikes By hand tighten the jam nut snugly against the cabinet when you are satis fied that subwoofer is level 3 5 16 Thread Jam Nut Figure 15 The ETC Spike HOME THEATER I
31. t had long been the practice of stereo buffs to connect their television to a stereo system The advantage was the use of the larger speakers and more powerful amplifier of the stereo system Even though the sound was greatly improved it was still mono and limited by the broadcast signal In the late 1970 s and early 1980 s two new home movie formats became widely available to the public VCR and laser disc By 1985 both formats had developed into very high quality audio video sources In fact the sonic performance of some video formats exceeded audio only formats Now with theater quality sound available at home the only element missing was the surround sound presentation found in movie houses Fortunately Dolby and DTS encoded DVD s emerged with the same surround sound information encoded on home releases as the theatrical release Additionally new high resolution home viewing formats such as HD DVD and Blu ray as well as high definition content provided via cable or sattelite have evolved which include multi chan nel encoded audio that is virtually master tape quality All that is required to retrieve this information is a decoder and additional speakers and amps to reproduce it Home theater is a complex purchase and we recommend that you consult your local MartinLogan dealer as they are well versed in this subject Each piece of a surround system can be purchased sepa rately Take your time and buy quality No one has ever
32. wanted signal Generally used to mean any unwanted change introduced by the device under question Driver See transducer Dynamic Range The range between the quietest and the loudest sounds a device can handle often quoted in dB Efficiency The acoustic power delivered for a given elec trical input Often expressed as decibels watt meter dB w m ESL The abbreviation for electrostatic loudspeaker Headroom The difference in decibels between the peak and RMS levels in program material Hybrid A product created by the marriage of two different technologies Meant here as the combination of a dynamic woofer with an electrostatic transducer Hz Hertz Unit of frequency equivalent to the number of cycles per second Imaging To make a representation or imitation of the original sonic event Impedance The total opposition offered by an electric circuit to the flow of an alternating current of a single fre quency It is a combination of resistance and reactance and is measured in ohms Remember that a speaker s imped ance changes with frequency it is not a constant value Inductance The property of an electrical circuit by which a varying current in it produces a varying magnetic field that introduces voltages in the same circuit or in a nearby circuit It is measured in henrys Inductor A device designed primarily to introduce induc tance into an electrical circuit Sometimes called a choke or coil Li
33. ween the grill and the wall This will avoid blocking the output of any woofers If after the full range of tuning techniques have been employed the subwoofer sounds like it has too much upper bass energy try pulling it away from the wall toward the listening position This will less en the reinforcement of these problematic frequencies from the wall and likely smooth out the response Repeat the setup procedure with the woofer controls after you move it see figure 13 Installing in a Cabinet It is common for people to place their subwoofer s inside of cabinetry The Grotto i s design does not compromise the ability to be successfully installed in such a configura tion It is recommended that there be a minimum of three inches of open space between the cabinet and the front of the subwoofer see figure 14 Ask Your Dealer Your MartinLogan dealer can suggest many options for optimal subwoofer placement They also have many tools at their disposal such as experience familiarity with the associated equipment and even sound analysis equip ment which may make the task of determining optimal subwoofer placement easier Enjoy Yourself The Grotto i is a very refined subwoofer and will benefit from care in setup With the above placement tips in mind you will find over months of listening that small changes can result in measurable differences As you live with your subwoofer do not be afraid to experiment with position ing u
34. wever nearly every room does to some degree Terminology Standing Waves Sound coming from a subwoofer bounc es around in a room until a pattern emerges this is called a standing wave Typically this is only a problem with fre quencies below 100Hz When this happens different parts of your room experience either an excess or a lack of bass Some people believe that having a room without parallel walls will eliminate this effect The truth is that non parallel walls only generate different standing wave patterns than those that occur in rectangular rooms Usually you can excite most of the standing waves in a room by putting the subwoofer in a corner Listening position determines which standing waves you will expe rience For instance if you sit in a corner you will hear most of the standing waves This can be an overpowering experience Sitting next to a wall can also intensify the levels of the standing waves that are experienced Resonant Surfaces and Objects All of the surfaces and objects in your room are subject to the frequencies gen erated by your system Much like an instrument they will vibrate and carry on in syncopation with the music and may contribute in a negative way to the sound Ringing boominess and even brightness can occur simply because surfaces and objects are singing along with your speakers 16 Room Acoustics Resonant Cavities Small alcoves or closet type areas in your room can be chambe
35. woofers Low Pass Filter control does not effect this connection Crossover settings for LFE In are controlled through the A V processor Right In Left In Connect to Main Out or Pre Out on your receiver pre amp Grotto i s Low Pass Filter con trol effects the signal received through these inputs Speaker Level In This set of binding posts pro vides a place to connect the subwoofer using standard speaker cable Grotto i s Low Pass Filter control effects the signal received through these inputs MARTIN LOGAN ESL GROTTO mo qng mowy Noya ul ad Up eT Ka m lt c4 ie E T 5 a lt uyy 10dB Speaker Level In 2 KA 2 6 ac power Figure 3 Rear connection panel Low Pass Filter Hz ag fi ka N 10dB x i Status Light The Grotto i is equipped with a multi color LED to indicate the current status of the woofers The following list explains the meaning of the different colors No color No power The subwoofer is not plugged in or the fuse has blown Green Play mode This indi cates the subwoofer detects an audio signal and has auto matically switched into play mode Yellow Standby mode This indicates the Power switch is set to Standby or the sub has detected no audio signal for more than forty minutes and has automatically switched into standby mode Red Initializing or Safe mode This indicates that the subwoofer
36. ws additional subwoofers to perform as dedicated LFE channels see figure 10 Connecting to the Right or Left In allows addition al subwoofers to perform as dedicated 2 channel subwoofers see figure 11 Repeat step 2 for each additional subwoofer in the chain using the same input for every additional connection Recommended Control Settings 1 Adjust the control settings of the first subwoofer using one of the five modes previously described Adjust the control settings of each additional subwoofer Use the method used to adjust the first subwoofer Note While the settings of each subwoofer should be similar you will probably find that each sub will need to be tweaked for optimal performance because of its unique room placement Regardless of how you use your subwoofer experimenta tion can often result in better sound Don t be afraid to try different settings You can always return the controls to their previous settings A sg Q mj mj Q GROTTO INO 491 INO 3 INO 949 GUT INO Ya Left Out 70Hz High 000 Left Out 70Hz High Pass Right Out Right Out l D gt E d v T Line Level Out Sub Out Ing qns Line Level In Left In LFE In Sub Out O qng U 349 our line Level In ul 4T uj 441 INO BEN U 437 BUTT ING 2437 ul Right In EVER Figure 10 Using multiple Grotto i LFE option Primary sub on right
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