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7

Room Acoustics & Placement

Wisdom Audio believes in equalization. Assume for a moment that you had a 
“perfect” loudspeaker: as soon as you place it in your room, its perfection is 
gone. In fact, even good rooms can introduce deviations of 20 dB to the re-
sponse of the system. This is particularly true in the bottom two octaves, where 
a subwoofer operates.

It seems strange to us to worry about tenths-of-a-decibel differences between 
one component and another when there are 10-20 dB problems right there in 
the room with you.

At the same time, room equalization is not a panacea. It does not solve all prob-
lems. In fact, and somewhat paradoxically, EQ works best when it has the least 
to do. It is best used as the “finishing touch” on an otherwise good system. Un-
fortunately, most people do not understand that the most important component 
in their system is their listening room. 

This manual does not have the space for a full description of everything that 
goes into creating excellent room acoustics; doing so would require a textbook 
of several hundred pages. Instead, we will give you some ideas, and some refer-
ences to pursue should you want to learn more.

Start With the Room

There are many myths floating around pertaining to what a “good room” should 
be like. One of the most common is that it should have non-parallel walls. With-
out going into the details, we recommend staying with rectangular rooms whose 
dimensions do not share common divisors. 

Thus a room with dimensions of 8’ by 16’ by 20’ would be quite poor (since the 
dimensions are all divisible by a length of 4’, and 16 is also a multiple of 8). By 
contrast, a room whose dimensions are 9’ by 16’ by 29’ would be much better, 
since none of the dimensions are mathematically related to one another.

There are infinite variations on this idea. If you have the flexibility to choose (or 
modify) your room dimensions to avoid such problems, do so. Either way, ca-
pable room optimization will be a big help making the most of what you have.

Rigid Walls

Another myth that should be dispelled is the notion that the walls (and ceiling 
and floor) of the room should be extremely rigid in order to reproduce good 
bass. Rigid, inflexible walls reflect energy extremely well; thus you will keep 
more of the bass energy in the room. This much is true. However, those rigid 
walls will only increase the amplitude of the standing waves that your room 
naturally supports. In simple terms, you will have more bass, but it will also be 
more irregular, with larger peaks and valleys in the response.

Walls that flex a bit (but do not rattle) are much better. Coincidentally, tradition-
al American residential construction standards (sheet rock on wooden studs) are 
not a bad place to start. You can do better still with professional help, but studs 
and sheet rock are better than poured concrete. (If your listening room is in the 
basement, a false wall can easily be built in front of the concrete. You probably 
need something like this for insulation and aesthetics anyway.)

Summary of Contents for S55i

Page 1: ...Owner s Manual Wisdom Audio S55i In Wall Subwoofer ...

Page 2: ...ote Setup via Modem 8 Surround Speakers 9 Subwoofer Placement 9 Room Treatment 10 Professional Acoustic Design 10 References 11 Installing the S55i in a Wall 12 Installing the S55i in the Ceiling 14 Tips and Ideas 22 Black out the HVAC and snorkel 23 Limited access situations 24 Installing under the floor 24 North American Warranty 26 Standard Warranty 26 Harsh Conditions Use 26 Obtaining Service ...

Page 3: ......

Page 4: ... Series About this manual This manual focuses on the S55i subwoofer itself In order to fully understand the system we recommend you also review the manual for the SC 1 System Controller or SW 1 subwoofer amplifier or MiniDSP 1 subwoofer processor without one of which this subwoofer will not perform correctly While we expect your local Wisdom Audio dealer to take care of the setup and calibration o...

Page 5: ...hat are specifically optimized for this application We call our unique implementation of this relatively old idea a Regenerative Transmission Line subwoofer or RTL sub for short All dynamic drivers develop energy on both sides of the diaphragm with the rear energy being 180 out of phase with the front energy If you allow the driver to operate in free space no enclosure the front and rear energies ...

Page 6: ...that contains the grille assembly also includes the pig tail for connecting the speaker to the system as well as some feet to support the S55i slightly above the sole plate to allow room for the wiring and the base board of the finished wall Rooms with unusually tall baseboards may require the S55i to be mounted somewhat higher still The grille itself is held in place magnetically Removing the gri...

Page 7: ...ar rooms whose dimensions do not share common divisors Thus a room with dimensions of 8 by 16 by 20 would be quite poor since the dimensions are all divisible by a length of 4 and 16 is also a multiple of 8 By contrast a room whose dimensions are 9 by 16 by 29 would be much better since none of the dimensions are mathematically related to one another There are infinite variations on this idea If y...

Page 8: ...de both placing the speakers at different distances from the side walls vs the wall behind them and placing them at odd fractions of the room s dimensions e g fractions in which the denominator is an odd number like 1 3 2 5 2 7 etc But nothing replaces your experience in your room combined with your dealer s experi ence in a variety of rooms Playing pink noise through the woofer sections of your W...

Page 9: ...nd ensures that you hear what was intended from a spatial placement point of view Too often the surround speakers are all behind the listeners cre ating a big hole in the soundfield between the front and the back L R C Sub 1 Sub 2 Ls Rs Rb Lb 22 30 90 110 135 150 0 a 7 2 channel system layout One possible exception to these guidelines if you have a THX certified pro cessor and are using the THX Ad...

Page 10: ...ions is one of the strongest arguments for the tall line source loud speakers that Wisdom Audio builds This leaves you with eight first reflections that you should consider minimizing somehow These points are easily found by having an assistant slide a small mirror along the four walls of the room while you sit at the listening position Any place on the wall where you can see a re flection of any ...

Page 11: ...g that he she can help you find such a pro fessional References Books on Acoustics The Master Handbook of Acoustics F Alton Everest TAB Books Sound Reproduction The Acoustics and Psychoacoustics of Loudspeakers and Rooms by Dr Floyd Toole Focal Press Suppliers of Acoustic Treatments Acoustic Innovations http www acousticinnovations com Acoustic Sciences Corporation http www acousticsciences com Ec...

Page 12: ...this area of the stud bay nor firebreaks The S55i will use a bit more than half of the available space in a standard eight foot 2 x 4 stud bay 2 Stand the S55i in front of the bay in which it will reside make the elec trical connections There are two methods commonly used for making these connections If you have access to the adjacent stud bay drill a hole through the 2 x 4 stud between where the ...

Page 13: ...anel and the stud surfaces to avoid such stresses as would be the case for any in wall loudspeaker 4 Tape and spackle the seams Note that there is a slight recess around the front edge of the S55i to facili ate taping and spackling yielding a smooth result 5 After everything has been painted slice the paint along the edge of the galvanized steel construction shield Remove and discard the shield It...

Page 14: ...be forced against an irregular surface If the studs are appreciably curved or warped in an installation the installer must insert shims between the S55i front panel and the stud surfaces to avoid such stresses as would be the case for any in wall loudspeaker All the following photos are illustrative of how the speakers would be installed in an attic space venting into the room below Installing it ...

Page 15: ... wrapping the Bass Snorkel after it has been adjusted to the final length and shape 8 dry wall screws 2 Place the ceiling flange assembly in the intended mounting location and use it as a template for marking the vent into the room Cut the drywall with a keyhole saw or similar tool 3 Screw the ceiling flange in its location ...

Page 16: ...e S55i flush with the corner of the en closure and screw into place Take care to ensure that there are no air leaks around the edges of the flange assembly You want all the low frequency energy transferred through the snorkel into the room ...

Page 17: ...htly taller than is needed for the joists in your installation If your attic has joists that are smaller than 2 x 8 you may need to trim the alu minum to a more suitable length using a utility knife Caution Be certain that the snorkel can be compressed somewhat before proceeding to the next step Once it is fully compressed any further pressure placed on it will be transferred directly to the ceili...

Page 18: ...Move the S55i into place above the snorkel and gently place its flange into the snorkel Test fit the S55i assembly to the snorkel and ceiling flange The snorkel should extend to the back edge of both flanges ...

Page 19: ...cond band clamp on the S55i flange The next step is to wrap the snorkel in the heavy Protecto Wrap which dramati cally deadens and stiffens the snorkel and minimizes any leakage of bass into the attic and adjacent spaces ...

Page 20: ...t position being careful not to change the length of the snorkel in the process This is a critical step as it locks the duct into its final position greatly stiffening the assembly and ensuring that the bass energy is vented into the room rather than leaked into adjacent attic space Once the snorkel is wrapped it is no longer capable to being adjusted for length ...

Page 21: ...ge that extends around the edge of the face of the S55i Fasteners should not be driven into the S55i else where as there are locations in which doing so could cause permanent damage and or compromise its performance 10 Finally attach the HVAC grille by screwing it in place The screws used on this grille will extend into the ceiling flange s wooden plate making an extremely secure cover ...

Page 22: ...22 Tips and Ideas It is impossible to cover every possible installation application of this versatile product But here are a couple ideas to get you thinking ...

Page 23: ... paint the area around the vent black In the process paint the inside of the aluminum duct black as well Several light coats will work better than trying to do everything in one heavy coat Install the HVAC grille over the blackened area You may want to pad the inside edges of the grille with foam weather stripping to minimize any possibility of a rattle developing over time ...

Page 24: ...m The same basic process applies and yields excellent results as long as you are careful to wrap the expanding duct tightly Installing under the floor The same basic process can be used to install an S55i in a basement or crawl space venting the low frequencies up through the floor In this case you should replace the standard HVAC grille with a heavier grate that is designed to with stand traffic ...

Page 25: ... removed or frozen in place with liberal amounts of glue in order to avoid rattles A lot of air will be flowing through these grilles in both directions Anything that can rattle will rattle The grate shown above was purchased from http www signaturehardware com hardware registers html It is made of cast iron has ample open area to avoid turbulence and noise and has no air flow control louvres to r...

Page 26: ...al tered or installed and calibrated by anyone other than an authorized Wisdom Audio dealer Any Wisdom Audio loudspeaker not performing satisfactorily may be returned to the factory for evaluation Return authorization must first be obtained by either calling or writing the factory prior to shipping the component The fac tory will pay for return shipping charges only in the event that the loudspeak...

Page 27: ...ice needs expediently Important Return authorization must be obtained from Wisdom Audio s Service Department BEFORE a unit is shipped for service It is extremely important that information about a problem be explicit and com plete A specific comprehensive description of the problem helps your dealer and the Wisdom Audio Service Department locate and repair the difficulty as quickly as possible If ...

Page 28: ...ity 90 dB SPL 2 83V 1m Maximum Output at one meter in 1 4 space 115 dB 30 Hz Power handling peak 240W Dimensions see appropriate Dimensions drawings on next page Shipping weight 43 lbs 20 kg For more information see your Wisdom Audio dealer or contact Wisdom Audio 1572 College Parkway Suite 164 Carson City NV 89706 www wisdomaudio com information wisdomaudio com Ph 775 887 8850 Fax 775 887 8820 ...

Page 29: ...29 S55i Dimensions ...

Page 30: ...30 Notes ...

Page 31: ...31 ...

Page 32: ... All rights reserved Printed in U S A Wisdom Audio 1572 College Parkway Suite 164 Carson City Nevada 89706 USA Telephone 775 887 8850 Fax 775 887 8820 www wisdomaudio com WISDOM and the stylized W are registered trademarks of Wisdom Audio ...

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