Doctor's Orders-Part Two-The New Listening Room Of Steve Williams

steve williams · May 10, 2013

The History

Most of you are aware by now that I moved back to Southern California in July last year after a 20 year hiatus in the SF Bay Area. It was there that I built my "dream" sound room. That room measured 18' W x 31' L x 9-12' H (sloped ceiling which was 9 feet high at the window and 12 feet high at the inner wall). My system then consisted of both two channel set up as well as a home theater with an 11' screen.

Here is a link to my prior set up

http://www.whatsbestforum.com/showt...-Of-Steve-Williams&p=3412&viewfull=1#post3412

My wife and I moved to the SF Bay Area in 1993 but with the resolve that we would always move home to Southern California. Just about this time last year our youngest daughter was graduating from the University of Boulder. It was then that not only were we aware of our empty nest but also that a few homes in our neighborhood were listed for sale. It was then that my wife suggested we consider listing our home. Well after 20 years in a home that I had built it was a difficult thought for me to consider as I loved our home and it was a source of wonderful memories. As a result, even though I always wanted to return to Southern California I was so attached to our home that I agreed to list the house for sale BUT only at a price that I felt it was worth rather than being dictated by the comps in our area (as I was torn about moving). As a result I listed the house at $200K over any comparable sold home in our area. We left for Boulder on a Thursday. The house was listed on the MLS the following day. The next day I was called by the broker to tell me that 3 people wanted to see the house on the Monday when I was back home (3 days after I listed the house). That next afternoon 3 different families toured the house and that evening I had 2 offers on my house, one which was $50K shy of my list price and a second which was not only a full list offer but so also a 30 day escrow. My wife and I took a deep breath as we suddenly realized that my wildest dream had become reality and that we were moving in 30 days. We now had to find a home to buy. We could have rented but I was opposed to this because I hate moving. Even if it is to the house next door it is still moving so we made a few day trip back to South Orange County and as luck would have it we found a really nice home of about the same size as the one we were selling. Both houses are ~4600 square feet but the new home did not have a dedicated room that I could convert to a new listening room. We moved in last July 6th and for 8-9 months my entire system sat in crates in one of our garages. Once settled in the house I started worrying because I coud see no option as to where to put this room. Believe it or not we considered moving but we really liked our new home. We live in the master planned community of Coto De Caza where my home sits on the 5th fairway of the south golf course. Even though both houses were about the same size the lot sizes were much different with that of my newer home sitting on a smaller sized lot. This pretty much excluded building "onto" the house as the rear yard was all landscaped with a pool. We have 3 garages and for a brief while I considered building the room into one of these garages but after working with an architect this just wasn't feasible. I must admit I was getting depressed about the distinct possibility, that after over 50 years in this hobby and always with a dedicated sound room that this was just not going to come to fruition for this one last "hurrah".

I did a lengthy search of acousticians as there are excellent ones who are members here at WBF. After a 4 week search I realized that if I were to do this any sound improvements put into the room could not be like my last room which was much larger. As a result every precious inch became valuable and I just couldn't spare any extra which would take away from the size of the room. My search brought me to the acoustician I finally hired. Bonnie Schnitta is a Phd in acoustics, electrical engineering and mathematics. It was with this knowledge and while working with the DOD and underwater sound mapping that she wrote a program which provides for mathematical mapping of a room's sound response. When she left the DOD, Bonnie took with her that part of the program which was hers and launched her business Soundsense based in New York city
www.soundsense.com

Her proprietary acoustical things are made through her company

www.noiseout.com

Dr. Bonnie Schnitta is the founder and president of NoiseOut as well as SoundSense, LLC – an acoustic consulting company she formed in 1981. Over the last three decades, Dr. Schnitta has headed hundreds of noise abatement and acoustic management construction projects in homes, churches, synagogues, theaters and recording studios. A CEDIA member since 2001, Dr. Schnitta holds a bachelor's degree in Mathematics from Purdue University, a bachelor's and master's degree in Mechanical Engineering and an interdepartmental Ph.D in Math, Computer Science and Electrical Engineering with a special emphasis in signal processing. She began her career working with ship designers, controlling the acoustics of oceangoing tankers. Although she originally focused on commercial projects, assisting restaurants and auditoriums with noise problems, Dr. Schnitta has branched out into the residential market. “I was just heartbroken to discover that homes were being designed with so little regard for acoustics,” she says.
Dr. Schnitta holds several patents, including an acoustical plumbing trap system, a method for analyzing activity in a signal, and the Paradise Effect™, a proprietary algorithm for the creation of an acoustically-correct and soothing environment. Dr. Schnitta has authored a number of articles on such topics as signal processing and acoustics management.

Bonnie made a site visit to my house in December, took measurements and then upon her return to NYC, plugged all the data in and called me a few days later stating that not only would things work but the room would sound very good. I guess this is what I wanted to hear. Sort of like asking an orthodontist if you need braces

The next post will contain all of the ideas and sound treatments added to the room as well as aesthetic treatments. I will follow that post with a synopsis of treatments that Bonnie has provided to me in a write up and I will follow this with several photos of the build out and the finished product

The room was finished end of March and I have been fine tuning the speaker placement, taking measurements and finally adding a pair of JLAudio F113 Fathom subs. I did have a pair of Gotham subs in my last room but I sold these as they for sure were just too much for the room

steve williams · May 10, 2013

Things I Considered For The Build Out

Here is a list of features the room has

Size 15 W x 20L x 9 H

1. The subfloor was created to withstand a force of 1500 lbs/square foot

2. Quiet rock was glued and screwed over the existing sheet rock of the walls and ceiling

3. Subfloor and walls filled completely with insulation

4. Commercial grade carpet rated for noise reduction

5. Thick, wide, solid core door with a special device housed in the bottom of the door which, when the door is closed releases a thick occlusive mat which creates a completely air tight seal. In other words there is no leakage of sound from under the door. It is air tight.

6. Each AC outlet in the room is a dedicated 20 amp line using a 20 amp Furutech GTX-D(R). Six total
http://www.furutech.com/2013/02/02/1746/

7. Two AC outlets in the front are 30 amp outlets each also on a dedicated line. These were wired with 10 AWG Romex for 30 amp specs but I use a 20 amp Furutech GTX-D(R) on each of these outlets, one for each amplifier

8. There are another two 20 amp dedicated lines in the rear corners of the room . Here I use a pair of MIT 20 amp outlets with noise suppression. I have my laser lights on each of these outlets

9. The AC outlets are installed horizontally rather than vertically so that there is no concern for AC cords coming loose from the outlet.

10. There are a total of 13 dedicated 20 amp lines in the room

11. Lighting is controlled by a Lutron GrafikEye 3000. None of the lights are incandescent but rather all are Halogen for the purpose of eliminating any hum from the circuits

12. I use LED rope lighting above the crown molding for effects

13. 20 amp AC floor outlet also added beside the chair for use with computer audio etc

14. Extra wide ceiling duct work used as in commercial rather than residential applications. The last 8 feet of the ductwork was lined with insulation to eliminate any possibility of noise from the HVAC

15. A separate (3rd) HVAC unit highly efficient and dead quiet was added to the room with furnace being up in the attic

16. All electrical for the sound system to be on one side of a separate subpanel with the HVAC being on the opposite side of the panel

17. Grounding done at the street

18. Custom bookcases built for storing music. The rear of the bookcases serve as a diffusor

Under construction.... the search is on (once again) for a better listening chair as well as different component racks

FWIW, everyone has been asking me to write this up with my thoughts but I have taken until now as I have had to get a grasp on what I have been hearing in order to comment more accurately. I just couldn't make any fair or proper comments until recently when I spiked the speakers and installed the Fathom subs. Further I wanted to be certain that after 9 months of no listening that this was not just a case of high expectation bias or the story of the Emperor's New Clothes

steve williams · May 10, 2013

Acoustical Treatments Provided By Acoustician

what was amazing about working with Bonnie and her mathematical mapping of the room was how accurate it was. Each time some thing was added or changed, she ran new measurements and from these speaker placement, sitting location etc were all determined. In fact after the bookcases were installed she told me to move the equipment rack 6" closer to the door. I was amazed as to how much better the new measurements looked

Here are the things I use

1. The single biggest room treatment was the use of floor to ceiling drapes which are thick and rated for sound reduction. The drapes have an inverted pleat with a ratio of 2.5 :1. In other words a lot of fabric was used to make the drapes

2. Between the drape and the drape backing isa proprietary fabric called Lumitex which will be described later in Bonnie's response.Essentially the drapes and Lumitex make for one big bass trap

3. Subfloor and walls filled with insulation

4. Noiseout2 is also a proprietary product of Bonnie's and was placed between the subfloor and the underpad of the carpet. Noiseout2 looks like a piece of linoleum but is very heavy. To use in my room took 2 rools and weighed close to 500 lbs

5. The Noiseout2 was caulked to the corners and side walls with Big Stretch Caulking to allow for slight stretch. The Noiseout2 makes the floor also into a large bass trap

6. Tuning tubes of many different frequencies placed in the rear corners and above the crown molding.

7. A large canvas painting in the front of the room which has been stuffed behind the frame with Paradise Foam which is highly absorptive

8. The entire attic above the room was turned into a large Helmholtz resonator using another proprietary product called High Hat Mufflers which sat above each high hat light fixture and each had different frequencies as determined by Bonnie. Eleven of these were used

In determining how what and where to add products in the room it was paramount to me that they not only be invisible but that they also not take away any precious room measurements, thus making the room smaller

What resulted was the proverbial "man cave" with enough room for me. As I change the component stands and seat, some more space will be freed up.

I'd like to now include some thoughts and explanation provided by Bonnie

steve williams · May 10, 2013

??It is commonly believed that many of the problems caused by placing speakers in smaller rooms cannot be solved using acoustic treatment alone. It was my goal to prove this common belief wrong. That is, a small room can be acoustically tricked into believing it is much bigger than it is and consequently sound truly amazing.
????MID AND HIGH-RANGE FREQUENCIES reflect from hard surfaces such as plaster, drywall, glass etc. That is, all surfaces need to be considered when applying acoustic treatment for these mid and high range frequencies.
A standard linear perspective of room treatment of mid to high frequencies is to view these reflections in a similar way that light reflects from a mirror. The acoustic surface interaction is not quite as exact as with a mirror, as some of the sound energy is scattered, and some is absorbed, but in simple terms you can think of hard walls as approximate acoustic mirrors. The standard approach to this simple analogy is to add absorbers, but it is important to understand the limitations of such materials. If you halve the thickness of most absorbers, the frequency above which it is effective moves up by an octave. Additionally, a space behind an absorber or most any surface will change its frequency response. Another method of acoustically addressing mid and high frequency reflections is to break them up; this is called ‘diffusion’. The approach to Dr. Williams’ listening room was to use all these tools plus a few newly patented products to acoustically correct the listening room.

????Dr. Williams’ listening room acoustic design - Summary
???Background – By Dr. Bonnie Schnitta:
Every room has its own unique set of acoustic constraints and dynamics. The only way to identify the acoustic issues and their root causes is to examine the specifications of the speakers and mathematically model the room for optimum acoustic response. Every room is unique and everything in the space will affect its sound. Surfaces, windows, doors and of course its overall shape will all dramatically change the way sound is perceived within the room.
Highly reflective surfaces will create large amounts of reflection and play havoc with pure tones.
Acoustic Treatment:

?LUMITEXTM:
The first and main acoustic treatment within the room was to include LumitexTM for the treatment of the mid and high frequencies. LumitexTM is a nonwoven Class A fire rated fabric. This thin (3.5 oz./sq. ft.) fabric creates a fairly even absorption across the speech frequencies and has a far better absorption in the lower frequency than foam or high density fiberglass. The absorbency of the fabric varies as does the airspace between it and the boundary of the room. For Steve Williams’ listening room the LumitexTM was placed between an open wave curtain fabric and a liner. The main purpose of the LumitexTM was to provide absorption. Since the LumitexTM curtain so perfectly addresses mid and high frequencies, it allowed for an easy focus and treatment of bass
??frequencies.
??????????This graph is slightly deceptive, since it does not do service to acoustic phenomena that is created by the Lumitex in the fold of the curtain. That is, the ultimate beauty of the curtain with LumitexTM as an inner septum is that the curtain’s texture and folds (that also provided a varying space from the boundary of the wall to the LumitexTM), resulted in an organic diffusion. This organic diffusion was part of the acoustic wave response to the boundaries in a manner that allowed the wave interaction be more in line with a room of larger dimensions.
????

?PARADISETM FOAM
A section of the forward wall did not have the curtain over it. On that section a beautiful canvas painting was place behind which was located ParadiseTM Foam. In the format in which it was placed behind the canvas painting it had a range of NRC from .6 - .95. The airspace allowed for a necessary frequency shift.

CARPET
The sound absorption coefficients of carpet depends on the pile height, pile weight, type of backing material and whether the backing is coated with latex, type of surface (loop or cut pile), and the type and thickness of pad (underlayment). In general, cut pile provides greater absorption than loop pile of otherwise identical construction. The type of pile fiber has minimal effect on absorption. Various carpets were reviewed with Pridmore Design in order to optimize the absorption. Since Lumitex typically has peak absorption around 2000 Hz, a carpet was chosen to have peak absorption at 4000 Hz in order to further naturally balance the room. Under the carpet and its pad was SoundSense NoiseOut2. This proprietary loaded vinyl aids in balancing the lower frequencies of a room, this is detailed in the next section of this document.

LOW FREQUENCIES, OR BASS, are typically associated with room modes, which are resonances relating to the room's dimensions. The smaller the room, the more widely spaced the modal frequencies are, so it can become a problem that the bass response will be uneven. On the other hand if properly addressed this treatment will prove to result in an almost magical sound. That was the goal of the treatment.
????????

In 2011 SoundSense received a patent for an acoustic muffler that solves the problem of significant sound energy transmission, or acoustic leakage, through openings in a ceiling or wall structure, such as a recessed light. It has several other acoustic properties, which were used to help perfectly balance Dr. William’s listening room.
First, it is important to understand its original application of the SoundSense high hat muffler. Objects that create a hole or opening in the structure in which they reside can significantly reduce the STC (Sound Transmission Class) and/or IIC (Impact Insulation Class) of the structure. A standard acoustic enclosure cannot be used on a heat generating unit, such as a recessed light, to solve an acoustic leakage problem. This is because there is substantial heat build-up when the heat generating unit is enclosed, causing a recessed light to strobe, or a projector to fail. This unique patented muffler design solves even low frequency acoustic leakage. Additionally, the muffler is class A fire rated and has achieved a fire rating of almost 2 hours.
?????For Dr. Williams’ listening room another feature of this muffler was incorporated into the listening room. Often when a room is designed for an audio experience, the room includes speakers with a strong low frequency capability, or separate subwoofers. The irony of the hole created by the recessed light(s) is that they may actually contribute to the room sounding better in the lower frequencies by acting as a cavity resonator.
The SoundSense muffler improves the acoustic separation capacity of the structure, while simultaneously allowing for the air flow required to prevent heat buildup that results in the malfunction of a recessed light, projector, or other heat generating mechanism. Since there was a volume of air above the ceiling, this allowed recessed lights and HVAC vents to be placed in the ceiling and convert the entire ceiling into an equivalent Helmholtz Resonator. This was then controlled for optimum efficacy and tuning by placing special SoundSense patented High Hat Mufflers over each recessed light and HVAC opening. Two sizes were used in order to balance the lower frequencies of the room.

?HIGH HAT MUFFLERS:
????
Dr. Williams’ listening room acoustic design - Summary
?????One approximation of effects of absorption is the Sabine reverberation time. The reverberation time that measures the echo tendencies in a room having volume V and absorbing area A (in units of feet) at a frequency f is:
T60 ( f ) = 0.49.V , (1) c.A( f )
N
A(f)=?? (f).A (2)
N being a number of surfaces in the room, c being the speed of sound, An being the area of surface n and ?n (f) being the absorption coefficient of surface n at the frequency f. Combining this with the logic of a Helmholtz absorber we can determine the absorbing frequency fH of the Helmholtz absorber.
This allows the architectural element to be designed for the frequencies that need to be balanced through the room. The architectural structure can appear to be any one of standard architectural structures that can be used in a room, from baseboards to crown moldings or ceiling beams. Depending on the intended outcome, the architectural element can either be a solid body, or what appears to be a solid device but has internal channels. This allows the architectural devices to not only reduce or correct the decay time in the room, but also make certain that the architectural elements do not produce undesirable effects.
?where
nn n=1

?SOUNDSENSE TUNING TUBES: The Paradise Architectural Acoustic Devices are sound modifying architectural structures. The final treatment of balancing the room in the low frequency was mathematically placing the patented SoundSense Tuning Tubes in the back corners of the room.
????

Dr. Williams’ listening room acoustic design - Summary
The mathematical underlining of the various shapes and designs of the architectural acoustic structures, or elements, described in this summary will be presented for a linear case to allow a better understanding of the underlining acoustical effects. An appreciation for a more precise mathematical description of the embodiments will also be discussed by additionally taking into account the non-linear aspects of the various embodiments.
Since the architectural acoustic devices, like other devices and methods
used in acoustics, are complex in nature, are often best practiced by empirically determining the appropriate values of the operating parameters, or by conducting computer simulations to arrive at best design for a given application. A computer simulation of Steve Williams’ listening room was performed. 2 sizes tuning tubes were placed in each of the back corners of the room.

?????????????SOUNDSENSE NOISEOUT 2
Another way to prevent low-frequency sound bouncing is to interrupt it with a heavy but non- rigid surface. Here the principle is the same as when bouncing a ball off concrete as compared to bouncing it off sand. This was accomplished in the Williams listening room by placing SoundSense NoiseOut2 on the floor under the carpet.
???When sound generated in a room strikes a surface, it is partially reflected, partially transmitted, and partially absorbed. This is true for each layer of material in a wall, ceiling, or floor. The wave interaction with the surface depends on many factors, but the main factors that are typically involved in calculations of reverberation time are the frequencies of concern, the rigidity and density of the surfaces, and the absorption of the various objects in the room. For the case of an empty room, the estimation of the reverberation time is simplified to the absorptive properties of the surfaces.
www.soundsense.com 5/7/2013 Page 6 of 7
???
The high STC wall configuration with the loaded vinyl layer simultaneously produced a significantly reduction in the reverberation time within the room. The use of SoundSense NoiseOut2 below the carpet achieved a high STC and a lower reverberation time, helping meet both the acoustical and the budgetary requirements.

?????... AND FINALLY THE BOOKCASES
There are generally two types of bass traps: resonating absorbers and porous absorbers. By their nature resonating absorbers tend toward narrow band action. The acoustic design was based on mostly resonating bass traps, so there was a greater control of the goal of a .4 decay time in the listening room for all frequencies. The final acoustic design piece to the room was to use the storage units on one wall as natural diffusers with airspace behind the back section of the bookcase. This allowed for another organic bass trap within the room.

IN CONCLUSION:
The room had a wonderful response. It had an optimum decay time of 0.4 across all frequencies. It felt like a room of dimensions greater than it was, the tones from Sinatra’s voice were pure and the harmonics of the melody from classical music were enchanting. The pressure wave interaction within the room was optimized so that the room “felt wonderful”.

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