My Final Listening Room in Words and Pictures


Greeting All,

A few years back, I created a post detailing the building of my final system.  With only a few changes, that statement has proved mostly true.  Creeping up on 10,000 views and receiving a lot of positive feedback, I thought it was time to complete the journey with a complimentary post on the building of the new home for that system.  If you’re interested, the original post can be found at https://forum.audiogon.com/discussions/my-final-system-build-in-words-pictures

Let’s start at the beginning.  At age 71, we decided to build our final "age in place" home.  Some friends joke that the house was designed around the stereo, and there is some truth in that.  I selected a bungalow design to guarantee adequate space in the basement development to provide the listening space along with other rooms I wanted.  I realize that only a few of us are in a position to create the ideal space we desire, having a blank sheet to begin with, but the take away from this post should be that anyone can tackle a major project if you put you mind to it.  I logged 135 days of construction and did everything myself with the exception of taping the drywall and installing the carpet.  

This is the floorplan I started with:

I’m a big believer in getting permits and inspections.

One of the first considerations was the room dimensions.   Much has been written on this subject and I read it all.  In the end I settled on a calculator that seems to refine the accepted approach.  The long read for that can be found here:

https://digistar.cl/Forum/viewtopic.php?t=557

In a nutshell, you can play with any combination of L x W x H until you move the yellow dot into a black area.  White is bad, Grey is so-so, and Black is spot on.

 

 

Let the fun begin.  Here is Day One:

 

As the listening room is only part of a 1300 sq ft development, much of the construction was based on creating a DRY basement space with plenty of air movement.  Anything that would avoid the damp musty smell that many basements fall prey too.  I hope  this part of the post will have some interest for most readers.

Step One:

Mechanically attach 2 inch rigid insulation with vapor barriers on both sides.  Seal all joints with 3M vapor tape

 

Step Two:

Cover and seal the entire concrete floor with "foundation wrap", available at Home Depot.  this prevents any moisture from entering the basement from the floor and also allows any moisture that may enter through the foundation to run under to subfloor and be reabsorbed by the cement floor.  Finally it allows you to lay a subfloor and T&G OSB and negates the need for any pressure treated lumber. No carpet or underlay getting damp and mouldy because it was laid on concrete.  

 

Step Three:

The framing.  I went with 2 x 4 studs on 16 inch centers.  A little overkill but I like things built solid

 

Step Four:

The wall systems in the music room are based on the room that Robert Harley (?), editor at TAS built in his own home.  Needless to say I only copied some of the ideas, and I found most materials could be sourced way cheaper if you look around.  For example, Home Depot wanted $14 per 12 foot furring channel.  I called a couple metal shops and found one that makes their own, exact same product, for $4.75 each.  His story is here:

https://www.google.com/search?q=absolute+sound+editors+home+listening+room+video&rlz=1CAFUBQ_enCA1075CA1075&oq=absolute+sound+editors+home+listening+room+video&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIHCAEQIRigATIHCAIQIRigAdIBCjM0NzkzajBqMTWoAgCwAgA&sourceid=chrome&ie=UTF-8#fpstate=ive&vld=cid:15e52085,vid:OtUcfiaN6CY,st:0

After insulating the entire room with Safe & Sound Mineral Wool insulation, and strapping the walls with rows of 1x4 for additional stiffness,  I secured a pattern of Genie Clips to the studs.  These are metal brackets with a large rubber isolation that goes against the stud.  Metal furring channels then clip onto these

 

Because the drywall will be "hung" on the furring channels, the surface of the drywall will be about 2 inches away from the studd face.  This created a slight problem attaching electrical boxes.  The work around was to make plywood gussets that would hold the boxes away from the studs.

 

 

Since I was going to attach a double layer of drywall, it didn’t matter that the gusset cut through the first sheet.  They were completely covered as normal by the second layer of drywall.

 

 

I used hundreds of thin vinyl spacers between the two sheets of drywall 

 


Side profile of the walls.

The theory is that the drywall is suspended on the furring channels and not physically attached to the studs.  This allows the walls to "vibrate" when sound waves hit them, and transfer the waves into heat, absorbed by the wall.  In essence, turning the entire room into a giant Bass Trap.  Hey, who am I to question people to do this for a living?  It’s very cool that if you are talking as you enter the room, the sound of your voice changes in your head.  The pressure in the listening room is completely different from outside the room.  All that material and design in action.

All the widow opening needed to be boxed in with 3/4 inch MDF

 

 

Most of the way there.

 

The basement walls are 9 feet tall but my ideal room size is only 8 feet, so I installed a suspended ceiling.  This allowed me to hide the cold air return and the central vac system I put in.  The ceiling tile was sourced from Home Depot and has a sound absorption rating of 70%

 


While all the instructions for installing a ceiling suggest you need laser levels and other specialized equipment, I hung the entire ceiling using a single 10" piece of 2x2.  Ten inches was the distance from the bottom of the floor joists to the top of the main supporting tracks.  Loosely hung a main support and then used the 2x2 block to set the hanging wires.  The entire installation took two days and it is perfectly square and flat.  Yes, I am pleased with myself. 🤣

I installed a total of 8 flush mount leds lights, on two different 3-way switches, both are dimmers.  One set for general lighting and one set for accent lighting.

Prior to painting the walls, all the trim was installed and sprayed in place.  

  

Finally the day arrived when I started to move boxes of equipment downstairs

 

And this is how you get SoundLab Majestic 745 speakers into the basement, when they won’t make the corner at the bottom of the stairs.  Thank goodness for 60 inch windows.

 

The Reveal.

 

 

 

 

 

 

 

The results of this project exceeded my expectations.  While my previous room sounded great, the soundstage in the new room is truly on another level.  Wider for sure, but the depth of the stage is all together different.  A three dimensional presentation I’ve never had before.  

On a few technical notes, I ran a dedicated 8 AWG line from the main panel to a 250 volts outlet, using double 30 amp breakers.  This line powers my Equitech 5RQ Step down transformer.  Providing fully balanced 125 volts power to my amps, through 1 meter Puritan Ultimate cables.  The 5RQ also powers my two 
REL s812 subs and my speakers.

A second 12 AWG 20 amp line runs to my front end equipment that is situated about 15 feet from the amps.  Long XLR cables from Sound Sensibility join it all up.   

It was a lot of work but extremely gratifying.  On a financial note, I asked the builder to quote the whole development for me, based on my building specs.  They quoted me 90K - 100K.  The total cost of the entire basement came in at $46,000.  That number includes all materials and the small amount of contracted labour for the taping and carpet.  All dollars are in Canadian currency.  

The EXTRA cost of the basement development, specifically inflated tied to the construction of the listening room was +/- $5000

I hope you have enjoyed this little journey with me.  My wife assures me there will not be another one.  🤣

Cheers,

bigtwin

@bigtwin - thank you. If your room is lively enough, I wouldn't worry, and if not, some more diffusion (or combined diffusion/absorption) might help. I contacted an acoustics expert (Jeff Hedback) and was very glad I did. I learned a lot about doing measures (in REW) and relating the results to what I hear. 

My Audiokinesis speakers were designed with some inspiration from Soundlabs, but they are quite different beasts - bipole two way with dynamic drivers (horn for the treble). 

There seems to be different opinions regarding the back wave from bipoles and dipoles -  tame it, let it be, diffuse it, etc. Obviously this is not a "one size fits all" situation. In my case, a fairly large room, the speakers work best six feet (or more) from the wall, increasing the image depth. Also some distance to the side walls, although this is less critical with the large toe-in (like 40 degrees) that Audiokinesis advices (I see that large toe-in is mentioned as a possibility also in the Soundlab setup guide). You have probably experimented a lot with positioning and toe-in, as have I. Two rules seem fairly clear. The backwave should sound like the front sound (spectrally correct). Also, the path length should be correct so that the reflected sound from the backwave arrives at least 10 ms after the front sound. At least, that is the Audiokinesis philosophy.  

 

@o_holter 

I had Jeff design my room and I built the room while my speakers were being built. He is extremely good and his design worked out perfectly. Did Duke recommend him to you as well ? I met Duke at Axpona in 2022 ( he is a really nice man and I enjoyed talking to him very much) and he suggested I call  Jeff. Jeff was great to work with and I can’t recommend him enough. 

@bigtwin 

Awesome work!  I'd like to attempt something similar.

Although I live in Canberra Australia, my house was built by a Finn on cold-climate principles, and has a full basement which is almost entirely underground.  I have not been able to waterproof the basement properly and it definitely is not sitting in permafrost!

The theory is that the drywall is suspended on the furring channels and not physically attached to the studs.  This allows the walls to "vibrate" when sound waves hit them

With that in mind, I believe you have a Rega turntable which is mounted on a side wall.  I was wondering which part of the wall you fixed the table to, and what the considerations were?  Could be fixed to the drywall, or to the studs, or to the outer wall I guess.

I have another more theoretical question.  My reading of your Soundlab speakers is that they can behave as a vertical virtual line source which stretches to infinity if the ceiling and floor are acoustically reflective.  Did that factor into your design?

Once again, I congratulate you on a fantastic job

 

@richardbrand  Because my drywall is suspended on channels, I was not able to use studs for the TT.  I suppose with some better planning, I could have installed some bracing in the right place.  My Rega P8, including the Rega wall mount bracket, only weighs 11 pounds.  I just used some appropriate drywall anchors.  They hold up to 175 pounds and its shear strength that's needed, so no problem. I can jump up and down in front of the TT and it doesn't skip a beat.  

 

 

As for "infinity and beyond", it's a bit of a non issue as the system is only producing sound that is actually on a recording?  The impedance curve on the 745's goes from 40+ ohms down to 1.6 ohms.  Again, the real world application would be how much audio signal is actually embedded in those regions?  The majority of frequencies are in the 8 ohm region.  But, if called upon, my amps are stable at 1 ohm and have the raw power where needed.  I did discuss the room design with Roger West, with detailed questions on best flooring and ceiling materials.  His answers played a big part in my selections.  It was interesting that Roger was adamant that the design of the SoundLab speakers virtually eliminates much of the issues pertaining to side and ceiling reflections.  I'm extremely happy with the results of this endeavor, but still plan to have someone come in with all the proper measuring equipment to see what fine tuning can still be achieved.  Not being an engineer, I hope my answers are mostly correct.  I find things above my pay grade on a daily basis.  Cheers.