Let's build a room. How big? What dimensions?

[Be Quiet...Listen]

7 hours ago, Crabsticks said:

Typically, in construction, you would use double plasterboard layers in situations where you are trying to prevent the spread of fire, or to stop sounds transferring from one space to another.

 

I don't see how good room acoustics and those ideas are connected.

I tend to agree with this. 
 

My question comes at a time where I’m considering the best measures before I enact a concrete plan. 
As we all know, everyone has a different opinion or experience. I just want to maximise my potential/results. 
Plasterboard and insulation are cheap enough, so subtracting or adding these materials is ultimately inconsequential to cost, but perhaps may be in terms of room performance? 

[Ittaku]

7 hours ago, Crabsticks said:

Typically, in construction, you would use double plasterboard layers in situations where you are trying to prevent the spread of fire, or to stop sounds transferring from one space to another.

Stopping sounds transferring from one space to another may be another consideration for a listening room, if you care about the other members of your household.

[Guest Peter the Greek]

8 hours ago, Steffen said:

As for the people outside the listening room, f*ck’em!

 

Not quite. You're going to miss out on dynamic range if the sound floor of the room is above that of the recording. All rooms have bass issues, they can be fixed with in room techniques and eq. You can't solve for a low sound floor any other way than building big, heavy, isolated, damped walls, floors, and ceiling.....doors, HVAC vents

[Be Quiet...Listen]

And what about this Green Glue???

[Crabsticks]

21 minutes ago, Be Quiet...Listen said:

And what about this Green Glue???

Green Glue

[Be Quiet...Listen]

3 minutes ago, Crabsticks said:

Green Glue

Yep, I have watched Dennis' video's on Green Glue. He's not a fan!

 

But, people still use it.

[Crabsticks]

3 minutes ago, Be Quiet...Listen said:

 

But, people still use it.

But should they? Used I the correct way, isolation or trying to remove vibration/sound transfer I can understand. Particularly, as mentioned earlier, if you have other people to consider.

 

I for one am interested in people's opinions on the best wall material to use in the listening room. Hard plaster? Timber panelling? Rammed Earth?

 

[Stereophilus]

6 minutes ago, Crabsticks said:

Green Glue

What a bizarre commentary... He explains it all very well, but justifies his stance of “don’t use green glue” by saying his company use “better” materials instead of green glue.  It’s basically an advert for his company, using the popularity of green glue as the click-bait.

[Crabsticks]

1 minute ago, Stereophilus said:

What a bizarre commentary... He explains it all very well, but justifies his stance of “don’t use green glue” by saying his company use “better” materials instead of green glue.  It’s basically an advert for his company, using the popularity of green glue as the click-bait.

Damn that click bait. I was more interested in the plasterboard comments.

[Be Quiet...Listen]

Let's not forget the cost involved with Dennis' work. I have no doubt that the science is beyond solid but the sheer cost is eye-watering! 

[Stereophilus]

12 minutes ago, Be Quiet...Listen said:

I have no doubt that the science is beyond solid...

Not really...  The “science” is that constrained layer dampening is generally a good thing in the construction of walls and ceiling of a dedicated audio room.  BUT, there is very limited science (biased observation only) in him saying “we think our product sounds better” compared to the alternative (ie green glue and plaster board).

[Be Quiet...Listen]

8 minutes ago, Stereophilus said:

Not really...  The “science” is that constrained layer dampening is generally a good thing in the construction of walls and ceiling of a dedicated audio room.  BUT, there is very limited science (biased observation only) in him saying “we think our product sounds better” compared to the alternative (ie green glue and plaster board).

When I said ‘science’ I was referring to his overall model. 

[MrC]

20 hours ago, GroovyGuru said:

Everyone has suggested something of value.  It's a case of collating what suits the sound and look you want. 

 

I don't think the perfect room exists.  The most important thing is get the room sound you want and can live with.  Better to have a room a little too big than a little too small.  I think minimum size is 8m x 5m. 

Agree with the theory of minimum size and I think 8m x 5m is about right, although many people cannot accommodate 8m in their houses.  Mine is 6m x 4.5m and then I optimized the room around those dimensions.

[Guest DrSK]

On 02/01/2021 at 7:08 PM, Ittaku said:

If you have reams of land to spare in an upcoming building development, how big would you make it? I'm thinking something oblong approximately 8.5 metres long, but there's no reason I couldn't go bigger. I'm planning on making the system suitable to fill a massive space too, rather than a room to suit a particular system. How big is big enough? How big is too big? Is it really just the bigger the better? I've seen recommendations in many places but just like acoustics of a studio, theatre, arena, chapel etc. it's part science and part art. Thoughts?

 

The bigger the room, the bigger the delays off reflecting surfaces due to path length differences. So unless you run around 100% frequency range treatment the reflections will go from imaging broadening to audible delays as a seperate source. 

 

A smaller room has image broadening from lateral reflection and will also shift the image up due to ceiling reflection. Rear wall reflection will also add to this and depth issues. Some of this can be beneficial. 

 

Here is what I would do. 

 

To answer the question of how big, I'd start with seating position and speaker placement. Essentially, how big is your desired triangle. 

 

Then add at least twice that seating to speaker distance for the seating to the rear wall. 

 

You don't want ceiling reflections. So you need enough height to install broadband diffusion on the ceiling without seating within the near field of the diffuser. This will set your roof height. All ceiling reflection is bad. 

 

Similarly I'd then look at rear and front wall diffusion. Expand the size to create the space including allowances for getting out of the near field. 

 

Same again for side walls. 

 

I'd only then consider basic estimates for reverberation and absorption.

 

Any mode calcs, except at very low frequency will be wrong because of the beneficial diffusion. Remember modes are nothing more than multiple reflections summed together and are the result of constructive and deconstructive interference.

 

I'd then consider break out noise and annoying neighbours or family. This will dictate wall and roof thickness. Generally low frequency noise is the issue and based on numerous designs of performance spaces, if you want music at high levels full range, you are talking about thick single leaf masonry construction or carefully tuned double leaf construction to ensure the two leaves don't resonate about the compressible air gap in between. 

 

With single leaf construction you can hide services behind a facing of perforated plasterboard etc with sufficient porosity to be transparent acoustically so that single leaf low frequency performance is maintained. Very easy to stuff a masonry wall low frequency performance by 15dB by a stud wall and gyprock. And of course with the perforated panel you can also use it for absorption or keeping it transparent by controlling open area, hole depth and backing material. 

 

After all this you will have an idea of the building footprint. 

 

The achievable result will be strong 3d imaging with room ambience from the diffusion without the liveliness impacting imaging. This is big budget stuff. 

 

 

Edited January 8, 2021 by DrSK

[aussievintage]

38 minutes ago, MrC said:

Agree with the theory of minimum size and I think 8m x 5m is about right, although many people cannot accommodate 8m in their houses.  Mine is 6m x 4.5m and then I optimized the room around those dimensions.

 

The room my TV/home theatre system is in,   is 8m x (nearly)5m,  and the acoustics are good - helped by a high ceiling and some natural diffusion from exposed bearers overhead.  Unfortunately it isn't my main listening room for music (even though I recently set up a smaller music system in there with the TV).   

 

Hmmmm...  maybe I should swap things around.

Edited January 8, 2021 by aussievintage

[henry218]

the context from Dennis's video about green glue is the target.

1 hour ago, Stereophilus said:

What a bizarre commentary... He explains it all very well, but justifies his stance of “don’t use green glue” by saying his company use “better” materials instead of green glue.  It’s basically an advert for his company, using the popularity of green glue as the click-bait.

the context from Dennis's video about green glue is the target of treatment. if LF pressure is your target, green glue is not effective.

 

it will take a lot of density of materials to absorb LF pressure, which is the most common problems in a small room.

the structure of the walls, structural integrity of the room, density of the walls and materials that you put in the room will be the defining factor.

 

in general, i think its best to :

1. Absorb LF pressure as much as you can (especially if you are using large speakers and multi subwoofers)

2. Absorb and diffuse midband range

3. Diffuse treble range.

 

 

 

[MrC]

1 hour ago, aussievintage said:

 

Unfortunately it isn't my main listening room for music (even though I recently set up a smaller music system in there with the TV).   

 

Hmmmm...  maybe I should swap things around.

My dedicated room is a dual listening and home theatre room.  Accoustic treatments on ceiling and 3 walls, Trinnov Altitude optimizer, 2 main speakers and subwoofers on isolation feet ... it sounds superb.

[Al.M]

2 hours ago, MrC said:

Agree with the theory of minimum size and I think 8m x 5m is about right, although many people cannot accommodate 8m in their houses.  Mine is 6m x 4.5m and then I optimized the room around those dimensions.

Except that a 5m wide room is not really enough if the listening triangle is say 3m wide to accommodate larger future speakers with only 1m distance from side walls and larger panel and other speakers get a bit tight. I would prefer about 1.5 - 2m distance to side walls, so a 6-7m wide room and to keep the rectangle shape then 9-10m deep, 3m ceiling for up to 2-2.3m tall speakers and distance from them and shorter speakers.

 

Also, comments about single leaf masonry wall, if using that make sure the vertical mortar joints are filled with no gaps to ensure maximum sound transmission reduction as many brickies will not do it because they are lazy or trying to save costs and time.

Edited January 9, 2021 by Al.M

[Al.M]

2 hours ago, DrSK said:

 

The bigger the room, the bigger the delays off reflecting surfaces due to path length differences. So unless you run around 100% frequency range treatment the reflections will go from imaging broadening to audible delays as a seperate source. 

 

A smaller room has image broadening from lateral reflection and will also shift the image up due to ceiling reflection. Rear wall reflection will also add to this and depth issues. Some of this can be beneficial. 

 

Here is what I would do. 

 

To answer the question of how big, I'd start with seating position and speaker placement. Essentially, how big is your desired triangle. 

 

Then add at least twice that seating to speaker distance for the seating to the rear wall. 

 

You don't want ceiling reflections. So you need enough height to install broadband diffusion on the ceiling without seating within the near field of the diffuser. This will set your roof height. All ceiling reflection is bad. 

 

Similarly I'd then look at rear and front wall diffusion. Expand the size to create the space including allowances for getting out of the near field. 

 

Same again for side walls. 

 

I'd only then consider basic estimates for reverberation and absorption.

 

Any mode calcs, except at very low frequency will be wrong because of the beneficial diffusion. Remember modes are nothing more than multiple reflections summed together and are the result of constructive and deconstructive interference.

 

I'd then consider break out noise and annoying neighbours or family. This will dictate wall and roof thickness. Generally low frequency noise is the issue and based on numerous designs of performance spaces, if you want music at high levels full range, you are talking about thick single leaf masonry construction or carefully tuned double leaf construction to ensure the two leaves don't resonate about the compressible air gap in between. 

 

With single leaf construction you can hide services behind a facing of perforated plasterboard etc with sufficient porosity to be transparent acoustically so that single leaf low frequency performance is maintained. Very easy to stuff a masonry wall low frequency performance by 15dB by a stud wall and gyprock. And of course with the perforated panel you can also use it for absorption or keeping it transparent by controlling open area, hole depth and backing material. 

 

After all this you will have an idea of the building footprint. 

 

The achievable result will be strong 3d imaging with room ambience from the diffusion without the liveliness impacting imaging. This is big budget stuff. 

 

 

Absolute way to go, finally some science, logic and experience.

[Steffen]

5 hours ago, Peter the Greek said:

 

You're going to miss out on dynamic range if the sound floor of the room is above that of the recording.

 

Yes, good point, intruding noises are something to be considered. All I’m doing in that regard at the moment is listening at quiet times at night (the amount of lawn mowing, tree lopping and circular sawing in our neighbourhood is staggering), and removing rattles from windows and furniture. I also try to make sure aircon, dishwasher and bathroom fans aren’t running.

 

What I was saying is that I don’t care about sound (esp. bass) escaping the room. Luckily, nobody in my house seems to mind and the neighbours haven’t complained. That’s probably in part because I never listen above 80dB.

 

[Be Quiet...Listen]

53 minutes ago, Al.M said:

Except that a 5m wide room is not really enough if the listening triangle is say 3m wide to accommodate larger future speakers with only 1m distance from side walls and larger panel and other speakers get a bit tight. I would prefer about 1.5 - 2m distance to side walls, so a 6-7m wide room and to keep the rectangle shape then 9-10m deep, 3m ceiling for up to 2-2.3m tall speakers and distance from them and shorter speakers.

 

Also, comments about single leaf masonry wall, if using that make sure the vertical mortar joints are filled with no gaps to ensure maximum sound transmission reduction as many brickies will not do it because they are lazy or trying to save costs and time.

Do you have a 7x11x3m room? 

[Al.M]

4 hours ago, Steffen said:

 

Yes, good point, intruding noises are something to be considered. All I’m doing in that regard at the moment is listening at quiet times at night (the amount of lawn mowing, tree lopping and circular sawing in our neighbourhood is staggering), and removing rattles from windows and furniture. I also try to make sure aircon, dishwasher and bathroom fans aren’t running.

 

What I was saying is that I don’t care about sound (esp. bass) escaping the room. Luckily, nobody in my house seems to mind and the neighbours haven’t complained. That’s probably in part because I never listen above 80dB.

 

It’s been covered in previous similar past posts, but the sound floor shouldn’t be a problem for average suburb house up to 300m away from busy traffic and rail noise sources and more for aircraft. The average external stud frame and masonry constructed wall will easily achieve a good noise floor to enjoy music with about 20-30dB(A) levels obtained within recommended levels. Windows are one main source of external noise entry so make sure to use at least 6.38mm laminated glazing with edge seals and not too large surface area (not more than 40% floor area, which is rare). If you want more sound reduction go for 10mm or double glazing. 

 

Here is a a good WA government guide on quiet house designs and estimates of likely traffic noise levels at distance outside your window and typical wall/window construction, see page 9 of the guidelines https://www.dplh.wa.gov.au/getmedia/0bd9e67d-1cb9-4b6c-a73c-65f7ea347c1f/SPP_5-4_Implementation_Guidelines

Basically, if the traffic noise outside the window isn’t more than about 55dB(A) normal 3-4mm thick windows are acceptable for achieving about 30-35dB(A) indoors facing the traffic. So if the room is facing away or side on it will be less. As an extra measure just go for 6.38mm thick windows to achieve about 3-5dB reduction than normal, which in subjective hearing loudness is about half quieter for what may come through the window. 

 

For lawn mowers and chainsaw noise they around 80 and 110dB(A) and very tonal at the operator end whereas traffic and rail is about 70-80dB(A) at the kerb so 10mm+ window glass and more is needed, but these shouldn’t be happening at night and too constantly, if they are a noise complaint should be lodged with the local authority to make sure they are complying with regulations.

 

 

If not already seen this article has some good points on room reverberation, coloration and not overdoing absorption http://artsites.ucsc.edu/ems/music/tech_background/TE-14/teces_14.html

Edited January 9, 2021 by Al.M

[Al.M]

53 minutes ago, Be Quiet...Listen said:

Do you have a 7x11x3m room? 

No, but the OP is asking about building from scratch and what size is good with no limits set. 7x11x3m room would be very large but not unachievable if it suits and land size available.

 

My room is 5x3.6x3m ceiling, which is in a 2m listening triangle. I could try the family kitchen area 5x10x3m and deal with the consequences after 

Edited January 9, 2021 by Al.M

[Crabsticks]

1 hour ago, Al.M said:

 many brickies will not do it because they are lazy or trying to save costs and time.

And also because that's not their job.

[MrC]

1 hour ago, Al.M said:

Except that a 5m wide room is not really enough if the listening triangle is say 3m wide to accommodate larger future speakers with only 1m distance from side walls and larger panel and other speakers get a bit tight. I would prefer about 1.5 - 2m distance to side walls.

I completely disagree ... 1 metre from the side walls is plenty of room (similarly from the front wall).  I have had my room analyzed and measured and it got the big thumbs up!!