What’s the perfect size for a hi-fi room?

[Frgirard]

My next home will have a basement which exceeds all of these relatively large dimensions, at 16’H, 24’W, and 50’L. Wondering what types of room treatments would be necessary to create optimal acoustics conditions for two-channel audio. I believe that apart from usual low frequency pressure issues, the primary challenge will be to shorten the naturally long reverberation times. Intend to cover the entire front wall with diaphragmatic bass absorbers as a first layer, then P-17 or even P-23 quadratic diffusers for the next layer facing the listening position. Also thinking about “burying” multiple diaphragmatic bass absorbers into the floor, at the midpoint between speakers and listening seat, to address the floor bounce which typically create a deep null between 150-200Hz. Side wall treatment will be mostly foam absorbers, covering perhaps 60-70% of the otherwise bare walls. Anything else?

Why make it so complicated?

 

[puppet]

Something like this? ... or a scaled down version of the Grant Park band shell in Chicago.

 

[Kegemusha]

Sound City Studio:
thinking of the the Niravan's and Radio Against the Machine's CD were recorded almost live in, I think it was VOX old factory.
They did not had standard size, it was almost squared.
I even think Neil Young recorded there, I remember seeing the movie.
They had a Rupert Neve studio console.

 

[QuadDiffusor]

Why make it so complicated?

Why not? Low frequency pressure requires absorption treatment which is different from mid/high frequency diffraction treatment.

 

[dasdoing]

Something like this? ... or a scaled down version of the Grant Park band shell in Chicago.

too much noise from the wind hitting the trees

 

[krabapple]

Cool - Half of those rooms look like they're from the set of 2001: A Space Odyssey.

A lot of them look like near field listening. Which is common in studios. But maybe that's just a trick of perspective.

 

[puppet]

too much noise from the wind hitting the trees

 

[dasdoing]

 

[Frgirard]

Why not? Low frequency pressure requires absorption treatment which is different from mid/high frequency diffraction treatment.

Low frequency pressure, yes maximal against the wall in an angle,where a corner bass trap can be used.
Diffraction or reflection, it's not the same thing.
Diffusion : works for one direction. For others direction, you generate phase accidents.
And

How Much Diffusion For Small Room - Page 3 - Gearspace.com

Quote: Originally Posted by diffusor.com ➡️ I have had enough of your and Northward's absurd and condescending comments about SMT diffusors and its customers. http://www.gearslutz.com/board/showp...2&postcount=25 Calling well-known mixers, monitor manufacturers and world-famous musicians...

gearspace.com

And
https://gearspace.com/board/showpost.php?p=15526228&postcount=15
Your room like my room are little room.
The plolyclindrical diffuser do not cause this kind of problem.

You must treat the room completely or do like me: separate the room in two part with mobile walls (I have choosen plexiglass in10 mm.

20"/5000 rayles give an absorption of 0,5 at 50 Hz. An easy way to treat a room, you have the place.
You will think after to setup the decay time.

As said André Vare 90 % of brainstorming and 10 % of build.

 

[QuadDiffusor]

Low frequency pressure, yes maximal against the wall in an angle,where a corner bass trap can be used.
Diffraction or reflection, it's not the same thing.
Diffusion : works for one direction. For others direction, you generate phase accidents.
And

How Much Diffusion For Small Room - Page 3 - Gearspace.com

Quote: Originally Posted by diffusor.com ➡️ I have had enough of your and Northward's absurd and condescending comments about SMT diffusors and its customers. http://www.gearslutz.com/board/showp...2&postcount=25 Calling well-known mixers, monitor manufacturers and world-famous musicians...

gearspace.com

And
https://gearspace.com/board/showpost.php?p=15526228&postcount=15
Your room like my room are little room.
The plolyclindrical diffuser do not cause this kind of problem.

You must treat the room completely or do like me: separate the room in two part with mobile walls (I have choosen plexiglass in10 mm.

20"/5000 rayles give an absorption of 0,5 at 50 Hz. An easy way to treat a room, you have the place.
You will think after to setup the decay time.

As said André Vare 90 % of brainstorming and 10 % of build.

Frgirard,

Thank you for the GearSpace link - a very good source of information! But I’m afraid I don’t quite understand the rest of your post, though it appears that you’re trying to volunteer helpful advice.

BTW, my future basement will not be “small”… at 16’H, 24’W, and 50’L, I’d wager that it‘s among the top 1% of audiophile listening spaces in size, which presents a unique set of treatment needs. My hunch is that the most important requirement would be to drop the very long reverberation time (RT60) inherent between parallel flat/hard/large surfaces down to the more optimal 0.4-0.6 seconds, as well as de-correlate and scatter the reflections. I believe this can be done primarily through Quadratic Diffusors on the front wall (broadband diffusion in the horizontal axis), assisted by the natural decay in the amplitude of reflected energy over the long distances between the two side walls spaced 24’ apart.

My listening seat and loudspeaker distancing will likely be in a 11’ equilateral triangle configuration. 2.5’ of space directly in front of the front wall willl be dedicated to acoustic treatments - a 14“ layer of diaphragmatic bass absorbers, and a 18” layer of P-23 Quadratic Diffusors. The loudspeakers be placed 8’ away from the face of the 2-layered front wall treatments, and toed-in slightly to the listening seat. Given the room dimensions, each loudspeaker will effectively be 6.5’ away from the side walls. Effectively, there will be NO back wall, as it will be 30’ behind the listening seat, with the empty cavity filled with miscellaneous furniture, cabinets, appliances, desks, etc. And the ceiling, being 16’ high, probably will only need a bit of mid/high frequency absorption treatment.

Are my acoustical treatment priorities appropriate? Any additional advice will be much appreciated !

 

[Frgirard]

Frgirard,

Thank you for the GearSpace link - a very good source of information! But I’m afraid I don’t quite understand the rest of your post, though it appears that you’re trying to volunteer helpful advice.

BTW, my future basement will not be “small”… at 16’H, 24’W, and 50’L, I’d wager that it‘s among the top 1% of audiophile listening spaces in size, which presents a unique set of treatment needs. My hunch is that the most important requirement would be to drop the very long reverberation time (RT60) inherent between parallel flat/hard/large surfaces down to the more optimal 0.4-0.6 seconds, as well as de-correlate and scatter the reflections. I believe this can be done primarily through Quadratic Diffusors on the front wall (broadband diffusion in the horizontal axis), assisted by the natural decay in the amplitude of reflected energy over the long distances between the two side walls spaced 24’ apart.

My listening seat and loudspeaker distancing will likely be in a 11’ equilateral triangle configuration. 2.5’ of space directly in front of the front wall willl be dedicated to acoustic treatments - a 14“ layer of diaphragmatic bass absorbers, and a 18” layer of P-23 Quadratic Diffusors. The loudspeakers be placed 8’ away from the face of the 2-layered front wall treatments, and toed-in slightly to the listening seat. Given the room dimensions, each loudspeaker will effectively be 6.5’ away from the side walls. Effectively, there will be NO back wall, as it will be 30’ behind the listening seat, with the empty cavity filled with miscellaneous furniture, cabinets, appliances, desks, etc. And the ceiling, being 16’ high, probably will only need a bit of mid/high frequency absorption treatment.

Are my acoustical treatment priorities appropriate? Any additional advice will be much appreciated !

Focus your acoustic treatment on absorption with easy-to-implement solutions, used in every studio in the world. 5000 rayles / 50cm gives 0.5 to 50Hz The minimum is 20 cm at 8000 rayles.

The Rod Gervais book or https://www.amazon.fr/gp/aw/d/1498740995/ref=dbs_a_w_dp_1498740995
Will be good advice.

 

[puppet]

Frgirard,

BTW, my future basement will not be “small”… at 16’H, 24’W, and 50’L,

Going to be interesting as to what you find down there.
Around here, going that deep means blasting ... then there's the ground water.

 

[BoredErica]

I hope to buy a house ten years from now, and I want to have a good idea of what I want in the computer/music room. There doesn't seem to be a consensus on what shape a room should be though apart from not square. I guess not "too small". But how close from head to speakers for example?

Hopefully a picture emerges in the next decade about how this ought to be done. If the room requirements are atypical then housing selection will have to match.

 

[QuadDiffusor]

Focus your acoustic treatment on absorption with easy-to-implement solutions, used in every studio in the world. 5000 rayles / 50cm gives 0.5 to 50Hz The minimum is 20 cm at 8000 rayles.

The Rod Gervais book or https://www.amazon.fr/gp/aw/d/1498740995/ref=dbs_a_w_dp_1498740995
Will be good advice.

Frgirard,
Thanks for the link; I purchased the Kindle version of Rob Gervais' book, and I'm looking forward to reading it!

 

[QuadDiffusor]

Going to be interesting as to what you find down there.
Around here, going that deep means blasting ... then there's the ground water.

Singapore's geography created a terrain largely of accumulated silt. As such, it's easy to dig deep into clay/sand without hitting bedrock, being mindful of not breaching utility pipes on the property perimeter. I will be selecting a location sufficiently elevated away and above the ocean, so hydrostatic pressure will not cause an ingress problem, as well as use modern construction materials such as polymer-infused concrete and flood mitigants such as drainage and pumps.

 

[youngho]

BTW, my future basement will not be “small”… at 16’H, 24’W, and 50’L, I’d wager that it‘s among the top 1% of audiophile listening spaces in size, which presents a unique set of treatment needs. My hunch is that the most important requirement would be to drop the very long reverberation time (RT60) inherent between parallel flat/hard/large surfaces down to the more optimal 0.4-0.6 seconds, as well as de-correlate and scatter the reflections. I believe this can be done primarily through Quadratic Diffusors on the front wall (broadband diffusion in the horizontal axis), assisted by the natural decay in the amplitude of reflected energy over the long distances between the two side walls spaced 24’ apart.

Are my acoustical treatment priorities appropriate? Any additional advice will be much appreciated !

With those dimensions, you could consider this approach:

 

[Head_Unit]

I didn’t [20 Hz in small rooms] was impossible. I said without ball sorts of problems...Aren’t room nodes and standing waves scientifically accepted issues?

Yes, but changing the size of the room just moves those up and down in frequency. The extreme of small rooms would be a car; my coworker once measured a 5" woofer in an Alfa Romeo prototype's door. Anechoically it rolled off slowly below 100 Hz; in the car it was flat to somewhere below 20 Hz. (Could it play loud enough to actually hear such a note? Eh, maybe not, but that's a whole different topic).

I think listening rooms should be big, with the speakers well out. That struck us at Upscale Audio-one reason the speakers sound great is Kevin has them well away from any walls, and the ceilings are tall. So reflections are more delayed and lower in level than in typical homes, plus the rooms are quite treated. The room modes then...become lower than the speaker passband, don't they? Mmm maybe not unless the room is crazy large? Getting too near bedtime to think it out clearly.

If your listening position is not unusually far away, more amplification would not be needed. The direct SPL will still be what it would be in a smaller (not teeny weeny) room except at the very low end where the room reinforces the bass if you're lucky.

 

[youngho]

Yes, but changing the size of the room just moves those up and down in frequency. The extreme of small rooms would be a car; my coworker once measured a 5" woofer in an Alfa Romeo prototype's door. Anechoically it rolled off slowly below 100 Hz; in the car it was flat to somewhere below 20 Hz. (Could it play loud enough to actually hear such a note? Eh, maybe not, but that's a whole different topic).

I think listening rooms should be big, with the speakers well out. That struck us at Upscale Audio-one reason the speakers sound great is Kevin has them well away from any walls, and the ceilings are tall. So reflections are more delayed and lower in level than in typical homes, plus the rooms are quite treated. The room modes then...become lower than the speaker passband, don't they? Mmm maybe not unless the room is crazy large? Getting too near bedtime to think it out clearly.

Don't forget about higher-order modes (multiples of the first-order modes, which for axial ones can be approximated by dividing 565 by the room dimension in question). It might be helpful to look at what Earl Geddes says about modal density here: https://www.dagogo.com/an-interview-with-dr-earl-geddes-of-gedlee-llc/.

 

[Hifiaudio177]

I'm about to build a new house and have specified a main level theater with dimensions of roughly 20x30x10 or so. Should I change those because they are multiples of 10? Maybe just make the height 11, and make the length 29?

 

[MakeMineVinyl]

Sound City Studio:
thinking of the the Niravan's and Radio Against the Machine's CD were recorded almost live in, I think it was VOX old factory.
They did not had standard size, it was almost squared.
I even think Neil Young recorded there, I remember seeing the movie.
They had a Rupert Neve studio console.

I was a recording engineer at Sound City in the late 70s. In reality, it was to me at the time just a very funky studio in a Van Nuys CA industrial building, pretty typical of such buildings in the San Fernando Valley. There was a defense plant maybe a half a mile from the studio down the 405 freeway that had a radar dish which when it was turned on would induce a blip noise every 10 seconds or so in all the electronics, including the Neve consoles in both studio A and studio B. Some takes had to be stopped because of the noise. Never in my wildest dreams would I imagine that Sound City would go on to achieve legendary status, much less for the time period I was there. None of the 'legendary-ness' rubbed off on me however.