Room Acoustics

I couldn't find a domestic range on the site, where is it or what are they called.

I was going to junk the DIY and go for the Offecct soundwave panels which are expensive but do look different.

 

I agree. The thing is - in most cases adequate room treatmet is not feasible. You can not significally improve the way your hi-fi sounds just by adding some heavy drapes or putting some "absorbing" thingies, shelves, and other absorbing/reflecting/dissipating stuff. It goes waaaaay beyond that, and nobody wants to ruin their living space.

One idea I'm still thinking of is a couple of large (like 1x1,5 m) batiks on a deep frame, reinforced by a thick layer of fiberglas or some similar sound absorbing material. The silk is sound-transparent, the absorbing material is not visible, what you see is some abstract art on silk. It should be great looking (no wife would say a word against it) and efficient when you need to cover large empty walls. The only thing that deters me so far is it's price. A good batik made to order costs a lot. And then again, I am not sure if it would be enough to improve things, and thinking about it mostly because I would like some art on my walls

There's one good newsletter on the Bryston site which is very pessimistic about any non-professional home "room treatments". And I can understand why.

And we have not yet started to talk about the way our brain perceives room reflectons and the way it makes corrections. One good example - your wife's/ mom's/ son's/brother's voice should, according to the theory, audibly change while she/he is moving around the room, because reflections change dramatically. Still it sounds the same all the time! It is because we are listening with our brains not ears. Tom Waits is not my brother but his voice remains the same for me regardles of the system/room.

 

Putting my anwer in laymans terms,is that the voice would be the wrong frequency,I would guess the voice only changes with echo,even then it would be recongnisable,but you would know the room had a problem.I have found,that it is the lower frequinces,below human voices that are more affected by room acoustics,in the case of my house anyway.

 

IMO one of the biggest problems is that you have to buy and try - and those things are not exactly cheap.

there is no way for avarage person to predict what exact treatment he needs - even acoustics professionals a lot of times get it completely wrong.

WAF thing is another issue............

another one is poor availability of comercial products outside USA, UK and, perhaps, very few major EU countries - shipping and import to other countries makes costs very high.

generally speaking most of DIY solutions are about absorbing foams - which is wrong approach - all 3 aspects of acoustics should be treated evenly.

biggest problem is bass - because solutions are bulky and expensive.

i saw few DIY attempts but,to be honest, didn't hear about one that really worked.

those bass traps are nice finished and seems to be much cheaper than ACS and likes.

 

Love the 'diffuser' model. With enough of those, you could recreate Dr. Who's TARDIS in your living room :lol:

The one called 'scrunch' could look quite good painted an appropriate colour.

 

I also.
What I've noticed is that people just make there own stuff by coping it from a website or got the specs from a friend. If it then absorbs the right frequencies or others is not important but strangely (like in the voodoo section) the changes in better sound quality is always terrific.

The point about absorbers or diffusors is very important but also very personal. Diffusors also absorb and should have two charts: Absorbtion and diffusion coefficient: who reads / have these charts when they buy ar make a diffusor or absorber?

 

The Dr. Who room was exactly my thought till I found out they (like the Luna) cost £80 each Scrunch and Swell are £55 each, a bargain

As a general comment in my experience a little treatment can go a long way and it doesn't (for DIY at least) cost much. The parts for my absorbers came in at under £100 for about 9 sqm of the stuff, wood, rockwool and speaker cloth. I put in exactly no effort and the panels don't look that exciting as a result but they can be made to 'blend' if you want to.

Room acoustics is certainly a science where experience counts but I've managed to get a big improvement in my room just by reading up on the free info available around the net.

 

I used to have 3 x 4ft x 2ft absorbers on my front wall (i.e. above/behind the speakers). They were basically MDF frames holding 2in Rockwool with a 2in air gap behind and some nice cloth over the front to match the curtains. They worked well at higher frequencies and stopped the room being too live.

Then I bought some IKEA diffusers (aka. BILLY bookcases) which sit behind the listening position. The absorbers had to go as the room now sounded too dead.

I could still do with some low bass absorption but just don't have the room for SuperCornerChunks. My low bass response is much better behaved anyway since I sorted the mains out ( ).

Sorry, but it's true! Mains is very important!

 

The common misconception that seems to be running through this thread is that the application of room treatment requires turning ones living space into something which resembles a professional recording studio.

In a hi-fi context less is most definitely more. The desired effect is not a perfectly flat room response (as with a recording studio) but one where any major room anomalies are lessened. Some corner treatment and spot treatment of early sidewall reflections is all that, in most cases, is needed. As was previously pointed out a diffuse and reverberant soundfield is a good thing, it gives presence and energy to music. A heavily treated room is certainly accurate (precisely what is needed for monitoring or mixing down in the recording studio) but is far from desirable for hi-fi.

The other principle objections are that the subject of room acoustics is too complicated for the layman to understand or successfully implement. This sounds a little defeatist to me and there's no easy answer – yes it's a complex subject. There are plenty of books on the subject as some useful room modelling software such as CARA 2.1 (for around £30).

That no two rooms are the same? most have corners, walls, a ceiling and a floor!

No two rooms will have exactly the same frequency response but most rooms will exhibit the same characteristics. For instance a build up of low frequency pressure in the corners and tri-corners.

Too expensive? Well you better sell the rest of your gear and get a JVC micro because when you think about it, it's all too expensive!


And one final point. Mains cables. Reminds me of those those classic lines..

Nigel Tufnel: The numbers all go to eleven. Look, right across the board, eleven, eleven, eleven and...
Marty DiBergi: Oh, I see. And most amps go up to ten?
Nigel Tufnel: Exactly.
Marty DiBergi: Does that mean it's louder? Is it any louder?
Nigel Tufnel: Well, it's one louder, isn't it? It's not ten.

 

I dont agree that its a misconception that room treatments are an eyesore. I think both DIY and home made diffusers/absorbers are hideous. If you're able (somehow) to hide them behind rugs etc they can be border on being aesthetically acceptable IMHO.

I also firmly believe that room treatments are cumulative, and that small measures (such as corner absorbers, small panels) are frequently too inconsequential to achieve the desired result.

I believe to truly get an acoustically perfect room great lengths are necessary, and yes, it will look like a recording studio, or worse a teenagers room covered in egg boxes.

All IMO . NB when I move next I will look at room treatments, but only where they can be visually out of sight.. more difficult than it seems I think.

 

With respect bottleneck (especially if you play a PRS! :MILD: ) you're reiterating the exact misconception I was speaking of.

In a hi-fi context it's neither necessary nor desirable to heavily treat a room as with a recording studio. The result would be very dull and very flat (although phase and frequency accurate). The desired effect is one of balance between direct and reflected sound.

The reason for this is that a typical living room already has plenty of absorptive and diffusive elements – curtains, carpets, sofas, bookcases, shelves etc. The trick is to apply judicious room treatment in specific areas to counter specific room responses which add an unevenness to the overall sound.

As for bass traps and the like being incompatible with home décor, get yer frilly shirt on man and be a bit inventive!

 

Most of the DIY/Audiophile treatments are ugly largely cos they're designed by and for geeks who don't want to spend much money. There are plenty of products for the commercial side, boardrooms, conference suites etc. that do the job and are designed to be 'invisible', for a price.

 

Sorry, their site isn't very user-friendly... This is the range I was referring to: ELiTE Pro System.

Dunc

 

Dunk,
and where are the diffusor and absorbtion coefficient charts for these products?

 

As others have said, the trouble with acoustic treatments is that they are invariably very ugly. Just look at that Auralex stuff for example, who wants to have a load of weird looking bits of grey foam all over their room? Even the wooden style diffusers I've seen, whilst not ugly are still weird. It's impossible to get proper room treatments that blend in IMO.

Fiddling with the positioning of speakers, sofas, curtains and other furniture is as far as it goes for me even though I do recognize that rooms and the way they interact with your speakers have by far the largest impact on the sound of a system. Mains? :ffrc:

Michael.

 

I personally think that the Auralex stuff looks quite nice, and could work very well with carefully chosen colours. However, if your aesthetic is that of "paint everything magnolia and have impractically light coloured carpet and pine furniture" then I think you have more fundamental issues with the room than the sound...

 

Cheers Dunc They're nicer looking than the foam but not quite what I was after.

Woohoo! I can almost navigate their site now so found there's data under the Support services - Product Technical support - General data, drop down menu.

And back on to the 'blending in'. Just seems to me that most people only see treatments as panels you splat about the room. Whereas if you have the time and/or money you could build them into the room. As well as their more obvious products RPG do wood panel systems and one with a smooth seamless finish. You can get absorber sprayed onto the ceiling Sona Spray and Knauf do perforated plasterboard for covering absorbers/bass traps that can be used instead of fabric. Or if you like fabric get one of the fabric wall systems installed and put all those diffusors behind it. Obviously not as cheap tat as a DIY bit of wood and fibreglass but I'm sure those treatments will cost close to the amount some have spent on pieces of new equipment.

 

Sorry I'm late. Here's my take:

As has already been pointed out, our hearing already has built-in compensation for room acoustics, at least within the most sensitive mid-band frequencies. Over compensation here will do more harm than good.

Bass resonance is a problem that is often worth addressing. Firstly, try positional changes of the speakers/listening chair. Secondly, acoustic treatments, bass traps, etc. as has been discussed. Thirdly, parametric equalization. Note that equalization will generally only work at the listening position.

Some speakers have been designed with separate bass speakers so that they can be positioned separately from the main speakers (see my web site if interested).

Ceiling and floor reflections can be detrimental to sound quality because they reach the ears as early reflections and are psychoacoustically important. Either buy yourself a set of Seventh Veil Nonsuch 4s, which have been designed to minimize the negative effects of floor and ceiling reflections or use the 'mirror method' below.

Despite, the compensation of human hearing above the room resonance frequencies, it can sometimes be worth doing a minimal amount of absorption/reflection if your room is acoustically hard or soft. The best way of doing this is to use the 'mirror method' as this uses the minimum amount of corrective material in the optimum positions.

Simply sit in your listening position and get a friend to hold a mirror along the wall, floor and ceiling between you and the speakers - you can often do this in your imagination using the 'imaginary mirror method'. Wherever you see the drive units in the mirror is where you put the corrective material.

For absorption, judicious positioning of bookshelves and paintings/pictures is as effective as anything else. Persian carpets and the like are ideal.

 

Please tell me how technically your speakers can minimize the negative effects of floor and ceiling reflections.

Thanks

 

It was all going well up to this point Steve. I'm not trying to be disagreeable but don't you mean diffusion? I think it's important the techniques of absorption and diffusion when applied to room treatment don't become confused.

Bookshelves will reflect and scatter far more than they will absorb. To absorb a material needs to be both acoustically transparent (such that energy can pass through) and complex (such that energy is lost as heat). Open cell polyurethane foam, mineral wool and fibreglass have these characteristics.

But it doesn't stop there. To absorb efficiently the material needs to be at least as deep as the quarter wavelength of a given frequency (and ideally it's three quarter wavelength also) since this is where wavelength velocity is greatest. In the case of 100Hz the quarter wavelength alone is about 35â€Â!

So the Persian rug also, while able to absorb shorter wavelengths, is going to be unabsorptive at anything much below mid-frequencies.