Room treatment

[rockmeister]

We talk a lot about how rooms matter, and the more I hear good and bad ones the more I agree…in fact a poor room setup can ruin a decent hi fi and a carefully adjusted room can make a poor one good. But often it’s discussed as though you either have the good luck to get a good one or bad luck if not. RUBBISH. A few simple rules, a bit of furniture moving and you can easily maximise your chance to make the most of any room you use. Try it and see if you don’t suddenly have controlled tuneful bass, sound-staging, imaging and non splashy treble! Most of the following is a mix of seeing good practice at various demo rooms, and using commonly available websites. It’s NOT prescriptive. Each room will need you to use some of this, maybe all, but if you try this as a start point, then some experimentation should give you a good chance of making a real difference.
The following basic rules always apply first.
• Avoid square rooms to put your HiFi in and cubes are a no-no.
• Always fire your speakers down the long length of the room.
• The amount of damping will depend on your furnishings. An over-furnished Victorian sitting room with big heavy furniture, full length curtains, wall to wall carpets etc will be over damped. A modern studio with glass walls scant furniture and a wooden floor will be under-damped. Somewhere between these two extremes. Most of us live.

So. On the diagram below start as follows.
1. Follow the rule of thirds to find your listening position. That’s 2/3rds of the whole room length, measured from the back (speaker) wall to your ears. Place sofa at 'A' and don’t move it again!
2. Start by placing you speakers so that AB = CD in length. At this stage, the gap from the walls around will depend on room size, but try to make AB/CD more than 7ft and less than 12ft, otherwise imaging can be affected.
3. Toe the speakers in so that they are pointing over your shoulders, to meet about 2ft behind your head.
4. Play music and make judgements. Adjust the speakers first by sliding them along the dotted line axis. Back = more bass, Forward = less bass. Listen for sound-staging and imaging and stop when you have the best compromise.
5. Try some or any of E,F,G and H as follows.
E: First reflection dampers. Look at the mirror image of the room. The dampers are placed where the dotted line drawn from the imaginary mirror speaker D2 and you, comes through the wall. Try placing your wall to ceiling vinyl rack there. Or a curtain.
F: Bass traps. Bass still overpowering? Get cardboard tube carpet roll insides, paint to match walls and place in corners.
G: Rug. Should be halfway between you and the speakers. Get SWMBO to choose it!
H: Sound still bright and splashy? Hang a rug here.

Finally, pour large G&T, sit back whilst friends sit boggle eyed in amazement at the sound and say stuff like, “well it’s quite easy when you know how really”. And “Oh it was nothing, just something I knocked up you know”.

[jonjin]

so, the question is, Rock, is your room like the above?

[rockmeister]

my room's a nightmare, but I rearranged it as above and the sound was markedly better....shame that it meant having to climb over the sofa to get to the kitchen....lasted about 20 mins before I got 'the look'.
Now I know this stuff, not only will french farmhouses have to conform before going on the list but more seriously, Those going to the Pie show to exhibit might give this a go...it'll turn any hotel room into a decent place to play your kit with a bit of time and care (Heathrow exhibitors please note....esp 2/3 rule for seating!)

[Mescalito]

The trouble is, I am not the only person to livwe in the house. My wife has an equal say. And hanging carpets on the wall does not do it for me. It certainly wouldn't do it for her.

Hi fi is just part of our lives. And certainly not the most important part.

Regards,

Chris

[rockmeister]

well, you pays your money and you makes your choice. I'm just pointing out free ways to improve your listening experience, but I've no shotgun to anyones head!

[listenup]

I have an oblong room, and fire the speakers across the narrow bit. Its dictated by the furniture and doorways, but I remember reading anarticle by the proprietor of a well known hifi shop that in general terms, they found it easier to complete satisfactory installions firing across their customers oblong rooms. Probably because there is less obvious reflection.

I would love to be able to move the speakers in and out to get their best position, but thats fixed.

[Faig]

Good article Rock, and an important part of hi-fi setup.

I would add that the first reflection points include the ceiling also, but there is little one can do unless you have a dedicate room not open to wife input. .

Another point worthy of note is that 'sound-proofing' a room is different than 'accoustically treating' a room. (for those thinking aboutneighbours etc).

[Sheva]

rockmeister wrote:

• The amount of damping will depend on your furnishings. An over-furnished Victorian sitting room with big heavy furniture, full length curtains, wall to wall carpets etc will be over damped. A modern studio with glass walls scant furniture and a wooden floor will be under-damped. Somewhere between these two extremes. Most of us live.

But you can compensate for this to quite a degree by selection of kit. My room is really well damped, and Audiolab (which i've heard sound awful on certain occasions elsewhere) sounds fine, and i'm sure i couldeven get away with a Cyrus/B&W combo here. However, i'm sure thesewould be a no-no in a minimalist apartment.

Likewise, a set-up of forgiving kit in the Victorian type living room would probably be the perfectcure for insomnia.

It's just a case of balancing it out.

[Purite Audio]

Rocky just looking at the photo's of your current room, have you ever tried putting some cushions or bookcases in the alcoves either side of the fireplace? Keith.

[rockmeister]

It's a biggish room (18 x 14) and the focals don't do overblown bass anyway...the reason I chose them in fact, so no need with them pulled this far out. I still get a good equilateral triangle even with the listening sofa pushed back against the wall (as in where I'm sitting in the photo), and if I do the 2/3rds thing with the sofa pulled forward, the speakers come even further out!
Silly that I can't actually practice what I preach...my lot fires across, not down, but the theories still good!

[jonjin]

most people won't be able to have th sofa one third the way into the room... having them against the back wall is an okay compromise but agree with everything else... it's very much speaker dependent as well eg rear firing ports etc etc...

also i find having a coffee table between you and the speakers adds reflections...

[mosfet]

There’s a well written guide on room acoustics pinned at the top of the DIY section.

[rockmeister]

is 'well written' underlined there?

[mosfet]

..doh

‘tis now

[mrwippy]

Faig wrote:

I would add that the first reflection points include the ceiling also, but there is little one can do unless you have a dedicate room not open to wife input. .

In the last few weeks I've installed (actually hug) a pair of 45" square ceiling treble diffuser/absorbers in the shed and they did prove beneficial. The other factor for treble problems isn't the wall behind the listener as most suppose (usually more of a bass problem, especially if like most you can't get your listening seat into the room)but the wall opposite (behind the speakers) - I'm looking to install 3.5 square meters of foam panelling here, which is a total pain as this is the wall I project on to but still "...its all about the music...".

Basically any large reflective area should be reduced and remember a bookcase/CD/LP rack is alsomostly reflective, so may achieve very littlefor higher frequency problems as these will act as diffusers not absorbers. Rugs are much better on the walls, but most are far too thin to be very beneficial, adding a space between them and the wall will help - adding acoustic foam to the space behind will be much better. For major bass issues, a combination of tuned resonators, bass trapsand multiple-subs would appear to be the only real resolution.


Edit for typo

[jonjin]

how about cd rack with randomly inserted cds, ie not full shelves... that way they might diffract more...

edit - typos/clarification

[daz-b]

Good post this, as Im working on improving room acoustics as my new little project. My room also doubles as the familly living room. Room is rectangle approx 3.5x5. I have to fire the speakers across the shorter width of the room and my listening position is v.close to the rear wall. As cant reposition furniture or speakers been first working on taming the bass. Done a number of tests to check bass response at listening position. No mass large bass traps aloud so I went down the parametric eq route and purchased a rives parc eq unit. Its totally cured my bass 'boom' issues.

My 2nd task is with taming the mids & highs. Been looking for ages at numerous foam based panels that not only perform well but also look good in our room. Finally decided on some vicoustic panels. Not the 'best' performers out there (according to data Ive read) but pretty dam decent, but look great and thats the compromise for me and the missus. Ive got on order a number of their 'wave wood' panels and their 'cinema round premium' panels. Looking to treat the front wall(behind speakers), rear wall, ceiling and one side wall (cant do other cos its a patio bay window area). Good thing about these as the missus can get involved and make some cool looking shapes out of the panelsby mixing and matching types and position/oriontation. Will start to receivesome of the panels tomorrow.

[jonjin]

looks nice... let us know how they sound... have you got a way of room measuring before and after?



JJ

edit - anyone remember the name of the company that makes the 'borg' diffusers?

[mrwippy]

jonjin wrote:

how about cd rack with randomly inserted cds, ie not full shelves... that way they might diffract more...

edit - typos/clarification

Yes, that would be better, will promote a more random scatter, but probably not that beneficial to the overallsound . Like all these options you need to know what the problem is and then go for the best method of resolution. Again, having the Shed gives me a large degree of freedom so I can try various options.Also, because I don't have to worry about the appearance (within reason)I'm happy to use studio (cheaper) products than domestic ones, with the "looks pretty" premium added on.

Actually the rooms a real mess at the moment as I've got out a load of photographic studio reflector panels, canvas backgrounds and equipement to sell.These are all leaning against the back wall (oposite the listening position)where I intend to add the foam tiles and I have to saythe room/system hasnever sounded better.

Paul

[bmckenney]

Just a couple of add on thoughts.....

I really like Cardas math for speaker placement for a room that is rectangular.

You don't have to always fire down the length of the room. It is perfectly OK to put speakers on the long wall in a near field configuration and treat the wall behind your head. It is great for cone speakers because it reduces if not eliminates first wall reflections. Very excellent imaging actually, if you can stand the front row presentation.

Planar's have a different disperertion and its less critical to treat the first reflection.

You guys in the UK can now get GIK Acoustic products and they now have litho art on some of their products which is very high WAF.

Another important part of speaker and room interaction is the floor. Suspended wood floors, decouple of the speakers. Concrete floor, couple them with spikes. Big impact on image smearing and bass response.