room influence.

[richluvsound]

I need room acoustic advice .Can anyone help me please
Rich

[Andyoz]

What's up?

[lfh]

More specifically -- what's the problem you're facing?

[boputnam]

I need room acoustic advice .Can anyone help me please ...You suffereing from half-space loading syndrome - or even something higher-order...? :blink:

[Andyoz]

I need room acoustic advice .Can anyone help me please
Rich

Rich, probably the best advice I can give is put those 4345's in a BIG room!

Where's the problem - low, mid or highs?

[Ian Mackenzie]

Let me guess: You broke the Room.

Its a real problem. I did that in the first week I built mine. Try liquid nails or Super Glue! Running 3 inch masking tape on all the windows diagonally helps.

I realised there was a big crack right through the 12 inch slab when the beer lab dripped Guinness all down the Manet on the floor below.

Luckily the owner was away.

The cat had to licked it off by the time I got down there to check it out!
A trip to the dry cleaners and she was right!

My suggestion is avoid playing "Close Encounters" or "Jurastic Park" loud for the first time. You might wet yourself.

[Ian Mackenzie]

This is one of the best references on the www.

http://www.ethanwiner.com/acoustics.html#resources

Take some pics 360 degrees of your room and post if you can and describe what you are hearing. Also tell us the measurements of the room incl ceiling height and what the room walls are made.

[4313B]

Let me guess: You broke the Room.:applaud: Yeah... rooms are a hoot and a holler...

[richluvsound]

thanks guys,

The room is a funny shape, 15 m x 4.2 m and 8 m high . The external walls are brick 400 mm thick , the mezz floor is timber joist and chipboard flooring .There is mezz floor that runs 10 m @ 4m from floor level . I sleep ,shower and shave upstairs . One half of the roof Is double glazed. I want to remove 4 m of the mezz floor to bring the light back . But in doing so I'll create a 8 m height over my sexy beast's. There is already an echo. I wiil post pics later.I'm looking for inexpensive solutions here. I dont own this place. so be creative.
Rich

[Andyoz]

If I read it correctly, the mezzanine cover 2/3rds of the lower floor. So you have two spaces that are coupled together by a 5m x 4.2m opening?

That's a tough one as you will be getting delayed energy coming back into the main space (could be up to 1 sec after). Can you hear that if you clap your hands.

I take it the speakers are in the lower section?

[boputnam]

I take it the speakers are in the lower section?Dood... These are 4345's...!! :rotfl:

[4313B]

Dood... These are 4345's...!! :rotfl:Oh shoot! That's an easy one then! Put them face to face, disconnected from any source, in a closet with a door on it.

[richluvsound]

Andy,I was waiting for you to come and help me carry them up the stairs. :applaud: it was hard enough carring the 4333 up.
bo, we will laugh all over London. When you you coming ?
Rich

[richluvsound]

This is one of the best references on the www.

http://www.ethanwiner.com/acoustics.html#resources

Take some pics 360 degrees of your room and post if you can and describe what you are hearing. Also tell us the measurements of the room incl ceiling height and what the room walls are made.

Thanks Ian , great site and easy to understand.
Rich

[Earl K]

I dont own this place. so be creative. - Rich

- Locate the offending reflective surface and
- then place, flyable acoustic baffles in the return path of those echos.

- To make acoustic baffles, buy ;

(i) 2' x 4' x 2" , acoustic sculpted foam.
- The brand names of Sonex or Auralex are both good. They come in a variety of colors . Make sure they are fire-retardant .

(ii) Glue this acoustic foam to a lightweight backing such as Foam-Board .
- The glue I use is made by 3M. It's called "Hi-Strength 90" ."Mid-Strength 80" might be all right / but I actually forget .

(iii) Foam-board ??.
- I use 1/2" thick Gator-board from a shop specializing in making lightweight display signs ( typically set on easels and used as one-offs in corporate events to give directions, etc. ) .
- The Gator Board is similar to a heavy duty "Foam-Core". Whereas foam core has a lighter-weight paper covering both sides of the foam-core / the Gator-Board is built with a heavier weight covering made from paper-board or lightweight box-board. Gator-Board is typically used as backing for larger / temporary signage .
- Gator-Board can come in fairly large sizes. I own flyable acoustic baffles as large as 6' x 8' ( though more typically, I use 2' x 4' or 3' x 4' baffles ) .

:)

[Ian Mackenzie]

I assume you are running the 45's the long length of the room.

There are ideally a few possibilities but we will needs to see pics

You might be able to run them the short length to help minimise the echos. If you are running the long length the return echo will be off the far wall and the roof. You could partition the open side (making 6 x 4m) with some DIY panel absorbers like Earl mentioned on the open side and the opposite wall. The build some diy diffusers and stack them in an array at the front and rear of the room.

You will need to experiement a bit and work away at it. If you go the diy route it will be quite reasonable.

http://www.srlaudio.com./customer_comment_pdfs/WoodsYI.pdf


http://www.srlaudio.com./acoustic_images/SRL%20Diffuser%20Panel%20Description.pdf

http://www.srlaudio.com/acoustic_images/diffusion_panel_%20catalog.pdf

http://www.mhsoft.nl/diffusor.asp#calcul

The moral of the story is don't go mad just with absorbers.

Ian

[Guido]

Richard asked me to post these pics of his room(s)

[Guido]

More

[Earl K]

Yeh, those acoustics will suck . :o:

& Yes, "Room Treatment" is in order . The more the merrier ( better ) :D

Off-Hand, at this point / I would commit my "treatment-resources" on a percentage basis of 75/25 ( the absorption to diffusion ratio )



:)

[Mr. Widget]

Yeh, those acoustics will suck.Oh yeah!


"Room Treatment" is in order . The more the merrier ( better ) :D
Ditto!



Off-Hand, at this point / I would commit my "treatment-resources" on a percentage basis of 75/25 ( the absorption to diffusion ratio )
I personally think most rooms will sound best with a 75/25 ratio... in this case, I'd go with heavy duty absorption on as many surfaces as you can afford financially and aesthetically. Sonex 3" thick panels by the carton would be a good start... alternatively, you could make up some fiberglas panels and conceal them behind heavy drapes or other decorative solutions.

Widget

[boputnam]

I assume you are running the 45's the long length of the room.:no:

They are facing across the far-end of the room - look closely at the right-hand wall, here...

I personally don't see the issue. I routinely have to deal with an 8-piece rock&roll band running their amps at 11 in rooms with far less treatment than this! :rotfl:

[Ian Mackenzie]

:no:

They are facing across the far-end of the room - look closely at the right-hand wall, here...

I personally don't see the issue. I routinely have to deal with an 8-piece rock&roll band running their amps at 11 in rooms with far less treatment than this! :rotfl:


I agree Bo. If you can't get it up to 11 that really sucks!:D

But where is his listening chair?. A bit more data is required.

[Earl K]

alternatively, you could make up some fiberglas panels and conceal them behind heavy drapes or other decorative solutions.

I agree with that concept overall / though I don't know all the drawbacks that one would encounter by bringing fiberglass into the home environment .

(i) I just spent the last 4 days doing sound for AGMs ( Annual General Meeting ) in a 350 seat movie theatre . The theatre chain was Cineplex Odeon ( I think ) .
- Anyways, I love what they're able to achieve with their minimal treatments. ( they really have it down to a science )
- The theatres' acoustics are quite "dead" / though not completely .
- These theatres start as concrete boxes with a raked floor .
- Apart from all the plush seating , the walls are "partially treated" with what appears to be open weave burlap covering a tighter woven wrap that completely seals in, 1" High Density fiberglass board ( 2' x 4' ).
- These panels are then fixed to the wall. They somewhat follow the rake of the seating ( ie climbing when the floor contour climbs ) .
- If I remember correctly, they never reach more than 2/3 up the side walls.
- It's worth a ticket to the theatre to check this approach out for ones-self . ( take a small mag-light )

(ii) These panesl could be made quite easily / though I would want to research the inner liner material since it needs to be permeable to sound while still retaining those glass fibers .

(iii) I really liked the aesthetic of what is achievable with ths approach / since a lot of custom coloring is doable .

(iv) Price wise, I don't know how the fabric/fiberglass approach compares to acoustic foam ( on a square ft basis ) / It would be interesting to know .


:)

[lfh]

I just did some "napkin calculations" for an old school LEDE (Live End Dead End) inspired approach (attached). The 1:st order reflexion points are marked by circles. Place absorbtion at the ones marked by 'a', e.g. 4" Auralex slabs (possibly with air gap for increased LF absorbtion). You could also treat the 1:st order points in the ceiling (midway between you and the speakers) with diffusors or absorbers (your choice).

With the original geometry (15 m length), the reflected wave will arrive about 64 ms after the direct sound, i.e. above the 50 ms that constitutes the critical limit for echos. OTOH the level will be about 18 dB down (assuming spherical propagation), and the wall has shelves etc acting as diffusors, so it may or may not be troublesome in practice.

A new wall at 6 m from the original rear wall will work just fine -- rear reflexes will arrive around 31 ms after the direct sound at -13 dB, i.e. outside the 20 ms gap recommended for LEDE (but well within 50 ms).

Don't add too much absorbtion (in particlar not too much HF ditto)! It more or less consensus to reduce early reflexes (within 15~20 ms of the direct sound) to 12~15 dB below the direct sound. Current thinking is that the preferred approach (if the power response of the speakers is "decent") to achieve this is to work with angeled walls (to redirect the specular reflexes) and diffusors (to scatter the reflexes) rather than just absorb the off-axis sound. The reason for that is that a diffuse sound field (with the "right" amount and timing of the reflexes) is needed to obtain spaciousness. Sometimes absorbtion is called for though (e.g. in this case with the monitors at hand and the short distance to the side walls), but still is should not be overdone, and the absorbtion put where it actually is needed.

As to "bass traps" the most efficient method is to use diaphragm (panel) type absorbers, since porous ones get impractical wrt size.


HTH,
Fredrik
(Disclaimer: It's late night over here now, and I didn't double-check my calcs -- the principles should be clear though)

[lfh]

John Storyk (see another recent thread about Electric Lady) nowadays builds control rooms where the monitors are located at the long wall. Here the distances to the side walls should be long enough to delay and attenuate (spherical propagation "loss") sufficiently (in principle easy to do with your room). The rear wall should in this case be fitted with massive diffusors, however. The new RPG low profile skyline could be a good choice -- but cheap is not the word that springs to mind (you can take the panels with you when you move, though). A large and well filled bookshelf is a low bucks alternative.

HTH,
Fredrik

[lfh]

I have heard the following rule of thumb from an experienced source (world class studio designer):

"50% untreated, 25% absorbtion, 25% diffusion" (i.e. a 50:50 ratio between absorbtion and diffusion)

As to RT60, shoot for 0.3 - 0.4 s (easy to estimate and measure).

Over and out.

[Ian Mackenzie]

I am working on a similar project with my listening room and will post some details when I have it set tup.

[richluvsound]

Guy's , I found this site : www.customaudiodesigns.co.uk - The prices seem reasonable. With a budget of 500 quid to buy stuff from here and some diy absorbsion panels and a few pointers from the boys with the experience I'll get it sorted.The diffusers I'll build. Could be an interesting project and possibly useful for others here. Thanks for your imput.
have a lovely sunday.
Rich

[Andyoz]

Rich,

With your skills you could build everything yourself. I wouldn't buy any proprietary products.

I have programs that will give you the designs for any type of QRD (diffuser) you could ever want.

The earlier posts are spot on. Set up gear along the long wall, tjis will minimize the strength of side wall reflections. These are particualry important. Reflections from the ceiling and floor are less important (it relates back to the hearing human hearing mechanism that is more sensitive to lateral reflections from the side as apposed to in the vertical dimension).

The diffusers are best for the rear walls.

Golden rule is not to overdo it with absorption...and don't buy that profiled foam stuf that goes on the walls...yuke!

[richluvsound]

I cant stick a wall at 6m I could hang a partition @ 5.4 m though . I'll post some drawings and we can have a go . By the way the Bryston is sick !:banghead: Rich

[lfh]

Here I'd start with a 2.5 m triangle according to the fig (to get enough front/ back wall clearances). With this geometry the side wall reflexes are sufficiently delayed and attenuated for operation without diffusors at the corresponding reflexion spots.

Let's await your drawings before digging deeper into this.

So far,
Fredrik

[boputnam]

I want to remove 4 m of the mezz floor to bring the light back . But in doing so I'll create a 8 m height over my sexy beast's. There is already an echo. It seems most are focussing on the lower floor - I've been intrigued by this issue...

Is it possible to have some linen fabric art on frames of ~12cm depth being approximately +4m height and stuffed with absorbent material, hung so they straddle the break between lower and loft floors? This would reduce direct refections into the loft (and versa-visa...).

[richluvsound]

bo,
if you go back to pics you can see a large yellow sculpture hanging horizontally . That was designed to be vertical suspended by stainless tensioned cables. I was thinking of stuffing it,covering it and hanging it verical in the gap- its 4.5 m high. Would it have to be symmetrical. Also, I have to keep the long walls free to paint on . I need to keep the 45's on the back wall. I realize I will need to be able to remove any side wall attachments when painting and put them back for listerning and HT . I also need the space build an anglo-german project in the very near future . So compromise is the virtue here.

Rich;)

[Andyoz]

You really need to clear out some space (fast) so I suggest you give me the 4435's for £500...:)

I'm always here to help!

[boputnam]

if you go back to pics you can see a large yellow sculpture hanging horizontally . That was designed to be vertical suspended by stainless tensioned cables. Ah...

Looking at that now, I'd actually make two or three more just like it, leave them horizontal and space them evenly across the ceiling of the listening area. You could cover them with fabric and stuff them with fiberglass. They'd make cool diffusers/absorbers. Fiberglass, while a hassle, is best because it will maintain shape and not slump or decrepitate.

Then, I'd make a large artsy hanging for the tall wall shared by the loft and listening area. It could be done two (or more...) ways:

- covered with linen and left either the color of the fabric or gently washed with water-based paints (you do not want to shine the surface). It needs be permeable and stuffed with fiberglass.

- covered with anything, even a painting could work, stuff the rear with fiberglass but mount it with a ~8cm gap between it and the wall. This would absorb sounds behind it. This would be more problematic, depending on how reflective (bad) the face is.

We built simple absorber panels like these and spaced them across the walls and ceilings of a bar we annually reunion at. The room had been unusable - now it is the place to play.

[Ian Mackenzie]

I hope the power amp is okay.

(Sounds the 45's have claimed a scalp)

Ian

[richluvsound]

Hi Ian,
Bryston.... I heard such good things. It might be great on LF and HF but what about the mid ? Its not for my 45's . I bought to run the 4333a's for which it does the job.Anyway the SAC's should be here next week . I have flipped the monsters down the room. for the time being . It sounds pretty bloody wonderful. Although not ideal, its solves the standing wave issue for the moment. I need to finish the kitchen and then tackle the room acoustics. And then my CC man in Germany needs some boxes bashing together. The Pass project is slipping down the list fast. I read one of your posts about bi-amping the 45's. I'll wait until I can get a really good xover built..... How busy are you ??????.

Rich

[Ian Mackenzie]

Hi Ian,
Bryston.... I heard such good things. It might be great on LF and HF but what about the mid ? Its not for my 45's . I bought to run the 4333a's for which it does the job.Anyway the SAC's should be here next week . I have flipped the monsters down the room. for the time being . It sounds pretty bloody wonderful. Although not ideal, its solves the standing wave issue for the moment. I need to finish the kitchen and then tackle the room acoustics. And then my CC man in Germany needs some boxes bashing together. The Pass project is slipping down the list fast. I read one of your posts about bi-amping the 45's. I'll wait until I can get a really good xover built..... How busy are you ??????.

Rich


I think you know the answer to that question..don't ask! (your 3rd on the list)

On a the acoustics front I have been dabbling in information overload and I must say it does not pay to spend too much time just dwelling on it.

I have resolved to buy eight 3 inch 24'' x 24'' foam tiles to help absorb some mid band issues on the upper area of one side wall..the other has some new heavy curtains (over balcony windows).Also on the list are four 6 inch x 24'' x 24'' broadband absorbers that I intend to experiement with for controlling early reflections near the speakers and behind the listening position. There will also be a fair bit for saw dust over the weekend while attempting my prototype QRD diffusers. The icing on the cake will be a very narrow band tunable parametric EQ built into a new class A active crossover.

[Ian Mackenzie]

I read Doug Self had hand in designing the new Cambridge Audio 840A.

Care to comment.

I wil post the flyer if interested. He has kept his age well..nearly as well as me (sezz I)

[Earl K]

Rich,

Since at this point in your life you seem to move around a lot and therefore experiencing various acoustic environments , I feel that you would benefit greatly by owning a copy of F. Alton Everest(s)' The Master Handbook of Acoustics . ( the pic is a clickable link to Amazon.com )
http://g-ec2.images-amazon.com/images/I/51CZ0B4XG3L._BO2,204,203,200_PIsitb-dp-500-arrow,TopRight,45,-64_OU01_AA240_SH20_.jpg (http://www.amazon.com/exec/obidos/ASIN/0071360972/102-5843832-0468158)

- There is a ton of info in there that you may not want to get into / otoh / there's stuff in there that will be useful for the rest of your life .
- It's a cheap investment for a great resource to a quite complex field of study .

- I own the second edition .
- I don't own ( & therefore haven't read ) the much more expensive book that was recently published by RPG, but here's a link to it. It's authored by Trevor Cox & Peter D'Antonio ( of RGP Systems ).

http://ec1.images-amazon.com/images/I/41Y264HKV8L._BO2,204,203,200_PIsitb-dp-500-arrow,TopRight,45,-64_OU01_AA240_SH20_.jpg (http://www.amazon.com/Acoustic-Diffusers-Absorbers-Theory-Application/dp/0415296498/ref=sr_1_1/103-9607338-1260626?ie=UTF8&s=books&qid=1179327496&sr=8-1)

:)

[richluvsound]

I read Doug Self had hand in designing the new Cambridge Audio 840A.

Care to comment.

I wil post the flyer if interested. He has kept his age well..nearly as well as me (sezz I)

Not sure how I should take that ! Or perhaps Cambride has a better reputation down under. Cambridge is sold by Richer sounds. A chain that predominately caters for entry level audio buyers. I understand Doug was involved greatly with Cambridge early on , but I was unaware they had made any significant contributions in recent years. But, as being as it's you i'll suspend my snobbery, open my mind and give it a read if you point me there.

I'll google Doug Self. Can he build me my crossover?:D

Rich

[richluvsound]

Many thanks Earl ,

I just ordered it . I ordered the first one you suggested," master handbook of acoustics "
Rich.

[lfh]

http://ec1.images-amazon.com/images/I/415YCP070BL._BO2,204,203,200_PIsitb-dp-500-arrow,TopRight,45,-64_OU01_AA240_SH20_.jpg (http://www.amazon.com/Recording-Studio-Design-PHILIP-NEWELL/dp/0240519175)

Also the white papers by Floyd Toole available at Harman's site is mandatory reading.

[Andyoz]

Yes, "Recording Studio Design" is excellent. Philip Newell does meander a bit when he writes but he has a wealth of experience.

I think Everest's book is the best all round introduction as a first read. I still refer to my copy all the time.

Philip also has written an excellent book on Loudspeakers.

http://www.amazon.co.uk/Loudspeakers-Reproduction-Philip-Richard-Newell/dp/0240520149/ref=sr_1_2/203-0810564-0502304?ie=UTF8&s=books&qid=1179349856&sr=1-2

[richluvsound]

you are all Top Geezers:D

Rich

[boputnam]

The icing on the cake will be a very narrow band tunable parametric EQ... I would suggest the Meyer CP-10 (http://www.meyersound.com/products/processor_drive_systems/cp-10/). I have a gaggle of these in the shop - all back from Meyer Sound for routine maintenance. As soon as I get a gig breather, I'm planning to swap out the home KT DN370 and go this route.

The incorporation of the Bryston xover and TAD TD-2002 CD's has mitigated the most eggregious of my system and 4345 frequency response - I need less EQ in fewer places, and fine control. Those of you who know the CP-10 will "get it"...

[Thom]

It doesn't look like it would go with anything else but when trying to please a wife also Asian rugs can help. I'm not suggesting that they are as effective as acoustic foam but they look nice. If you buy a nice looking one. I was suggesting hanging them. Many people do.

[Ian Mackenzie]

I would suggest the Meyer CP-10 (http://www.meyersound.com/products/processor_drive_systems/cp-10/). I have a gaggle of these in the shop - all back from Meyer Sound for routine maintenance. As soon as I get a gig breather, I'm planning to swap out the home KT DN370 and go this route.

The incorporation of the Bryston xover and TAD TD-2002 CD's has mitigated the most eggregious of my system and 4345 frequency response - I need less EQ in fewer places, and fine control. Those of you who know the CP-10 will "get it"...


I don't get it. I tort you said ya was a user being a them there Rock doctor?
Gaggle of them para diddle tweakers will give you RSI in your oversize mitts Dude.:D

[Ian Mackenzie]

Bo,

Are you still running the stock 3145 networks?

Apparently as noted elsewhere.

In view of this I would certainly cross reference post 46 to the colouration threads where it belongs.

Ian

[richluvsound]

The books you guys suggested arrived today. Master Hand Book and the Phillip Newel on Loudspeakers. Hours of fun and blank expressions.
thanks, Rich:o:

[Andyoz]

Philip Newells book is very good. Not too technical and he seems to cut through the BS and get to the point.

His description of the benefits of 'horn' designs was a revelation to me.

[boputnam]

I don't get it. I tort you said ya was a user being a them there Rock doctor?
Gaggle of them para diddle tweakers will give you RSI in your oversize mitts Dude.:DUh, I missed this. Sorry.
Uh, I don't get this. Sorry.

The CP-10's are dispersed through the rehearsal studio (2), shop (1), small system rack (1) and loose. A bit of a luv affair... :o: