The AVF speaker reviewer's new room.

Member 96948

Distinguished Member
Okay chaps; Within the next three weeks or so I (I should say we, but lets face it, this is my room) will be taking possession of my new [-]dedicated listening/cinema room[/-] house which we've bought for several reasons, but we all know it's because of the brick built, slate roofed outbuilding that will be my new dedicated boys toys room. Scratch that - This isn't about toys, it's about pure, unadulterated listening pleasure.

I'm obviously not about to approach this build blind and have therefore been reading up on room acoustics like a mad thing and have developed my own ideas, but as I contribute a fair bit to the forum in general, I thought it only fair the forum should have a chance to contribute some ideas toward a room that will be dedicated to listening to and reviewing kit that you will read about on this forum.

As such, it will have to fulfill the dual role of a stereo and multichannel listening space as it's primary function - Viewing pleasure will be constrained to fit around the audio side, so whilst I'd ideally like to fit my current Carada Criterion 88" 16:9 screen in; If it has to give, it has to give. There will be a projector because I can't live without one, but it should be noted that the rear wall (the end with the door in) is a lightweight concrete block wall to separate the room from the garage, so there's no reason why the PJ need to even be in the room. The other end wall (nearest the side door) is a stud wall with the 1000L oil tank (it's the Fens - gas hasn't reached everywhere yet!) in and can be butchered within reason.

I'm half tempted to demolish the entire internal shell to give a clean slate start as blockwork and any amount of carpentry is well within my capability.

So, here's the picture below. The dimensions of the room (as measured as of about three hours ago) deliver about 2300cu ft (if I don't raise the ceiling) which if you believe the Americans is on the small side, but I'm not going to try and place a pool table or beer fridge within that volume. The door on the side wall has to remain as its the primary access, but the door on the short wall will be blocked up. The chamfer (approx 60deg) at the top of the side walls is due to the roof trusses, but the ceiling could be removed and/or raised/lowered to virtually the apex (about 11.3ft) of the underside of the roof. I therefore have room to accommodate whatever construction is necessary within the roof void -bass traps, the lot. The floor is mass concrete ground bearing slab, so not about to resonate or go anywhere fast.

The Sketchup:



So there you go - It's a blank canvas and I can build virtually anything within that space. The limits are that I will have to buy it out of my own pocket and I will have to build it myself. I'm pretty tasty at DIY and absolutely anal when it comes to getting things right. I may not be as fast as a tradesman, but I work in construction and will get it absolutely right.

The forum will benefit as much as I will (okay, I'll benefit more:D) but I want your input.

Post away......

Russell
 

Canti1982

Active Member
I like the fact that the room is a fairly realistic size, it seems representative of what people consider a fair listening space. In fact most probably have smaller rooms than this.

It will be interesting to see what you do with it, let us know how you get on :smashin:
 
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Amioa

Active Member
2 channel or full surround or both?

scratch that, reread it.

if you require assistance with design, I will be happy to help.
 
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Member 96948

Distinguished Member
It will be for both even if I would predominantly use it for music. I intend to wire it for 9.2 to allow for front height channels - I'm not fussed about width channels and there wouldn't be enough room for them anyway. I'm going to wire that lot into the walls, but also include an under floor conduit to account for stuff that hasn't been thought of yet. I may also wire single ended and balanced connections for at least the 5.2 channels to take care of active speakers and if interest is shown, I'd hope to include box-outs that allow the possibility of demoing in-wall/ceiling speakers too.

Russell
 
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Member 96948

Distinguished Member
if you require assistance with design, I will be happy to help.
Indeed - help in any way shape or form would be welcome.

As I say, It's pretty much a blank sheet, so my initial intention was simply to float the floor on acoustic batten and then construct a 4x2 studwork box within the existing room.

I had considered going for non parallel walls to reduce slap echoes, but after research decided that would just make the room modes harder to calculate/predict.

So my thoughts are Superchunk bass traps in Knauf RS45 for each of the four corners with more of the same used to make 1200x600x100mm absorber panels mounted at all of the first reflection points (with respect to the front stereo pair) and then play it, quite literally by ear as regards more treatment on the walls.

What I'm unsure about is the ceiling - Do I go for a cloud of more absorbers, or given that there appears to be some flexibility with respect to the void above, go for an in ceiling bass trap? If the latter, How do you go about the calculations?

Russell
 

Member 96948

Distinguished Member
Just for a laugh, based on the estate agents dimensions I did this a while ago:

I might have been a touch OTT on the Supechunk bass traps, but knowing that I am likely to build an entire studwork sub-room, I decided to scale the studwork to fit the Louden ratios available with the then thought to be fixed ceiling height.

Any thoughts?

Russell
 

Amioa

Active Member
id definately use the ceiling space to make a bass trap, check the dimensions and see what the standing waves will be but yes, you can get some pretty heavy duty bass trapping in there without compromising the room too much. you could also use the front wall and shorten the room slightly (perhaps to get the best ratio) and use the front wall as a trap too, it works well to do that. Ill see what ratio will work best within the given size, the only thing that I think would suit you better would be to look at doing something diffuse at the rear, it will open the room feel up and make its feel bigger than it really is.
 

Member 96948

Distinguished Member
Thankyou, this is the sort of advice I wanted.

I had assumed that the idea might be to (generally) go with a reflective room and simply absorb all of the first reflection points. I take it (and I am extrapolating) that you're coming it at from the live end, dead end of the spectrum?

I'm interested because after my original scriblings, I had spent a while considering QRD diffusers in place of the rear wall absorbers and maybe placing similar adjacent to the listening sofa on the side walls. In other words, placing absorbers at the first reflection points in the front two thirds of the room and placing QRD diffusers at the first reflection points of the rear third.

I'm clearly wandering around, so contributions to the issue are obviously welcome.:)

Russell
 

Darkstar_surfer

Well-known Member
Your going to build a 2300 cu ft sealed sub and sit inside it. :smashin:

Regarding wall treatment I would start with curtains, full height, full width, on all four walls. The really heavy type like you see on cinema walls. Then add base traps to augment this. We have dark brown velvet black out curtains down two walls and when I get REW working I should be able see what difference it made.

On another subject you have got to have a beer fridge. :D
Not for your personnel use of course but to entertain your fellow AVF friends you invite round for demo's. :lease:
 

Amioa

Active Member
Your going to build a 2300 cu ft sealed sub and sit inside it. :smashin:

Regarding wall treatment I would start with curtains, full height, full width, on all four walls. The really heavy type like you see on cinema walls. Then add base traps to augment this. We have dark brown velvet black out curtains down two walls and when I get REW working I should be able see what difference it made.

On another subject you have got to have a beer fridge. :D
Not for your personnel use of course but to entertain your fellow AVF friends you invite round for demo's. :lease:
i'd not cover all 4 walls with curtains, the high and mid range will be killed off, which wont make it a pleasant room to use.

as a general rule of thumb i'd split the room into 3rds, the front third as pure absorption, the middle third as a combination of diffusers and absorbers, while the final third would be diffuse. Bass traps can be added by positioning above and below the primary treatments. The reverberation time to aim for would be 0.3secs I think. Curtains can be used on the front sides to allow a bit of variable acoustic because the multi-use aspect of the room might require it, but it will all depend on final setup.
 

Amioa

Active Member
Thankyou, this is the sort of advice I wanted.

I had assumed that the idea might be to (generally) go with a reflective room and simply absorb all of the first reflection points. I take it (and I am extrapolating) that you're coming it at from the live end, dead end of the spectrum?

I'm interested because after my original scriblings, I had spent a while considering QRD diffusers in place of the rear wall absorbers and maybe placing similar adjacent to the listening sofa on the side walls. In other words, placing absorbers at the first reflection points in the front two thirds of the room and placing QRD diffusers at the first reflection points of the rear third.

I'm clearly wandering around, so contributions to the issue are obviously welcome.:)

Russell
similar to live end dead end, for 2 channel the reflection free zone type system works well but for surround channels it needs to be adapted slightly. You are on the right lines though definately.
 

Member 96948

Distinguished Member
I do hope so, but initially it's going to be a bit of a slow burner - We can't move in for at least 3 weeks.:(

Russell
 
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rex911rex

Active Member
Great to see this thread come up. I am doing almost the same but with the obligatory pool table. It was to be the gym but my ideas developed over time. Will be used for mainly home theatre and not 2 channel music. Set aside this evening for learning about room acoustics and stumbled upon this. Bookmarked



 

Member 96948

Distinguished Member
The thing I notice first about your proposed design is that you appear to have a bar at the rear of the room. The room I'm about to take over already has a brick built bar at the rear and it's the first thing I will be knocking out...:(

BTW; Have you started a thread for your build?

By way of progress on my room; The chain's solicitors tried to exchange on Friday only to be snookered by our vendor's solicitor (bear in mind that our vendor is B&Bing Mon-Fri in the mean time) who went home at 1:30pm for an early weekend. Do these leeches have no concept of a full working week, or that other peoples lives are being put on hold will they toss it off on a fixed price?:mad:

Russell
 
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rex911rex

Active Member
This building is yet to be built so I have a blank canvas. The bar at the back is to have a sink and fridge as it will also be used as an area for the kids to use as it is close to the pool. I would rather them use this area than the main house as it is closer.
 

Member 96948

Distinguished Member
Contracts exchanged today - Move in on the 25th.:clap:

Damn! I'm going to have to start taking this seriously now.:eek:

amioa has drawn up some fantastic sketchups of an intended design, but rather than embarrass both of us by nailing our colours to what will be an evolving mast, the reveal will be gradual, in much the same way as the build. Likewise, thanks in advance to Linx08 who has unbelievably offered his help based purely on the wage of sufficient tea and biccies. I suspect he'll quite literally get more than he's bargaining for*.:)

The first element to tackle will be the floor as this is what the entire structure of the room will stand on. amioa and a few people I've talked to in the past suggest that this floor should be floating in order to provide sound insulation and act as a ruddy great room wide bass trap as effectively it will be sprung.

In essence the floor is just a load of 100x47mm (4x2" in protestant) timber at 600mm centres to accept 1200x600mm T&G flooring, the spaces inbetween the joists stuffed with rockwool. The floating will be performed by rubber spacers that provide the compliance (springiness) and the usual suggestion is Auralex U-boats a purpose designed solution.

I have two problems with U-boats. One is that, based on Auralex's recommendation of one every 400mm, I will need about 150 of the little sods at £2 each, the other is that when you look into Auralex's recommendations for how many are required to support what, they immediately cop out by offering no technical data on which to base calculations.

For a spring to work, you need to know what its spring rate (load capacity) is - How much weight needs to bear on it to start it actually springing and how much will squash it flat and thus make it rigid and ineffective. You don't need to be a genius to work out that the entire weight of the walls (plus the stuff I'll be hanging on them) and ceiling will be bearing on the edge of the floor, whilst the middle will bear comparatively little except under the seating, subs (I like 'em heavy) and possibly speakers and rack where it will be a bit higher.

T'internet is a wonderful thing and it turns out that U-boats are made of 60-durometer (a measurement of permanent material deformation under a given load) EPDM rubber, the base of which is 12mm thick, so that is all you need to buy - 12mm thick EPDM of the correct density and that can easily be found on a 1.4m wide roll at about £25/m. A single metre should make about 560 so that's job done and £275 saved before I start. Job's a goodun. I just need to do a bit more reading on loadings, calculate the entire weight of the structure and bias the EPDM pads toward the higher loading areas. Not entirely scientific, but that's more thought than Auralex put into the issue.....

I also know a man-with-a-van timber trader who picks up stock direct from the docks and specializes in finding a home for seconds - packs of flooring that have had their corners knocked about either during shipping or during on/off loading. Should weigh in at about £3 per sheet and you'll never see them, so who cares?. I need about 80 sheets for a double thickness and even a rough calculation shows that the saving on U-boats just payed for the flooring. Ding dong.

For the 100x47mm timber and Rockwool, I'll just batter my suppliers in my day job, but I should see the entire floor in for the sunny side of £500 plus my labour which is free. The DIY ethos of this build is thus fully maintained

The design for the intended floor should look like this:



Any thoughts welcome as ever.:)

Russell

* I make a mean sandwich.
 
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Amioa

Active Member
have a look at acoustic flooring mat to go under the T& flooring, also look at joist tapes, plenty of those around, and much better than 'foam' that some companies sell stuck to boards, some of those foams deform and after a while the floor creaks...

ive bookmarked the thread now, so i should be able to keep up!
 

Member 96948

Distinguished Member
Well, we're in.:clap:

As is the nature of most house moves, it was less than smooth and three days on, we still feel like we are living in a holiday let - It doesn't feel like ours yet.

A slight complication is that I decided that I wasn't prepared to knock/drill holes in walls to mount my 92" screen and the associated projector so, as a result of a brief conflab with Steve Withers (our very own video reviewer), I'm now the owner of my first small screen experience; An LG 50PK590.

I have to say that as someone who has had the benefit of various plasma demos down the years, including Kuros, my expectations were fairly limited and yet I'm fairly blown away by the picture I'm now experiencing. Sure, the blacks aren't deep enough to leave you wondering where the panel is when the lights are out, but in all but the darkest scenes the in-picture contrast is very good.

I'm especially impressed by the pre-calibrated THX settings; THX Cinema is apparently the setting of choice for dark rooms, with THX Bright Room available for rooms with high levels of incident light. I have a south facing window of 8ft wide to the right of the screen and I have yet to find, even with the the low winter sun, a reason to use the bright room setting. Motion handling seems very smooth with 576i/50 (Eastenders) 1080i/50 (Rush HD - I'm a Skiing fan) and indeed 1080p/24 (Avatar) which I finished watching about 20mins ago.

Last night I watched three programs via BBC iPlayer that we had missed during the house move and if I had considered myself a stripped-out feature purist before, I was thus immediately proved wrong - The LG Netcast features are well worth the extra over the 50PK350 that I was set to buy.

The point I'm getting round to is that the LG is going to be the day-to-day screen in the house and as such, I'm going to build a floating wall for it. As the intention of buying the LG was to try and minimize the impact of AV in the living room, the floating wall will also incorporate in-wall speakers and possibly in-ceiling speakers for surrounds. I'm thinking Tannoy iDW4DC for the front three and ceiling surrounds - At £90(ish) each, they're not a huge outlay.

Any thoughts welcome, as the floating wall build is not exactly difficult and needs to be quick so I can get to building the real room. I'll start a new thread for the floater.

Russell
 

sammy the squid

Distinguished Member
Congratulations on moving into your new house Russell :) i had a 'traveller' type phase a few years ago and i think its fair to say the old gaff will truly feel yours once you've spent a fair bit of time in it and added your own personal touch:D

Really looking forward to seeing this room develope from scratch, im hoping to see the makings of a true reference room with plenty of pictures along the way. Good luck squire:thumbsup: May the dewalt be with you!

Regards

asif
 

AngelEyes

Well-known Member
I know you are going to have fun with this Russell and it is nice you are sharing the build and from the looks of it get down to the nitty-gritty/sciency stuff that is sometimes missing from these build threads too. :smashin:

I thought I would pick up on the probably minor point of your preference for height channels over width. I listened to a great interview with the founder of Audyssey and he was quite vehement that the biggest improvement would be found with the width speakers and that the height speakers made only a minor difference to the sound in comparison.

I was origianlly lead to believe that the extra speakers were to provide gimmicky 'effects' and perhaps widen the soundstage but it seems they are more about improving the overal sound quality experience as much for 2 channel as multichannel. Apparently the positions and algorithms for the width speakers were designed to emulate one of the best sounding concert halls in the US and these width speakers are there to emulate the 1st reflection points or some such hocus pocus.

If I find the link I'll send it to you, I think it may have been badger or Paul who posted the link a few months back, interesting stuff.

Anyway, I look forward to seeing your build evolve and as you know how much I like a good sandwich, am more than happy to help out whenever you need it.

Adam :)
 

cjwood555

Active Member
Just a note - recording studio suspended floors are often (normally) isolated with continuous strips of neoprene rubber - you may be able to find it cheaper than the epdm.

Chris
 

Amioa

Active Member
Just a note - recording studio suspended floors are often (normally) isolated with continuous strips of neoprene rubber - you may be able to find it cheaper than the epdm.

Chris
yes - joist tape is a good example, but be wary of tapes or strips that are too soft, in 6 months you will have creaking floorboards where the rubber squashes too much and no longer correctly supports the flooring - its a BIG problem in domestic construction but as the rubber works ok for the first couple of months, the fault is then not picked up.
 

Linx08

Active Member
Yeah, congrats Russell glad your in, we'll have to catch up soon and arrange what tea bags you need to get in :D

Linx
 

Member 96948

Distinguished Member
Sorry chaps, been a bit busy for the last few days. I take the point about rubber compressing and is in part why I intend to stick with a known grade of EPDM - It's basically the same Durometer hardness as a car tire, so it won't deform over time.

I also take the point about width channels, but in order to achieve the upper end of the 45-60deg angle required by the front stereo pair, there is insufficient room for width channels. I may just drop the idea of 9.2 and stick with 7.2 passive and 5.2 active provision. Anyway, the idea of acoustically treating a room for accurate reproduction, only to impress the sonic signature of another room via post processing seems unattractive to me at least!

In the mean time, I'm not rushing to spend hours in a sub zero room in the dark and still can't find half of my stuff, so I'll content myself with the floating wall for now, and try and crack on with the main room over Xmas, so maybe a preliminary get-together may be in order around then, no?

Russell
 

Amioa

Active Member
if need be.
 

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