Room Design

I'm toying with the idea of building an extension to increase my living area as house prices are so volatile. i'd be building upwards on a bungalow and plan for a living area, bedroom and en-suite.
of course my hi-fi will be a consideration when planning the construction, methods and materials used.
now i know suspended floors and 1st floor living rooms are problematic and in the past i've been very lucky with having solid concrete floors however i'm sure these problems can be mitigated with careful design. i'd also like as much soundproofing between floors as possible.
so my request is - any tips, suggestions, links, whatever to relevant informations would be much apprieciated.

 

If I was building a listening room I'd seriously consider installing speakers in the wall. Not sure how easy or sound-friendly it'll be but I'd certainly investigate it. IMO it may the best place for large 15" DCs.

 

Yes, they can to a large extent and it's not necessarily expensive when done as part of new build.

Silly question first - have you stuck your head through the loft hatch and checked the roof isn't built from trussed rafters? (W-shaped rrames at close centres) Pop goes your budget if so!

(I dont have time to respond in further detail right now... back later)

 

I've looked at over 200 houses on ''right move'' in my budget to get the best possible lounge. It's very hard to get what you want, architechts seem seldom concerned with audio quality.

My main concern would be the room dimensions - including the ceiling height. You can somewhat ''play'' with the absorbative/reflective qualities of the walls ceiling and floor after all.

I know felix knows a shit load more about this than me however, it's his profession I believe.

 

How far are you willing to take this? An RFZ room with full diffusive back wall would be nice if you can do it!

Maybe you should simply budget for an acoustician to design the room with you and the builders. Better than trying to design it yourself and fucking it up.

If you simply want to know the best shape for modal behavior I can give you a list of some. Nothing wrong with upstairs rooms form music IMO, in fact I have found most to sound better, probably because the floor doesn't reflect bass frequencies as strongly thus minimizing modal interaction on that axis. Brick walls are nice, as I've noticed cavity walls have a tendency to resonate, but you can build better cavity walls that also soundproof well, like Endust (IIRC) did with his room build he posted pics of.

 

If you're thinking of doing some or all the work yourself, diynot.com is a useful resource.

 

Tenson, that's really strange - I've had the exact opposite experience with concrete floors.

They seem to give you tight, punchy bass - Julians last house as an example, Robbo's as another - much better than the suspended floors I've come to know and rue!

 

Well I've never had issues with upstairs rooms, though I haven't tried it in a modern flimsy build house.

It certainly makes sense that a solid, more dense reflective floor will give more modal issues.

 

Exactly, isn't this the accepted view?

 

Life is full of common misconceptions

Case in point, most studios use floating floors. Mostly they do it to reduce transmission of vibration, but it obviously doesn't make it sound crap or they wouldn't do it. Just make sure the space between the floorboards is stuffed full of cavity insulation. You could even vary the gaps between boards to create a slot resonator.

 

You make it sound like going to the dentist

 

the budget should be pretty respectable however this isn't going to be an audio specific room just a living space with an eye towards audio.
it will all be being done professionally, my aunt and uncle are both architects so they will probably be involved at least in the initial design phase. i'm planning to address things like electrical supply, networking and hopefully some solar panels on the roof to help with rising energy costs amongst other things.
i'd rather measure twice and cut once with this and if it means spending 10k more to get it right first time then fine - although i'd prefer it not to of course.
in wall speakers aren;t really feasable. and if they were they;d be active funktion 1's - no no no get thee behind me satan...

felix i'd really aprieciate any and all input you have on this - why would those particular types of rafter cause problems and if i have them what sort of extra costs would be involved? (ballpark of course).

tenson, any links to that particular build? also my main concern is noise propogating downstairs i realise that total isolation isn;t possible but if you have any thoughts regarding construction methods or materials i'd welcome your input.

 

Sorry it was Elberoth, not Endust. Here is the link to his build - https://www.audio-forums.com/as-rediect/showthread.php?t=15669&highlight=listening+room+build

I'll post up some useful info for you to get you started once my camera battery is charged up.

 

Here is a list of favorable room ratios with regards to even distribution of room modes.


Here is an RFZ control room illustration. The walls (and ceiling not pictured) are angled such that all first reflections head to the back wall and are then diffused. There is a reflection free zone in the middle where you get only direct sound and diffuse sound from the back wall.


Here is a soundproof double cavity wall construction.


Here is a soundproof ceiling, and in the case of an upstairs room, the floor.


Here is a graph showing sound transmission loss from brick walls of certain density vs. frequency.

 

thats awesome thanks a lot. i'll copy that lot off and save it to give o the architect...

 

you mean.... I'll pass it to me aunty?

 

Neither have I, it's the concrete "boxes" that give you problems.

Re. the floor construction, is there any way you can redo the ceiling layer below as well as the floor layer above, i.e. reseilient hang the ceiling below. That's the best way to improve the insulation inconjunction with loading up the floor layer above.

If you have to do it all from above, take at look at using a properly engineered resilient mount for the floor layer such as these (download the pdf for CDM-ISO-LAT).

http://www.cdm-uk.co.uk/buildings_ISO_floor.html

These mounts can provide good low frequency sound insulation if you load them up enough...i.e. 2no. layers 18mm T&G floor sheeting with 19mm Gyproc Plank sandwiched in the middle. It all depends on the reonant frequency of the floor+mount system. You want to get that as low as possible out of the audible freq range, i.e. 10Hz. The only issue is your floor height will increase several inches. It also acts a nice little controller for room modes.

 

to be honest the current ceilings were constructed by a total muppet - rather than using proper platerboard or whatever they used offcuts to save a few quid so every few years they crack and move apart one of the things i want to do is have the ceilings re-done so this problem is minimised. so a few quid spent on doing this the right way to minimise sound transmission is definately on the cards.

 

The cheapest way to improve the ceiling layer is to use Gyproc RB1 Resilient mounts. Incredibly simple things but they work (I've tested them). Mount 1no. layer of 19mm Plank and 1no. layer 12.5mm Wallboard on the RB1 bar. Scan down the page in this link for "Gypframe RB1 Resilient Bars

http://www.british-gypsum.bpb.co.uk/literature/data_sheets.aspx

You can also upgrade the floor layer using their "SIF" floor channels.

The problem with joist floors is the floor and ceiling layers are structurally linked and that cause a nasty drop in sound insulation around 100-150Hz. Listen to a TV playing downstairs in a house and you'll hear it a low-frequency murmur that's really annoying.

 

consider replacing floor/ceiling insulation with rockwool which is heavier and more sound absorbant. rockwool is available in different weights and the denser the better and more expensive.
if you are doing an attic conversion you need to consider the ceiling/floor interface as described above but also consider the roof acoustics to prevent too much sound escaping thro the roof construction and annoying neighbours or attracting unwanted attention from passers by of your super hifi.. double thickness plasterboarding to u/side of rafters and possibly rockwool too.
just a few tips from someone who has done an attic conversion but has found out that it is alot better to have heavy bass systems contained with in a brick room
cheers