Sound Proofing...When do you have enough?

[Silent Screamer]

18 hours ago, smithc4w said:

***. Also see https://rel.net/reference_system_listening_golden_mean_sound_room/  this just came into my inbox from REL and there is a link to a PS Audio article on room design in it ***.

 

A couple of points regards room shape -

 

It is quite common in higher end (and not so higher end) recordng studio control rooms to have non parallel walls etc to control standing waves, flutter etc, Google recording studio control rooms design or similar to see some.So it does work. In most of those examples cost is high though. It is important in these examples  as it is rhe starting point of those recordings you purchase.

 

A lot of acoustic design principles go well back in history - the design of churches, for instance, was not done by accident but by learnt craft ( certainly before computer modellng!). They learnt what they needed to build to acheive the sound they wanted, which is what we are doing now with the aid of computers - so you still need to know what you want as an outcome.  

 

I installed and commissioned a studio/ control room in Hobart back in the mid 80’s designed by Sandy Brown Associates from London in which the control room had non-paralel walls and a magnificent bass trap up into the ceiling at the back.Probably done without computer modelling (as we know it today). It was a nice acoustic space (no longer exists unfortunately)

 

The photo on an earlier postis of the control room at the Federation Concert Hall in Hobart, a much simpler fitout - the acoustic treatment for that was about $20K.

 

Good reasonably priced non-foam absorbers, diffusers and base traps are made by Primacoustic, primacoustic.com. They are made of fibreglass and paintable or could be covered in acoustically transparent cloth. Distributed by Ambertech. Certainly cheaper than the Aro Technology fitout by far..

Throughout the course of the thread different opinions have been offered on trying to achieve perfect golden ratios room. In the last few days I have come across a upper floor / roofing solution I am very interested in. Rather that try to design to golden ratios I am trying to see if I can design the room around the upper floor. Obviously I am not going to totally dismiss the golden ratios, but as @davewantsmoore pointed out, you don't need a perfect room to start with, you only need a "not bad" room.

 

With the new roof / floor in mind I have extended the dimensions of the HT room a few more hundred mm to 9 meters long and 6.9 meters wide. I am also looking to run a beam across the room in the middle for greater floor / roof support. I decided against tapering the walls as there appears to be minimal gain for the extra effort, but I will slope the roof to cover the low hanging beam in the middle (kill two birds...)

 

Rather than waste room size I will look at balancing internal room size losses, against improvement in room modes, but I won't be going crazy trying to get a perfect room like I was planning before. I just need to make sure it is not a bad internal room design, i.e multiples of another wall.

 

[Guest Peter the Greek]

42 minutes ago, Silent Screamer said:

Seen mineral wool mentioned in many American videos, did you buy it here?

Its "rock wool" or "rock mineral wool"

[Silent Screamer]

Been trying to work out how I could capitalise on the hollow sections of the floor. I might be able to push old air out of the room using them. Same in my workshop.

 

[almikel]

6 hours ago, Silent Screamer said:

run a beam across the room in the middle for greater floor / roof support.

do it only if needed - what do those things span?

 

6 hours ago, Silent Screamer said:

I might be able to push old air out of the room using them.

I like the lateral thinking   - but be careful not to introduce a flanking path

[Silent Screamer]

1 hour ago, almikel said:

do it only if needed - what do those things span?

 

I like the lateral thinking   - but be careful not to introduce a flanking path

From their website they can span up to 20 meters. I am only planning to span 9 meters (12.8 meters total), but being that there might be some deflection due to bass, I would rather the span was shorter.

Edited January 25, 2019 by Silent Screamer

[Guest Peter the Greek]

You really want flexible,  lined duct inside damped mass. Also, with smaller pipe comes higher velocity = bad

[Silent Screamer]

1 hour ago, Peter the Greek said:

You really want flexible,  lined duct inside damped mass. Also, with smaller pipe comes higher velocity = bad

I was thinking possibly PVC pipe could be run inside them. Could also be handy for running ducted vacuum from room to room.

[Guest Peter the Greek]

Personally,  I wouldn't. I don't think ducted vacuum is a good idea either. The less penetrations the better and as I say you want larger ductwork,  say 300mm. This starts getting quite technical,  you can either engage a HVAC engineer,  or just oversize everything and hope for the best

[The Bluesman]

I'm a Plasterer and been in the trade for a long time now, done many sound proof rooms, 2 layers of 16mm Fire check  works really well, ad Rockwool insulation and you are there, don't forget doorways they need to be sound proof as well, I've done jobs where the owners have gone to the trouble of double doors, all of this eats into precious space and costs

[almikel]

16 hours ago, Silent Screamer said:

From their website they can span up to 20 meters. I am only planning to span 9 meters (12.8 meters total), but being that there might be some deflection due to bass, I would rather the span was shorter.

9 metres is less than half, 12.8 still well and truly within spec.

You won't get deflection of the concrete from the bass, maybe 20 people jumping up and down in time in the bedroom above would make it deflect? If you make the concrete deflect due to bass, you've at least ruptured your ear drums, or worse. 

You were planning an inner skin/ceiling on the underside of the concrete which absorbs most of the energy (well it will if it's designed/working properly).

 

IMHO putting a beam in where it's not needed is the "wrong" sort of over-engineering - spend more on professional design or Greenglue or Fyrecheck or a baffle wall or....more comfortable chairs...or...

 

cheers

Mike

 

[Silent Screamer]

6 hours ago, Peter the Greek said:

Personally,  I wouldn't. I don't think ducted vacuum is a good idea either. The less penetrations the better and as I say you want larger ductwork,  say 300mm. This starts getting quite technical,  you can either engage a HVAC engineer,  or just oversize everything and hope for the best

I am rethinking this... For air in and out of the room, I think I would need to put too many holes in the concrete to be viable as an air duct, plus as mentioned it could also cause sound issues in the room by not being using flexible hose, or air speed issues due to limited size.

As for ducted vacuum I was planning on doing this anyway. The benefit of the hollow core is I only need to cut through the top layer to duct the pipe work into the hollow which can then be piped to the far side of the house where I plan to collect it into one main collection pipe connected to the vacuum system. If I go with a conventional poured in situ concrete floating concrete slab I need to drill all the way through the slab then drill through walls as well. Another really need benefit of hollow core is for plumbing in the shower.

 

[Silent Screamer]

6 hours ago, The Bluesman said:

I'm a Plasterer and been in the trade for a long time now, done many sound proof rooms, 2 layers of 16mm Fire check  works really well, ad Rockwool insulation and you are there, don't forget doorways they need to be sound proof as well, I've done jobs where the owners have gone to the trouble of double doors, all of this eats into precious space and costs

Nothing stops me making my own special doors for the HT room from 16mm board.

[Silent Screamer]

27 minutes ago, almikel said:

9 metres is less than half, 12.8 still well and truly within spec.

You won't get deflection of the concrete from the bass, maybe 20 people jumping up and down in time in the bedroom above would make it deflect? If you make the concrete deflect due to bass, you've at least ruptured your ear drums, or worse. 

You were planning an inner skin/ceiling on the underside of the concrete which absorbs most of the energy (well it will if it's designed/working properly).

 

IMHO putting a beam in where it's not needed is the "wrong" sort of over-engineering - spend more on professional design or Greenglue or Fyrecheck or a baffle wall or....more comfortable chairs...or...

 

cheers

Mike

 

 

Fair comment... I have been trying to think about how the precast walls might go up and how to hold them in place while the rest of the walls go up. The precast walls would need to be in place before the higher level garage footings are poured. The precast wall would act as a side wall for the concrete footings to be poured.

 

 

Edited January 26, 2019 by Silent Screamer

[almikel]

9 minutes ago, Silent Screamer said:

As for ducted vacuum I was planning on doing this anyway.

I'm with PtG - I don't like ducted vacuum as a concept - sure install it in the rest of the house, but installing ducted vac into a custom theatre room that you've spent $1000s on isolation just introduces a flanking path.

 

mike

[Silent Screamer]

Just now, almikel said:

I'm with PtG - I don't like ducted vacuum as a concept - sure install it in the rest of the house, but installing ducted vac into a custom theatre room that you've spent $1000s on isolation just introduces a flanking path.

 

mike

I hadn't really thought about ducting for the home theatre room, but for that I would either manually vacuum, or run a tube down to ground level. I won't be listening to any music while vacuuming is being done upstairs.

 

How much of a concern would the pipe work inside the concrete be when it also has another ceiling inside the HT room? Seems like there would be a fair buffer between the sound and a plastic pipe inside the concrete floor.

[Silent Screamer]

The only carpet that side of the house upstairs is the master bedroom directly above the HT room.

 

[almikel]

2 minutes ago, Silent Screamer said:

How much of a concern would the pipe work inside the concrete be when it also has another ceiling inside the HT room? Seems like there would be a fair buffer between the sound and a plastic pipe inside the concrete floor.

agreed - that's not a flanking path

3 minutes ago, Silent Screamer said:

manually vacuum

good idea

 

4 minutes ago, Silent Screamer said:

or run a tube down to ground level

equals flanking path - don't bother.

Just for comparison check out the baffling used for fresh air intakes for HVAC in an isolated room...

 

[Silent Screamer]

2 minutes ago, almikel said:

equals flanking path - don't bother.

Just as easy to manually vacuum, especially since it a big room on a different floor.

[Guest Peter the Greek]

1 hour ago, Silent Screamer said:

Nothing stops me making my own special doors for the HT room from 16mm board.

I did that, its not worth the effort IMO. Better off with two communicating fire doors with seals - works better, simpler, easier to use etc etc. I'll not do this again. 90x45 frame, filled with 10mm layers of MDF with GG in between. The seals were the short coming of this.

 

[almikel]

25 minutes ago, Silent Screamer said:

or run a tube down to ground level

to make that suggestion, as someone about to spend many $1000s on a custom room I would suggest 2 things:

1. as mentioned in the first page of this thread, go back and re-read everything on the soundproofing site starting with https://www.soundproofingcompany.com/soundproofing101
2. engage a professional for your room design

You're about to spend a lot of $K - a few $K spent on good design upfront IMHO is excellent risk mitigation for providing a good result for your room.

I'm sure @Peter the Greek could provide some suggestions...but in the meantime bury yourself in the wealth of information available on the Soundproofing site.

 

mike

 

[Silent Screamer]

42 minutes ago, almikel said:

to make that suggestion, as someone about to spend many $1000s on a custom room I would suggest 2 things:

1. as mentioned in the first page of this thread, go back and re-read everything on the soundproofing site starting with https://www.soundproofingcompany.com/soundproofing101
2. engage a professional for your room design

You're about to spend a lot of $K - a few $K spent on good design upfront IMHO is excellent risk mitigation for providing a good result for your room.

I'm sure @Peter the Greek could provide some suggestions...but in the meantime bury yourself in the wealth of information available on the Soundproofing site.

 

mike

 

Well I wasn't suggesting running it down a wall inside the room, was thinking possibly under the ground and then through a wall. But yes well worth reading up on the website.

[almikel]

 

1 hour ago, Silent Screamer said:

But yes well worth reading up on the website.

even more so with your comment below

1 hour ago, Silent Screamer said:

Well I wasn't suggesting running it down a wall inside the room, was thinking possibly under the ground and then through a wall.

whichever way it's routed that's a (edit) direct flanking path - sound can travel both ways through the vac piping system.

Edited January 26, 2019 by almikel
clarification

[Silent Screamer]

1 hour ago, almikel said:

 

even more so with your comment below

whichever way it's routed that's a (edit) direct flanking path - sound can travel both ways through the vac piping system.

ok well just easiest to not have one in the HT room at all. Manual it is.

[Silent Screamer]

Worked out a way to do the vacuum plumbing for the rooms with carpet (except the HT room) without cutting through the floor. Means a hole through one wall but that can't be helped. This way it can be installed after the house is built.

 

Edited January 26, 2019 by Silent Screamer

[Guest DrSK]

I’d recommend just hiring a professional acoustic engineer. Everything you are trying to design for noise control is basic bread and butter that can be completed by a recent grad with some guidance and basic software for a room. There are also plenty of traps with using cavities in wall and ceiling construction etc that can make matters worse if they are not tuned correctly you should be aware of. They can most easily be predicted with software now. 

 

In terms of budget, I just designed an entire 200 seat school performance space and function rooms, music teaching spaces etc to meet environmental criteria at a residence 50m away as well as the stage design and internal acoustics for around the $14k mark.

 

I reckon you could get your room sorted including environmental measurements for under $3k. Less if you just want to do the best you can with the space you have rather than meeting set targets and use the volume control to please the rest of the family and neighbours.

 

For internal acoustics and music don’t make the mistake of a dead room. Most people have too much absorption that is unevenly distributed and unbalanced for the room response. Start sparse as it is far easier and cheaper to add more than remove carpet etc. RTs are normally reasonably short anyway (say 4.5m by 7m room) and it is far more important to have good speaker positioning and control of reflections in terms of magnitude and time delay. PS Audio’s test room is a good lesson, small space packed with diffusers and book shelves for more diffusion.

Edited January 31, 2019 by DrSK