Acoustics advice for a dedicated HT room

[bujji]

Hello everyone,

I am a newbie at acoustics and trying my hand at setting up a dedicated AV room in my under construction house (wiring stage) in Hyderabad and am looking for recommendations from fellow forum members and experts.

I could squeeze in a 12'x15' room for the HT. The walls are of regular clay brick/cement construction with a false ceiling at 9' high (regular gypsum - channels laid, pending boards)- windowless and a single teak wood door. I do not have the budget for any hifi equipment now but thought I would rather wire the room and invest in making it acoustically good, when I can, given that it is in construction phase. I plan on buying the equipment in installments over the next couple of years. Movies, music and web series is the primary use case. I have scourged the net and came up with a plan for making the room sound good. Here are the details:

- Build a 'room within a room' with wooden/aluminum frames on all four sides and stuff them with Roxul Pro370 Safe and Silent Stone Wool 80kg/cu.m. They come in 50mm slabs and it was suggested to make the layer 100mm thick and leave a 10 cm gap between the brick wall and the wool.

- For the Ceiling, Two layers of 1" Thermocol sheets directly stuck to the concrete ceiling to help with heat and a little bit of absorption. Stuff a 100mm layer of the same Roxul rock wool to rest on the inside of the false ceiling channels before the gypsum boards are attached.

- Floor is thin wood rafts stuck over vitrified tiles. Planning to put a rug in front of the TV.

- Plan cabling for a 7.2.4 atmos setup. Already planned for Projector.


Current Equipment (not much)

- TCL 65" 4K UHD LED Smart TV
- VIZIO 28" 2.1 Soundbar (SB2821-D6) with a satellite sub-woofer


I am not sure if I am going for an overkill and risk making the room sound dead - some say 'just put in corner Bass traps and you will be good'. My questions:

1. Is it sufficient for good acoustics or is there anything you would want me to change?
2. Should I have the front wall (behind the TV) also stuffed with Roxul.
3. How should the cover the frames on the walls after I install the rock wool inside them?
4. I would be losing almost a foot of space on each side with this setup - anything I can do to make occupy less space?
4. Anything else you would suggest.


Thank you in advance.

 

[Nikhil]

Welcome to the forum!
Good luck with your home theatre build!

Regards


.

 

[swamytk]

Welcome @bujji! Wish you all the best for your Home theatre!

 

[prateekatasniya]

Hello everyone,

I am a newbie at acoustics and trying my hand at setting up a dedicated AV room in my under construction house (wiring stage) in Hyderabad and am looking for recommendations from fellow forum members and experts.

I could squeeze in a 12'x15' room for the HT. The walls are of regular clay brick/cement construction with a false ceiling at 9' high (regular gypsum - channels laid, pending boards)- windowless and a single teak wood door. I do not have the budget for any hifi equipment now but thought I would rather wire the room and invest in making it acoustically good, when I can, given that it is in construction phase. I plan on buying the equipment in installments over the next couple of years. Movies, music and web series is the primary use case. I have scourged the net and came up with a plan for making the room sound good. Here are the details:

- Build a 'room within a room' with wooden/aluminum frames on all four sides and stuff them with Roxul Pro370 Safe and Silent Stone Wool 80kg/cu.m. They come in 50mm slabs and it was suggested to make the layer 100mm thick and leave a 10 cm gap between the brick wall and the wool.

- For the Ceiling, Two layers of 1" Thermocol sheets directly stuck to the concrete ceiling to help with heat and a little bit of absorption. Stuff a 100mm layer of the same Roxul rock wool to rest on the inside of the false ceiling channels before the gypsum boards are attached.

- Floor is thin wood rafts stuck over vitrified tiles. Planning to put a rug in front of the TV.

- Plan cabling for a 7.2.4 atmos setup. Already planned for Projector.


Current Equipment (not much)

- TCL 65" 4K UHD LED Smart TV
- VIZIO 28" 2.1 Soundbar (SB2821-D6) with a satellite sub-woofer


I am not sure if I am going for an overkill and risk making the room sound dead - some say 'just put in corner Bass traps and you will be good'. My questions:

1. Is it sufficient for good acoustics or is there anything you would want me to change?
2. Should I have the front wall (behind the TV) also stuffed with Roxul.
3. How should the cover the frames on the walls after I install the rock wool inside them?
4. I would be losing almost a foot of space on each side with this setup - anything I can do to make occupy less space?
4. Anything else you would suggest.


Thank you in advance.

View attachment 37834

Frankly speaking if you are spending so much.. better take professional help..
For example thermocol sheet is of no use.. other products give far better results.

 

[Deleted member 38504]

Frankly speaking if you are spending so much.. better take professional help..
For example thermocol sheet is of no use.. other products give far better results.

Best advice. Get professional advice and help. If u have a dedicated room, get the best from it. DIY may be fun and all, but there are limitations. After spending so much on equipment etc, spend a little more and hire a professional to help you set it right.

I recently got some work done in my ht room wrt acoustics. Got help from a professional setup. Very well worth the money spent. And it’s not expensive as some may think.

 

[elangoas]

Build a 'room within a room' with wooden/aluminum frames on all four sides and stuff them with Roxul Pro370 Safe and Silent Stone Wool 80kg/cu.m. They come in 50mm slabs and it was suggested to make the layer 100mm thick and leave a 10 cm gap between the brick wall and the wool.

Not much experience with acoustics, neither an expert.. but have read topics for fair understanding..

- You have anyways planned for dual subs, and given that it is a dedicated room, you should have the flexibility in positioning them ideally to reduce the room resonance.. If you are able to do that, then upto 80/90Hz in the subwoofer range you wouldn't need any room treatment..

- The room treatment would predominantly begin for frequencies above 90Hz (subwoofer crossover)..

- Please check the absorption co-efficient of the density of the material you are planning to use.. The lower the density of the material used, better the absorption rate..

1) Density of the material (lower the better)
2) Thickness (more the better - 1/4th thick of the wavelength of the target freq)
3) Area (again more the better, but may be not fully)..

For the Ceiling, Two layers of 1" Thermocol sheets directly stuck to the concrete ceiling to help with heat and a little bit of absorption. Stuff a 100mm layer of the same Roxul rock wool to rest on the inside of the false ceiling channels before the gypsum boards are attached.

Absorption on ceiling, nice.. I too had planned absorption on ONLY ceiling as it is a living room, but yet to execute it, though have the wooden structure ready to hold absorption..

Seems like you have planned, absorption on all 5 surfaces..

I could squeeze in a 12'x15' room for the HT

Plan cabling for a 7.2.4 atmos setup

I would be losing almost a foot of space on each side with this setup - anything I can do to make occupy less space?

If you have planned for 7.2.4 set-up in a 12 x 15 room, then i suppose 12ft will be the width of the room.. Absorption on both the side walls, will bring the room width to 10ft and make the surrounds closer to your listening position..

I have a 14 (W) x 11 (L) room, and run a 5.4.2 set-up.. I have the surrounds on the width of the room, at my ear level and like it that way..

You may need to check your preference for surrounds..

Should I have the front wall (behind the TV) also stuffed with Roxul.

This would be better option and you may reduce (or) skip the side wall absorption, as your room width also reduces and would bring the surrounds more closer to you than other speakers..

How should the cover the frames on the walls after I install the rock wool inside them?

Spandex, Acoustically transparent cloth.. Easy to stretch and pin on wooden frames holding the absorption material..

If you decide to do entire front wall absorption, the do consider acoustically Transperant screen to position the L-C-R behind the screen and bring the center speaker to ear level..This is will also cover the absorption area,nearly hiding it..multiple benefits..

 

[prateekatasniya]

Hello everyone,

I am a newbie at acoustics and trying my hand at setting up a dedicated AV room in my under construction house (wiring stage) in Hyderabad and am looking for recommendations from fellow forum members and experts.

I could squeeze in a 12'x15' room for the HT. The walls are of regular clay brick/cement construction with a false ceiling at 9' high (regular gypsum - channels laid, pending boards)- windowless and a single teak wood door. I do not have the budget for any hifi equipment now but thought I would rather wire the room and invest in making it acoustically good, when I can, given that it is in construction phase. I plan on buying the equipment in installments over the next couple of years. Movies, music and web series is the primary use case. I have scourged the net and came up with a plan for making the room sound good. Here are the details:

- Build a 'room within a room' with wooden/aluminum frames on all four sides and stuff them with Roxul Pro370 Safe and Silent Stone Wool 80kg/cu.m. They come in 50mm slabs and it was suggested to make the layer 100mm thick and leave a 10 cm gap between the brick wall and the wool.

- For the Ceiling, Two layers of 1" Thermocol sheets directly stuck to the concrete ceiling to help with heat and a little bit of absorption. Stuff a 100mm layer of the same Roxul rock wool to rest on the inside of the false ceiling channels before the gypsum boards are attached.

- Floor is thin wood rafts stuck over vitrified tiles. Planning to put a rug in front of the TV.

- Plan cabling for a 7.2.4 atmos setup. Already planned for Projector.


Current Equipment (not much)

- TCL 65" 4K UHD LED Smart TV
- VIZIO 28" 2.1 Soundbar (SB2821-D6) with a satellite sub-woofer


I am not sure if I am going for an overkill and risk making the room sound dead - some say 'just put in corner Bass traps and you will be good'. My questions:

1. Is it sufficient for good acoustics or is there anything you would want me to change?
2. Should I have the front wall (behind the TV) also stuffed with Roxul.
3. How should the cover the frames on the walls after I install the rock wool inside them?
4. I would be losing almost a foot of space on each side with this setup - anything I can do to make occupy less space?
4. Anything else you would suggest.


Thank you in advance.

View attachment 37834

There are few basics which if done right gives multiple folds value for money..

 

[bujji]

Thank you all for your responses. Will definitely consider hiring a consultant. Like I've mentioned, I don't plan on purchasing equipment immediately, but just looking to do some room treatment when it is in the construction stage itself.

Thank you @elangoas for your detailed advice. Will start with the front wall and ceiling absorption and see if that is sufficient. Agree with you on the surrounds - would have to see how best I would like them and work around them to reduce side wall absorption. I will also reduce the Roxul density to 60Kg.

Will keep this thread updated once done. But please do keep the advice coming .

 

[liverpool_for_life]

First of all, many congratulations on thinking about the room acoustics first up! Very nice.

I am not sure if I am going for an overkill and risk making the room sound dead

I'm no expert, but I think this is likely based on your plan.

- some say 'just put in corner Bass traps and you will be good'.

That's too simplistic as well. I expect that somewhere between your approach and the above is what you'll likely require.

I'll second the advice to leave the side walls alone. Depending on the speakers you intend to purchase, you may find that absorption on the front wall (behind the speakers) is likely going to provide the highest dividends.

Also, you may find that a few strategically placed panels in the ceiling may well be enough. Good luck!