• Hello and Welcome to HiFiVision.com - an online community for the home entertainment and tech enthusiasts!

    If you would like to ask a question, participate in a discussion and view attachments please Register yourself.

Help needed with Room Acoustics (DIY or Ready to Use)

Wharfedale EVO4.4 Speaker

drkrack

Well-Known Member
Joined
Aug 29, 2016
Messages
1,300
Points
113
Location
Hyderabad
My dedicated HT Room (14x17x9ft) has the components and furniture as per the attached images. My current issues include
1. High Frequency sound echos- sometimes becomes Harsh and interferes wit Vocals, it is too bright & harsh at times
2. Vibration of the Doors & Wardrobes with Deep Bass settings
3. to Improving overall performance
4. The Sound causing Nuisance to Rest of the House - Absorption or Proofing

I am confused whether to go with DIY Rockwool Panels ( I'd prefer DIY routelike these https://www.youtube.com/watch?v=zoz8bTi59sA)

or readily available foam tiles and bass traps . I have a carpenter to help me with the woodwork if required.

I need to cover the following areas
1. Back of front Floor standers
2. Back wall of Sitting area (front of the washroom)
3. Sides Left (above PC) and Right (in between Large Windows) - the reflection Points
4. The Ceiling
5. Covering the Doors and Wardrobe fronts

Any Suggestions on How to go about and sourcing of materials (both online & locally) will be very valuable.
Budget upto 75-90k INR ( The professional quote is 2.25L !:mad:)
 

Attachments

  • My HT Room.jpg
    My HT Room.jpg
    10.7 KB · Views: 560
  • 2016-11-02 21.38.09.jpg
    2016-11-02 21.38.09.jpg
    7.8 KB · Views: 559
  • 2016-11-02 21.38.29.jpg
    2016-11-02 21.38.29.jpg
    13.3 KB · Views: 559
  • 2016-11-02 21.38.14.jpg
    2016-11-02 21.38.14.jpg
    14.2 KB · Views: 559
  • 2016-11-02 21.38.43.jpg
    2016-11-02 21.38.43.jpg
    9 KB · Views: 560
  • 2016-11-02 21.38.19.jpg
    2016-11-02 21.38.19.jpg
    9.7 KB · Views: 552

saikatbiswas82

Well-Known Member
Joined
Jun 24, 2012
Messages
1,305
Points
113
Location
Kolkata
My dedicated HT Room (14x17x9ft) has the components and furniture as per the attached images. My current issues include
1. High Frequency sound echos- sometimes becomes Harsh and interferes wit Vocals, it is too bright & harsh at times
2. Vibration of the Doors & Wardrobes with Deep Bass settings
3. to Improving overall performance
4. The Sound causing Nuisance to Rest of the House - Absorption or Proofing

I am confused whether to go with DIY Rockwool Panels ( I'd prefer DIY routelike these https://www.youtube.com/watch?v=zoz8bTi59sA)

or readily available foam tiles and bass traps . I have a carpenter to help me with the woodwork if required.

I need to cover the following areas
1. Back of front Floor standers
2. Back wall of Sitting area (front of the washroom)
3. Sides Left (above PC) and Right (in between Large Windows) - the reflection Points
4. The Ceiling
5. Covering the Doors and Wardrobe fronts

Any Suggestions on How to go about and sourcing of materials (both online & locally) will be very valuable.
Budget upto 75-90k INR ( The professional quote is 2.25L !:mad:)
If you know any rockwool supplier nearby, I think in diy approach it should cost below 50k. This should contain 4 corner bass traps (floor to ceiling). 4 side absorbers (1st n 2nd reflection pt), 2 celling absorbers and 1 center back wall absorber. All absorber panels considered here would be of 4" thick. Everything should be housed in plywood frame.
I think further professional guidance might not be required.

IMHO. YMMV.

Sent from a handheld device. Some typos may creep in
 

drkrack

Well-Known Member
Joined
Aug 29, 2016
Messages
1,300
Points
113
Location
Hyderabad
If you know any rockwool supplier nearby, I think in diy approach it should cost below 50k. This should contain 4 corner bass traps (floor to ceiling). 4 side absorbers (1st n 2nd reflection pt), 2 celling absorbers and 1 center back wall absorber. All absorber panels considered here would be of 4" thick. Everything should be housed in plywood frame.
I think further professional guidance might not be required.

IMHO. YMMV.

Sent from a handheld device. Some typos may creep in

Thanks for the pointers, the Local Rockwool dealer is quoting 2.5k for 10, 2"Panels of 4ftx2ft size. I was Planning to put 2" panel with 1" gap from the Wall for proper absorption ; most of the demo rooms using 1" panels, the professional setup person also suggested 1" panels, apart from the price quoted this was enough for me to ditch him . wouldn't 4" be an overkill ? 2" +1" gap from the wall wouldn't suffice ?
I'm using this guide to base my decision
http://www.bobgolds.com/AbsorptionCoefficients.htm

These are the materials available on Amazon India

1. Preformed acoustic Panels with acoustic cloth covering
Microsound 1x1ft but 1"panels @ 3000Rs for 4Panels
MICROSOUND Fiber Glass Wool with Acoustic Fabric: Amazon.in: Electronics

2. 4ftx2ft 2" , 8 panels without Cloth (this is fiberglass not Rockwool , Less absorption capacity, but less toxic , and allergenic) @ 5500

SIPLA Glass Wool Sound Insulation Board: Amazon.in: Electronics

Definitely I will go for Ply Framework any other suggestions regarding material choice would be welcome.
 

saikatbiswas82

Well-Known Member
Joined
Jun 24, 2012
Messages
1,305
Points
113
Location
Kolkata
Thanks for the pointers, the Local Rockwool dealer is quoting 2.5k for 10, 2"Panels of 4ftx2ft size. I was Planning to put 2" panel with 1" gap from the Wall for proper absorption ; most of the demo rooms using 1" panels, the professional setup person also suggested 1" panels, apart from the price quoted this was enough for me to ditch him . wouldn't 4" be an overkill ? 2" +1" gap from the wall wouldn't suffice ?
I'm using this guide to base my decision
http://www.bobgolds.com/AbsorptionCoefficients.htm

I have seen rooms with 1" panels and the room was boomy like hell. Going anything below 4" with 1" gap from wall will not serve the purpose IMHO.

I just can't believe the professional snake oil setup. They will spend 20-25k for materials and will charge 10 times more. WOW!

Id recommend to visit few more shops to get few more quotes.

2" +1" gap from the wall wouldn't be sufficient at all. Again IMHO.

Just to give you an idea .... To trap a proper bass frequency, one might need 7 ft thick panel. However that's not possible in practical scenario.

So go ahead with absorbers and diffusers in mix n match mode.

Sent from a handheld device. Some typos may creep in
 

sdurani

Well-Known Member
Joined
Jun 29, 2011
Messages
760
Points
63
Location
US
wouldn't 4" be an overkill ? 2" +1" gap from the wall wouldn't suffice ?
I'm using this guide to base my decision
http://www.bobgolds.com/AbsorptionCoefficients.htm
According to the guide you linked to, 2" starts to lose effectiveness below 500Hz while 4" maintains broadband absorption down to the typical crossover point.

The problem with too-thin absorption is that the panels end up acting like a form of tone control, where the highs get absorbed but the mids and lows don't. IF you want that effect, you can save yourself a lot of money by just turning down the treble knob on your receiver.

Better to have broadband absorption (down to roughly 100Hz - where the subwoofers will take over) so that you're not changing the tone of the sound, just reducing the ringing (long decay times) in the room. The absorption coefficients you linked to show that 4" of rockwool is needed to do that.
 

mano2ht

Member
Joined
Mar 7, 2016
Messages
120
Points
18
Location
CBE
Thanks for the pointers, the Local Rockwool dealer is quoting 2.5k for 10, 2"Panels of 4ftx2ft size. I was Planning to put 2" panel with 1" gap from the Wall for proper absorption ; most of the demo rooms using 1" panels, the professional setup person also suggested 1" panels, apart from the price quoted this was enough for me to ditch him . wouldn't 4" be an overkill ? 2" +1" gap from the wall wouldn't suffice ?
I'm using this guide to base my decision
http://www.bobgolds.com/AbsorptionCoefficients.htm

These are the materials available on Amazon India

1. Preformed acoustic Panels with acoustic cloth covering
Microsound 1x1ft but 1"panels @ 3000Rs for 4Panels
MICROSOUND Fiber Glass Wool with Acoustic Fabric: Amazon.in: Electronics

2. 4ftx2ft 2" , 8 panels without Cloth (this is fiberglass not Rockwool , Less absorption capacity, but less toxic , and allergenic) @ 5500

SIPLA Glass Wool Sound Insulation Board: Amazon.in: Electronics

Definitely I will go for Ply Framework any other suggestions regarding material choice would be welcome.

38Kg Density , 2 inch panel bundle will cost you 750 rs , there will be 11 panels in a bundel (each 2 feet x 1 feet) , search suppliers in indiamart with your location. Be careful in choosing fabric to cover it.

To make bass trap , go for super chunk one. You will need min two bundles for each corner (assuming 9 feet roof) . It should have minimum 1 and 1/2 feet depth to absorb low frequency . Dont ever keep flat panels in corner , they wont do nothing with low frequency and it ill be waste of money ,time and real estate.

I have used rockwool in my room and i found that i m prone to allergy .But how ever some other members are doing good with it seems.So take care of it while you deciding material.
 

drkrack

Well-Known Member
Joined
Aug 29, 2016
Messages
1,300
Points
113
Location
Hyderabad
I have seen rooms with 1" panels and the room was boomy like hell. Going anything below 4" with 1" gap from wall will not serve the purpose IMHO.

I just can't believe the professional snake oil setup. They will spend 20-25k for materials and will charge 10 times more. WOW!

Id recommend to visit few more shops to get few more quotes.

2" +1" gap from the wall wouldn't be sufficient at all. Again IMHO.

Just to give you an idea .... To trap a proper bass frequency, one might need 7 ft thick panel. However that's not possible in practical scenario.

So go ahead with absorbers and diffusers in mix n match mode.

Sent from a handheld device. Some typos may creep in


Yeah i am considering a Diffuser at the back of the Front and Center drivers instead of a an absorber. The reverbation frequency check app shows much skewing in the High freq range, Mid range and Low freq seems fine , so Lot of echoing is muddling the sound . My first objective is to target the HF range.
see attached images

According to the guide you linked to, 2" starts to lose effectiveness below 500Hz while 4" maintains broadband absorption down to the typical crossover point.

The problem with too-thin absorption is that the panels end up acting like a form of tone control, where the highs get absorbed but the mids and lows don't. IF you want that effect, you can save yourself a lot of money by just turning down the treble knob on your receiver.

Better to have broadband absorption (down to roughly 100Hz - where the subwoofers will take over) so that you're not changing the tone of the sound, just reducing the ringing (long decay times) in the room. The absorption coefficients you linked to show that 4" of rockwool is needed to do that.

4" rigid board on either side with 1" gap ~10" - I'm afraid will eat up a feet of my space approx , I'm bit concerned about it as well. I am not Targeting at 100% absorption, I should not be left with completely damp room either, some amount of bright sound & Dynamic Range I do enjoy.
Got a quote for Roxul 40 equivalent rigid board with 128Kg/m3 density (13 panels for 3000 Rs) again 4ftx2ft with 2" thickness.

38Kg Density , 2 inch panel bundle will cost you 750 rs , there will be 11 panels in a bundel (each 2 feet x 1 feet) , search suppliers in indiamart with your location. Be careful in choosing fabric to cover it.

To make bass trap , go for super chunk one. You will need min two bundles for each corner (assuming 9 feet roof) . It should have minimum 1 and 1/2 feet depth to absorb low frequency . Dont ever keep flat panels in corner , they wont do nothing with low frequency and it ill be waste of money ,time and real estate.

I have used rockwool in my room and i found that i m prone to allergy .But how ever some other members are doing good with it seems.So take care of it while you deciding material.

Yes Rockwool is allergenic, also Oncogenic beyond doubt; the acoustic cloth covering it matters a lot , if its thick it'll interfere with absorption & it is too thin it may allow the wool strands to escape causing allergies . Also it doesn't smell well, what is your experience ?
Point Noted about Flat panels, corner placement.

1. I wil need a DIY video suggestions for Bass traps, The Diffusers for back of front speakers can be bought as tiles I think, any other Hacks ?
2. Acoustic cloth for covering the Panels can anybody suggest ?
3. Wouldn't aluminium Framework be much sturdy and easy instead of Ply ?
4. also This cool video uses , Bath towels (Which I can get per Kg basis & Can be removed and Washed if required + No allergy, no Oncogenecity !) Any ideas
https://www.youtube.com/watch?v=pABvTWSxOes

Again Thanks Everyone for Chipping in with your useful suggestions; For making me believe that this can be done in DIY way.
 

Attachments

  • Roxul.jpg
    Roxul.jpg
    34 KB · Views: 441

sdurani

Well-Known Member
Joined
Jun 29, 2011
Messages
760
Points
63
Location
US
4" rigid board on either side with 1" gap ~10" - I'm afraid will eat up a feet of my space approx.
No need for air gap, since 4" of rockwool will absorb broadband and keep the treatments from acting like a tone control. This is based on the guide you yourself linked to.

Also, don't worry initially about side wall absorption and instead concentrate on treating the front wall (and middle of the back wall). Front wall reflections come from the same direction as your L/C/R speakers and will muddy the soundstage while reflections from the side walls have been found to be pleasant since they widen the soundstage.
I am not Targeting at 100% absorption
You are targeting mid to low frequencies, which 2" rockwool does a poor job of absorbing.

Speakers radiate mid to low frequencies like a lantern but beam high frequencies like a flashlight. So high frequencies don't interact with the room as much as mid to low frequencies (which are being sprayed in all directions).

When your L/R speakers are pointed at the listening area, the high frequencies are beaming directly towards the listeners. It is the mid to low frequencies radiating from the sides of the speakers that are reflecting off the side walls of the room. Those are the very frequencies that 2" of rockwool doesn't absorb well. Again, I'm just going by the absorption coefficients you linked to.
 

drkrack

Well-Known Member
Joined
Aug 29, 2016
Messages
1,300
Points
113
Location
Hyderabad
Great DIY effort and the pictures are self explanatory, thanks for sharing ; You have used a plain rockwool which is prone to get scattered and cause allergies etc.
I'm talking about Rigid Rockwool boards which are bound by resin, the chances of fibers escaping is minimal.
Actually I'm looking for Owen Corning 703 or equivalent which I'm unable to source locally. Its a rigid fiberglass board, which is used in most demo rooms I've visited. Its less allergenic, less messy, smelly etc unfortunately has lower acoustic absorption quotient.

Can Anyone share local contact details for procuring fiberglass board?
No need for air gap, since 4" of rockwool will absorb broadband and keep the treatments from acting like a tone control. This is based on the guide you yourself linked to.

Also, don't worry initially about side wall absorption and instead concentrate on treating the front wall (and middle of the back wall). Front wall reflections come from the same direction as your L/C/R speakers and will muddy the soundstage while reflections from the side walls have been found to be pleasant since they widen the soundstage. You are targeting mid to low frequencies, which 2" rockwool does a poor job of absorbing.

Speakers radiate mid to low frequencies like a lantern but beam high frequencies like a flashlight. So high frequencies don't interact with the room as much as mid to low frequencies (which are being sprayed in all directions).

When your L/R speakers are pointed at the listening area, the high frequencies are beaming directly towards the listeners. It is the mid to low frequencies radiating from the sides of the speakers that are reflecting off the side walls of the room. Those are the very frequencies that 2" of rockwool doesn't absorb well. Again, I'm just going by the absorption coefficients you linked to.
I believed that the airgap was mandatory, didn't know that it can be avoided if a 4" board is used. I'll definitely look at it. Thanks for your useful information on other aspects as well.

The picture in previous post, I've marked is showing more than 100% absorption in the high frequency bands, I've marked it - it is with 2" Rockwool board with 128kg/m3 density. It's only 65% absorption with less than 125hz bands. ALSO The 4" boards, I'm hardly getting 48kg/m3 density boards, which aren't adequate to exploit the 4" advantage.

I'm uploading the reverberation data if anyone can decipher further suggestions on this basis, it'll be very helpful.
 
Last edited:

saikatbiswas82

Well-Known Member
Joined
Jun 24, 2012
Messages
1,305
Points
113
Location
Kolkata
I think 48kgm rockwool boards are available in Kolkata

Sent from a handheld device. Some typos may creep in
 

sdurani

Well-Known Member
Joined
Jun 29, 2011
Messages
760
Points
63
Location
US
I believed that the airgap was mandatory, didn't know that it can be avoided if a 4" board is used.
An air gap is a way of getting something for nothing. Placing an absorber away from the wall will improve its low frequency absorption, but air is not a replacement for absorption material.

Here's 2" rockwool (128kg/m3) with no air gap (blue) and with 1" air gap (green). The difference in absorption is negligible.



I'm hardly getting 48kg/m3 density boards, which aren't adequate to exploit the 4" advantage.
Not sure what you mean by "exploit the 4" advantage". Whether using 128kg/m3 or 48kg/m3, 4" absorbs more in the mid to low frequencies than 2" does.
The picture in previous post, I've marked is showing more than 100% absorption in the high frequency bands
When you place absorbers on the front wall and side walls, the mid to low frequencies are the ones radiating around the speaker cabinet and being absorbed. High frequencies will be beaming at the listeners. So, high frequency absorption is not a concern, since those frequencies will be pointing AWAY from the absorbers.
 

mano2ht

Member
Joined
Mar 7, 2016
Messages
120
Points
18
Location
CBE
Great DIY effort and the pictures are self explanatory, thanks for sharing ; You have used a plain rockwool which is prone to get scattered and cause allergies etc.
I'm talking about Rigid Rockwool boards which are bound by resin, the chances of fibers escaping is minimal.
Actually I'm looking for Owen Corning 703 or equivalent which I'm unable to source locally. Its a rigid fiberglass board, which is used in most demo rooms I've visited. Its less allergenic, less messy, smelly etc unfortunately has lower acoustic absorption quotient.

Can Anyone share local contact details for procuring fiberglass board?

I believed that the airgap was mandatory, didn't know that it can be avoided if a 4" board is used. I'll definitely look at it. Thanks for your useful information on other aspects as well.

The picture in previous post, I've marked is showing more than 100% absorption in the high frequency bands, I've marked it - it is with 2" Rockwool board with 128kg/m3 density. It's only 65% absorption with less than 125hz bands. ALSO The 4" boards, I'm hardly getting 48kg/m3 density boards, which aren't adequate to exploit the 4" advantage.

I'm uploading the reverberation data if anyone can decipher further suggestions on this basis, it'll be very helpful.


Hi ,

Usually fiberglass and rockwool should cost same , Resin Bonded fiberglass is available locally which ill be similar to Owen Corning 703 .

I took the photo while doing , now i have covered with the cotton fabric one layer and acoustic fabric as second layer . There is no scatter but how ever smell is not controlled that much.

As a additional info , even super chunk bass trap have no control on very low frequency . (Frequency like Edge of tomorrow initial bass sweep ) Doors and windows started to vibrate heavily.
 
Last edited:

mandeep

Active Member
Joined
Dec 8, 2007
Messages
741
Points
43
Location
Mohali (Near Chandigarh)
Use Armstorng/Saint Gobain 2x2 ft2 ceiling tiles with High NRC, club them together for much better NRC. Rockwool/Glasswool are very DANGEROUS OPTIONS health wise, avoid them at all costs.

Or use woodwool Board.

PM me for details

NOTE: I am not a Armstrong/Saint Gobain dealer or distributer
 

sud98

Well-Known Member
Joined
Nov 13, 2008
Messages
2,282
Points
113
Location
bangalore,india
Use Armstorng/Saint Gobain 2x2 ft2 ceiling tiles with High NRC, club them together for much better NRC. Rockwool/Glasswool are very DANGEROUS OPTIONS health wise, avoid them at all costs.

Armstrong tiles are only in white colour in the market so really poor for Home Theater. Not sure of Saint Gobain.

Where did you get that its dangerous?

My source for it being lowered in danger from possibly carcinogenic (in 1987) to not carcinogenic is 2001

https://www.workcover.nsw.gov.au/me...tic-mineral-fibres-smf-glasswool-and-rockwool
 

sound_cycle

Well-Known Member
Joined
Jan 12, 2014
Messages
1,123
Points
83
Location
Hyderabad

mano2ht

Member
Joined
Mar 7, 2016
Messages
120
Points
18
Location
CBE
May be Resin Bonded will not fly off in air , other than that it is prone to fly in air .Need good fabric to cover
 

drkrack

Well-Known Member
Joined
Aug 29, 2016
Messages
1,300
Points
113
Location
Hyderabad
Still researching on the health effects of rockwool and glasswool.
With newborn at home can't take the risk of allergies.
Seems Glasswool or fiberglass is much better, though I can't source it easily locally. Any links to local suppliers of glasswool?

Any other materials one can suggest?
Thanks
 
Top