Need Help On Room Acoustics

[S_Sridar]

Dead Room fears

God made sound sound to travel in a straight line- radially.

If you are in a position of the line of the firing of the speakers,
there is no way that the sound will bet absorbed before it reaches you.

There can be a nullification of the sound waves by interference,
but that is a not a possibility as no channels of the speakers ever interfere
in any music source.

And I had mentioned in my first note;
You have prepare your complete schema first, and then start the job

When one goes about it in a piecemeal manner, one tends to lose sight of the gameplan, and
one begins to wander, given the myriad of options and techniques available.

 

[S_Sridar]

link;
Soft Sound In Stock Studio Foam

Forget about the commercial part, just focus on the information provided

 

[santhosh]

Lot of useful information here and interesting discussions between Sid, Sridar and other members.

Before we hijack Pandu's build thread completely with our questions, may I request mods to move these discussions to a new thread that I have created namely "The Room Acoustics" Thread.

http://www.hifivision.com/av-enhancers-room-acoustics/13653-room-acoustics-thread.html

TIA

 

[sidvee]

When one goes about it in a piecemeal manner, one tends to lose sight of the gameplan, and
one begins to wander, given the myriad of options and techniques available.

I agree - and in that context, as I mentioned in another thread, Pandu seems to be on the right track. (Hopefully this will bring the focus back to the OP's thread). When I met him I was impressed with the amount of research he had done. His plan is quite reasonable and IMHO his room is going to sound much nicer after the treatments, as he is going after bass first by treating the room corners and first reflection points next, while keeping the right amount of liveliness in the room. His plan of using triangular corner busters is very valid and very efficient as I have heard a room that used GIK triangular corner busters that sounded awesome in bass control.
Cheers
Sid

 

[pdhanwada]

Pictures related to the design

bass traps: As I said in the earlier post I was filling three corners from floor to roof with corner super chunks. For each corner corner wedge dimensions are of 17 X 17 X 24 where in right angle is between 17 inch sides of the wedge. Each wedge is 3ft height and I would need three of those to fill in one corner from bottom to top.

You can see the second picture each of these wedges are placed one over the other. On the net I have seen that there would be no frame but just the corner will be filled with wool from bottom to top and just get it coverd with burlap and fabric. I went the framed way so that I can build the bass trap outdoor and place it in the corner. Another advantage of making them 3ft ones is being I can move them and experiment with them.

Covering of the bass trap will be done using burlap and the foam 4mm thick and over which Fabric comes in. So there will be three layers of filteration happening.

Thanks
Pandu

 

[pdhanwada]

Progress:

It has been a week since it started. because of the rack being built it is taking time. It would take another week.

I plan to hang three 4' X 4' from the ceiling covering the first reflection point on the ceiling. As we have talked about the rockwool flakes comming out of the I would covering the bottom portion with impervious plastic sheet.

For the rest of the frames and bass traps burlap+foam+fabric will be covered.

Question for sidvee and others.

My frontwall has the projector screen comming down. Should I need to treat the wall too. I will see If I end up with additional rock wool may be I will do it. It should impact high frequencies but my bass will get treated as the screen will be hanging over the panels.

 

[vinay]

The fabric does not have in-direct holes, take care.

 

[santhosh]

My frontwall has the projector screen comming down. Should I need to treat the wall too. I will see If I end up with additional rock wool may be I will do it. It should impact high frequencies but my bass will get treated as the screen will be hanging over the panels.

Pandu, you should treat the front walls fully. When the screen is down, your absorption of highs and mids will be poor (unless you are using a screen that is acoustically transparent) but low frequency will still be absorbed as it can pass through the screen or any material that is not a dense absorber. You fill find noticeable improvement in sound quality, imaging, focus, soundstage if you treat your front wall.

 

[pdhanwada]

The fabric does not have in-direct holes, take care.

Vinay,

What do you mean by in-direct holes. can you elaborate.

Thanks
pandu

 

[santhosh]

The fabric does not have in-direct holes, take care.

Pandu, Vinay says the fabric may not be acoustically transparent.

From the looks of it, it looks like poly silk? Try raw silk (real silk and also called dupion), it is porous. I have used it in my HT.

 

[pdhanwada]

I checked the fabric. When I blow air thru it flows but not freely. I think it is transparent but may not be 100 percent. It is fluffy. I am sure it will not reflect it.

I did few experiments. Light passes thru it. Try to listen to my own voice by closing my ears by using the cloth. I could hear my own voice. It is transparent. But do not know to what extent.


Thanks
pandu

 

[vinay]

It is good that you have done these exercises with the fabric, i must say it looks rich and beautiful.

I think you should also consider Santosh's and my fabric, the one which i have used is similar to sport shoes of Nike & Reebok.

In my case i had done a lot of dry run running into several days with different fabrics at floor of the shop and in my mini theatre, it was quite a tough call, i wasted enough money in these tests.

V.

 

[pdhanwada]

Vinay,

I am pretty much fixed on the fabric as of now. Until I see any problems with it I am not intending to change it.

As I write I just finished a long day in HT diy work. Today all the first reflection panels 8(2 side, 3 ceiling, 1 back, 2 front) are done. Also done are 9 bass traps three on each corner.

This was a big day for me as I had never worked with ROCKWOOL. My self along with 2 carpenters started working at around 2 pm. After 8.5 hours, All panels and bass traps are filled with rock wool and covered with Burlap and foam. Next step would be cover the panels with the fabric. I need a tailor's help. I should get that done before teh weekend. Also polishing work needs t be done on my rack .


As mentioned earlier we took precautions like covering the face with mask and cloth, wearing gloves, wearing full sleeves. At the fag end of the project we see there are little bit of itches on the forearm. Other than that it went pretty well.

I think I have one more week of work of finishing here and there. Otherwise most important part of it done.

Will post the pictures tommorrow. Tired working hard but thoroughly enjoyed it. Need to go to bed now;

I might have rockwool left for 2 4X4 4 inch panels in excess. If any of the forum members of hyd need let me know. I need to throw it away with in a day or two.


Thanks
Pandu

 

[vinay]

The Story Continues - Making Of A Private Theatre

Hello Pandu,

No news from you.

Indeed if you are not having any acoustic problems with the fabric then there is no question to change while in my case i realized at least twice that there were acoustic and related problems with the fabric, and i had to buy the entire stretch again, but i was smartly able to use them for some other purpose.

In my case the guy who put up the fabric on walls was a sofa maker, he did a great job.

Well at the time of using glass wool, covering the face with mask and wearing gloves, i did not know it was so important, i learnt it only via santosh.

It is at points of time when we realize that the work is done, but we do realize that it is not in order or something is lacking, so we need to take complete care and see at the things again and again, to see if there is a missing link etc.

So we will await the latest pictures.

Indeed one gets tired during the making of a private theatre and not to forget the extent of money which goes into, how much ever one may plan the budget, but if one has a passion then the budget will just not be visible as the cost would have over flowed so much.

I had to throw away glass wool worth about Rs.3,000/- as it is very difficult to get someone who is interested in it. Furthermore i had some other things also which got wasted due to trial and error, etc.

V.

 

[pdhanwada]

Status:

A new cabinet done, It is 80 inches wide and 26 inches tall. Spray polish is not done. WIll get it done later.

Acoustic panels All done. I hung up all the first reflection panels, Corner traps.

My ceiling panels are not fixed yet should get it done next week.

Meanwhile I had the first listen of my system in almost a month. The sound quality is day and night difference. It is biggest and cheapest upgrade since I bought my system 4 years ago.

In these four years, I had got a REL sub, MHDT havana Dac, Acoustic ZEN matrix reference and Silver reference interconnects. Acoustic treatment beat them all left and right.

Cost of the Project 30 K( acoustic treatment) and 20K for Cabinet+ painting+miscellenoust.

7K for Rockwool,
12K for Plyboard
8K for Labour
2K for cloth
2k for miscellenous items

All the panels are 4 in thick, 6 Corner traps are 17 X 17 X24 each three feet in height. 3 corner traps are 14 X 14 X 19 each three feet in height.

Really happy how it turned out to be. Long research helps.

Will post pictures of my room in next few days. I am out this weekend.

Thanks
pandu

 

[pdhanwada]

ImageShack Album - 12 images

Link for my pictures.

After a week's listening I am extremely happy with my system right now. High's have softened out. BASS has got really extended. Never I use hear the Big drum in my earlier setup. In every song I can hear that.

I think the corner traps have done the trick for Bass department. They are bulky in 17 X 17X 24.

When I do A & B listening test, I can see the difference between with DAC and with no dac. There is signicificant difference in the quality.

With respect to aesthetics, I am not too much into it. My wife saw after it was completed, said it looks like a studio. The Fabric has given a rich look.

Thicker Fabric I selected wiped out all the fears related to ROCKWOOl becoming airborne.

The ceiling panels have a extra layer of Plastic sheet placed beneath the cloth there by avoiding the Rockwool getting showered.

I am happy with my equipment, Most times I am unhappy with my recordings now. Best recording are sounding great, Even the not so great ones are also fine but with poor recordings I still skip the CD go to the next one.

Thanks
pandu

 

[himadri]

Congrats Pandu
truly an inspirational and laudable effort. enjoy
himadri

 

[santhosh]

Congrats Pandu. Your HT Looks good. Thanks for sharing your experience on your DIY corner bass traps. I might take the plunge and make some corner traps too some soon.

Please share some more pics of the entire room. Your Paradigm's look :licklips: