Another DIY attempt for room treatment

[s_sachin]

Attempting to treat corners and first reflection points in my 100 Sq ft. HT room.

I have got the plywood frames complete so far, some pics here. This weekend going to stuff these with rockwool, a layer of burlap and then 6mm foam and cover with cloth.

Still deciding whether to put burlap or not. Any inputs ?

Like to thank pdhanwada for step by step guidance and Sidvee giving very useful inputs for my room.

By s_sachin at 2012-09-06

By s_sachin at 2012-09-06

By s_sachin at 2012-09-06

By s_sachin at 2012-09-06

Hopefully all this pays off

 

[ukjeyaraj]

I dunno much about room treatment. But this is a great effort. Best wishes for you to get the desired output.

 

[pranavkumar]

Great effort, tell us what material would you be filling the these bass traps ?

 

[s_sachin]

Great effort, tell us what material would you be filling the these bass traps ?

50 mm thick rockwool traingle slabs.

 

[neo9999]

Hi Sachin,

Good effort to put in the DIY home theatre. Welcome to the club.

Can you please explain the purpose of using the burlap and then foam over on top of it?

The rockwool material would be providing the acoustic treatment, so IMO foam would be the odd man out. you can use burlap to cover or use a thin ply (4mm types) with holes drilled to cover the frames. You can check my thread or other senior members threads in this forum on what all items to use.

Neo.

 

[s_sachin]

the foam if for even and safe packing of the rockwool inside, and would give good white background to the cloth on top which is semi-transparent.

I am assuming 6mm foam would be porous enough not to obstruct anything ? Am i wrong ?

 

[pdhanwada]

Sachin,

Good job on the acoustic treatment front. Having foam, burlap and then the cloth means we have three layers of filters present on Rockwool from getting airborne.

My guess you sufficient rockwool available I would prefer you to make couple of them to be placed on the behind the listner.

You are on right track. Keep it up.

Thanks
pandu

 

[Sumanta]

Friends, I am lost.
I mean, why the corner? Is it for standing waves? Then it should be those confronting walls, isn't it?

OKAY, first question, room treatment means basically trying to avoid reflecting sounds, right? Then how reducing reflection in corners help? I mean there sounds will change direction but do not create standing waves.
Educate me please.

 

[s_sachin]

Since bass builds up the most in the corners of a room, this is an ideal location for any bass trap

Quoted from here
Acoustic Treatment and Design for Recording Studios and Listening Rooms

 

[pdhanwada]

Friends, I am lost.
I mean, why the corner? Is it for standing waves? Then it should be those confronting walls, isn't it?

OKAY, first question, room treatment means basically trying to avoid reflecting sounds, right? Then how reducing reflection in corners help? I mean there sounds will change direction but do not create standing waves.
Educate me please.

In an untreated room, while the music is running please walk around and find out the decibel level of the bass. It is usually more at the corners and less in the middle.

By creating bass traps, it will even out the decibel level of bass frequencies.

Thanks

 

[sidvee]

Looking good Sachin. Good room acoustics is the most important aspect of a decent hifi system and sadly the most neglected. Amazing to see megabuck systems in totally untreated rooms wherein listeners struggle with speaker placement and other issues and consequently blame equipment, recordings etc, changing equipment often while ignoring the root cause. Wonder what they are really listening to! Worse to see thin carpets etc. placed on walls as acoustic treatments when they will not absorb anything below 200-300 hz (at-best) below which lies the most problematic frequencies. Anyways coming back to your query, IMO the porosity of 6mm foam should not be an issue to corner bass traps. In the end, with the proposed treatment, you should perceive tighter bass, reduced boominess and most importantly better definition of midrange whose intelligibility may be getting smothered by bass peaks. If possible try a subjective measurement of your room, before and after, with test tracks from the internet and with a smartphone db meter app. You will be amazed to see how the curve smoothens out after room treatment.
Cheers,
Sid

 

[jaudere]

In an untreated room, while the music is running please walk around and find out the decibel level of the bass. It is usually more at the corners and less in the middle.

By creating bass traps, it will even out the decibel level of bass frequencies.

Thanks

I have read this logic but I am still confused. I agree that bass levels in the corners may be higher but then we don't sit in corners to listen to music. My chair is 4 feet from back wall and 5 feet from side walls when I listen to music.
So if I walk around with music playing and I find the bass to be higher at corners,and then I put bass traps, how will it affect bass at my listening position?

@ OP, why did you feel like putting up bass traps? was the system boomy at the listening position or is it just that after reading room treatment you felt the urge to try it out? If it was boomy, did you try changing crossover frequencies/subwoofer volume level ? What was the result?

 

[pdhanwada]

I have read this logic but I am still confused. I agree that bass levels in the corners may be higher but then we don't sit in corners to listen to music. My chair is 4 feet from back wall and 5 feet from side walls when I listen to music.
So if I walk around with music playing and I find the bass to be higher at corners,and then I put bass traps, how will it affect bass at my listening position?

By putting bass traps we are going to decrease the reflections and make the frequency distribution even.


Bass frequencies have higher energy levels compared to higher frequencies. They dont die quickly they keep on hanging for long even after the sound from the source has died down. Higher frequencies die faster as compared to lower frequencies. SO It is very important to treat bass frequencies.

Ideally speaking we would not want to have any reflections from the walls, floor or roof. Unfortunately the sound gets reflected this creates certain frequency cancellations and certain frequencies resonate such that we hear them at higher decibel level. These are the ones at the corners.

Ideally speaking we need to treat all the walls corners and everything. But treating the corners is the first point and single most important point.

It is all about opitimisation and make use of least treatment to get best output.

If you need more info please go thru the website Ethan Winer - Home Page

Thanks
Pandu

 

[jaudere]

But should everyone treat room or only those who are not happy with the sound at listening position should treat the room.

I tried some minor treatment but the issue is that to test the sound before and after room treatment is not easy because there is too much time lag between the sound without treatment and sound with treatment. I could not appreciate much difference. So I don't know whether all this is worth the effort or no. Measurements will prove some changes but whether it will improve my perception of already excellent sound quality is a big question mark in my mind. I have done the most inexpensive things (those which did not need s single rupee to be spent.

 

[Sumanta]

I have read this logic but I am still confused. I agree that bass levels in the corners may be higher but then we don't sit in corners to listen to music. My chair is 4 feet from back wall and 5 feet from side walls when I listen to music.
So if I walk around with music playing and I find the bass to be higher at corners,and then I put bass traps, how will it affect bass at my listening position?

Exactly! Thanks Jaudere.

I have never measured anything with any instrument for my stereo. I did use my AVR's inbuilt Audissey room equalizer or something like that. But for stereo reproduction through that AVR was not to my liking.
My another question is, do you feel the difference or problems through your ear or you just measure it and correct it? Or is it both?
I have (in my listening room) all my windows and doors open, have the front wall bare, have bare minimum sound absorbing furnitures (a recliner, a bin bag), curtains but still hear no echo, boom or colouration. I have a loft too in the room with some cloth suitcases. I have wooden wall cabinets full of cloths in the back of my recliner. I hear no difference whether they are ope or close. But I did hear differences when I had the same OBs in a different room where there were two such wall cabinets in front of listeners. Opening those cabinets used to reduce imaging and SPL a lot.

 

[sidvee]

I am no expert - but this is what I do. Acoustics at the listening position matters the most. The best way to measure this is to download a test tone signal from the internet. Also download a soundlevel meter app for your smartphone or even better get a sound level meter. Using the c weighting on the meter sit at your listening position and let the tones play and measure the frequency response of your room and graph it. You will see all the peaks and valleys of your room response at the listening position. The bass region 200hz to 20hz will have the most peaks and valleys. This means that some bass frequencies are over emphasized and some are getting suppressed due to the room. Suppose you see a big valley at 40 hz say, that means the upright bass in jazz (which plays at this frequency) is being suppressed and you will not hear this instrument at your listening position (or it will be very low - most people will wrongly assume that the speaker cannot reproduce those frequencies and plan to add a sub. or change speakers etc). Now place acoustic treatments - bass traps in corners will be most effective at smoothening out the bass range peaks and valleys mainly by absorbing the peaks. Do your measurement again, you will see that the graph is smoother and the sound is better. Again at the end of the day there will be some subjectiveness involved based on user preferences (note - some people like boomy bass or super bright high frequencies) but more often than not the sound with treatments is the more accurate one - closer to what was actually recorded.
Cheers,
Sid

 

[s_sachin]

Just finished the panels , fixing to the wall is pending.

Immideate reaction .. wow no bass boom .. and nice details at low volumes.

By s_sachin at 2012-09-13

By s_sachin at 2012-09-13

By s_sachin at 2012-09-13

By s_sachin at 2012-09-13

 

[blackscorpio]

s_sachin,

That's really cool. Nice fabric design adds little contrast to your room. Congratulations on finishing it so successfully.

I am in the same boat and want to DIY my panels and RT. Actually, I am in USA currently and want to pick up some materials needed for this job, can you guide me which material is good and how much would I need, lets say, for a setup like yours. What fabric did you use? What is the total cost of the project?

My initial thought was to buy some acoustic foam and pickup some fabric from USA. Appreciate your help.

TIA.

 

[pdhanwada]

Sachin,

Good job. Yours being a small room, It was more essential to have room treatment more importantly bass treatment.

The difference what you are going to experiance is going to be much bigger than changing a dac or a cable or a preamp.

I have found In Small to Medium rooms, The bass treatment provides significant improvement in sound quality.


Thanks
Pandu

 

[pdhanwada]

s_sachin,

That's really cool. Nice fabric design adds little contrast to your room. Congratulations on finishing it so successfully.

I am in the same boat and want to DIY my panels and RT. Actually, I am in USA currently and want to pick up some materials needed for this job, can you guide me which material is good and how much would I need, lets say, for a setup like yours. What fabric did you use? What is the total cost of the project?

My initial thought was to buy some acoustic foam and pickup some fabric from USA. Appreciate your help.

TIA.

I dont think you need to get any stuff from US for Room treatment. Per Sachin's method you need, Rockwool, plywood and fabric which all can be sourced locally.