Effects of speaker placement & Room treatment

[rajesh srinivas]

Just a hazard warning - raw glass wool is considered very dangerous if its fine particles inhaled and also may result in "khujlee"

So handle with care if you plan to use.
Instead glass wool sheets (white in color) can be used as a safer option.

raw glass wool is not recommended for acoustics,its rigid sheets which work well in absorbing sound.

Usually the glass wool sheets which we get are yellow in colour,,where you have come across white sheets????.

To be safe the best way is to cover them wih 4 to 6mm foam sheets to ensure glass wool dust does not come out,and further with breathable cloth on it...

r\s

 

[bose]

Where to buy glass wool on cheap?

 

[sound_cycle]

Where to buy glass wool on cheap?

Local Stockist | ROCKWOOL

ciao
gr

 

[rajesh srinivas]

Define "best acoustic room treatment"

Simply means "Getting Your Room to Sound Great"

I have no idea about room treatment for HT having different requirements, not included in my interests

I am mainly concerned with HT,so no point in giving the details,but just can tell you Briefly for HT.

For Getting your room to sound great with acoustic treatment requires combination of 3 items:

Bass Traps to absorb the low frequencies
Acoustic Panels to absorb the mid/high frequencies
Diffusers to scatter the remaining frequencies

Curious Q : Apart from the imaging from two sources requirement what are the differences really ? Do room modes matter ?

For taming standing waves or so called room modes matter a lot for HT and to get perfection needs lot of permutation and combination,at the end its only our ears which can finally decide...so we have to keep on experimenting to achieve results..

r/s.

 

[sound_cycle]

Simply means "Getting Your Room to Sound Great"



I am mainly concerned with HT,so no point in giving the details,but just can tell you Briefly for HT.

For Getting your room to sound great with acoustic treatment requires combination of 3 items:

Bass Traps to absorb the low frequencies
Acoustic Panels to absorb the mid/high frequencies
Diffusers to scatter the remaining frequencies



For taming standing waves or so called room modes matter a lot for HT and to get perfection needs lot of permutation and combination,at the end its only our ears which can finally decide...so we have to keep on experimenting to achieve results..

r/s.

Ummm, I would like to most humbly point out that you are wrong, twice over, 1) You ***cannot*** ear it out. It has to be measured, human hearing is sensitive to about the third of an octave or so IIRC, 2) you cannot absorb bass below about 400 Hz or so with 4" thick absorbtion, that is the physics of it. so you cannot address roomboom.

What you have described as specific to HT applies to stereo listening too, so what is the difference, is there any - from the audio point of view

By the way if you have dealt with high low and mid, what is left to diffuse I guess you typed in a hurry

Please remember audio is physics, music/ appreciation can/ should be about feeling, but that former is not

ciao
gr

 

[sash]

So, suppose i'm having trouble comprehending movie dialogue and place a thick absorption material behind the speaker and now the results are acceptable to my ear, i shouldn't do it? I should only attempt it when i have mastered physics and got a whole array of measuring instruments? How do you know speakers aren't manipulating what the sound engineer recorded? How do you "measure" that? Does the sound engineer release a frequency graph for his movie sound track?
Most of us go by our ears - of course it is not perfect, but i usually stop when things are acceptable to me....until the next opportunity when i have some time or when i feel something is missing. It goes on..

 

[sound_cycle]

So, suppose i'm having trouble comprehending movie dialogue and place a thick absorption material behind the speaker and now the results are acceptable to my ear, i shouldn't do it? I should only attempt it when i have mastered physics and got a whole array of measuring instruments? How do you know speakers aren't manipulating what the sound engineer recorded? How do you "measure" that? Does the sound engineer release a frequency graph for his movie sound track?
Most of us go by our ears - of course it is not perfect, but i usually stop when things are acceptable to me....until the next opportunity when i have some time or when i feel something is missing. It goes on..

It is a given that your room (and hopefully it is not your speakers) are "aren't manipulating what the sound engineer recorded"

The measurement is rather easy - free software (REW) and USB mic.

The sound engineer does not have to release a frequency graph, if you want to visualize the audio there are tools.

The problem with ears and eyes are they are not trustworthy and will adapt. Not reliable. If the goal with all the spend on eqpt, high res formats and treatment is to reproduce sound that is close to the original, laying on the treatments without measurement IS going to be counterproductive. I certainly do not have the training or a "super ear" to get by , earing it. What I did by way of treatment or placement - before measurement - was pure crap and I have had to redo some of it. An mm or two matters by the way - and once you know what you are listening for even with out "the training or a "super ear" I spoke about, I can make out that something has been changed - I might not be able to tell you what though

If you want to be all combative and touchy about it, I am okay with not continuing this. I am not pretending to be an expert or claiming to have PhD in acoustic physics or anything in case you are riled about that missing disclaimer. It is just that the topic interests me.

"Getting Your Room to Sound Great" I guess is about purpose building/ reshaping a room for good acoustics, that is not my path, I am doing something else, treatment / correction to live with a perfectly horrid room for audio and still have good sound. To the ear and to the mic.

gr

 

[keith_correa]

It's not about knowing a lot about physics and you don't need a frequency graph of any music. And of course your speakers are changing [the magnitude of change differs between crossovers and drivers and design principles employed] what the sound engineer intended you to hear. And on top of that the room mucks things up. The holy grail is to listen "flat" [as much as possible] at your listening position. Heard about a frequency sweep? You can use that and a calibrated mic. to determine problematic areas and then ameliorate them using the various techniques available.

 

[sash]

Ok, i guess we are talking about different levels here. I'm probably at the "clap test" level and probably will graduate to more empirical methods. But we must understand that even without all that science, we may be able to benefit from basic treatment like rugs on the floor etc

 

[keith_correa]

But we must understand that even without all that science, we may be able to benefit from basic treatment like rugs on the floor etc

Understood! There's no denying that there may be a benefit. What we need to understand is that this benefit is derived using an imperfect and biased measuring "instrument" - the human ear and there is more benefit to be had...

 

[sash]

It is a given that your room (and hopefully it is not your speakers) are "aren't manipulating what the sound engineer recorded"

The measurement is rather easy - free software (REW) and USB mic.

The sound engineer does not have to release a frequency graph, if you want to visualize the audio there are tools.

The problem with ears and eyes are they are not trustworthy and will adapt. Not reliable. If the goal with all the spend on eqpt, high res formats and treatment is to reproduce sound that is close to the original, laying on the treatments without measurement IS going to be counterproductive. I certainly do not have the training or a "super ear" to get by , earing it. What I did by way of treatment or placement - before measurement - was pure crap and I have had to redo some of it. An mm or two matters by the way - and once you know what you are listening for even with out "the training or a "super ear" I spoke about, I can make out that something has been changed - I might not be able to tell you what though

If you want to be all combative and touchy about it, I am okay with not continuing this. I am not pretending to be an expert or claiming to have PhD in acoustic physics or anything in case you are riled about that missing disclaimer. It is just that the topic interests me.

"Getting Your Room to Sound Great" I guess is about purpose building/ reshaping a room for good acoustics, that is not my path, I am doing something else, treatment / correction to live with a perfectly horrid room for audio and still have good sound. To the ear and to the mic.

gr

Not too long ago, i guess you were also where we are right now
http://www.hifivision.com/av-enhancers-room-acoustics/50532-umik-1-measurement-mic-6.html#post639638
What happened between now and then? Were you able to calibrate using REW? Is there a thread of the journey? I just downloaded REW to see what i can learn and thinking of getting a UMIK-1 from someone returning from US

 

[sound_cycle]

Not too long ago, i guess you were also where we are right now
http://www.hifivision.com/av-enhancers-room-acoustics/50532-umik-1-measurement-mic-6.html#post639638
What happened between now and then? Were you able to calibrate using REW? Is there a thread of the journey? I just downloaded REW to see what i can learn and thinking of getting a UMIK-1 from someone returning from US

It's here, bumbling steps and all . on hfv on the two or three threads i started. much of it here http://www.hifivision.com/av-enhancers-room-acoustics/53080-room-treatment-advice.html

REW will give you the graphs and measurements, before and after treatment. For instance use the impulse plots to figure out and kill early reflections, or to figure out if your bass traps or broad band absorbers are doing anything. Or if your DRC is doing anything for that matter

REW can do but however is not great at correction, I did not quite figure out how to set up the filters correctly and used the fb2k plugin which was very limited.

I listen to two speakers, in a (audio wise) horrid room and to me DRC was the way to go. A lot of time reading the 'net led me to add the stipulation that the solution had to preserve phase - for imaging.

I now have DiracLive running and it is a very enjoyable listening experience. Tight bass, room boom mitigated, very decent imaging and speakers that disappear on many tracks (it is all very limited in z though, chasing that will probably mean a change in DAC and/or speakers and I am not going there, if it ever happens it will be DAC change first)

It is sonically, light years away from what I was listening to when I signed up on hfv about two years back

My gains from the basic stuff ie postioning / treatment / DRC are enormous. which is why I am so enthusiastic about emphasizing their importance

ciao
gr

 

[sash]

Thanks sound_cycle, i think i'll start trying this out too. One question though, do i need a measurement mic like the UMIK-1 or would the PC mic be a decent starting point? I do understand that pc mic freq range could be very limited

 

[sound_cycle]

Thanks sound_cycle, i think i'll start trying this out too. One question though, do i need a measurement mic like the UMIK-1 or would the PC mic be a decent starting point? I do understand that pc mic freq range could be very limited

Getting Started with REW

see the equipment needed section at the bottom of the page. Because the microphone sensitivity varies across frequencies you need either a very good and expensive one OR one which has been calibrated. The UMIK one comes with a calibration file. I recollect seeing a bunch of youtube videos (from RMAF IIRC) which explained all this and how to go about making a measurement.

ciao
gr

 

[sound_cycle]

This was a discussion that started off on another thread.

As it is OT on that thread, I thought that maybe we could follow it on this one.

IKON 6 works well in a room as small as 10x12. No boom, no overhang. All that with basic room treatment worth less than rs. 5000

The boom (because of room modes) is directly a function of the dimensions of the room.

It is not a function of the speaker. Therefore IMHO saying that speaker x does not have room boom issues is not a valid statement.

I used the amroc room mode calculator, to work out that for a 10x12 feet room (I assumed 11 ft height) the first five modal frequencies are

1 46.89 Hz
2 51.15 Hz
3 56.27 Hz
4 69.39 Hz
5 73.24 Hz


Let's say the speaker is a small BS that does not go below 55 Hz and therefore does not excite 46.89 and 51.15 Hz. We still have some fairly low frequencies that CANNOT be addressed with the simple broad band absorption type treatment. In such a small room probably there is no possibility of sufficient chunky bass traps to mitigate. The membrane type traps or other solutions are AFAIK significantly more expensive than 5K INR.

In a typical Indian bedroom sized room better placement is on the long wall. Images lock much more easily and instrument placement is beautiful. On the short wall they need basic room treatment

Maybe.

Getting the image right is not determined by dimensions or a very generalized prescription.

The chief image killer is early reflections.

The goal would be to damp them -10db within the first 15 m/s.

I am incapable of earing it out.

An average living or bed room has way too many sources of early reflections And the back wall is always going to be very close. And probably not treatable.

ciao
gr



[/QUOTE]

 

[raghupb]

So a "small multi-purpose room" may not be the ideal listening space for music even when measured and treated.
What does one do when there is no choice of room and treatment to house the music system?

Cheers,
Raghu

 

[sound_cycle]

So a "small multi-purpose room" may not be the ideal listening space for music even when measured and treated.
What does one do when there is no choice of room and treatment to house the music system?

The answer sadly is very clear, with a 11 x 14 room such as we have been talking about from the start of this discussion

You will have two speakers playing.

You almost certainly cannot get stereo listening.

You will have boomy sound

Game Over for the hifi listening quest, with speakers that is.

Headphones are probably the way to go maybe ( no experience, but rooms do not affect them)

I am not talking of opinion, it is the physics of this illusion we chase, it is about how our brain perceives sound.

It ***is*** about the room.

I have a horrible one I know from my problems before I eventually came to realize what the problem was. (BTW I am not alone I have read several FM post that they do not have stereo listening happening)

ciao
gr

 

[sidvee]

Not sure on room dimensions being discussed here. Is it 14' x 11'? If so YES you can have good sound in such a room provided you do some room treatment. My reference room is 14' x 12'x 8.5' (10' real ceiling with an armstrong false ceiling at 8.5'). I currently have Ascendo C8R speakers in my room placed at 4' from the wall behind the speakers on the short wall and at 28" from side walls. My listening position is 8' away and there is approx. 2' from the rear wall at my sitting position. I have 6 GIK 244 panels 4 in 4 corners and 2 at the first reflection point. Additionally I have 4 vicoustic wavewoods behind the speakers, 4 GIK gridfusors on the armstrong drop ceiling - at the first reflection point in the ceiling and 1 echobuster absorber behind my listening position. Room is carpeted with additional rug over the carpet. Using a Radio Shack db meter and test signals I have measured a fairly smooth response from my sitting position upto 36hz. There are no undue peaks (>+5db) corresponding to boomy mid bass frequencies, nor are there any peaks to indicate brightness in treble frequencies - I can listen to 2-3 hours of music without any fatigue - and I am very sensitive to brightness and sizzle in upper octaves. I have used both floor standers and bookshelves in the room and yes placement is important even after treatment as boom can appear. Of-course common sense is the key here, if you put in large floor standers with 12" woofers then they are going to overpower the room(unless ofcourse they are open baffle - you can search for my experience with spatial audio open baffles on the forum). My normal remedy when I feel boominess is to move the speakers laterally into the room and boom disappears. Of-course soundstage width is compressed a bit, but this is much better than boom. Room treatment is the key in smaller rooms.
BTW I have superb stereo imaging (pinpoint) with piano playing represented holographically in the space between the speakers with sound shifting in space as the keys are struck, and I have soundstage depth that to me subjectively feels like 8 feet with layering of intruments in that space. I also have a soundstage that is wider than the width of the speakers and about 8' high. I have had many senior FM's listen to my setup and they all more or less agree. So please note unless you have a room like the size of a small bathroom, good sound can be achieved by proper placement and judicious room treatment. Of-course if you want to listen to a live symphonic orchestra in a small room then "Laws of Physics" will take precedence and there is no way regardless of room treatments or DSP or magic that your small room will sound like a large venue/hall.
Cheers,
Sid

 

[sdurani]

So a "small multi-purpose room" may not be the ideal listening space for music even when measured and treated.

Bigger rooms are usually (not always) better, but you can still get excellent results in small rooms.

When you say "small", what dimensions are you talking about? When you say "multi-purpose", how many speakers are you thinking of?

What does one do when there is no choice of room and treatment to house the music system?

Start with placement (speakers and seating) to get the smoothest bass in the room, with the fewest/smallest peaks & dips.

Then place absorption at locations where reflections contribute least (or are even detrimental) to stereo reproduction, like most of the front wall and the middle half of the back wall. Side wall absorption comes down to personal preference, depending on how wide/big you like your soundstage to be.

But the first and easiest thing to start off with is placement, since it doesn't cost anything.

 

[rajesh srinivas]

Good sound can be achieved by proper placement and judicious room treatment. Of-course if you want to listen to a live symphonic orchestra in a small room then "Laws of Physics" will take precedence and there is no way regardless of room treatments or DSP or magic that your small room will sound like a large venue/hall.

1. Well said sidvee,this is the one and only solution we have currently i.e (room treatment/proper placement) to tame room modes or early reflections and to see that we do get clear sound from the speakers,and ofcourse with proper experimentation.

2.REW is the best software for measuring and analysing room and speaker responses,as all agree but they are not good at any correction,to achieve good results analog correction is prefered.

3. The above methods implies to stereo as well for ht,only thing is the qty of absorbers and diffuser varies,but these cannot be implied in smaller rooms.

4. For taming freq below 300hz,is either to have thicker absobers (6 to 8 inches) on all corners ground to ceiling though results are not fully achieved or can place another sub opposite to the existing one (center of the wall) or even have 4 subs to even out the bass in all corners of the room,so that you dont have to increase the vol which results in boomy bass and in turn standing waves.

So a "small multi-purpose room" may not be the ideal listening space for music even when measured and treated.
What does one do when there is no choice of room and treatment to house the music system?

Cheers,
Raghu

In such a situation best way to listen to music is through head phones of good make.

I am not talking of opinion, it is the physics of this illusion we chase, it is about how our brain perceives sound.

just reading laws of physics about sound and chasing illusion is not the only solution,we have to implement methods and take certain measures to correct them,as pointed out by sidvee and me you just have to follow them,thats the only way we can listen to proper sound.

r/s