Untreated room bass response

[r_w]

I haven't done any room treatment at all... it's the one thing that can ruin a lounge.

 

After some building work at home and a wall coming down I thought I'd better re calibrate the subs and have the following plot.

 

How does this measure up with those who have implemented room acoustic treatment?

 

The room used to be a big L, now it is a bigger rectangle with a dividing wall that goes through it but only for circa half the length.

 

I should probably do a quick diagram of the room.

 

Feedback much appreciated.

 

TAI

 

[r_w]

A quick knock-up of the room, probably not so accurate to scale:

 

[semente]

I haven't done any room treatment at all... it's the one thing that can ruin a lounge.

 

After some building work at home and a wall coming down I thought I'd better re calibrate the subs and have the following plot.

 

How does this measure up with those who have implemented room acoustic treatment?

 

The room used to be a big L, now it is a bigger rectangle with a dividing wall that goes through it but only for circa half the length.

 

I should probably do a quick diagram of the room.

 

Feedback much appreciated.

 

TAI

 

[ATTACH=CONFIG]29869[/ATTACH]

 

You should measure each channel separately.

How much smoothing did you apply to the curve?

What signal did you use, frequency sweep or pink noise?

 

Looking at your plan I would intuitively choose to position each the main speakers in front of the windows with the fireplace between them.

 

R

[r_w]

No didn't do each ch separately - I wouldn't ever use different eq on L/R channels as a point of principle.

 

I used 32 averaging with full range pink noise.

 

I don't want to rearrange the room, it's by far the best layout for living in... and it sounds great.

 

There has to be a compromise.

 

... but how does the plot look, great, good, ok, poor, compared to those with room treatment?

 

TIA

 

 

You should measure each channel separately.

How much smoothing did you apply to the curve?

What signal did you use, frequency sweep or pink noise?

 

Looking at your plan I would intuitively choose to position each the main speakers in front of the windows with the fireplace between them.

 

R

[semente]

The asymmetric positioning of your speakers requires different EQ'ing for each speaker, or at least different subwoofer settings (which is more or less the same).

 

But regardless of your principles you have to measure each speaker separately if you want meaningful results (even if you don't address each one differently).

 

Pink noise is fine, but your curve looks overly smooth.

Can you adjust smoothing to 1/12 or at least 1/6 octave?

 

R

[sphinxsix]

The bass response in treated rooms often looks similiar. Or worse.. Do you think the bass in your room is boomy.? If so - its source is probably the sub in the corner. Move it away from that place and listen/measure the difference. I personally for this reason prefer my subs placed closer to the rack than the speakers but if you place them like that you can have a strong sidewall sound reflection from your right speaker. You can try to place some absorbing material in the area of the reflection.. But it's quite possible you will have stereo imaging problems even then. The smaller the distance of the speaker from the wall - the stronger imaging problems.

[r_w]

Well I don't listen to music one speaker at a time, so if the plot is smooth with both having the same eq, based om my principles that's a sensible goal.

 

Most of the sub in the corner is going through the window, it isn't really a traditional corner, there's only about 6 inches of wall before the glass begins.

 

 

 

But regardless of your principles you have to measure each speaker separately if you want meaningful results (even if you don't address each one differently).

 

 

R

[r_w]

Bass is tight, sounds good. Was wondering if the room size has helped the need not to have acoustic panels.

 

It's a tough compromise getting a good living space that sounds good.

 

Interesting that you think some treated rooms might have a worse plot, that's positive feedback.

 

 

 

The bass response in treated rooms often looks similiar. Or worse.. Do you think the bass in your room is boomy.? If so - its source is probably the sub in the corner. Move it away from that place and listen/measure the difference. I personally for this reason prefer my subs placed closer to the rack than the speakers but if you place them like that you can have a strong sidewall sound reflection from your right speaker. You can try to place some absorbing material in the area of the reflection.. But it's quite possible you will have stereo imaging problems even then. The smaller the distance of the speaker from the wall - the stronger imaging problems.

[sphinxsix]

Love big rooms acoustics. In the case of your room the basic room resonance (stronger standing waves possibility) frequencies are around 38-45Hz (I don't know its height - it can influence it too) - provided the two room spaces connection is quite wide open. Probably if you measure it with 1/6 - 1/12 octave as semente suggested you will see it. If not - you are lucky

[semente]

Well I don't listen to music one speaker at a time, so if the plot is smooth with both having the same eq, based om my principles that's a sensible goal.

 

Most of the sub in the corner is going through the window, it isn't really a traditional corner, there's only about 6 inches of wall before the glass begins.

 

You can choose not take separate measurements, that's up to you, but you'll be ignoring speaker interaction.

 

It would be helpful if you were to tell us how much smoothing you applied to the FR plot and perhaps widen the horizontal scale to 2-300Hz.

 

R

[Iain]

Bass is tight, sounds good. Was wondering if the room size has helped the need not to have acoustic panels.

 

It's a tough compromise getting a good living space that sounds good.

 

Interesting that you think some treated rooms might have a worse plot, that's positive feedback.

 

Fortunately, my room problems were minor, so my sub-woofer's single-band on-board parametric equaliser sorted a 75 hz peak quite well.

 

If your sub-woofer doesn't have an-board PEQ, consider one that does for your next upgrade.

[r_w]

My subs have 3 band parametric eq but making the room bigger has significantly reduced the need for eq'ing.

 

Floor is wood boards that have a 5 foot cavity underneath, making the room even bigger.

 

I'll take a pic of the sub settings.

 

 

 

Fortunately, my room problems were minor, so my sub-woofer's single-band on-board parametric equaliser sorted a 75 hz peak quite well.

 

If your sub-woofer doesn't have an-board PEQ, consider one that does for your next upgrade.

[Fitzcaraldo215]

Bass is tight, sounds good. Was wondering if the room size has helped the need not to have acoustic panels.

 

It's a tough compromise getting a good living space that sounds good.

 

Interesting that you think some treated rooms might have a worse plot, that's positive feedback.

 

The deep bass under 100 Hz is almost invariably where the biggest room induced non-linearities occur. Forget acoustic panels. Most off the shelf acoustic panels really do not do much below 100Hz. For example, check the graphs for the big, expensive ASC tube traps at their site. You will see that they will be doing much more above 100 Hz, which you may find undesirable. Others are similar.

 

Floyd Toole once said that absorbative treatments are unfortunately a wide frequency band solution to what is a narrow band problem in most rooms. And, treatments for the deep bass have to be huge, often ugly, structures due to the large wavelengths involved.

 

The answer that is effective is DSP Room EQ, either manually dialed parametrically or auto-calibrated via a software suite. Professional acousticians use it widely. I have used it for years with great success in an untreated room, currently Dirac Live. I would never be without it in some form. Your bass may sound fine to you until, that is, you hear what mike calibrated EQ can do.

 

I strongly favor the auto-EQ approach because it saves huge amounts of time vs. tuning individual frequency bands manually via parametric EQ. You do not have to become an acoustics expert to use auto-EQ. Much more learning, remeasuring, etc. is required to use parametric effectively. And, I, for one, prefer multi-mike point averaging to see what the room/speaker response is. That complicates measuring, remeasuring, etc. for parametric. But, it is built into many auto-EQ software packages.

 

And, your graphs would seem to indicate you need to use a much less smoothed graph to spot the response problems in the deep bass.

 

Yes, a bigger room is generally better than a smaller one in terms of modal effects. But, I have had some large, high ceiling rooms that still benefitted from EQ - in the 7-8 dB range. I have seen narrow modal peaks in the > 15 dB range in a number of smaller, low ceiling rooms. Every room dimension and even furniture matters, and oblique modes not easily predicted by the dimensions can "gang up" at certain frequencies or their harmonics. Measurement is the only answer.

[Axiom05]

Bass is tight, sounds good. Was wondering if the room size has helped the need not to have acoustic panels.

 

It's a tough compromise getting a good living space that sounds good.

 

Interesting that you think some treated rooms might have a worse plot, that's positive feedback.

 

The frequency response that you are measuring is only one part of the equation, and often not the most important. What you are showing gives no information about the time domain behavior. Only waterfall plots will show you how long the low frequencies "ring" within the room. Most people use bass traps more to reduce the resonance time than to smooth the frequency response. A smoother frequency response is usually a result of improved time domain behavior.

[r_w]

I'll have a look at doing waterfall in REW, not sure how but I'll take a look.

 

Thanks.

 

The frequency response that you are measuring is only one part of the equation, and often not the most important. What you are showing gives no information about the time domain behavior. Only waterfall plots will show you how long the low frequencies "ring" within the room. Most people use bass traps more to reduce the resonance time than to smooth the frequency response. A smoother frequency response is usually a result of improved time domain behavior.

[r_w]

These are the settings, I assumed 1/48 would be most accurate:

 

Smoothing is turned off in prefs (default = no smoothing), I didn't turn it on.

 

 

You can choose not take separate measurements, that's up to you, but you'll be ignoring speaker interaction.

 

It would be helpful if you were to tell us how much smoothing you applied to the FR plot and perhaps widen the horizontal scale to 2-300Hz.

 

R

[semente]

Thanks.

1/48 will provide a lot of information but I find the plots too smooth for such resolution.

Perhaps it's because of the horizontal scale, which is showing an uncommonly narrow frequency range.

 

R

[r_w]

Current settings (same for both subs):

 

[mordante]

A few years ago I have had some measurements done in my living room. These are the results. Since then I've but up 3 116*236cm absorption panels on the ceiling. They are 4 cm thick and hang 5cm from the ceiling. I have not had any measurements done since then. In the coming year I plan to invest some more in acoustics.

 

 

 

 

 

[sphinxsix]

@mordante May I ask about your room dimensions? (or some more detailed description if it has some unusual shape)

[mordante]

@mordante May I ask about your room dimensions? (or some more detailed description if it has some unusual shape)

 

My room is aprox 410cm wide, 650cm land and 260cm high. I have two way speakers that stand in the length of the room. I cannot remember how far the speakers are from the walls.

 

The ceiling panels did help. The sound is more coherent, greater clarity. The next step for me would be to place absorbers at the first reflection point on the wall en next would be some bass traps in the corners behind the speakers.

 

However my budget is limited. Also my listening room is also my living room.

 

This this thread

 

http://www.computeraudiophile.com/f8-general-forum/ceiling-panels-installed-what-have-i-been-waiting-27705/index2.html

[Cornan]

I know that several companies have free services for room treatments. Here is one example from Auralex called Room Layout Express RLX | Room Layout eXpress

[crenca]

The deep bass under 100 Hz is almost invariably where the biggest room induced non-linearities occur. Forget acoustic panels. Most off the shelf acoustic panels really do not do much below 100Hz...Yes, a bigger room is generally better than a smaller one in terms of modal effects. But, I have had some large, high ceiling rooms that still benefitted from EQ - in the 7-8 dB rangem. I have seen narrow modal peaks in the > 15 dB range in a number of smaller, low ceiling rooms. Every room dimension and even furniture matters, and oblique modes not easily predicted by the dimensions can "gang up" at certain frequencies or their harmonics. Measurement is the only answer.

 

Interesting thread guys. I have learned to trust my ear and I am currently integrating a sub. I have heard it said - and my own experience tells me there is alot of truth in it - that if your using manual parametric EQ (which is what I use) or even (especially?) auto-DSP (such as Dirac) to EQ your way out of a more than 6db trough/peak, your trying to do to much (in other words you need to resort instead to "organic" room treatment, speaker/sub placement, etc.). Ideally, you should keep most of your EQ no more than 3 db.

 

Also, as far as impulse response by keeping your sub(s) on the same plane (not behind speakers as is typical) that *should* eliminate that issue in the main, no?

 

comments, criticisms, suggestions?

[Iain]

Interesting thread guys. I have learned to trust my ear and I am currently integrating a sub. I have heard it said - and my own experience tells me there is alot of truth in it - that if your using manual parametric EQ (which is what I use) or even (especially?) auto-DSP (such as Dirac) to EQ your way out of a more than 6db trough/peak, your trying to do to much (in other words you need to resort instead to "organic" room treatment, speaker/sub placement, etc.). Ideally, you should keep most of your EQ no more than 3 db.

 

Also, as far as impulse response by keeping your sub(s) on the same plane (not behind speakers as is typical) that *should* eliminate that issue in the main, no?

 

comments, criticisms, suggestions?

 

My sub-woofer is positioned on an adjacent wall 90 degrees off-axis from the front speakers. I know nothing of Dirac, but I tried Audyssey a couple of years ago and didn't like it's effect on sound quality in general.

 

What works best in my current environment, is simply adjusting multi-channel speaker distance settings and sub-woofer PEQ manually. I consider "room treatments" as odd and unnecessary distractions to musical enjoyment.

[sphinxsix]

Untreated room:

 

 

+/- 5db

 

 

'Lightly' treated room:

 

 

+/- 5db (in the bass department)

 

@r_w See.?

 

 

@mordante 6,5m is responsible for approx. 80Hz peak, 4,1m - for app. 50Hz one. The theory and reality go together.

 

@crenca As for subs placement - I prefer them to be aprox. in line with the speakers but 20-30 cm won't make a difference (the bass wavelengths are to long to create serious phase distortion). I'm against heavy equalizing too. I remember noticing that the sound from my laptop is more bass thin than from the CD player (cables). I thought the necessary correction (JRiver parametric EQ) will be 2-3db. 0,6db proved to be enough. I hate the view of many acoustic panels in my listening room which is always my living room too. Bookshelves (filled with books) are fantastic and cheap. If you already have the books... I'm quite curious how would measerments of my room look as it has the best acoustics of all the rooms I lived in. It's big (40 sq.m) and very irregular (a loft) which always helps. If you're curious about the details - I posted some information on 'What Are the Best Sounding Speakers You've Ever Heard.?' thread. The photos are in one of my albums. My experience is that (with some experience) the basic things as for room acoustics improvement are usually easy to detect and to do on the cheap in a way that won't hurt our eyes!