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Tackling room resonances

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Re: Tackling room resonances

Postby TNGator » Wed Aug 07, 2019 10:08 pm

room66 wrote:Not sure if this has been suggested already ... Helmholtz resonators work very well for low frequencies.
We built one ourselves for a 50Hz peak in our room.
There's some threads on gearslutz forum how to.
You may try this
Hey thanks guy. No hadnt heard of this. As it happens, i only joined the gearslutz forum yesterday so I'll bounce over and do a search. Thanks again.
ps... I got my REW configured and my test mic arrived. Have been able to do a sweep of the room but...... I havent the foggiest on how to read the graph. I may as well be looking at a chest x ray.
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Re: Tackling room resonances

Postby Sam Spoons » Wed Aug 07, 2019 10:56 pm

TNGator wrote:
Sam Spoons wrote:Given that a couple of duvets can make a significant difference can you post some pics of your DIY traps in the room? It seems a shame to righty them of after the money and effort and there may be other reasons why they don't see to be working as you expected.

Hi Sam. I didn't test the duvet just yet. But yes that is on the menu. You see my plan is to try out this REW software I downloaded starting with a naked room then bring in the DIY stuff and re-test. Im hoping to see what DIY stuff works, doesnt work, kinda works etc. My home made absorbers might work if i select a higher range of frequencies in the REW sweep. At present Im testing from about 40Hz to 300Hz. I just picked that range arbitrarily.
Now my panels may not need to be ditched but I might have to put deeper sides on them. I really made them too shallow which was a silly goof on my part. Im concerned about the weight of the panels and wood can be very heavy. That guy on YT who tested bathroom towels? Tried it. Didnt make a blind bit of difference to the graph. I'll keep you updated Sam. Bank holiday weekend here. So...pub :)

I think measuring in a small room is a bit of a red herring unless you have pro kit and extensive knowledge.

To achieve any effect below 300Hz you'll need a panel at least ¼ wavelength or 25cm deep so its not surprising your 50mm panels are not tickling your graph. Just listen to the room and ask yourself "does the room sound better than before the treatment?"

Don't worry about deep sides BTW, just spacing the panels off the wall will be almost as effective in improving the response at lower frequencies.
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Re: Tackling room resonances

Postby TNGator » Thu Aug 08, 2019 7:35 am

Sam Spoons wrote:
TNGator wrote:
Sam Spoons wrote:Given that a couple of duvets can make a significant difference can you post some pics of your DIY traps in the room? It seems a shame to righty them of after the money and effort and there may be other reasons why they don't see to be working as you expected.

Hi Sam. I didn't test the duvet just yet. But yes that is on the menu. You see my plan is to try out this REW software I downloaded starting with a naked room then bring in the DIY stuff and re-test. Im hoping to see what DIY stuff works, doesnt work, kinda works etc. My home made absorbers might work if i select a higher range of frequencies in the REW sweep. At present Im testing from about 40Hz to 300Hz. I just picked that range arbitrarily.
Now my panels may not need to be ditched but I might have to put deeper sides on them. I really made them too shallow which was a silly goof on my part. Im concerned about the weight of the panels and wood can be very heavy. That guy on YT who tested bathroom towels? Tried it. Didnt make a blind bit of difference to the graph. I'll keep you updated Sam. Bank holiday weekend here. So...pub :)

I think measuring in a small room is a bit of a red herring unless you have pro kit and extensive knowledge.

To achieve any effect below 300Hz you'll need a panel at least ¼ wavelength or 25cm deep so its not surprising your 50mm panels are not tickling your graph. Just listen to the room and ask yourself "does the room sound better than before the treatment?"

Don't worry about deep sides BTW, just spacing the panels off the wall will be almost as effective in improving the response at lower frequencies.

Hi Sam. Well to be honest I wouldn't spend hundreds on that test gear. I knew it existed but I always thought it was expensive gear just for the pro studio. But when I found REW was free and the test mic was only 30 euro I thought..hey why not. Ive been advised on this forum that in a small room, wall panels wont do much and bass traps would be a much better idea. So Im slowly getting educated on this stuff. With that, Im going to concentrate on the corners i.e. traps. Yes I'll experiment with some home made "deep" devices and test. I had also heard as you mentioned, about keeping a space behind them. Im not sure of the science how this works but the tip seems to be...keep them away from the wall. And anyway Sam, like the rest of us here, there's only so much i can do. Im in my small living room which is a perfect shape, has a fireplace jutting out, a window facing me and a door on either side of me which are not opposite each other. So yeah...its not Abbey rd. I'll do what I can but if I turn down Nerd avenue I'll never get back on the freeway.
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Re: Tackling room resonances

Postby Hugh Robjohns » Thu Aug 08, 2019 9:15 am

There are basically two separate issues to deal with at a project studio level. The first is mid-band and HF reflections from the mirror points that mess up the stereo imaging and colour the midrange room your monitor speakers, and the second are the standing waves that give a lumpy bass.

Standard broadband panels of 2 - 4 inches deep will deal with the first issue pretty effectively.

Dealing with LF standing waves is much, much harder. As Sam says, if you go down the lossy absorber route -- using mineral wool or foam etc -- then you need a lot of it in very deep panels, which is rarely practical in a small room -- although you can often make use of corners quite effectively to gain more depth than would otherwise be possible.

But there are other, less invasive solutions... It's just that they are far more complicated and expensive to build. Limp mass membranes are one option, and resonant cavity absorbers are another...
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Re: Tackling room resonances

Postby Sam Spoons » Thu Aug 08, 2019 10:32 am

REW is great, I have it but you are measuring the bass region and wondering why your mid/high frequency absorber panels are not making any difference. No surprise that they make little or no difference ;) . If you set the frequency limits to 300-3000Hz you'd see a difference and, hopefully, you'll hear a difference too.

Don't worry about an imperfect room, as Hugh says the mid/high absorbers help to improve stereo image and tonal balance in the mid and high frequency ranges, in an ideal word they would be symmetrical around the mixing position but if you can't do that just do your best* with the room you have you should still hear an improvement.

*good headphones are the standard means for checking mixes in an imperfect mix environment.
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Re: Tackling room resonances

Postby blinddrew » Thu Aug 08, 2019 12:56 pm

Sam Spoons wrote:*good headphones are the standard means for checking mixes in an imperfect mix environment.
And pretty much essential for checking your low end in even a fairly well treated project room.
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Re: Tackling room resonances

Postby TNGator » Thu Aug 08, 2019 8:36 pm

Sam Spoons wrote:REW is great, I have it but you are measuring the bass region and wondering why your mid/high frequency absorber panels are not making any difference. No surprise that they make little or no difference ;) . If you set the frequency limits to 300-3000Hz you'd see a difference and, hopefully, you'll hear a difference too.

Don't worry about an imperfect room, as Hugh says the mid/high absorbers help to improve stereo image and tonal balance in the mid and high frequency ranges, in an ideal word they would be symmetrical around the mixing position but if you can't do that just do your best* with the room you have you should still hear an improvement.

*good headphones are the standard means for checking mixes in an imperfect mix environment.
Hi Sam. Not sure if this was for me but Im testing different ranges not just the base frequencies. 'll keep testing my absorbers and move up the frequency range. Hopefully I'll find they at least work in the upper ranges. Although the advice Im getting on the forum is that Im probably not experiencing any problems in the upper range. apparently small rooms get problems with lower frequencies. Hence the importance to concentrate on getting bass traps and not wall panels.
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Re: Tackling room resonances

Postby Sam Spoons » Thu Aug 08, 2019 9:45 pm

My understanding is that it's not quite as simple as that, an untreated room will have problems across the whole range but the bass is hardest top deal with.

TNGator wrote:
Sam Spoons wrote:Given that a couple of duvets can make a significant difference can you post some pics of your DIY traps in the room? It seems a shame to righty them of after the money and effort and there may be other reasons why they don't see to be working as you expected.

Hi Sam. I didn't test the duvet just yet. But yes that is on the menu. You see my plan is to try out this REW software I downloaded starting with a naked room then bring in the DIY stuff and re-test. Im hoping to see what DIY stuff works, doesnt work, kinda works etc. My home made absorbers might work if i select a higher range of frequencies in the REW sweep. At present Im testing from about 40Hz to 300Hz. I just picked that range arbitrarily.
Now my panels may not need to be ditched but I might have to put deeper sides on them. I really made them too shallow which was a silly goof on my part. Im concerned about the weight of the panels and wood can be very heavy. That guy on YT who tested bathroom towels? Tried it. Didnt make a blind bit of difference to the graph. I'll keep you updated Sam. Bank holiday weekend here. So...pub :)

I was replying to that particular post, forgive me if i missed some reference to wider range testing (I can't take time to re-read the whole thread just now). If you had no treatment in the mid/high range you would almost certainly find stereo image and detail compromised but, yes, the bass end is most troublesome in small rooms and, quite likely impossible to fully control hence the fact that the advice is directed that way.

FWIW my own room sounds pretty good and works for me as a (compact/bijou) recording mixing and rehearsal space but the bass end is going to be a bit wayward. I used REW when I first installed the treatment but have now moved on to just enjoying my 'studio' for what it is, i.e. not Abbey Rd but a nice place to play, record and listen to music. It's not perfect (far from it) but it serves my needs (and for mixing headphones let me check the low end for any obvious anomalies).
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Re: Tackling room resonances

Postby TNGator » Thu Aug 08, 2019 10:27 pm

Sam Spoons wrote:My understanding is that it's not quite as simple as that, an untreated room will have problems across the whole range but the bass is hardest top deal with.

TNGator wrote:
Sam Spoons wrote:Given that a couple of duvets can make a significant difference can you post some pics of your DIY traps in the room? It seems a shame to righty them of after the money and effort and there may be other reasons why they don't see to be working as you expected.

Hi Sam. I didn't test the duvet just yet. But yes that is on the menu. You see my plan is to try out this REW software I downloaded starting with a naked room then bring in the DIY stuff and re-test. Im hoping to see what DIY stuff works, doesnt work, kinda works etc. My home made absorbers might work if i select a higher range of frequencies in the REW sweep. At present Im testing from about 40Hz to 300Hz. I just picked that range arbitrarily.
Now my panels may not need to be ditched but I might have to put deeper sides on them. I really made them too shallow which was a silly goof on my part. Im concerned about the weight of the panels and wood can be very heavy. That guy on YT who tested bathroom towels? Tried it. Didnt make a blind bit of difference to the graph. I'll keep you updated Sam. Bank holiday weekend here. So...pub :)

I was replying to that particular post, forgive me if i missed some reference to wider range testing (I can't take time to re-read the whole thread just now). If you had no treatment in the mid/high range you would almost certainly find stereo image and detail compromised but, yes, the bass end is most troublesome in small rooms and, quite likely impossible to fully control hence the fact that the advice is directed that way.

FWIW my own room sounds pretty good and works for me as a (compact/bijou) recording mixing and rehearsal space but the bass end is going to be a bit wayward. I used REW when I first installed the treatment but have now moved on to just enjoying my 'studio' for what it is, i.e. not Abbey Rd but a nice place to play, record and listen to music. It's not perfect (far from it) but it serves my needs (and for mixing headphones let me check the low end for any obvious anomalies).

Hey no worries Sam.. All tips and advice greatly appreciated. I guess at the end of the day what we are all trying to avoid is a situation where our music sounds great at home....but the demo we sound to a publisher sounds awful on their system. I suppose the good ol car test is as good a test as any. I often wonder if the guys who are putting stuff on Reverb Nation etc are using pro studios. The quality is incredible.
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Re: Tackling room resonances

Postby Sam Spoons » Thu Aug 08, 2019 10:39 pm

:thumbup:
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Re: Tackling room resonances

Postby TNGator » Fri Aug 09, 2019 7:43 am

Sam Spoons wrote::thumbup:

Have a look at this Sam. Very complicated, very techy BUT... the important DUMMYS bit is right near the end. If your room is less than 17 by 23 then you have to concentrate on the low end. And Ive no doubt NO ONE here is in a room that big.
Go to 5 min 52. Well I guess that puts that to bed. Bass traps it is :)
Happy FFFFFFFFRiday Sam
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Re: Tackling room resonances

Postby Martin Walker » Fri Aug 09, 2019 10:42 am

TNGator wrote:
Sam Spoons wrote::thumbup:

Have a look at this Sam. Very complicated, very techy BUT... the important DUMMYS bit is right near the end. If your room is less than 17 by 23 then you have to concentrate on the low end. And Ive no doubt NO ONE here is in a room that big.
Go to 5 min 52. Well I guess that puts that to bed. Bass traps it is :)
Happy FFFFFFFFRiday Sam
Xave

Er, did you intend to add a link to your post TNGator? :beamup:


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Re: Tackling room resonances

Postby Mike Stranks » Fri Aug 09, 2019 11:51 am

Martin Walker wrote:
TNGator wrote:
Sam Spoons wrote::thumbup:

Have a look at this Sam. Very complicated, very techy BUT... the important DUMMYS bit is right near the end. If your room is less than 17 by 23 then you have to concentrate on the low end. And Ive no doubt NO ONE here is in a room that big.
Go to 5 min 52. Well I guess that puts that to bed. Bass traps it is :)
Happy FFFFFFFFRiday Sam
Xave

Er, did you intend to add a link to your post TNGator? :beamup:


Martin

I've PM'd him Martin to say it's gone missing...
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Re: Tackling room resonances

Postby Sam Spoons » Fri Aug 09, 2019 5:37 pm

TNGator wrote:
Sam Spoons wrote::thumbup:

Have a look at this Sam. Very complicated, very techy BUT... the important DUMMYS bit is right near the end. If your room is less than 17 by 23 then you have to concentrate on the low end. And Ive no doubt NO ONE here is in a room that big.
Go to 5 min 52. Well I guess that puts that to bed. Bass traps it is :)
Happy FFFFFFFFRiday Sam
Xave

Obviously haven't seen the vid yet but I don't recall saying you didn't need/shouldn't install bass traps (I have three fairly big ones in my 4 x 4 metre room) just that you do ned to treat the mid/high end too. Effective bass treatment may be impossible, again that's no reason not to attempt it, but bass traps alone (even if effective) will not give you a good sounding room.

Do post that link, you have piqued my curiosity now :thumbup:
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Re: Tackling room resonances

Postby Dennis J Wilkins » Fri Aug 09, 2019 6:35 pm

Hello,

Haven't the time to read all posts in this thread, being buried with testing (beta and for product reviews) and trying to wrap up an article for SOS that has been mentioned in other SOS forums (not sure of the final title for the article, but the working title is Studio Acoustics and Room EQ Wizard). I've seen several comments here about small rooms and low end - all true! Low end is impossible to truly flatten using acoustic treatment alone since even 50 Hz requires something like five feet of rock wool or equivalent to begin effective absorption!

As indicated in my April article, Studio SOS: Home Studio Upgrade I use software room correction (ARC 2.5) to tame some big peaks and dips below a few hundred Hertz since I have about all the bass absorbers I can fit in my small room. Systems like ARC and Sonarworks Reference 4 do help to really flatten the frequency response up to a few hundred Hertz, but the other problem in a small room is decay time, which EQ/phase correction cannot directly affect. However, removing a typical low resonant peak , which may be 10-20 dB above the midrange level even with some bass trapping, will also help reduce the decay time at that frequency since it won't be starting at a boosted level.

Watch for the upcoming article (not sure when, but likely in two installments). BTW, REW 5.19 is the current version and works well, but 5.20 is coming soon with some improvements which I will describe. It is an incredible tool, but can take a bit of effort to gain proficiency in its use and interpretation of results. I'm trying to provide some simple steps for making measurements and figuring out what they mean.

cheers
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Re: Tackling room resonances

Postby TNGator » Fri Aug 09, 2019 9:48 pm

Martin Walker wrote:
TNGator wrote:
Sam Spoons wrote::thumbup:

Have a look at this Sam. Very complicated, very techy BUT... the important DUMMYS bit is right near the end. If your room is less than 17 by 23 then you have to concentrate on the low end. And Ive no doubt NO ONE here is in a room that big.
Go to 5 min 52. Well I guess that puts that to bed. Bass traps it is :)
Happy FFFFFFFFRiday Sam
Xave

Er, did you intend to add a link to your post TNGator? :beamup:


Martin

Ooops...sorry y'all. My goof.

Link is https://www.youtube.com/watch?v=3-iFsWUrOhs
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Re: Tackling room resonances

Postby Sam Spoons » Fri Aug 09, 2019 9:53 pm

Ta, will watch tomorrow when I have (hopefully) decent WiFi.
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Re: Tackling room resonances

Postby tbozaudio » Sat Aug 10, 2019 3:35 am

I have a very small tracking room. I am also a drummer.... argh. Fought with room issues for a long time. Tried everything I could to get a decent sound. I finally came to the conclusion that I will never be able to get anything good while tracking and embraced the fact that I needed to approach things very differently. I identified the “nasties” ie, SPL, Standing waves, comb filtering, phase, terrible reflections etc.... pretty much every component talkative works against you! To try to compensate for all this is pretty much literally impossible.

I approached things from a different perspective. Make the room disappear. The thought is very much like a green screen in the video world. I can always add room simulations in combinations with mild reverb to create different rooms.

I framed a 9x9x9 room with 2x4’s and added a bass trap space in one corner of the wall. Then I researched what absorption material I thought would work to deal with all the low end and SPL. Ended up with 3.5” insul-shield and went wall to ceiling with it. I have read so many articles that say that dead room this and that, but I was beside myself with how my drums responded. Great attack, totally natural decay and super warm and punchy.
The best thing is that I can totally envelope my kit into any room sim and make it sound very good. The insul-shield is a semi-rigid panel, so it’s not stifling at all. It gives me incredible control and eq responsive
Throughout the spectrum with no appreciable bumps or dips. Now, I will have to say that I took into consideration the preamps I have which are super clear, high output and very low noise. The transparent preamps works well with the warmth and punchlines of my tracking space. The room has turned out to be a lifesaver.

Not saying this is for everyone. I can just say, I’ve never had such ease with mic placement, very nice response from the kit and total predictable outcomes before.
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Re: Tackling room resonances

Postby blinddrew » Sat Aug 10, 2019 10:08 am

I wonder if we might add this thread to the useful information archive?
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Re: Tackling room resonances

Postby TNGator » Sat Aug 10, 2019 10:25 am

tbozaudio wrote:I have a very small tracking room. I am also a drummer.... argh. Fought with room issues for a long time. Tried everything I could to get a decent sound. I finally came to the conclusion that I will never be able to get anything good while tracking and embraced the fact that I needed to approach things very differently. I identified the “nasties” ie, SPL, Standing waves, comb filtering, phase, terrible reflections etc.... pretty much every component talkative works against you! To try to compensate for all this is pretty much literally impossible.

I approached things from a different perspective. Make the room disappear. The thought is very much like a green screen in the video world. I can always add room simulations in combinations with mild reverb to create different rooms.

I framed a 9x9x9 room with 2x4’s and added a bass trap space in one corner of the wall. Then I researched what absorption material I thought would work to deal with all the low end and SPL. Ended up with 3.5” insul-shield and went wall to ceiling with it. I have read so many articles that say that dead room this and that, but I was beside myself with how my drums responded. Great attack, totally natural decay and super warm and punchy.
The best thing is that I can totally envelope my kit into any room sim and make it sound very good. The insul-shield is a semi-rigid panel, so it’s not stifling at all. It gives me incredible control and eq responsive
Throughout the spectrum with no appreciable bumps or dips. Now, I will have to say that I took into consideration the preamps I have which are super clear, high output and very low noise. The transparent preamps works well with the warmth and punchlines of my tracking space. The room has turned out to be a lifesaver.

Not saying this is for everyone. I can just say, I’ve never had such ease with mic placement, very nice response from the kit and total predictable outcomes before.
Wow...thats a lot of work bro but well done. Sadly I cant do anything on such a major scale in my room. It's a walkthrough room with two doors and a fireplace jutting out on one wall. Plus...it is my living room. But great job man.
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