Helmholtz resonator and room modes

The box is 1.52mx0.54mx0.52m And you're right, that box is about 100 times smaller than the room. I always wondered how it could ever imact the room response but the internet is full of people claiming (even graphs proving it) that they got a difference of 6-10dB...

This comment brings me back to my 1st post where I said that my old studio had the problem where by the trap had to be almost the same size as the room to actually do anything LOL.

Alan.
 
This comment brings me back to my 1st post where I said that my old studio had the problem where by the trap had to be almost the same size as the room to actually do anything LOL.

Alan.

Then I guess it leads to the conclusion that Helmholtz resonators just don't work as studio treatement...
 
Then I guess it leads to the conclusion that Helmholtz resonators just don't work as studio treatement...

They do if the studio is big enough to fix the Helmholtz resonator you need. I:e Abby Road. For small studios you need a bass trap of a different design, maybe a bass trap in all the corners, remembering that corners also occur between the ceiling and walls, so there is plenty of room to place a lot of smaller bass traps.

Alan.
 
They do if the studio is big enough to fix the Helmholtz resonator you need. I:e Abby Road. For small studios you need a bass trap of a different design, maybe a bass trap in all the corners, remembering that corners also occur between the ceiling and walls, so there is plenty of room to place a lot of smaller bass traps.

Alan.

Yeah but with a bigger room doesn't the mode frequency get lower thus the energy greater leading to the fact that you need an even bigger helmholtz resonator... :/

So far I haven't tried membrane absorbers, maybe they could work... That's what the guys at GIK acoustic are suggesting... Does anyone have thoughts on these..?
 
So far I haven't tried membrane absorbers, maybe they could work... That's what the guys at GIK acoustic are suggesting... Does anyone have thoughts on these..?

Since you asked... :)

I didn't do the full-tilt "membrane" design...which is a completely sealed trap, and harder to build right...but I did employ a "membrane" philosophy in the mega-bass traps I built, using the foil-backed side of the insulation for that purpose. Plus, the traps can be rotated to the "soft" side, since these are not permanently mounted. They are free standing, and can be placed on top of something to raise them, or even stacked (to a point).
Not sure what materials you can get out there...but most of this stuff is fairly common, or there's other similar/equivalent material that you can find/use.

Here's my bass trap DIY: Bass Trap Madness
 
Since you asked... :)

I didn't do the full-tilt "membrane" design...which is a completely sealed trap, and harder to build right...but I did employ a "membrane" philosophy in the mega-bass traps I built, using the foil-backed side of the insulation for that purpose. Plus, the traps can be rotated to the "soft" side, since these are not permanently mounted. They are free standing, and can be placed on top of something to raise them, or even stacked (to a point).
Not sure what materials you can get out there...but most of this stuff is fairly common, or there's other similar/equivalent material that you can find/use.

Here's my bass trap DIY: Bass Trap Madness

Thanks for the repy :)
I must admit that your traps do look great but what are the characteristics..? do they actually go low enough for my needs..? Have you done some measurements preferabely with them turned on one side and then the other...?
 
I did a lot of measurements before and after, and with the traps in various position.
Bottom line...the traps reduced some o the low end issues...but I had no misconceptions that I could make the room perfect, and I wasn't really trying, because without a really large room, perfection isn't going to happen...and even then, it takes a lot of proper ground-up building with acoustics in mind to make a large room measure great, but rarely perfect.

I think you need to do the best you can, and move on with what you have. I don't there is a bass trap solution that will give what you are shooting for...so find the best you can, and stop doing measurements. :)
I would also see how good you can get it without the sub...and consider its value if it is the main source of your low end issues. Maybe use it for pure playback purposes, and leave it off during critical mixing.
 
You can always turn down the sub.... :) Maybe the sub crossover frequency is messing things up.

I agree with the getting things close then just do what you do. Trying to make a room perfect in frequency response is impossible and could be likely taking away from the time you are mixing and learning how to work with what you have.

Miro and I have disagreed at points in the past. But I am with him 100% on this one. Move forward man. :)
 
Hey guys, as you might have expected I still haven't moved on... :D
Anyways, I did some tweaking of the sub and did some new measurements I'm uploading the before (green) and after (red) pictures.
What do you think, is it an improvement or is it even worse..?green spl.jpggreen waterfall.jpgred spl.jpgred waterfall.jpg
 
Then I guess it leads to the conclusion that Helmholtz resonators just don't work as studio treatement...

Correct.

Unless they are about one third of the room volume. And half is even better...

But that's far from practical unless you're dealing with a very large room that is too large. Now who can show me a (home) studio that is too large?

I've been in one, exactly. And even in that case, the problem was solved with removable absorbing walls, cause they also used it for live events.

I've also seen pics of a guy in Italy, who built the biggest subwoofer in the world attached to his new house. The sub's volume is bigger than his big living room, horn loaded at the front and has a tuned Helmholtz chamber at the back. I suppose that would work.

Also, when measuring mics, a small Helmholtz chamber works very well for some measurements. Usually some kind of tuned tube.

With resonators, you get a small bandwidth, so tuning is central to the problem. Enlarging the hole in a fixed size cabinet won't change the frequency, but it will affect bandwidth and effectivity. Not what you're looking for.

FWIW. I've been experimenting with subs for a long time. I'm unable to get 2.1 setups to work as a studio monitor. Sure, watching disaster movies works very well. But monitoring? I don't think so.

I'm guessing your sub is on the floor, in the middle of the room? Have you tried moving the sub? It could very well be in the perfect position to produce 38 Hz resonance because of distance to side walls and ceiling. A triple resonance can only be treated by moving the source, imho.

I've stopped caring about sub 40 Hz. When my speakers turn muddy, I apply a HPF. It's not the speaker's fault, as they weren't designed to reproduce rumble from a passing-by 40 ton truck that isn't audible to us, humans. There's no music sub 40 Hz, unless you're mixing a church organ in an acoustically sound church. These can reach 16 Hz in rare circumstances. The only speaker I know that can reproduce that more or less accurately, is the Klipsch Horn, if placed in a corner. Coincidentally, I was listening to four of those yesterday night, in a discotheque. I was wondering how these small active Behringers could go so low. I couldn't hear the Klipsch Horns, but boy, I could feel them :D
 
FWIW. I've been experimenting with subs for a long time. I'm unable to get 2.1 setups to work as a studio monitor. Sure, watching disaster movies works very well. But monitoring? I don't think so.

:thumbs up:

That's been my suggestion all along...lose the sub, and measure/fix the room acoustics without it.
The sub can be turned on for pure listening moments when the low end rumble is desired...but I wouldn't monitor with the sub, or worry about treating a less then optimal size room for sub use when monitoring...

...but obsessions can be difficult to satisfy! :D
 
What do you think, is it an improvement or is it even worse

I don't how much better the "red" is...you've managed to reduce some things, for sure, and you've smoothed out the highs from 2k up, which I think is more critical than the sub lows you are chasing. The bigger concern are the two huge dips at 1k and 2K...which are you upper mids/highs, and is the area most associated with clarity and harshness for a lot of instruments and voices. With those big dips, you might over-correct in that 1k-2k range, which might translate to harsher upper-mids/highs...so something is wonky there.

Again...turn off the sub...work the room to get the best measurements possible without it...and then just turn on the sub and place it where you think it *sounds* best...without doing any more measurements....and just use it for listening, not for monitoring.
 
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