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  Topic Review (Newest First)
09-14-10 12:31 PM
bpape
Re: Are helmholtz resonators and diffusers all we need?

4 x 38 = 152Hz. If there was a harmonic of the 38Hz that was interacting with something else, it's not there now and the other can be showing through.

Bryan
09-14-10 12:28 PM
giankam
Re: Are helmholtz resonators and diffusers all we need?

How can it be that adjusting the 38Hz region it affects also 100/200Hz range?

Please anybody can explain or make any consideration? I really don't get it.

Thanks
10-27-08 10:05 PM
bpape
Re: Are helmholtz resonators and diffusers all we need?

They can vary quite a bit. I suspect that's why there are no specs on that site since they will vary greatly depending on how it's tuned. It would be nice to have a sample set though at say 2 different tunings so one could properly estimate what would be needed.

Bryan
10-27-08 10:01 PM
fredk
Re: Are helmholtz resonators and diffusers all we need?

Thanks for the link omholt. The debth of the resonators is in the same ballpark as I was modeling using some online tools.

I have some space that I could use for resonators, but I have no idea if it would be enough to be effective.

Quote:
atledreier wrote: View Post
So how do one know how much/many H-boxes to build?
Quote:
You'd need several of them.
After doing a lot of reading, that about sums up what I have found. I have yet to find anyone who has published information quantifying the effectiveness of helmholtz resonators.

I did find one book on Amazon that got quite deep into the math behind figuring out the tuning of resonators and difusors, but there was nothing to quantify effectiveness. It may well be that the nature and complexity of room acoustics does not lend itself to quantification.
10-27-08 05:06 PM
bpape
Re: Are helmholtz resonators and diffusers all we need?

Again, there's a lot more to it than just frequency response. Impulse response and decay times are also important.

As for reflective at the 1st reflection points, that can work if:

- You're within the proper timeframe
- The speaker has an almost perfect power response way off axis or they're extremely directional
- You don't have close proximity of the speaker to the side boundary that would require SBIR correction.

There are lots of different ways to attack room acoustics and lots of different preferences for how a person wants the room to sound.

The hard floors shown above wouldn't necessarily be bad in a purely 2 channel setup and as shown since the ceiling is pretty much completely covered with diffusion and tuned resonators.

Bryan
10-27-08 04:11 PM
omholt
Re: Are helmholtz resonators and diffusers all we need?

Quote:
atledreier wrote: View Post
Once again.. all that stuff, and a thin rug on the floor...

I'd at least have SOMETHING in the 1.st reflection point after all that money spent..
Why, when it's measuring flat? They have another room where there's actually tiles on the floor. But together with all the acoustics treatment, it's not a problem. They way they have set up the room is by taking measures after every acoustic treatment. These guys know what they're doing.

The discussion is really more if this approach is better then using broadband bass traps. I personally don't know, but wish to find out. It probably depends on the speakers. But if we stick to speakers that measures neutral, I think it's probably a matter of taste. People who sell their products say though that most people prefer a room that's treated this way over a room with rockwool/broadband panels when they get to listen to both.
10-27-08 04:10 PM
avaserfi
Re: Are helmholtz resonators and diffusers all we need?

Depending on the speakers polar response and resonances characteristics the something you will want in the first reflection locations will be a reflective. Of course, this is presuming the loudspeaker is placed such that this reflection would arrive to the listener in 4-10ms range.

I am not saying that this is the ideal option for most speakers, it isn't as most are too resonant, but it is an example that shows there is no ideal treatment for one room. It is very dependant on loudspeaker-room interaction. This is a case where a problem can be minimized with proper room treatments while this same treatment would actually stifle realism in a higher quality system.
10-27-08 04:03 PM
atledreier
Re: Are helmholtz resonators and diffusers all we need?

Once again.. all that stuff, and a thin rug on the floor...

I'd at least have SOMETHING in the 1.st reflection point after all that money spent..
10-27-08 04:00 PM
omholt
Re: Are helmholtz resonators and diffusers all we need?

Here's some pictures from another room that has acoustic products from the same company. They have a very different approach then GIK and RealTraps. Helmholtz resonators for the bass and diffusorers for midrange and treble. I'm not sure if they use any fiberglass/rockwool behind their diffusers, but I'm quite sure they don't. Some say this is the best room they ever been in, but I've also heard other comments.



10-27-08 03:48 PM
atledreier
Re: Are helmholtz resonators and diffusers all we need?

All that stuff on the walls, and very little in the ceiling, and a rug on the floor...
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