[terry j]

Originally Posted by Ethan Winer

The three sets of measurement is shown in that video are what's needed:

Frequency Response
Modal Ringing
Reverb decay time versus frequency (RT60)
--Ethan

Ok ethan, thanks. can you explain what the 'modal ringing' measurement is? (I use rew if that helps)

I did not bother with FR, for many reasons, but also because I use eq (deqx). In any case, you can see the FR from the waterfall.

(BTW, it would be good if you -or others- interpreted what you see. these are quick and dirty measurements)



and here is the T 30, does not seem to be rt 60 in rew??(????)




Hmm, do I need bass trapping???

hope that starts to help, thank you so much.

Originally Posted by Lupo

Hello!



Yes!

The important thing is to follow the correct barker code sequence for the length you're using. It's listed in the wiki page. Or any other code that gives you the desired autocorrelation properties.

Oh, I have missed that, I assume it is in this forum? will look, thanks for that, good data to know.

I'd still go for a continuous large prime QRD if you can, over a compound one based on many smaller. The barker code will help alleviate the repeat problems, but a larger unit doesn't have them at all.

I would have thought that too. But this is the problem with the net really, all kinds of opinion.

What I mean is (making sure you did not think that I was casting aspersions at you!) I linked to the dutch site earlier (does not like being linked to I see) and that guy on another forum was adamant that it HELPS that the sequence is repeated.

At this stage, anyone with data on diffusion is an expert (to me with my lack of knowledge), so your point and Jason's point (with graphs) conflict with 'another experts' opinion.

So the main point is that these things are cleared up, without ruffling feathers. I am very much tending towards your opinion on this matter...and I hope this thread goes a long way in sorting these things.

I think fractalistic design is more useful with 1D diffusers. With 2D using 2" well width, the design frequency extends to about 3500Hz. Above this limit, the scattering will still be significant. If it extends 1-2 octaves above the limit, like it does below the number theoretical limit, it'll nearly reach ultrasonic.

Funny how these things work. I asked that question as a 'what about...', thinking that there is nothing new under the sun really, so if it was not around already it must have been a silly idea.

then just tonight I found this from Room Acoustics

Golden Horn Diffusor panels: The GH is essentially a diffusor within a diffusor. Built from plastic, the GH contains a number of “bars” of seemingly random length, much like a traditional Skyline®-diffusor. The special thing with the GH is the fact that on the top of each “bar”, there is another irregular surface, with seemingly random “pits”, which makes the GH hugely effective over a very wide frequency range. The size of a GH-module is 55 x 55cm, and it is effective from 900 to 16000Hz. I used four on each side wall, giving very effective diffusion of first reflections.

So it sounds like it HAS been done!

Google Translate

Whether it is worthwhile or not is another question. (hmm, letter style just changed)

Bass diffusion should be just as great as high end diffusion, if you can afford the loss of space. Make sure the material used is substantial enough to reflect the LF.

In the sonotube thread, alvares I think it was made a comment that diffusion was not useful under the schroeder frequency (?), still maybe worth a try at some stage eh? Will let you know if I do try that.

Waiting in anticipation for the pic and explanation! =) Hehe.. Know the feeling!

Hopefully I can get some spare time this weekend, may as well make a useful product rather than just a test. And if I can work out how to get the date and time stamp working on my camera then we can see just how long it does take. Might make enough to end up with the opposing qrd directions in a diamond pattern, then I can try it behind me and see what I think.

But really, first things first, I think I need some serious bass trapping as the foundation for all this stuff.




Thanks for the write up of what you're doing. I gotta tell you that it is a welcome relief to talk about things that matter, I am sick of the usual audiophile garbage about changing cables etc.

As someone else said in this thread (paraphrasing) 'cables, ...sheesh'