ETF results..... and help interpreting RT60

[impact_kent]

so i finally got one of my hr824s stood up in the (proposed) live room to test with etf, using my motu 2408, mackie 8 bus board, and a behringer omni test mic.

I'm only running the demo of ETF, but i obviously need to buy the full. Very revealing


My frequency response is all over the map. Problems with every mode..... of course, theres not an ounce of absorption in the gypsum covered cinder block Box. With hardwood floors. This weekend, different story.

Anyway, My RT60 doesnt seem so hot. I mean, first off, all kinds of modes are making all kinds of peaks and nulls. Playing test tones and walking around the room is really intense, just hearing the peaks and nulls just by walking around.... very interesting.

RT60..... mine is anywhere from 400 to 900 on average across the frequency range, with a 1600 peak at about 61 hz (also a big peak on the linear freq readout)

Anyway, what is my target rt60 when i'm installing my broadband absorbers, and how much will i need (coverage % wise), ballpark maybe.

Just trying to get an idea. Just ordered 350 sq ft. of 2 inch mineral wool.


Jeez, btw, room is 20'2" by 20', ceilings slope from 8'11" to 9'7"

darn square floor.


thanks

[knightfly]

This link is just what you need -

http://www.saecollege.de/reference_mate ... m#verbcalc

Enjoy... Steve

[impact_kent]

yeah, i've messed with that.... just did it again, with some nice exacting values for the small portion of carpeting on one part of the floor, and measured for the glass on the walls.

It started giving me negative values in the low frequency range, however, so i pulled all the glass/other surface data out, and it gave me these values for each frequency.

It says there "Estimated RT60 of your room is [calculated value] seconds "
I'm trying to figure out what to shoot for. I don't really want RT60 values of over 1000 ms do I? I want it down under 100 i thought, for a small room such as this. Thats what I want to figure out, is after I've placed some absorption, done some diffusion, etc, where do I want those figures to be when testing through ETF?

So I have the estimates. And I have the tested results through ETF, which are worse.

My instincts *know* that this room sounds like junk, I mean, I'll use my ears here, but If I place absorption, and try out placements and such, spend some time experimenting with the room, and my ETF measurements are giving me like 200 ms RT60's, is that good enough? Or should I really push it? And what is considered "too dead"?

Like I said, I'll use my ears. I just don't understand the point of RT60 values for treating a room if there is no target, nothing to compare it to, i.e. "such and such studio has a live room of blah blah size with x RT60".......or something.

I've been told 59 ms is good, I read it somewhere. I don't know if it is, or if that's particular to a certain room size. I understand it is frequency specific, but in a small room, 1000-1600 ms can't be "good" or "acceptable." Cuz it sounds like crap.

[knightfly]

There's more to that page than just the calculator; did you read John's explanations/charts BELOW where the calculator is? Steve