Film-Tech Forum ARCHIVE: Acoustic simulation software

This is topic Acoustic simulation software - recommendations in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=011193

Posted by Eric Robinson (Member # 2966) on 03-26-2012, 08:13 PM:

We have an auditorium which has fairly unintelligible dialogue due to high levels of echo. While I could follow and recommend the standard techniques of sound absorption panels and traps, I thought it would be interesting to try an acoustic simulation program to see how and where these panels and traps would be most effective. Does anyone here use this type of software and does anyone know of any freeware type of software that might be available?

Posted by Dominic Espinosa (Member # 2122) on 03-26-2012, 09:56 PM:

EASE is only about $900 for a minimum 2 user license. Might be a good investment if you're going to be doing more than 1 remodel and wont be bringing in outside techs.
Otherwise there's PAMM which is open source as is CARA. Both are largely unsupported and have a steep learning curve.

Posted by Eric Robinson (Member # 2966) on 03-27-2012, 12:26 AM:

Regarding EASE, yes it may be good, but looking for open source or freeware.

PAMM looks more like it is geared for something other than audio acoustics for theatre sound.

And, CARA looks good; however, the sources I checked indicated that it was to be paid for.

Thanks though.

Posted by Dominic Espinosa (Member # 2122) on 03-27-2012, 01:02 AM:

CARA is free, I have it.
It's the training and hardware they want to sell you.

Posted by Chuck McGregor (Member # 6826) on 03-27-2012, 06:38 AM:

I have not run the software let alone used CARA, but in looking at their information, here are a couple of observations. The program seems obviously aimed at small (home theater) rooms. As well, it seems geared toward discrete listener locations rather than seating areas in a program like EASE.

As to the accuracy of the program's predictions, I compared the directivity data used for its calculations to that of EASE. It appears to be at least two orders of magnitude lower in resolution. Imagine your car odmeter turning over once every 10 miles versus once every 1/10 mile. It would be interesting to compare reverberation predictions using the same room data.

Certainly no harm in seeing what it does, but personally I wouldn't spend too much money on treatments for a commercial cinema based on its results.

Posted by Dominic Espinosa (Member # 2122) on 03-27-2012, 09:37 AM:

That's good to know, Chuck.
I've only ever used it in my house, not a commercial installation. I should've pointed that out earlier as well.

Posted by Eric Robinson (Member # 2966) on 03-27-2012, 07:01 PM:

Thank you Chuck.

FYI: I really enjoyed reading your contribution to the topic in the digital cinema forum: topic: do high frequency drivers decay over time. This was one of the most interesting posts I have read for quite some time.

I have an older version od Smaart which I could use to measure acoustics. I thought about fabricating some type of sound absorption panel which I could move around the auditorium to measure the its effects on the environment; however, this is just not practical.

Posted by Chuck McGregor (Member # 6826) on 03-27-2012, 10:01 PM:

What you can do is the reverse. Rather than place "test" absorption, see if you can locate where where untoward sound reflections are coming from, i.e where you might want to put it. Cup your ears or use a high tech device called a megaphone (difficult to construct I know [Big Grin]

) to "directionalize" your ear(s). You were going to do it by listening anyway [Smile]

Listening truly objectively and quantitatively to sound takes practice and has the huge, added benefit over any test instrument of instant, qualitative analysis - your perception. That is a function no test instrument has.

Thank you guys for the kind words.

Posted by Cameron Glendinning (Member # 3516) on 03-28-2012, 02:12 AM:

I had a lot of luck with treating/ deadening the backstage areas with black tissue faced fiberglass ductliner and cheacking that the horns are actually correctly installed and angled down into the middle, back 2/3 of the seating areas. I have even swapped in 60 x 40 horns, replacing the typical 90 x 40 horns now typically found in cinemas.

By creating a quiet enviroment for the speakers to operate from, and killing off the earliest reflections that bounce around backstage that have the biggest effect on intelligibility.

Posted by Monte L Fullmer (Member # 2797) on 03-28-2012, 03:41 AM:

Temp fix is to EQ the center channel by dropping off the lows so the voice can be heard better...