Archived from groups: rec.audio.pro (
More info?)
On Mon, 20 Dec 2004 02:23:36 GMT, Ron Capik <r.capik@worldnet.att.net>
wrote:
---------------8<-----------------
>
>I did a test using files I'd converted to 32 bit (Sound Forge 5)
>and it seemed to work just fine... [all (saved as} 32 bit results]
>Don't quite know how to ckeck the conversion quality though...
-- Sound Forge lets you change the bith depth at your will during
work; I'm usually working at 16 bits all the way; sometimes I record
and work at 24 bit. But a procedure of mine requires a temporarily set
64-bit floating depth (I3E), the maximum bit depth SF can work with.
Sound Forge always makes temp files accordting to bit depth set. If
you change this to 64-bit float, your abt. 30 MB file wil likely grow
to a couple of hundreds MBs.
I work with the temp floating point files unchecked but I will check
it. I think it might have something with SF's internal processing
precision, just like many plug-ins are "internally" working at 24, 32
and I suppose even higher bith depths to maintain quality.
>> < ..snip.. >
>> There are other deconvolvers out there but nothing that is
>> remotely close to the noise immunity of Acoustic Mirror.
>> You've almost got to have a negative SNR to have it affect
>> the result. Long ago I talked to the developer of that plug
>> and he said that there was a "trick" used to achieve that
>> immunity. I've since seen the paper describing the trick
>> but testing shows me that no one else has incorporated it.
Interesting! -- BTW, there are quite a lot 3rd-party impulse files
recorded as *.wav on the Internet. Now to use these with Acoustic
Mirror, you'd rename their extensions to *.sfi. But genuine Sonic
Foundry impulses are quite good ones; Sonic Foundry even published a
set of "Test Tones" to be used in production the acoustic impulses.
This would require a portable loudspeaker which should possibly be
omnidirectional (a hard to find thing nowadays) and a good microphone
and field recording set.
Normally to get an impulses without having to reproduce anything, one
should slam the ping-pong ball in a room or space to the hard and
neutrally sounding surface like concrete, stone etc. The first knock
and its reverberation would be yours.
I had an idea to pick up some impulses in numerous churches and old
spaces in my area; some of them are having excellent acoustics. I
would need a good mike (perhaps I might lend a Brüel & Kjaer one-inch
set with a pre and pistonphone, hmm, perhaps) and I'd need an omni
loudspeaker. Now this is harder to find. I remember Grundig of Germany
did manufacture some models of omni loudspeakers, two types of their
Audiorama spheres* and some desktop cube models. But this has been end
sixties--beginning seventhies.
--------8<------------------
Edi Zubovic, Crikvenica, Croatia
PS. * Here a picture --
http
/www.audiogold.co.uk/archive/Loudspeakers_Grundig_Audiorama_137.html
Now what a whopping price for these oldies. Hmm, given the age, and at
the price, one should surely check what's mint here and what isn't...
))
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