Re: [LAU] My first impulse response

On Thu, Apr 26, 2007 at 08:05:01PM +0200, Arnold Krille wrote:

> Am Donnerstag, 26. April 2007 schrieb Tim Howard:
>
> > On 4/26/07, Arnold Krille <arnold@email-addr-hidden> wrote:
> > > BTW: As access to weapons is somehow restricted here in germany (and my
> > > wife doesn't like me getting a toy gun either) I was thinking of creating
> > > the pulse for IRs with some kind of a clapperboard or similar. These old
> > > things we used in physical education come to my mind. Is that usable or
> > > should I convince my wife to allow me a gas pistol or blank pistol?
> > I think it's fairly common to use a balloon pop as the impulse, but
> > that doesn't yield as high-quality results as a sweep. It's cheap,
> > though!
>
> Ah, that is a good idea!
>
> I know the sweep has best results but I want to measure things like
> under-the-local-bridge or inside bigger cellars and the like and carrying
> speakers there is not an option. My laptop with the (broken again) tascam
> interface has to suffice...

The volume of a balloon bursting is still quite low compared to a gunshot.
For the latter you need a blank pistol, gas pistols don't produce such a
loud "bang".

One other alternative to consider is to take along a portable radio or some
such and use that as the speaker. Al it needs is a line input to connect to
your computer. There are also small portable active speakers normally used
with ipods and the like. You don't need a big speaker as the frequency response
can be equalised later (Aliki will soon have this built-in). I'm pretty sure
that even a small speaker with little power will give better results than any
other method - just make the sweep long enough to compensate for the low level.

Another trick to make life 'on the road' easier is that you do not need Aliki
during the measurement. Export the first channel (F) of the sweep file, play
it back with any player and record with any recording app. Back home convert
the recorded WAV file into an .ald and put that in the 'capture' directory.
I've a little app to do the conversion.

-- 
FA
Follie! Follie! Delirio vano è questo !
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-user