Audio Amplifier AppMod
Archiver
Posts: 46,084
I have a problem with a BS2sx, using a BOE and the Audio Amplifier
AppMod. My program uses FREQOUT to generate tones in rapid succession
to get a sort of R2D2 sound. The problem is that I get some sort of
ticking sound at the start of each tone. When I connect the AppMod to
an external speaker--actually, it goes into a sound mixing board--the
ticking sound is even more noticeable and annoying.
Any way to get rid of this and just get a straight tone sound?
Robert Carter
AppMod. My program uses FREQOUT to generate tones in rapid succession
to get a sort of R2D2 sound. The problem is that I get some sort of
ticking sound at the start of each tone. When I connect the AppMod to
an external speaker--actually, it goes into a sound mixing board--the
ticking sound is even more noticeable and annoying.
Any way to get rid of this and just get a straight tone sound?
Robert Carter
Comments
One way to suppress the objectionable tick that might work in
software is to double up the frequency. For example, instead of
freqout 0,20,1000
use
freqout 0,20,1000,1005
The stamp can generate two frequencies, and putting in two at one or
a few hertz apart creates a beat note that softens the attack. For a
long tone, you are stuck with the beat note, but the method can be
effective with short notes. When the frequencies are one hertz
apart, the beat note has a half-period of 1/2 second. The frequency
separation to use depends on the length of the tone. For a note that
is going to last 1/20 of a second, you could put the two frequencies
at 10 hertz apart to get a clean 1/2 cycle, or 5 hertz apart to get a
clean 1/4 cycle attack. Experiment!
You might try a lowpass filter after the freqout, either by itself or
in combination with the above. That could remove the harshest part
of the tick.
10k
freqout ---/\/\---o----> to hi-Z preamp
|
===== 0.001uf
|
Vss
which gives a 3db frequency of about 16khz, or, use a 10mH inductor
with a 0.01uF capacitor for about the same cutoff frequency, but with
a sharper cut.
-- best regards
Tracy Allen
electronically monitored ecosystems
http://www.emesystems.com
mailto:tracy@e...
>I have a problem with a BS2sx, using a BOE and the Audio Amplifier
>AppMod. My program uses FREQOUT to generate tones in rapid succession
>to get a sort of R2D2 sound. The problem is that I get some sort of
>ticking sound at the start of each tone. When I connect the AppMod to
>an external speaker--actually, it goes into a sound mixing board--the
>ticking sound is even more noticeable and annoying.
>
>Any way to get rid of this and just get a straight tone sound?
>
>Robert Carter