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Subject: Re: Silence detection
From: Martin Borus (
Date: 2004-01-03

Am 2 Jan 2004 um 17:28 hat kurzhaarrocker geschrieben:

> Thank you for testing. I'd love some feedback though - from anybody
> who played around with it. What I am interested in is:

After playing with it for a while here's some first feedback.

> Do you think the trigger modes (off, no rearm, rearm) have good names?
> Are they understandable easily?

I did not understand them right away - how about "one" and "repeat" (the same names
used for the repeat menu)

> Assume you have the intension to start a recording with a trigger but
> stop it manually. Is it sufficiant that the user can set a stop
> threshold to 0% (-89db) (maybe displayed as "off") or is it necessary
> to put that into an additional trigger mode?

A display of "off" should be OK.

Currently I can only go down to -75db. I'd love to go down as much as possible -
because I plan to use the feature to record CDs and when I activate a 2 second pause on
my CD player I will get perfect track marks..

BTW, on the digital input prerecording seems to have problems: When I set
"Start for at least" 1 second with 2 seconds prerecording still the first bit of every track is missing.
At "Start for at least" 0 second it seems to work and there is no silence before the track
(which should stay this way).

> The same applies when you want to start a recording manually but want
> it to stop automatically on silence. (only that start threshold 100%
> (0db) is equivalent to off)

On my recorder I had to start the first recording manually anyway - it would
not start right away.

Trigger [rearm]
Prerecording [2s]
Start above [-75db]
for at least [0s]
Stop below [-75db]
for at least [1s]

Seems to produce great results when recording CDs.

For tape recordings, there's something else missing in my opinion:
You have start, stop and rearm. This way you could lose bits of "silence" between
the tracks. If you want to keep the original recording length in any case, a third
option might be needed:

In my example I would set the the
Start above [-30db]
for at least [1s]
Stop below [-60db]
for at least [15s]

and add these options:

Activate Split below [-40db]
for at least [1s]
after at least [90s]

Activate Split should work in a way that when the Split is activated, the next time
the start rule would apply again a split is made - using the start prerecording

In the menu I had some more "problems":
I went into the menu with the source selection microphone. Within the menu the microphone was
on and I could hear the sound over the speakers. It stayed on when I left the menu.

Finally I played with the splitting rock. That worked well. I got an error message (because my source
was a mp2 file with a radio programm) but it still worked. Any chance this can be extended to a A-B cut that
will allow you to set two points and save what's inbetween?
Splitting longer files like radio shows means you might have to copy 100MB of radio twice just to
cut a 5MB bit with the song you want to keep...


Page was last modified "Jan 10 2012" The Rockbox Crew