Search found 6343 matches

by Trebor
Fri May 01, 2009 7:50 pm
Forum: Audio Processing
Topic: Molding a tone to a given audio sample (matching silences)
Replies: 20
Views: 4758

Half-wave rectification ?

If you performed half-wave rectification on the square wave before using Steve’s Amplitude Modulation code that may help. Here is a bit of Nyquist code which allegedly performs half-wave rectification returning only the positive half cycles of signal … ; pos neg and rectify functions by Steven Jones...
by Trebor
Fri May 01, 2009 7:12 pm
Forum: Audio Processing
Topic: Molding a tone to a given audio sample (matching silences)
Replies: 20
Views: 4758

Re: Molding a tone to a given audio sample (matching silence

I went ahead and tried this. I played with the settings quite a bit, but the best I could get it to do was to silence the unwanted tones in the front, and half of them in the end - it had no effect on those in between the signals I want to keep, or the first half of the end. I didn’t quite apprecia...
by Trebor
Fri May 01, 2009 6:20 am
Forum: Audio Processing
Topic: Molding a tone to a given audio sample (matching silences)
Replies: 20
Views: 4758

Re: Molding a tone to a given audio sample (matching silence

To finish it, all I have to do is get the parts of wave that are under an amplitude of, say, 0.6 to go silent. I'm sure there exists an easy bit of code for this. There should be a simple way of doing this with nyquist code: if left channel is less than 0.6 then make amplitide of right channel zero...
by Trebor
Thu Apr 30, 2009 10:15 pm
Forum: Audio Processing
Topic: Molding a tone to a given audio sample (matching silences)
Replies: 20
Views: 4758

Re: Molding a tone to a given audio sample (matching silence

Stevethefiddles amplitude modulation code would do the job on the first bit of signal where the square wave doesn't go below zero (sim (mult (aref s 1) -0.5) (mult (sum 0.5 (scale 0.5 (aref s 0)))(aref s 1))) http://www.audacityteam.org/forum/viewtopic.php?f=28&t=9100&p=37121 Do you only want 19KHz ...
by Trebor
Wed Apr 29, 2009 6:53 pm
Forum: Audio Processing
Topic: Removing thumps and bumps
Replies: 15
Views: 10901

Re: Removing thumps and bumps

kozikowski wrote:I'm clear this is counterproductive, but the full quality WAV Exports are easier to clean and/or manage. MP3 introduces its own errors.

Koz

Agreed the the original WAV would provide the very best quality but a 2-3 minute WAV is probably too big to email (over 10Mb).
by Trebor
Tue Apr 28, 2009 6:15 am
Forum: Audio Processing
Topic: Removing thumps and bumps
Replies: 15
Views: 10901

Re: Removing thumps and bumps

I don't have a site to post sound clips; is there an upload area on this board? (Haven't looked). Some people on this forum use http://www.sendspace.com accounts to send files, (yucky casino adverts, but "lite" version is free), other file sharing sites are available. If you can post an mp3 of Yehu...
by Trebor
Mon Apr 27, 2009 4:01 am
Forum: Audio Processing
Topic: Removing thumps and bumps
Replies: 15
Views: 10901

Dr Frankenstein will see you now

Like I said a cut and paste may be possible: it depends what the violin is doing around the time of the thump and the thump duration.

I will have a bash at making a repair if EddyKilowatt posts a link to some audio.
by Trebor
Sun Apr 26, 2009 10:12 pm
Forum: Audio Processing
Topic: how to convert mp3 to raw ?
Replies: 2
Views: 4211

Re: how to convert mp3 to raw ?

By "raw" I suspect they mean an uncompressed format such as WAV.

Note: If you convert an mp3 to wav the wav version will occupy approx ten times the amount of memory as the mp3.

Uncompressed files (e.g. wav), use less CPU time than compressed ones (e.g. mp3), but use much more memory.
by Trebor
Sat Apr 25, 2009 6:32 pm
Forum: Audio Processing
Topic: Removing background noise
Replies: 8
Views: 1604

Re: Removing background noise

You could replace the bit of crowdsound with the ref's whistle, with a bit of crowdsound without the ref's whistle, i.e. dub it ... dub 1. a. To transfer (recorded material) onto a new recording medium. b. To copy (a record or tape). 2. To insert a new soundtrack, often a synchronized translation of...
by Trebor
Fri Apr 24, 2009 5:29 pm
Forum: Audio Processing
Topic: Removing thumps and bumps
Replies: 15
Views: 10901

Cut and paste ?

It would be possible to attenuate a low frequency thump without affecting the high frequency violin by using equalization. 1.3 has a graphic equaliser built-in. A "classic" 15 band graphic equaliser plug-in for 1.2 can be downloaded from here . It may be possible do a repair by cutting out the noise...