Search found 6352 matches

by Trebor
Tue May 12, 2009 9:41 am
Forum: Windows
Topic: 1.3 selected but 1.2 was downloaded
Replies: 4
Views: 912

1.3 selected but 1.2 was downloaded

Yesterday I tried to download the latest version of 1.3 from sourceforge.net ...
wanted 1-3 but got 1-2.PNG
wanted 1-3 but got 1-2.PNG (6.88 KiB) Viewed 1000 times
but the version which was downloaded was 1.2

[I have a backup copy of 1.3 so this is not a problem for me,
but I thought I'd mention this download problem here]
by Trebor
Mon May 11, 2009 4:17 pm
Forum: Audio Processing
Topic: How to get the frequency/hz of a give audio signal?
Replies: 4
Views: 2222

I need to find out what khz any specific remote control operates on. You could scale down the frequency by 10 by using a decade counter to make the ultrasonic audible ... Frequency division Frequency division (FD) bat detectors synthesise a sound which is a fraction of the bat call frequencies, typ...
by Trebor
Sat May 09, 2009 6:06 am
Forum: Audio Processing
Topic: Holding a tone in Audacity
Replies: 5
Views: 2418

Re: Holding a tone in Audacity

Apparently no sustain effect in Audacity,
but there are echo, delay, and compression which may give you the effect you require.
by Trebor
Sat May 09, 2009 2:32 am
Forum: Audio Processing
Topic: MP3
Replies: 4
Views: 832

Re: MP3

Possibly not installed the lame encoder ? ... http://audacityteam.org/help/faq?s=inst ... m=lame-mp3
by Trebor
Sat May 09, 2009 2:07 am
Forum: Audio Processing
Topic: Holding a tone in Audacity
Replies: 5
Views: 2418

Re: Holding a tone in Audacity

... the sound wave doesn't have a very large amplitude to be able to see easily on where the zero crossing is. If you put the curser over zero on the vertical the scale on the left it turns into a magnifying glass with a "+"in it, then left mouse click (repeatedly) to magnify the waveform, right mo...
by Trebor
Fri May 08, 2009 9:54 am
Forum: Audio Processing
Topic: Holding a tone in Audacity
Replies: 5
Views: 2418

Re: Holding a tone in Audacity

To avoid clicks when using repeat you should trim the sample so it begins and ends at zero-crossing points, and the beginning and end of the repeated sample are complimentary: if waveform is falling at end it should be rising at start, or vice versa. [You could extend a sample somewhat (say 50%) by ...
by Trebor
Wed May 06, 2009 2:42 pm
Forum: Audio Processing
Topic: Molding a tone to a given audio sample (matching silences)
Replies: 20
Views: 4758

It does work ...

From top to bottom: 1000Hz square wave, Half wave rectified 1000Hz square wave, 19KHz "sine", 19KHz "sine" amplitude modulated by the rectified 1000Hz square wave. 1ms_Pulses_of_19KHz.png [I put "sine" in quotes because at a sample rate of 44.1KHz a 19KHz sine wave is more like triangular waveform].
by Trebor
Wed May 06, 2009 2:07 pm
Forum: Audio Processing
Topic: Molding a tone to a given audio sample (matching silences)
Replies: 20
Views: 4758

Positive Half Wave Rectification, Eureka !

I have butchered one of David Sky's plugins to produce the positive half wave rectification required, (guess where I have applied it in this waveform) HalfWaveRectified.png I have attached a zip file containing the aforementioned butchered plugin which I have called "Half Wave Rectifier (+ve)" which...
by Trebor
Sun May 03, 2009 12:19 am
Forum: Audio Processing
Topic: removing white noise
Replies: 2
Views: 567

Re: removing white noise

The noise reduction in Audacity 1.3 is much improved over 1.2 You can find it on 1.3 by clicking on "Effect" ,"Utility", "Noise Removal", "Noise Removal". You then select a "noise profile" : a bit of audio which should be silent (but in your case has white noise type hiss). Then reselect "Noise Remo...
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...