Hello. How do select a proper single cycle waveform?

[David_Hobson]

Hello,
I am a new user of Audacity version 2.0.3 for windows.
I am running Windows 7 Professional 64-bit with an Intel Corei3 processor and 8gb RAM.
I use a Focusrite Scarlett 18i6 interface with many software synths and hardware synths for music and video creation.

I have been relying on my old Macintosh G4 OS 9.2.2 for chopping up single cycle waveforms utilizing “Bias Peak”. Bias Peak is a simple interface for mastering stereo or mono files, performing the usual tasks like: normalizing, trimming, change pitch, time stretch…you get the idea. And Mastering of course.

In Peak, when you want to zoom in on a simple waveform (like a digital waveform from an additive synth, for instance) you can see the wave cycles, and you can use the "selection tool to select the point at which the cycle starts at “zero” and then ends at zero. The selection tool in Peak automatically knows where “zero” is, and will snap to it when you are close. When you have properly created the start point(at zero) of the cycle you can then drag the selection area to the end of the cycle (zero) and when you are in the ballpark, Peak will know to move the end point to the “true” zero location. When you have made this selection you can loop the result and be confident that you have a proper single cycle waveform which you can then save as whatever file format you choose…and import into your selected instrument and play it.

So, (the advice for posting topic said more information was better than less…lol)
My question is, i hope, not complicated.
How do you use Audacity to the same thing that I do in Bias Peak?
I know that you import the file…I did this.
I know you zoom in on a selection until you see the repeating cycles (whatever pitch they were recorded at).
And, I know that I can use the selection tool to select the start point of the cycle , and the select all the way to the “end” of the cycle.

But,
I cannot figure out how to make the selection points automatically “nudge”, “jump” or “snap” (not sure what Audacity calls it) to the points at which the cycles are at “zero”.
If I could figure that out, it would be a great start to phasing out my old, unreliable Mac G4.

I have included a couple of screen shots to explain this to anyone who may not understand my terminology or my incorrect use of terms so that we are on the same page:

Image-1 shows the waveform and the selection tool placed at as close to zero as I can get.
Image-2 shows the selected single cycle waveform.

I have searched the forum posts and have come up with the length of a cycle at the given pitch and so forth…but I want to know if Audacity can do what I want it to do.

Thank you for your time, and any possible information.
David Hobson.

[steve]

@David Hobson

(the advice for posting topic said more information was better than less…lol)

Yes indeed. The more information in the question the shorter and quicker the answer.
In this case the answer is: “Z”.

To flesh out that answer a bit:
Zoom in and drag select so that you are close to zero crossing points, then press the “Z” key (easy to remember - “Z for Zero”).
“Find Zero Crossings” is also in the Edit menu: http://manual.audacityteam.org/o/man/edit_menu.html#zero

Note that for stereo tracks the zero crossing points may be in different places in the left and right channels, so you may not get the “snapping” that you want. In this case there is no alternative than to zoom in really close and make the selection manually.

[DVDdoug]

FYI - In general, you can’t select the exact zero-crossing in the digital domain, because the zero crossing usually occurs between samples. It gets easier to “get close” with low audio frequencies and/or high sample rates (i.e. with more samples-per-cycle).

[kozikowski]

it would be a great start to phasing out my old, unreliable Mac G4.

Just a note that Audacity isn’t a “WAV Editor.” It has some interesting biases to production audio editing rather than sample- by-sample scientific editing.

Audacity doesn’t edit MP3. It pulls MP3s inside itself, converts to a very high quality internal format, and then creates a whole new MP3 when it’s done. This can significantly increase the compression noise and distortion of your show. This burns people regularly.

Audacity will not save a sound file. I’m sure you hit this one by now. Audacity saves Projects but Exports sound files. That’s important. AUP is an Audacity project manager text file. It’s not sound.

Bias is a chopped-down larger program, right? You should try out the Audacity effects like time stretch and pitch shifting before you put the G4 in the dust bin.

Koz

[David_Hobson]

Hello Again,
Thank you for all of your replies!

@steve

@David Hobson

(the advice for posting topic said more information was better than less…lol)

Yes indeed. The more information in the question the shorter and quicker the answer.
In this case the answer is: “Z”.

To flesh out that answer a bit:
Zoom in and drag select so that you are close to zero crossing points, then press the “Z” key (easy to remember - “Z for Zero”).
“Find Zero Crossings” is also in the Edit menu: http://manual.audacityteam.org/o/man/edit_menu.html#zero

Note that for stereo tracks the zero crossing points may be in different places in the left and right channels, so you may not get the “snapping” that you want. In this case there is no alternative than to zoom in really close and make the selection manually.

“The answer is: “Z” …” lol.
That was what I was looking for…thank you very much.
I need to read the manual and not be so lazy.

@DVDdoug

FYI - In general, you can’t select the exact zero-crossing in the digital domain, because the zero crossing usually occurs between samples. It gets easier to “get close” with low audio frequencies and/or high sample rates (i.e. with more samples-per-cycle).

Thank you Doug,
You have helped by pointing that bit out. I will sample at higher sample rates and at lower frequencies.

Great Forum.
Thanks again,
David Hobson