# Can I use Windows Audacity to verify a tremolo speed bpm?

Hi all, newbie here

I am learning classical guitar tremolo technique, wonder if I can find/verify at what tremolo speed a classical guitarist performs on certain pieces. E.g. David Russell played this piece:

I copied part of this YT video, used an online Audio Extractor to extract only an audio clip in WAV format to analyze in Audacity. Try to to verify at what speed, e.g. 140 beats per minute (one crochet, 4 notes to a click on metronome), or which was the actual BPM?

I am able to open this WAV file to have an idea, see attached. However, I donâ€™t know what to do next to create, or extract the information to show the frequency of each beat in the tremolo, as it is repeatable, also to show the actual beats per minute (bpm), thus the tremolo speed in this wonderful piece?

Any thoughts on how to go about doing this, assuming this is possible, what are the commands/steps?
Dave

Not easily or necessarily reliably. However, here is the first part of the recording starting from https://youtu.be/MTIhlf85zTc?t=49

Near the middle you can see the tremolo.

Here I have labelled the visible peaks (there appears to be space for two peaks between [5] and [8] but they are not very distinct.

From the Selection Toolbar I can see that the first 10 peaks occupies 0.616 seconds, which is an average of about 0.06 seconds per â€śwobbleâ€ť.
The speed (frequency) can be calculated as â€ś1 Ă· wavelengthâ€ť (where â€śwavelengthâ€ť is the average length of one wobble.
Out comes the calculator:
1/0.06 = 16.667 wps (wobbles per second)

Note that the speed varies. That one is quite a fast tremolo. Some of the others are a bit slower.

Wow, thanks so much Steve for your quick response!

I can easily agree that it is not easy and reliable to extract the tremolo speed, also that David â€śmodulatedâ€ť his tremolo speed to express his emotion, also to create such musicality required -otherwise it will sound like a typewriter!

Because of these, if I know how (as good as you do), I would use the first 5 repeated â€śwobblesâ€ť, the first 5 peaks for more accurate estimate? Or using the first 10 peaks but assuming 9 even cycles, due to the blank between 5 & 6 seems occupying 2 wobbles?

If so, each wobbleâ€™s cycle will be 0.616/9 = 0.06845 => 1/0.06845 = 14.61 wps (wobbles per second), or multiply by 60 seconds, it would be 876 wpm (wobbles per minute)?

As it seems too many to be believable, considering each wobble a group of 4 notes with a click in a tremolo, it would make sense to assume each bass note (a crochet or quarter note) represents a click. If so, 876/4 = 219 beats per minute seems to be a reasonable guess?

Would you agree with the above rationale for such a nominal 219 bpm, meaning at times David played at lower and/or even higher than this assumed speed?

Thanks again!

I think that around 15 wps is about right for a fast tremolo / vibrato.

I noticed that thereâ€™s very little tremolo on the first note, so I crudely added a 15 wps tremolo to the first note.
Hereâ€™s â€śbefore and afterâ€ť

Ignoring the question of musicality, I think the â€śspeedâ€ť of the tremolo that I added is close to the speed that we calculated.

Thanks again, Steve for your help!

Around 15 wps makes sense. However, my â€śextrapolationâ€ť from wps to bpm must have missed a few steps in the process. As they say, the devil is in the details! When posting the same question in my regular forum â€śclassicalguitardelcamp.comâ€ť, a response suggests when using a metronome to synchronize with every thumb stroke, the sought-after bpm is about 156 bpm. I tried my metronome, with my â€śnot-so-well-trainedâ€ť ears, I found 160 bpm, in close agreement with that observation.

Originally, I was wondering if Audacity can be fine tuned to show more resolution in a â€śwobbleâ€ť. However, this would take an experienced user of Audacity (I know you are) and a lot of effort to look at all possible tools in this app to deduce something not usually existed, and not without doubt. So much effort for something if can be done in another way (using a metronome) may not be worth it!

Still I appreciate your time doing this!
Dave