Randomized Wow & Flutter

It’s good to see “more randomized flutter” is planned for an upcoming release, but I would ask to do the same for wow. IMHO, that would make for a more accurate tape emulation. I listened to some other tape emulating pedals I have, and indeed they all add some randomness to wow, whereas on the Ribbons it just sounds like a consistent sine or triangle wave.



My initial shot at the wow parameter was based on a listen of a sine wave printed to tape on my Sony TC-440, a machine with some pretty heavy wow. I thought, “that sounds pretty sinusoidal, let’s roll with that”. Not terribly scientific though. Let’s see how we can improve it.

I took some time this morning to re-print a sine wave to my TC-440 and analyze it. Here is the audio clip:

I then did an FFT of the audio data and created a spectrogram of the pitch data. I traced the max value over time and filtered it to see if we could get an accurate picture of the wow over time (top graph).

Sure enough, it isn’t perfectly sinusoidal and is more complex than my original approach. By analyzing the frequency components of that vibrato signal (bottom graph), we get a good idea of how to approximate the wow of this machine.

Alright Jaak, now that you’ve walked us through your little scientific analysis and proved that real tape wow is more random than your current implementation, what’s the verdict? Will you do it?

Sure - why not. I’ll play around with a couple of different approaches to emulate the characteristics described above while also providing control for frequency and depth. We’ll see if I can find something that feels just right. If someone gets mad that wow isn’t perfectly sine-like anymore I’ll blame you @MarkF786 :laughing:


Here is another measurement from my Channel Master Model 6549. We see there is typically a main sinusoidal component with varying frequency and amplitude + additional sinusoidal components mixed in. Of course the flutter is the more complex and noisy variation surrounding this signal (but that’s another topic for another time).


Hi Jaak,

Thanks for investigating this and considering the change/feature. Nice analysis of the wow from your tape decks! I suspect there are various mechanical components that cause the wow, making it not so periodic as a single sine wave.

I’d imagine this change would be welcome by most pedal users, more accurately simulating a tape deck. If they just want a normal vibrato, likely most of them already have a vibrato pedal they could use.

I have a couple versions of the Generation Loss pedal, and on them both the wow and flutter have some randomization, which really adds to the “realism”.



I’ve hijacked this post and am now using it to document my wow and flutter findings!

Wow and Flutter measurements from EchoPlex EP-3:


Wow and Flutter measurement from Tascam Portastudio 424 Mk II. No wow on this machine, just flutter.


Jaak, I had considered requesting randomized wow & flutter, but I too thought about how real wow sounds on a tape deck and decided your take on it was good enough. I have faith in whatever you do.

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I like wow that makes you seasick. A lazy mutated sine wave is cool.