Howl: A formant synthesizer 4+

Daniel Clelland

Designed for iPad

    • 4.3 • 32 Ratings
    • Free



HOWL is a simple vocoder/synthesizer. It uses formants to simulate the human voice and a pitch-space keyboard to help you find interesting melodies.


• Simple synthesizer (just a sawtooth wave nothing too complicated okay)
• Simple vocoder (four parallel bandpass filters, a bit like the Klatt engine)
• Audiobus support, so you can pipe your own audio through the vocoder and/or send the output to other software
• Adjustable pitch-space keyboard
• Cool FX (bitcrush, reverb, vibrato and tremolo)

Download it today!

HOWL is also open source (check out the code at

What’s New

Version 2.3

Fixed Audiobus support

Ratings and Reviews

4.3 out of 5
32 Ratings

32 Ratings

Blinkenlighten ,

Thank you for making this app

Lots of well thought out features, this app is a thing of beauty. The world is a better please because it exists.

It took me a bit to get used to controlling the knobs by angle. My instinct was the click the knob and hold, dragging up and down to change the value. That interface makes it easier to do fine adjustments but as is it is totally workable.

RobotSlavesNow ,

Fun, easy & cool

that’s not just what my business card says; it applies to howl too. this app totally fills my formant needs (which were considerable in Q2 and expected to increase for the rest of the fiscal year) and adds enough fx options to make it more than a novelty. the interface is excellent

lostproductivity ,

Very nice

Plays well with AUM and Audioshare (Audioshare being a source). Just don't forget to play (and/or lock) it while filtering and turn the knobs down a bit so you can hear your source audio coming in. Very excited to further mangle more sound experiments.

App Privacy

The developer, Daniel Clelland, has not provided details about its privacy practices and handling of data to Apple. For more information, see the developer’s privacy policy.

No Details Provided

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