Early Schroeder reverberators consisted of the following elements:

A series connection of several all-pass filters.
A parallel bank of feedback comb filters.
A mixing matrix.
The all-pass filters provide colourless high-density echoes in the late impulse response of the reverberator. These all-pass filters may also be referred to as diffusers. While all-pass filters are colourless in theory, perceptually, their impulse responses are only colourless when they are extremely short (less than 10 ms or so). Longer all-pass impulse responses sound similar to feedback comb-filters. For steady-state tones, however, such as sinusoids, the all-pass property gives the same gain at every frequency, unlike comb filters.

The parallel comb-filter bank is intended to give a psychoacoustically appropriate fluctuation in the reverberator frequency response. A feedback comb filter can simulate a pair of parallel walls, so one could choose the delay-line length in each comb filter to be the number of samples it takes for a plane wave to propagate from one wall to the opposite wall and back.

Thus, one may choose the comb-filter delay-line lengths more or less arbitrarily, and then use enough of them in parallel (with mutually prime delay-line lengths) to achieve a perceptually adequate fluctuation density in the frequency-response magnitude. In four such delays are chosen between 30 and 45 ms, and the corresponding feedback coefficients are set to give the desired overall decay time.

What’s New

Version 1.2

iOS 15 compatibility.
Framework update.
Inter-App Audio compatibility.

Ratings and Reviews

4.4 out of 5
11 Ratings

11 Ratings

Tenente ,

Simply good

I’m getting a lot of use out of this simple reverb.
I use small amounts, stays in the background and sounds like real reverb unlike many iOS reverbs that sound like a reverb-based effect - if that makes sense.
Read the other reviews for more creative ways to use this!

Jayammon ,

The app description has some useful tidbits in it, but

in my audio app usage configuration, which is audio (mic) monitoring, of my voice, the app didn’t seem to come through in what had been described in the app’s description. Hopefully the developer will see this one through, and give the app more features. I’m somewhat inclined to believe that I’d even seen the app preview images as different from what’s being offered, now. Somewhat a bait and switch notion <_<… hmm. Maybe someone at Apple’s Quality Control could look in to this. There aren’t a whole lot of audio unit and Inter Audio Apps of this sort coming out; I would have appreciated the feature, but I suppose I could make do with some other app, if I go and search around, or learn about the functionalities of what I have that does work.

De Altruit ,

Interesting play on harmonics present in Synthesizers

Really enjoy how this reverb brings out the deeper harmonics present in my favorite synthesizers, Thanks Dev! We enjoy your work for our music production.


App Privacy

The developer, Jorge Reales, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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