Hi all!

I´ve bin looking around for at tool that can both play a loop, and at the same time add incoming sounds (from external mic) to that loop. A friend of mine told me that I should have a look on Pd and MAX forums for patches, but can´t seem to find what I´m looking for.

The basic idea of the tool is that sounds should be added to a over all (lets say 5 min)Loop, where the recorder is controlled/triggered by a treshold or gate of incoming signal. This way I imagine that only sounds over a certain amplitude will get recorded, and sounds below the treshold will be ignored. To help preventing clicks a 2 ms fade in and out on the incoming signal would be to prefere.

Does anyone on this forum know of a patch that can do this, or what/where to look for.

Best regards

Jens

There's a discussion on the thresholding end going on in the forum right now. The best tool for seamlessly layering loops seems to be a combination of [delwrite~] and [delread~]. you'll want to set up an infinite feedback loop. After that, it is just getting all the timing right, and generating your ramps with [line~] or [vline~].

Hi Jens, welcome,

The technique of "sound on sound" was very popular in the 1960s. Those early electro-acoustic composers used tape machines with loops of course, with the erase head disabled.

What makes the technique work well digitally is

1. Thresholding (as you are trying)
2. DC blocking
3. Low pass filtering
4. Saturation/jailing/compression

(2) is very useful in a digital system to stop a slow buildup of a DC signal that will take the signal out of bounds in the end,

(3) stops a gradual buildup of hiss or other comonents that aren't really part of the sound but will fill up the headroom.

(4) is the secret recipe for tape loop/sound on sound simulation. You want 100% feedback, no more, no less. But that means you either start with a very quiet signal, or the signal goes out of range quickly. Putting a soft limiter in the feedback loop gives space for the accumulating signal to build up in layers. Try a compressor/limiter/gate in the feedback loop too. This creates a very interesting artistic effect where the later material modulates the earlier material .

Hey, obiwannabe and nestor,

Thanx for your thoughts and help on my project! It really gave me something to work on and think about. obiwannabe the idea of Saturation/jailing/compression and Low pass filtering will indeed be taken under consideration. Have been looking around and have found some patches made for bioacoustic work that include treshold triggering, but of course not the overdub idea. exciting field of work that bioacoustic!
Will have to team up with someone who can create the patch you commented on.

Best regards,

Jens

Related question!

Right now I have a simple record-to-table abstraction. You push to start, push to stop, and then you end up with a table (with a name specified as an argument to the abstraction) that can be read, chopped up, granularized, etc, by other abstractions in the main patch.

I want to add standard looper pedal functionality to this abstraction:

• its own playback mechanism
• overdub while playing
• punch in/out while playing
• possibly eventually some echoplex / SooperLooper functionality (extend loop length, change tempo, reverse, etc)

I see how I could easily do the first three with delwrite~ and delread~, but then I'd lose the ability to have it in a table and allow other parts of the patch to use it as source material.

Anyone have any suggestions? Perhaps something like this? This thread (http://puredata.hurleur.com/viewtopic.php?pid=8969#p8969 ) makes me think I might have problems. Plus, is there a guarantee that the tabwrite will happen after the tabread?

[phasor]        [inlet~]
|\               |
| [tabread4~ $1] /
| |   __________/
| |  | 
| [+~]
| |
 X
[tabwrite $1]

Can anyone attest to this solution's success or offer alternatives?

Thanks!

EDIT: Gah! I realized this won't work because tabwrite requires control input for its index, and tabwrite~ doesn't work that way - it just accepts a bang and starts only on block boundaries.

There's also domien's solution:
http://puredata.hurleur.com/viewtopic.php?pid=5168#p5168

... but doesn't that have the same block boundary problem?

Thank you all so much for your help!

Another note: If you go the delwrite~ delread~ route, you also lose the ability to load files and then overdub them.