Anybody have an idea of how to make an effect in Pd that would work like an analogue tape loop with a record head and play head and adjustable speed? I know there are delay effects possible that are very similar to this but they don't achieve a specific thing I am looking for which is the way the sound changes according to the speed of both the recording and playing - i.e. if the tape speeds up the loop goes faster (and higher in pitch) but the overdubbed recording continues and plays 'normally' at the adjusted speed (although with a shortened loop length). When the tape is then slowed back to normal what has just been added to the loop will drop in pitch and play slow. And an inverse effect would come about if the tape ran slowly or came to a stop (hence the squeak at the beginning of old recordings, as the tape goes from 0 up to it's speed across the record head)
Is this a matter of creatively manipulating delay lines? Or sampling rates? I can't perform the mental gymnastics to see how this could be achieved without a variable write speed.

@beem I didn't look at David's contribution, but to me it sounds like you want a delay line with adjustable feedback from a variable tap (delread4~). The delay amount simulates the tape speed. I never did this with a real reel-to-reel, but the erase head would have been engaged in record, so the fact that the tape is in a loop is irrelevant, no?

@beem I think it should be as easy to compile for a mac as it is for Linux.
From a terminal...... cd into the src folder..... and then type make and press return.
You can look inside the file "makefile" first..... but I don't see anything extra that you would have to do for "make" to work on osx.
You should then have a ipoke~.pd_darwin binary made for your system.
Put it in a startup path and [ipoke~] should create.

If you want to see if it is worthwhile and you have a copy of 32-bit vanilla (0.47) you can test the patch using the .pd_darwin already compiled in the zip.
David.

@jameslo it's not quite that effect - with a delread the loop is resampled and degrades as it speeds up and is slowed down again and the variable write speed isn't achieved either. It's been a long time since I used the reel-to-reel but I have a vague memory of putting a bit of card or tape over the erase head.

@whale-av thanks! i'll try that

@beem Ok..... it does what you want apart from the squeak at the beginning...,... but I don't remember the Echoplex or the Roland space echo doing that..... (If you don't like it I still have some tape loops for the Roland). It could have been tape hiss rapidly changing pitch I suppose.
Somewhere I should have a recording on reel-2-reel of John Martin doing the whole Pink Floyd thing on his own through an Echoplex...... 1971 I think..... but I no longer have a tape machine....
I have modded it to be able to change the tape loop length........ space_echo.pd
You can erase the whole loop if required........ [const 0(
You can reduce the speed to zero.
You can run the tape backwards........ a new feature....
Credit to @mjhbrowne for the original......... https://forum.pdpatchrepo.info/topic/10972/distorted-sound-trying-to-simulate-a-bucket-brigade-delay/3
Credit to @katjav for [ipoke~]
David.

@whale-av this is FAR OUT! thanks a lot!

it took a while for me to understand the difference between a delay effect made with ipoke~ and one made with vd~ but with some experiments i got it, it's really amazing with changing delay times!
it's a pity ipoke~ is not on deken...

last night i managed compiled ipoke~ on my raspberry pi and it works quite well
ipoke~.pd_linux

@rg.kies sweet, would you share a demo patch with us? I would like to play with it.

@EEight space_echo.pd that I posted above uses it...... and ipoke~.zip that I posted further up has help and testing patches......
David.

Yeah i just modified whale-avs space echo and added midi and synchronization stuff thats specific to my other patches..

A couple of threads and a patch that should be linked / added to this thread.
https://forum.pdpatchrepo.info/topic/14226/circular-buffer-issues
https://forum.pdpatchrepo.info/topic/13447/signal-rate-circular-buffer
64-bit virtual [ipoke~] from @jameslo
Space_Echo_virtual_ipoke.zip

@whale-av I remember leaving that ipoke~ translation unfinished--something or other wasn't adjustable and I think you identified it in the original thread. In my defense I was eager to get the eff out of San Francisco and put that whole sorry episode behind me . If anyone is seriously trying to use it I would be happy to revisit it once I get past my current show in a few weeks.