//// day + night = : lcrp.2019.equinox.1 ////


Uh oh, maybe I built it up too much haha. It’s subdued, but I’m hearing what I think is a cool mixture of the birds and insects in Kurodama’s night recording (the impulse) and the atmosphere, wind (and bells) in my day recording. The bells strike like a high pitched drum roll partway through, and there are some interesting dynamics I’m not sure the source of…


In my case, I’m curious what exactly convolving a long form sound on another does. I understand the idea (well sort of, not really the math) behind using an impulse response to derive a convolution reverb. But with a piece of music (or field recording) that has peaks and valleys (and frequencies aren’t present at equal amplitude like they ideally are with a sweep)…I’m curious what that does


That sounds really cool. Can’t wait to hear it!!

I like it when sounds emerge unexpectedly, too. For some reason, Miles Davis’ trumpet arose out of stretched version of Jason’s farm recording. I’m guessing it’s that chicken again.


Maybe someone else can speak more intelligently to that but my experience doing this a bunch with soundhack back in the day (but using two 30-60 second sounds, nothing as long as 45 minutes – it still took a really long time on my laptop back then) is that it’s incredibly dependent on the source material. There’s a kind of smearing of the sound and a kind of filter resonance effect, but otherwise imho results feel pretty unpredictable depending on the sounds involved. If it didn’t take so damn long to do it might be easier to build up an intuition for how things will mix together, but I’ve never been very systematic about it.

Here’s 60 seconds of an excerpt from Matt Turner & Jeff Song’s Love & Fear album (with lots of unintentional line noise in the recording, I should have previewed first) convolved with 60 seconds of a tape of the Minneapolis Symphony Orchestra playing Mahler’s 1st symphony.

The Mahler excerpt:

The Matt Turner / Jeff Song excerpt (plus tons of line noise!)

And the two convolved together:

Also! Here’s the 15x speed convolution of the field recordings – I’m probably going to play a bit more with this because there’s time and why not:


Apologies if you get this already, but every sound being convolved plays out for the duration of the impulse response file. So if you have a long impulse you very quickly get many layers of sounds playing concurrently.

I’ve played with this quite a bit - at one extreme using a bunch of off-station shortwave as the impulse response, at the other the Funky Drummer drum loop. Sharp dynamics and shifts in the sound are most obvious if you only send short bursts at the convolution algorithm, otherwise the number of layers happening results in that slurred kind of effect.

When I played with using a drum loop as an impulse response, I sent short synth stabs into it at the start of each bar and set the tempo so this created a constant beat, with the result a bit like drums through a vocoder. The fun was then playing with the envelope of that stab - it created weird blurring effects that are really their own thing. I should go back to that track. :slightly_smiling_face:


sorry to flog a dead off-topic topic but

i am one of those special dummies with a rather absurd physical copy of this thing! haaaaaa oy vey. i look at it frequently.

unsurprisingly, julius smith has nice treatments of both cyclic and acyclic convolutions, as special cases of OLA STFT. (“spectral audio processing” is another one that is arguably worth having on dead-trees.)

if you are really interested i could probably pitch in for some development of some kinda command-line tool for this. (which is to say: non-realtime cyclic or acyclic convolution of a relatively long audio file, with a relatively short file as IR, in freq domain.) not that soundhack won’t do the job, but heck, it’s 2019


My dummy implementation is in cython – I was waffling on doing the FFT b/c I couldn’t decide if I should use numpy since it’s already a dep of the project, or something like KissFFT for the FFT which I could call from the c extension more directly and maybe avoid some overhead?

Bottom line is I haven’t thought through this very much but I would love to bring this into pippi and bundling it as a standalone cli thing sounds even better. (Can be both!) Would love to work on that!

(PS I’ve been dabbling in desktop GUI stuff, made a simple piano roll thing… would love to make this a standalone tool thing, I have nothing but <3 for soundhack but yeah I also can’t use it on linux anymore so! :slight_smile: A standalone cross-platform tool for that would be sweet. I’d love to work on that.)

Here’s the time-domain version fwiw, not that it’s anything!


It’s definitely going in an interesting direction! I really like it when the more percussive sounds come in (bells?) and you can hear the sounds in the sounds kind of. Quite eerie and alien. What’s your plan? Just do the convolution and make that the final track? or is this more to produce the raw material? Sorry if you’ve stated this before, I’ve not been watching this thread for a bit and maybe I missed something going through the posts.

Just like most others my start has been slow. Right now I’m randomly messing with the field recordings in the attempt to create raw material to work with and see where it takes me. My approach would be to mostly work with loops, extracting parts that have some sort of inherent rhythm to themselves, layer things. I think I am mostly inspired by Helm’s album Olympic Mess.


The sped-up convolution sounds kinda neat by itself but yeah now I’m thinking I’ll continue to play with it further. My idea at the moment is to treat the convolution as a wavetable (sampling from it, reducing it to a curve by envelope-following, etc) and use that as control params for further processing on the original field recordings.

Trying to keep the “balance” theme in mind, I might also treat the originals as wavetables/curves and do some more processing on one with wavetables from the other, etc.

So basically the plan is to keep screwing around. :slight_smile:


Just realised this weekend coming is the last one before we finish up!


Whoa, that snuck up quick!! Thanks for the reminder. I will upload my two tracks today…

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Right, I think I’m done!
Where do we send our finished tracks? @jlmitch5?


You can upload it to that drive folder where the samples are located.

It might be good to name:

Your Artist Name + Sample Artist Name - Song Name [Day + Night].wav. Where day and night are the same order as artist names


Uploaded my two tracks last night.

Working with field recordings is a bit new for me, so this was a fascinating challenge!


Sad to not get involved with this one, but looking forward to hearing everyones work.

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My track should be finished tonight or tomorrow. It’s taken a turn somewhere between dark ambient and musique concrète; pretty different from anything I’ve done so that’s already makes this project a personal success for me.

But as with any piece of music I make, the hardest part will be naming it!


Hoping to finish mine in time as well! Maybe should have realized sooner that the deadline was a few days away from my moving day…


I’ve relied on working in the interstices of life more than usual for this project! I think I’ve got the structure right and most of the details in the ballpark of where I want them, so I’m at the point where it could be done in an hour or another eight – hard to say. (I do plan on submitting by deadline, regardless!)

Definitely been a very different experience for me, too, and particularly by challenging me to engage in a set of aesthetic values in the opposite direction from where I’ve been pulled of late. This has led me to learn entirely new tools and revisit approaches to sound design and composition from a new perspective, so it’s been a great experience no matter what!


I’ll have mine in late on the 28th… but it’ll be there. Hoping to get a little more processing done through the 0-Coast for it.


Uploaded my track just now. Super excited to hear everyone’s work soon and how they interpreted the sounds / prompt :slight_smile: