I thought I would be able to figure this common problem by myself but I'm really stumped and becoming too tired to think mathematically.

My problem is that I am trying to sweep the frequency of a bandpass filter up and down. I want to cover the majority of the audible spectrum with this filter sweep, but when it sweeps up and down, I want it to sound like it is sweeping "evenly."

If I just use a linear function to sweep up and down, moving the frequency up and down, it doesn't sound even, because it takes a lot longer to sweep from 10000 hz to 20000 hz than it does to sweep from 100 hz to 200 hz, even though the difference in frequencies in both cases is an octave, which sounds like the same difference in pitch in terms of psychoacoustics.

When the filter sweeps up and down, it has plenty of time to showcase the high frequencies, but as it reaches the lower frequencies it just flies right through them. I'm wondering what sort of equation I can use to change this, so that the time it takes for the filter to sweep through one musical interval is constant, regardless of where in the spectrum it is.

I'm really tired and confused after spending too much time playing with exponents and logarithms and wishing that I had payed more attention in my math classes. I hope I've still been able to make myself clear.

A thought just occurred to me. When you are using speakers, the sound from the left speaker will affect the sound from the right speaker, so if the same signal is present in both channels but it's delayed in one, the phase difference can cause the signals to be added or subtracted.

In the "sweet spot" between the two speakers, if the two channels are out of phase, you will hear certain frequencies being amplified or attenuated.

If I am listening with headphones, I can hear the signals independently in each ear, so even if I'm listening to two sine waves that are 180 degrees out of phase, I will be able to hear both independently, and I will interpret the difference in phase as a delay that will effect my spatial imaging of the sound.

If I were listening with speakers instead, wouldn't this same situation with two sine waves that are 180 degrees out of phase cause the sound to be completely attenuated (depending on where I am seated in the room)? Does this mean that mixing with headphones can lead me to overlook some issues that I would normally hear with speakers?

Sorry, I guess this isn't really a PD-specific question; it's more of a general audio production thing that will be important no matter what applications I'm using.

Hey everyone!

I've been working on this patch a little bit at a time for the past two weeks or so. It's nothing too complicated, but I really like how it has turned out.

Visit my brand spanking new soundcloud page to listen or just download the patch in the attachment and tweak it yourself.

http://www.pdpatchrepo.info/hurleur/add2.zip

Hey everyone, sorry to bother you with such a newbish question, but I'm looking for an easier way to make sequences in PD.

I'm a windows user, and I just downloaded and installed seq24. It seems pretty easy to set up sequences for different instruments using seq24, but how do I get it to send the data to PD? I tried just setting the MIDI data to be sent to channel 1 using the Microsoft MIDI Mapper, and then in PD I set the driver to ASIO so it would use the Microsoft Sound Mapper... I guess this doesn't have anything to do with MIDI though.

I tried just making a [notein 1] object and attaching some number boxes to it, and then I started to play a sequence in seq24. I guess it's not that simple.

Anyway, I probably look like an idiot for not knowing how to set this up, but can someone point me in the right direction anyway?

Hey guys, I'm new here and I'm pretty new to Pure Data. I wasn't sure whether to post this in the output~ section or the patch~ section, but it probably doesn't matter that much.

Here is a fairly small patch that I've been working on for the past day or so. I'm using two 3-oscillator FM synths that are playing random minor notes to form different chords. One synth has a short attack, medium decay, and a noticeable delay, while the other has a long attack and acts as a sort of synth pad.

I also added some drums into the mix, but I'm not really satisfied with them.

Anyway, it's nothing phenomenal and the guts form a very disorganized mess (I probably should have used more subpatches). Still, I like the sound and the mood it's producing... it kind of reminds me of a bowed vibraphone.

Check it out if you get the chance - It should just start if you press the big button but I'm fairly new to all of this stuff so I apologize if I screwed up the patching somewhere and it doesn't work (I think I'm getting a stack overflow error but I'm not sure where it's coming from or what it's doing. It happened when I copied the contents of extractions into subpatches and deleted the abstractions to make it fit in one folder). Feedback would be much appreciated!

http://www.pdpatchrepo.info/hurleur/ColdShell.pd

Oh, I see! I actually like that solution a little bit better, but I don't seem to have an [exp~] as a signal object (I do have the non-signal version). I guess I could just use [expr~] and approximate e instead.

Anyway, I can see this being very useful. Thanks for the help!

I just realized that I can use mtof~ to do what I want by just sending it values between 0 and about 135, and section 3.1.1.4.3 of Johannes Kreidler's PD Tutorial seems to have an explanation of how this works using an exponential function. I guess the answers are all here for me...

Hmmm, I was actually going through the FM tutorials in MSP a few nights ago. There were some great sounds even in that simple patch, but nothing quite like the stuff in this patch. I guess it just shows how much you can get out of a little variation and weighted randomness.

Out of curiosity, does anyone know if this is a legitimate Autechre patch, or is it something someone else made in their style? Either way, it's pretty awesome. I'm surprised that all of the sounds seem to be synthesized through FM; I have no idea how to generate half of those sounds.

The random object generates numbers from 0 to its right argument every time it receives a bang, so if you use this number to control the frequency of a sound generator, it can definitely play a different note every time.

It would kind of help to see your patch for this, because I'm not sure where you are going wrong.