Forums > MaxMSP

Hello World! seq object sync question

November 24, 2006 | 5:25 pm

Hi can any one tell me if you use multiple seq objects in a patch if they are using the same time base. If I start a few identical seq objects with a single bang they appear to stay in time. Is there something keeping them in time or are they just freewheeling and just appear to still be in sync, like a bunch of stopwatches all started at once?

I need to make a patch with a few seq objects that have different length midi files but follow the same tempo


November 25, 2006 | 6:41 pm

Not entirely sure about the direct answer to your question… but if you’re trying to keep multiple midi files in sync you might want to check out Eric Singer’s SeqPlayer object:

http://ericsinger.com/cyclopsmax.html

The object will play through a small part of the sequence everytime a bang is received. (i.e. play a quarter note’s worth of the sequence on every bang). In one of my current projects I am using an audio-rate metronome generating bangs to step through a few different SeqPlayer objects simultaneously. Even if there is drift within a beat, the objects all realign on every beat. It has proven to be a really easy way to ensure sync over time.

Hope that helps.

/dan


November 27, 2006 | 2:15 pm

Hi thanks for that looks like a useful object. My problem really though is this:
I need to have a four track sequencer with all four tracks looping with different durations e.g track one is 8 beats long track 2 is 9 beats long etc. I only need one note-on at the beginning of each sequence but they need to all use the same tempo. This is a patch for triggering videos that are musically related.

So my question remains, are multiple instances of the seq object locked to the same timebase?

BTW I left my patch on all night and it was still in sync in the morning, guess I am just looking for some conformation to give me peace of mind :-)


November 27, 2006 | 10:03 pm

You might want to check out seq~… which, I believe, runs at the audio rate using an object such as phasor~ to drive it. You could hook up several of them to a single phasor to ensure sync.

I feel bad that I keep diverting from your direct question, but the truth is I’m not really sure and there don’t seem to be a lot of other takers on this thread.

What kind of complexity was there in the test patch that you let run overnight? My guess is that the seq objects will stay pretty much in sync as long as there isnt a lot of other processing going on…. but if you start doing a lot of other stuff like loading and rendering multiple videos, i’m not quite sure that they would stay in sync the way you would like.

Maybe one of the gurus out there can step in and confirm/deny?


November 28, 2006 | 2:23 pm

Doc Op you were right, as soon as I triggerd four imovie objects the whole thing went pear shaped. I was really dissapointed that even the MIDI went in and out of tempo. The videos drift in and out of sync. the MIDI does go back to the correct tempo (after a few seconds)

Having a look at sync~ but I have just realised that the imovie has no audio! doh

I thought this one was going to be simple but is proving a headache.

for anybody reading, this is the challenge. (simplified)

I want to trigger four videos (with audio) of different lengths. the lengths are related musically i.e video 1 is 8 beats video 2 is 9 beats and so on
they will all loop but be sequenced from the same tempo base. polyrhythmic video if you like.

A four track step-time sequencer that allows each track to be a different length and can loop indefinitely could use single note on for the triggering of each video. this is where I am stuck!

I could maybe generate this behavior using logic audio and a VJ app like Grid pro, leave the audio in Logic and trigger the video via MIDI. No doubt I could capture the result and show that , but I really want this to run in real time so that we can all hear (and see) what the generative permutations sound like after a few hours. The nature of the polyrhythms means that there is no repeat point in the music for hours and hours.
If I get to exhibit this I will credit all who helped! Looks like I am looking for a sci/art collaboration contact me off list if you are interested, I am in London.
Thanks for reading.


November 28, 2006 | 4:54 pm

jitter! it’s worth the cash and effort.

On Nov 28, 2006, at 2:23 PM, Carl Rohumaa wrote:

>
> Doc Op you were right, as soon as I triggerd four imovie objects
> the whole thing went pear shaped. I was really dissapointed that
> even the MIDI went in and out of tempo. The videos drift in and out
> of sync. the MIDI does go back to the correct tempo (after a few
> seconds)
>
> Having a look at sync~ but I have just realised that the imovie has
> no audio! doh
>
> I thought this one was going to be simple but is proving a headache.
>
> for anybody reading, this is the challenge. (simplified)
>
> I want to trigger four videos (with audio) of different lengths.
> the lengths are related musically i.e video 1 is 8 beats video 2 is
> 9 beats and so on
> they will all loop but be sequenced from the same tempo base.
> polyrhythmic video if you like.
>
> A four track step-time sequencer that allows each track to be a
> different length and can loop indefinitely could use single note on
> for the triggering of each video. this is where I am stuck!
>
> I could maybe generate this behavior using logic audio and a VJ app
> like Grid pro, leave the audio in Logic and trigger the video via
> MIDI. No doubt I could capture the result and show that , but I
> really want this to run in real time so that we can all hear (and
> see) what the generative permutations sound like after a few hours.
> The nature of the polyrhythms means that there is no repeat point
> in the music for hours and hours.
> If I get to exhibit this I will credit all who helped! Looks like I
> am looking for a sci/art collaboration contact me off list if you
> are interested, I am in London.
> Thanks for reading.
>
>


November 28, 2006 | 5:55 pm

That’s just what I was going to say…. Jitter for the win.


November 29, 2006 | 6:11 am

>> I want to trigger four videos (with audio) of different lengths.

[snip]

Have you tried Quartz Composer?


J. Simon van der Walt —– Composer
< http://www.jsimonvanderwalt.com>


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