Forums > MaxMSP

Change tempo of metro immediately?

Nov 02 2012 | 2:09 pm

This seems like a classic in the forums, but I have yet to find a definitive answer: Is there a way to make the metro object change its tempo (almost) immediately upon receiving a new tempo value?

As it is now, it waits until the next "tick" before changing tempo, which is kind of long if you have a tempo of, say, 1000. Some suggested the tempo object would react immediately upon a new tempo value, but as far as I can tell, it also waits until the next value.

Nov 02 2012 | 2:30 pm

If you send a bang to tempo right after you change its speed, then it will restart with the right tempo.


Nov 02 2012 | 2:32 pm

I tried that, but that becomes very messy when you are changing the tempo with a slider. I’d rather avoid the re-trig, but it seems that might be difficult.

Nov 02 2012 | 2:48 pm

sorry not to be more help but I recall that someone (?) recently posted a patch in relation to a ‘bang’ timing/quantizing issue, which used the delay object in a novel/unique way; kind of like a sample-and-hold effect. Maybe you could trawl the forum for that? You could use the delay object to quantize bangs from your slider+trigger.


Nov 02 2012 | 4:41 pm

If you are willing to go into the signal domain, train~ has the behavior that you search for.

Nov 02 2012 | 11:11 pm

to change the speed immediately you simply need to stop and restart it.

i´d use a [t 1 f 0] for that job.


Nov 03 2012 | 12:00 am

Here’s an absurdly hard way:

-- Pasted Max Patch, click to expand. --

Nov 03 2012 | 3:02 pm

Thanks for the suggestions, Roman and mzed, but Roman – your example still means there will be an extra trigger every time the slider slides from one tempo to another (resulting in lots "extra triggers"), and mzed, you are definitely the closest to getting this to work, but it seems there are some inconsistencies, resulting in the trigger not always immediately catching on to the tempo change.

Nov 03 2012 | 3:10 pm

With the metro object, you are going to have either one problem or the other. You need to "debounce" the slider input in some way, which will inevitably introduce some latency.

I wrote an elaborate solution called tempo~ that is in the cnmat downloads: It uses phasor~ as the timing mechanism. As jvkr says, train~ will also work.

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Forums > MaxMSP