Forums > MaxMSP

Two Strange & Inexplicable Bugs

February 16, 2009 | 4:35 am

Hi, so I have created a sampler module that uses groove~’s loop function for sample accurate retriggering. However, there are two exceedingly strange problems that I can’t seem to figure out. The first seems more straight forward than the second, so I’ll start with that:

1. In the patch I have provided, there is a high pitched buzzing that occurs between drum hits. After debugging I have found that this occurs from playing the sample with groove~ in reverse. It seems to be the value of the first sample in the .wav file used. For some strange reason, the way reverse is implemented in my patch seems to cause groove~ to stay stuck on this sample. This doesn’t happen when one normally plays a wav file in reverse with groove~ and I have no idea why it would happen in my use of groove~.

2. When adjusting the slider values of the various modules within this patch, something exceedingly bizarre sometimes occurs: the metros driving the sequencer modules stop sending out bangs. It’s as simple as that: the metros all simultaneously stop banging and I have no idea why. It doesn’t happen consistently, I haven’t found a way to guarantee that the metros will stop banging, but i promise you this has happened numerous times, much to my frustration. I will try to record this happening on video and post it later. It has happened to me with just this patch opened, so please tell me if this happens to you as well.

I am on a Macbook Pro, Intel processor, if that is useful information.

Thanks for any help. I really do hope this can be solved as I was very happy with my idea for this patch and would love to have it working properly and consistently.

Attached below is the module. Unzip the file – the main patch is called "GrooveRolls".

Much thanks. Your help is very much appreciated.


February 16, 2009 | 5:01 am

i just tried this: try turning reverse on for every step – it really illustrates my reverse problem.


February 16, 2009 | 5:04 am

figured out my reverse problem: i didn’t connect the incoming playback speed to my [< ~] object in my drumGroove module. Still don’t know what causes the metros to stop banging tho.


February 16, 2009 | 5:08 am

i spoke too soon – i still get the same problem with reverse. it seems groove~ gets stuck on the first sample value and thus keeps on outputting a high pitched buzzing.


February 16, 2009 | 5:30 am

lol, i’m pretty much having a conversation with myself here, but i fixed the bug by adding a [!=~] to groove’s sync phasor and connecting that to a [*~], with the other input being the groove’s output.

– Pasted Max Patch, click to expand. –

tho, i don’t think i should have to do this. if that bassdrum sample is played in reverse in the groove helpfile, there’s no buzzing the same way there is in my patch. but w/e, this method works too.


February 24, 2009 | 4:52 pm

If it was looping the same first sample value every time (I haven’t tested the bug…) it would create either silence or a dc bias… just a straight line.


February 24, 2009 | 4:56 pm

< ~ 0 , for your second inlet, will only always produce a 1 or 0, and is converted and issued as a re-trigger in the form of max message int to the groove object.

If you want a sample-accurate retrigger-er, I’ve made one, and it uses count~ and sah~, groove~ will create buzzing sounds from having it re-snapped to the beginning. I think I get what you’re going for but… groove~ needs a max message to re-trigger the wave, which means it could never exceed 50hz (1000/20ms).

Get in touch with me at midinerd@gmail.com.


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