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womble dung
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Joined: 07/13/2016 - 18:19
PCM synth- finding an 'anomaly' with a basic 8 beats

I've a clip (actually the intro, after engine noise and  before main kicks in, on The Cramps- ''Garbageman''

I prepard the clip using Audacity and it is BANG ON and set to 140bpm, YET when it goes into PCM at same speed, it is always a little TOO SHORT< so just sounds like there's a skip in an old record...
ANY advice? been stuck on this all afternoon and need help!

please note: it loops perfectly when i play the clip in Audacity.

It's the first issue i've ever had with PCM, and i've been fine using it to makes sample loops since the rfirst day i started exploring it.
it isn't as ifd i need to adjust speed, so far as i can tell. WHy? because there is the tiniest bit ALWAYS missing in PCM that is DEFINITLEY in the clip.
Just normal 2/4, in other-words goes ''bomp bomp bomp bomp'' twice! lol (The kick drum hits x8)... WHATEVER.. there is a peice  missing on the last beat in PCM that IS NOT missing in the actual clip used! Again, making it sound (if you remember scratched/damaged vynil in the past) like a skp in the record.

womble dung
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Joined: 07/13/2016 - 18:19
incidentally, i have re-done

incidentally, i have re-done the clip from scratch four or five times now and it keewps doing it! AAAARrrgggh!

womble dung
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p.s.

p.s.
As i ONLY really need to use PCM so far for making these clips into sample/loops, I have never needed, so far, to bother using any of the buttons under the sample name at top left...
Maybe i need to do something there?
I thought maybe that start/end bit?
BUT, here is where i figure PCM keeps missing the bit at the end, even though it is only a few seconds long, i can shorten where the clip finishes, buit if i try to, (considering i don't know if this is even the right thinking)  use ''end' to extend it.. there seems to be no more TO extend...

So the only fix i can think of would be to do as much length of repetitions of the clip in Audacity, and add later in ableton to chop and mix  it in where appropriate....
HASSLE HASSLE HASSLE

SToons Music
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Joined: 03/01/2018 - 02:48
If you can, put the clip on a

If you can, put the clip on a cloud like Google Drive and send a link.

UncleAfx
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Joined: 03/06/2016 - 20:08
One possibility- if you

One possibility- if you created the clip in audacity, maybe you were using a different sample rate? Caustic is designed to work at 44100 Hz.
If sample rate isn't the issue, then depending on how many measures your clip is, check the end sample length. At 140bpm, one measure should be 75600 samples. If you're adding up to less than that, then that's your problem. Have a look at this online calculator: http://www.bertkoor.nl/MusicCalc.html

At the bottom of the page, set the table up so that 1 bar = 4 1/4 notes with 4 beats then enter your bpm and it will show you the length and # of samples.

Another way to check inside of caustic is to create a blank sample the length you want, then you have a reference where you can check the end sample and in the pitch shifter you can check the time.

Maybe though the easiest quick fix is where you mentioned earlier - the buttons under the sample name. Set the sample to play once and as long as you're close to begin with, try adjusting the cents up or down by 1 cent at a time until you get it where you want it.

womble dung
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Joined: 07/13/2016 - 18:19
I Will certainly upload and

I Will certainly upload and show an example of original clip from audicy in a loop. And the EXACT copy of that same clip being looped in PCM synth.
I very much highly douby the sample rate would in any way cause this effect. Wrong sample rate is more likely to cause popping and hissing and the like.
Whereas, what i happening here is the clip, when loop in PCM synth just will not come out as long as it should. It is always too short, and it's just not doing what i'm telling it to do! lol
2nd day now and, ha ha, am still ripping my hair our here as i've some great grooves laid down and ready for the bugger.

O)H! and all my associated  devices are indeed already  set to 44100 hence too, that this appears not to be my issue. Unless again am missing something. Definitely very open to learning if something in this respect can and will help! Hell yeh!

THe link is at: https://metapop.com/aira-ites/tracks/pcat134bpm-up2-140bpm-then-cuts2aud...
(I've set a download link under the track. I only just realised i've gone and deleted the PCM from the saved folder. And can't be bothered setting up again at moment with some other things to do. But could do tomorrow should i need. or we figure it out. It's gonna be a kick-myself one huh?)

Clip begins with PCM at 134BPM, then after a few seconds slides up to 140BPM.
Once that cuts out, then Audacity will kick in with a far stronger signal, and though not as exact as the finished peice loop will; be, does run along with the written drum groove in the way i want the thing to do.

Am itching to get this industiral rockbilly/ska techno stomper dam well finished enough to do a demo upload! know that feeling when you know it's a ripper? (at least in the world inside your your own mind!)

SToons Music
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Joined: 03/01/2018 - 02:48
K I'm lost. You originally

K I'm lost. You originally wrote that it was a loop exported at 140 that wouldn't loop right in the PCM. Nothing about changing tempos etc. Now you reveal that you're changing the tempo, indicating that you're trying to glide the tempo up or something.

Only way to help is if your intent is written more concisely and you post the Caustic file so the issue can be dissected.

Note that tempo can be ramped evenly in DAWs like Audacity, not in Caustic. In Caustic the tempo will suddenly shift. So the tempo cannot "slide up" as you put it, it will shift up. In this case, of you wamt a sudden shift on tempo, that would likely require using the wave editor and setting up a second tempo adjusted loop on a different key.

Listening up the clip on a web page is inadequate. From my perspective, there would need to be a way to download the loop set up at one specific tempo so that others would be able to create a workable solution.

SToons Music
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Joined: 03/01/2018 - 02:48
Just as an example, let's use

Just as an example, let's use this as a starting point.

It works perfectly at 134, there are no gaps, nothing. So what next?

Caustic Song file (optional): 

SToons Music
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Joined: 03/01/2018 - 02:48
Ok, so now I'm getting

Ok, so now I'm getting somewhere, perhaps I was wrong about how Caustic deals with tempo keys, it's ramping the tempo at some point instead of a direct shift. There doesn't appear to be documentation available so I'm making assumptions at this point, maybe it's addressed in a YouTube tutorial or something.

In this example there are 2 loops in the PCM, one at 134 and then another at 140. When I attempted to set a tempo key to 140 in the song I got what you described, and it sounds like the first loop is getting cut off early. See attached example.

Edit : so yes, by turning on the metronome and comparing playback it's clear that Caustic is ramping, not switching, from one tempo to another. With each subsequent measure the first loop is getting further off-tempo compared to the metronome.

Caustic Song file (optional): 

SToons Music
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Joined: 03/01/2018 - 02:48
So in this next example, I

So in this next example, I placed another tempo key 1/64th note before it switches to 140. By doing so the tempo remains at exactly 134 up until 1/64th note before it switches to 140, therefore the transition is pretty much inaudible. You will see if you check out the sequencer.

Caustic Song file (optional): 

womble dung
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Joined: 07/13/2016 - 18:19
lol... Sorry... it was a long

lol... Sorry... it was a long day/night.. all seemed obvious to me... The loop is should be 140. But simply started the first clip around 134 where it almost made a loop (just not what am after opf course) ... but when brought up to the right speed it just isn't doing it, even though, when the audio cuts, and the stronger audacity clip loops EXACTLY the same clip, IT IS FITTING in a perfect (slight slip) count.
btu the 1 2 3 4 5 6 7 8 kick and that guitar riff keep rolling fine...

But that first one... lower, faster, it just won't do it.... it ain't playing... IT IS THE SAME CLIP!

SToons Music
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Joined: 03/01/2018 - 02:48
I don't have a clue what you

I don't have a clue what you're talking about at this point.

I posted 3 examples yesterday. In 2 of those examples the loop is working at both 134 and at 140.