Looping Waveforms

When I get a click sound at the beginning of a loop I go to the program screen and press window and play around with the attack levels, works for me pretty much all the time. I can also lose the qucik click at the end of the sample with using decay. check it out

from what jj said, it appears that the original pitch of the sample affects whether or not it will click too. you need to choose the right pitch (or pitches) that will fit exactly into the 44100 samples/second, otherwise you get aliasing.

There is something more to this.

I just made a pad like program today, and could here some sort of aliasing/buzzing type noise over the top. Thing is, you only here this aliasing on certain octave ranges - higher up the keyboard it's all good.

So if there is no clicking/aliasing on certain keys - why does it happen on others? I mean, if the loop points were off, then it wouldn't sound good on any keys right? Bu this sounds sweet on some, and then bad on others!

If anyone wants to test this in their 1K, here's a couple of links to the program file and the sawtooth wave I used:

PAD1.PGM
SAW.WAV

Start high up the keyboard and work down. Then note the slight buzzing introduced on the lower octaves (and this is not anything to do with internal distortion because I checked nothing would be overloading to make sure).

jigginz wrote:There is something more to this.

I just made a pad like program today, and could here some sort of aliasing/buzzing type noise over the top. Thing is, you only here this aliasing on certain octave ranges - higher up the keyboard it's all good.

So if there is no clicking/aliasing on certain keys - why does it happen on others? I mean, if the loop points were off, then it wouldn't sound good on any keys right? Bu this sounds sweet on some, and then bad on others!

If anyone wants to test this in their 1K, here's a couple of links to the program file and the sawtooth wave I used:

PAD1.PGM
SAW.WAV

Start high up the keyboard and work down. Then note the slight buzzing introduced on the lower octaves (and this is not anything to do with internal distortion because I checked nothing would be overloading to make sure).

I would say that this is just typical of trying to stretch a wave form across octaves. Historically if you look at other synths that use a digital wave for an oscillator they do the same thing. The Ensoniq ESQ1 or SQ80 do the exact same thing. They alias like crazy on certain keys but not on others. Just a characteristic of using a sample that gets longer and shorter to make it sound higher or lower in pitch I would assume.

Luke

I noticed short loops induced clics too..but if the loop is longer there aren't no clics anymore.
There's just got to copy the waveform so that the loop is long enough. That uses memory a bit more but it works for me

loozman wrote:I noticed short loops induced clics too..but if the loop is longer there aren't no clics anymore.
There's just got to copy the waveform so that the loop is long enough. That uses memory a bit more but it works for me

So, this is not a bug.

Since getting the JJ OS, i'm really taking a good look at the 1K for it's synthesis possibilities, all because of the magic WHOLE button. Tweaking the 2 seperate filters, applying some Filter Envelpe and some LFO, you can create some nice polyphonic patches with this little beast. Who needs a 4K!

JJ really turned the 1K into a serious production tool. Big Props.

rich_biatch wrote:this is just a cheap interpolation algorithm. if you want nice interpolation, get an emu e4 range sampler, they have near flawless interpolation. and theyre cheap!

This is the first thing that I have read regarding this issue that makes sense. If the loop points work flawlessly in a wave editor, other mpc's, or other samplers then it should work in the 1K w/ JJ. I would be curious to know if people with the akai os have the same problem. It has been a long time since I have tried this with the akai os. I think this is something that can be fixed. It happens randomly and only at the loop point which leads me to believe that it has to be poor interpolation of the loop point. Some times the aliasing is louder than other times even when holding down the same key.

This is a real shame if you ask me. Why have the ability to create instrument programs if you can't play without clicking and popping.

I have tested this:

had a collection of samples that were pre-looped using Peak-loop flawlessly with no crossfade.
loaded them into the 1k and got aliasing
loaded them into the sampler plug-in in Ableton and didn't get aliasing and no crossfade was necessary

so....it has to be the 1k

Blinky-Live- wrote:Got a reply, can't say i agree with it...

A click noise comes out of change (i. e.Tune:01:00) of a wave-like pitch with steep rising edge.

It is because the frequency component 20kHz or more is included.
Since the sampling rate is 44.1kHz, the waveform containing a frequency component 20kHz or more is normally unreproducible.
(Limit of hardware)

As for the sound recorded using the SAMPLE RECORD function of MPC1000, the sound of 20kHz or more is cut.
Therefore, please LOOP and use the sound recorded by the SAMPLE RECORD function of MPC1000.


: The following waveforms contain the waveform 20kHz or more.
: This waveform is normally unreproducible.
*
* *
* *
* *
* *
**** **************
-->||<--Over 20KHz( Under 50uSEC )

: The following waveforms do not contain the frequency of 20kHz or more.
: This waveform is normally reproducible.

*
* *
* *
* *
* *
* *
*** **********
->| |<-20Khz( 50uSEC )

Sample rate=44100Hz
A3=440Hz = 100 sample point ##### Just 100 sample ####
MPC1000 [Trim] St:0000000 End:100
::: It's play without noize
* *
* * * *
* * * * <- Wave form
* * * *
* * * *
**** * *******
<---100 point-->
__|__|----------__|__|__|__|__|__|__|__|__| <- sample point 44.1K
^

Sample rate=44100Hz
MPC1000 [Trim] St:0000000 End:100
rogram Tune:+02:00 ==> B3=493.8Hz = 89.1 sample point

::: It's play with noize
|<---2040uSEC-----> <---- position actually reproduced.
|<---2025uSEC--->|<------ exact position.
* | *
* * | * *
* * | * *
* * | * *
* * | * *
**** **** *****

<---89 point -->
__|__|----------__|__|__|__|__|__|__|__|__| <- sample point 44.1K
89 90

493.8Hz =2025uSEC
89 point =2018uSEC
90 point =2040uSEC
Since a loop is not made in 2025uSEC
A wave like sound which repeated 2018uSEC and 2040uSeC hears.

*
* *
* *
* *
* *
* *
*** **********
In such a wave-like case, a noise can be heard few.

In a sign wave, a noise cannot be heard.


JJ

if this is true then the samples i have that were recorded at 16-bit 44.1K should work, but the don't. this is not a matter of truncation. why would it loop on an S3000xl or an MPC 2000xl? They would have the same problem.

yeh something is deffenetly sus there, i never had to use envelopes to declick on the 2000xl it just worked.

I know this thread is ancient but I found a way to loop instrument samples seamlessly in OS2XL.

Option #1 - Use the XFADE loop setting and Convert to a regular loop (this changes the character of the loop and makes it sound faster)
Option #2 - After doing your best to find zero crossings in your loop, copy the loop portion of the sample into a new sample and then use the Edit > Combine function to create a sample containing 2 reps of the loop. Then use the XFADE loop setting and try to line up the loop start as precisely as you can (it will sound out-of-phase). Then use Convert to regular loop and it should come out perfectly looping (not sounding like a crossfade)

I only succeeded in doing it once so far, so maybe the process can be simplified, but at least it seems possible.

I recall that there’s a bug or similar problem with samples under a certain size, it might’ve been 800 samples or something... my memory is dodgy on this. I’d suggest trying to double up the samples a few times using Option #2 and figure out when it goes away. Good luck!

Unfortunately that doesn't make it go away - I tried. You get random clicks and pops at the loop points no matter how long the loop is. I think that's why it's referred to as a "phrase sampler", the hardware wasn't designed for looping arbitrary loop points seamlessly. I did have success with the technique I posted so, maybe the conversion feature does something fancy behind the scenes to make it seamless.

Elektron84 wrote:Unfortunately that doesn't make it go away - I tried. You get random clicks and pops at the loop points no matter how long the loop is. I think that's why it's referred to as a "phrase sampler", the hardware wasn't designed for looping arbitrary loop points seamlessly. I did have success with the technique I posted so, maybe the conversion feature does something fancy behind the scenes to make it seamless.

Hah... just tried to do this on JJOS3, and yeah, click city. I loaded back into JJOS1 and it works properly with a single cycle and not having to double it up. I'll play around and see if I can remember how to get it to work properly, it's definitely something weird happening at the loop point because the more you double up the sample, the less often you hear the clicking. There might be something to tweak... I'll definitely check it out.

I played with this for a while, and it seems to be a legit error. I posted a bug on the JJOS site against JJOS OS3. If I hear anything I will write back.

JJ got back to me... he sent me the link to the JJOS page http://www7a.biglobe.ne.jp/~mpc1000/128 ... 4_loop.htm

Apparently to loop properly, you need at least 256 samples after the end point. I could speculate on what the issue is, but this is a pretty easy fix. The instructions above post up a pretty good set of steps to go through, and how to confirm that you have a zero point cross. Hope that helps.