Post your views and questions about the Akai MPC2500
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By jahrome Sat Oct 15, 2005 6:04 pm
Does the MPC 2500 has real-time timestretch?

The answer to this question is yes.

Sampled phrase loops must be chopped using the MPC 2500s Chop Shop function. Once this looped is chopped, you would convert it to a Patched Phrase. You can then assign this Patched Phrase to a program and pad.

Once the Patched Phrase is assigned to a pad, hold down the pad to play back the Patched Phrase. While the phrase is playing back, adjust the tempo of the sequence. The Patched Phrase will respond accordingly.

Again, yes. The MPC 2500 has real-time timestretch :D
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By Kalei Sat Oct 15, 2005 9:04 pm
Would you mind posting an audio example of a break-drumloop using this? Im interested in the quality of it.. Maybe start with the original bpm and then stretching it slower? Faster doesnt really tell quality well..

Thanks

Kalei
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By jahrome Sat Oct 15, 2005 9:29 pm
I will see what I can do.
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By Kalei Sat Oct 15, 2005 9:56 pm
Thanks man!

By elmacaco Sun Oct 16, 2005 12:50 am
A drumloop isn't really such a challenge, IMO, you just chop it into the individual drums and there you go. Timestretching a vocal or symphonic sample is more of a real test. If you would, try it with something like an extended vocal sample with music an all, like a minute of a song, then slice it into as many pieces as you can for a real test of timestretch.

Also, changing the tempo of a sequence probably isn't the only way to alter the Patched phrase, By Altering the initial tempo of the PP you can do it independantly of the rest of your track, which is very useful. The thing I am wondering is can you cnage the original tempo of a patched phrase sample during playback, in the middle of the sample? Realtime? The best would be if it was linkable to Q link but I might be expecting too much.

it is cool that they have that added release thing for each slice if you are slowing it down. Straight from recycle, but recycle adds a kind of reverb, I wonder if that's what the 2500 does or if it's something else.

By sleepersriddle Sun Oct 16, 2005 1:12 am
thanks for xplaining that...

See to me that doesn't sound like what i would call 'time stretch'; some might agree w/me and some might not.

Cause I think of the "chop into slices and pull the slices apart/together" method as something like 'slicing' or 'recyling', not really time stretching... i mean that sounds the same as what the loop player in Reason does right?

Good time stretching (like in an audio editor, or some of the modes in Ableton Live) either uses much smaller slices and crossfades between them to achieve granular resynthesis, or maybe some fancy frequency domain method.

..So a further question i have is, how small are the slices? Would it just be like sixteenth notes, or much smaller then that?
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By Kalei Sun Oct 16, 2005 2:25 am
elmacaco wrote:A drumloop isn't really such a challenge


It depends on how much its stretched really. Im more used to work with druml00ps than voices when timestretching so I think it would be better, for me, that is. But I do see your point.
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By jahrome Sun Oct 16, 2005 2:48 am
sleepersriddle wrote:
thanks for xplaining that...

See to me that doesn't sound like what i would call 'time stretch'; some might agree w/me and some might not.

Cause I think of the "chop into slices and pull the slices apart/together" method as something like 'slicing' or 'recyling', not really time stretching... i mean that sounds the same as what the loop player in Reason does right?

Good time stretching (like in an audio editor, or some of the modes in Ableton Live) either uses much smaller slices and crossfades between them to achieve granular resynthesis, or maybe some fancy frequency domain method.

..So a further question i have is, how small are the slices? Would it just be like sixteenth notes, or much smaller then that?


Sorry fellas..no 'granular resynthesis'.

The Chop Shop feature is exactly like Recycle. As far as of the current OS, it will chop samples at a maximum of 64 samples to achieve this. To get around this limit, I had to chop a loop into 4 segements. Than chop each segement into 64 with the Chop Shop function to convert them to a Patched Phrase. You can take this method further by chopping the initial sample into more segments(more than 4 like the example above) and than chopping these segements further before coverting them to a patched phrase.

The only hardware I know of that does what you are asking about are Roland Products that contain the variphrase technology. As far as software, many of the highend DAW programs have this function.
By GrantB Sun Oct 16, 2005 4:38 am
jahrome wrote:Does the MPC 2500 has real-time timestretch?

The answer to this question is yes.

Sampled phrase loops must be chopped using the MPC 2500s Chop Shop function. Once this looped is chopped, you would convert it to a Patched Phrase. You can then assign this Patched Phrase to a program and pad.

Once the Patched Phrase is assigned to a pad, hold down the pad to play back the Patched Phrase. While the phrase is playing back, adjust the tempo of the sequence. The Patched Phrase will respond accordingly.

Again, yes. The MPC 2500 has real-time timestretch :D


That is not timestretching. There is a very big difference between choping and timestretching.
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By jahrome Sun Oct 16, 2005 4:57 am
GrantB wrote:
That is not timestretching. There is a very big difference between choping and timestretching.


Time stretching is changing the tempo of a loop without changing the pitch. The MPC does this in realtime and also does it the old way by just dialing in a tempo and processing the sample. You get good results both ways.

By GrantB Sun Oct 16, 2005 5:47 am
jahrome wrote:
GrantB wrote:
That is not timestretching. There is a very big difference between choping and timestretching.


Time stretching is changing the tempo of a loop without changing the pitch. The MPC does this in realtime and also does it the old way by just dialing in a tempo and processing the sample. You get good results both ways.


Not quite. Timestretching is changing the length of a sound by selectively inserting or removing sample data.

Take a continuous pad sample with no drums, chop it into 8 or 16 parts, re sequence, and slow it down 25%. Hear the gaps? That is chopping, not timestretching and all mpcs can do it (some much easier than others). Now take the same original sample and timestretch +25% in sample edit mode. No gaps. That is timestretching, but none of the MPCs do it in real time.

The 2500 has timestretch and chopping automation features, but not real time timestretch.
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By jahrome Sun Oct 16, 2005 6:11 am
GrantB wrote:
Not quite. Timestretching is changing the length of a sound by selectively inserting or removing sample data.

Take a continuous pad sample with no drums, chop it into 8 or 16 parts, re sequence, and slow it down 25%. Hear the gaps? That is chopping, not timestretching and all mpcs can do it (some much easier than others). Now take the same original sample and timestretch +25% in sample edit mode. No gaps. That is timestretching, but none of the MPCs do it in real time.

The 2500 has timestretch and chopping automation features, but not real time timestretch.


Technically you are correct. No MPC does what you described as I mentioned above. The MPC Chop Shop function is exactly like Recycle. You can call it timestretch or chopping or what ever you choose. But the ultimate goal is to change the tempo of a sample without changing its pitch. Speeding a sample up using the chop shop feature sounds pretty good as good as any 'timestretch' because there is no removing of any sample data. Slowing it down to the extremes, you will hear the gaps between the slices. You will have to use the standard timestretch feature if you don't want to hear these gaps. Using the traditional timestretch function, it is possible to hear artifacts in the stretched sample.

Akai wrote:
Q. What is Chopshop and Patched Phrase?
A. Chopshop is used for sampled phrases such as a drum beat. This function measures the amplitude on a drum beat and
“chops” the rhythm sections into separate parts onto the pads of the MPC. This is great for making a drum kit from a sampled
beat.
Patched Phrase takes one sample and divides it into several regions which creates sequence data used for playing these
regions. This allows you to move the regions together giving you the effect of time stretching a sample in real time without
changing its pitch.
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By Kalei Sun Oct 16, 2005 8:53 am
Are you saying chopshop and pathed phrase is the same thing then?
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By jahrome Sun Oct 16, 2005 4:08 pm
Kalei wrote:
Are you saying chopshop and pathed phrase is the same thing then?


They are linked but not the same.

Chop Shop slices the samples. The chopped samples can be then assigned to a program (each slice assigned to a pad) or you can convert them to a Patched Phrase (all the chopped samples assigned to one pad).