Card Player VS Raw Player VS Sample Players

Hi all,

I’ve seen there’s no Card Player page on the new Docs portal - Core Package - docs @ O|D

But there is this info on the Wiki - ER-301/Card Player - O|D Wiki

This unit can play WAV files directly from the card without using any RAM.

As I use dozens of Card Player units in my projects, I’m really curious to know more about it. I know there is already this topic with interesting information about it - Card Player - #12 by ringhof

Not sure what the concurrency limit is for files played back from SD. I’d say it very likely depends on the performance characteristics of the SD card itself, as they aren’t all equal.

I just ran a small test. had 10 loops (all mono / 44100-16 / 30-70 sec.) played from my card (sandisk ultra). which went fine. i couldn’t notice any drop outs, but the loops made a big brew of noise anyway :heart_eyes:.

When i can run 8 loops simultaneous with a CPU load of 10% i still have plenty of head room for other chain units.

So I guess the right way is to use a combination of different types of units to avoid both RAM and SD card overload and be able to use as much samples as possible.

Can you tell me your experience with the different types of sample players units and how do you use them?

In the topic I’ve linked, they are also talking about the Sample Player unit:

The sample player actually has to load the sample file into RAM, and gives a lot more control (slicing, re-pitching, playback speed, etc.).

I’m guessing this unit changed its name in posterior firmware updates to 2 different units: Variable Speed Player and Clocked Player; I’m understanding now the Variable Speed Sampler through the Docs page - Variable Speed Player - docs @ O|D

As there is no Docs page for the Clocked Player and the Wiki page isn’t 100% clear to me - ER-301/Clocked Player - O|D Wiki
I would like to know more about it from somebody with experience.

Anyway I’m guessing both this units load the samples in the RAM.

Thanks in advance!

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The Clocked Player is just the Variable Speed Player with the playback speed controlled by a clock signal. Specifically, the playback speed is adjusted in real-time so that playback (of the sample or slice) finishes exactly when the next clock pulse is expected.

The Clocked Stretch unit is another version of this but uses granular stretching to change speed without affecting pitch. Clocked Stretch’s non-clocked version is Grain Stretch.


Thanks for your answer and your work Brian, so please correct me if I’m wrong:

Card Player
Do not use RAM - Little CPU load (we know that 8 loops 4416 / 30-70 sec. use around 10% of the CPU)

Raw Player (48kHz or 96kHz)
Use RAM - Minimal CPU load

Variable Speed/Clocked Players
Use RAM - Medium CPU load

As there is a limit related to the performance of the SD card itself, I’m wondering if the players have any difference in this aspect. Example: With the same SD card you can have more samples (same MB) contemporarily using Raw Players instead of Card Players (or viceversa).

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The maximum number of audio files that you can simultaneously stream from the SD card is going to depend heavily on quality of the SD card and the amount of FAT32 fragmentation.

For this reason, I’ve never tested for the maximum number of simultaneously playing Card Players. The main purpose of the Card Player is just to enable playback of super long samples that would not fit into RAM.


I manage to use 13 card players (48/32) at the same time. The shortest file was 4mins and the longest 14min. At that point cpu was at 80% and crackles started to appear due to SD speed I think.

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Ok, I understand.

I usually use Card Players as I mainly use one-shot percussive sounds at 44kHz.

I manage to use 13 card players (48/32) at the same time. The shortest file was 4mins and the longest 14min. At that point cpu was at 80% and crackles started to appear due to SD speed I think.

That’s insane.

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FYI, the Variable Speed Player is better for playing short one-shot samples.