Concatenate samples to use as slices in Flexi


I want to build multi sample drum kits from downloaded kit library files.

For example, 5 snare samples from softer to harder. I know I could have multiple samplers and trigger one or the other via velocity with the help of a graphic shaper or similar. But I think it’s cleaner and more cpu efficient to have the 5 snares as slices in a Flexi Sampler and trigger slices via offset-velocity. This would be more cpu friendly right?. Certainly easier to manage.

ive done this in the past having koala on an AUM track, loading the samples there, then Drambo in a fx slot and record the output from koala , where I hit every pad in one go and record all hits as one file in Flexi. Then “detect transients” in Drambo. I use Koala cos it’s fast and it has drag and drop.

It works but it’s cumbersome. Can you think of any method to speed this up?. If I could maybe join (concatenate) the samples before hand and just import that into Flexi... it’d actually be nice if the Flexi recorder had a way to append instead of replacing.

Thanks in advance,


  • I don't think using the sampler would eat more CPU. Also, I wouldn't mind using 20 samplers in one track.

    The slice approach is handy for splitting up an audio file into individual hits but if you have separate files already, I would load them into the sampler (Sampler menu => Create zones from folder). If 4 velocity layers are not enough, just use two different notes to map the samples to and distribute the hits by their velocity (a/b/a/b...). This will make it easier to keep the velocity response intact.

    I would use separate sampler modules for each velocity layered instrument so that you can easily swap out snare drums by choosing a different preset in your "snare sampler" for example.

    By using your own idea of a drum instrument mapping standard without overlaps, you can have all these in one track and still change individual instruments of your drum kit.

  • @rs2000 ”If 4 velocity layers are not enough, just use two different notes to map the samples to and distribute the hits by their velocity (a/b/a/b...).”

    I don’t get how I’d go about this. Say I want 8 velocity layers. I map them to 2 notes like you say. Then map those 2 notes with velocity (a 1-x Switcher?), so vel 0-63 plays note 1, 64-127 plays note 2. The second note would expect the 4 samples to be mapped around 0-127, right?. But It’d never get anything below 63... so you’d still only get 2 lares each, 4 overall. You could do some vel remapping or whatever, but that’d screw up the actual velocities...

  • You interleave the 2 x 4 zones in terms of sound and volume, not velocity, and play them accordingly.

    Different approach, same effect.

  • edited December 2020

    Hey I’m not sure if this will work for you, but I also needed more than 4 velocity layers for a sample set I was mapping. i used the Flexi sampler, and set it to play slices, with each slice triggered by velocity. This allowed me to get 15 velocity layers for each note. This requires as many flexis as voices you want to map.

    obviously, this is only really practical if you have a sample smaller sample set, but allows you to get way more dynamic ‘layers’.

    the routing chain (for each voice / note) is midi note filter> midi to cv> flexi. And then to a mixer.

    So if you had a Hang Drum with 8 voices but 15 dynamic layers, you’d have 8 different Flexis, fed by their own note filter and and midi to cv converter. You can adjust the note filter to select sample key range as well. All of this can be saved in an instrument rack.

    I’m currently working on a 16 velocity layer Salamander Grand project following this template. There will be about 40 Flexi samplers when all is done. No idea what cpu performance for that is gonna be like.

    *to get individual velocity layers into a single wave file I just use auditor. Automatically appends and merges multiple files.

  • edited December 2020

    I always go back to Flexi aswell. It’s more comprehensive, has more options... I guess Sampler would be better for “tuned” instruments, but for drums and such, Flexi seems a lot more manageable, plus the “speed” dial is really cool to add dynamics, a lot better than quirky sounding “pitch”. I just made like 6 drumkits and sine there were no velocity layers I used “shot sampler” (cpu paranoia), only to discover it doesn’t have velocity, so now I’m gonna have to redo them in Flexi.

    Im interested in the “Auditor” workflow!. Right now I map the different velocity samples to sampler (which requires extra steps with the naming issue) , and then record the output to Flexi. It works but it’s time consuming. Do you just select multiple files in Auditor as in a batch process?. I read about a Linux lib where you could concatenate samples, but that’d require desktop, I wish it could be done via Shortcuts.

  • There are various options.

    Place all samples onto the timeline of a linear DAW like Audio Evolution, Cubasis, Auria and export the mixdown.

    Or play all samples inside Drambo using Sampler or whatever, triggered by sequencer steps and record all with Flexi. If you group samples with similar length, you can use the fixed grid slicing in Flexi so you don't even have to worry about setting slice markers.

  • @Tahiche ill do a run down of the auditor process when I get home. It’s basically just select (multiple files at once) and then export. It exports a merged WAV. Really fast

  • Even though this package is "built" for the Octatrack, it works great for creating sample chains for Drambo:

    I especially like that you can set every slice to the same length so you can be sure it'll import as expected into Drambo (though Drambo's transient detection is pretty solid).

  • ☝️This is what I’m doing at the moment. But Auditor like @aleyas points out or gtbg seems way faster.

    @quartzite, soX is the lib i was talking about, this is a really handy wrapper. I wonder if when it does sub-folders as in

    “Example: if you have a directory 'samples', and with sub-folders for different kits, you use process them in one batch:

    gtbg ot --samples "c:/samples/"

    does it process the individual directories independently?. That’d be a life saver. Like if you have a “drumkit” for and inside subdirs like “kicks, snares...” each with multiple samples... will it concatenate each subdir to a different file?. Like kick.joined.wav. Snare.joined.wav

    it would be interesting to have this soX stuff on iOS. You could do it on a jailbroken device, not the case. Can apps include/install third party libs like this?. I’m wondering if someone could make a little wrapper-app, would be useful.

  • edited December 2020

    @Tahiche @quartzite @aleyas

    Sox cannot process sub folders but I'm writing aliases or bash scripts to do that, using scripts for often needed tasks is much more convenient anyway.

    My best bet on a non-jailbroken iDevice would be Pythonista, a Python environment for iOS that comes with a native GUI library and lot of third party libraries included and it would be easy to share a zip file with all samples to Pythonista, then let it unpack and merge them, then export the concatenated wave file.

    It does not stop there: Pythonista could also write the correct slice markers into a Flexi preset file and if you have WebDAV enabled in Drambo, upload everything to the correct Drambo locations so all you have to do after that is open the new preset with Flexi.

    Another good reason to learn Python and Pythonista.

  • If memory serves me, gtbg had no problem handling subfolders one layer deep, I don't think I tested more. The one thing I remember is that it'll generate a chain for all the samples in a subfolder, but then it'll also make a HUGE chain out of all the samples it generated in the subfolders. You just have to delete that, its a quirk. I used it a lot 6 months ago and haven't since, so hopefully I'm remembering right.

    Here is a sample of a call I ran. You can pass Sox commands through gtbg which is really helpful (for example, I wanted all my samples to be mono): gtbg chainOt --samples "/Users/matthew/gtbg" --sampleRate 96000 --bitDepth 24 --post "remix 1"

  • I purchased Auditor per @aleyas advice. Seems perfect to concatenate samples. Thanks for the tip!. I can't see I'm gonna use it much for other purposes, (wish it could host au fx to batch process) but it does serve the purpose of creating concatetanded samples quite well. I then load those into Flexi.

    One thing I'd like and I guess is possible but font know how.... Can you place the samples on a "beat" so that they're evenly spaced out?. I see how it can be done manually but it's too much work...


  • Sure!

    I wonder why you would have to use Auditor for concatenating samples if you can chain&mix two Flexis with both source samples and record the result with a third Flexi.

    Fixing samples to the beat is done inside Flexi using slices and triggering them by keys.

  • chaining flexis takes a long time. I was actually mapping notes across Sampler and recording the output to a flexi (via a step sequencer to automate). Still takes a while. I’m talking about drums with, say, 16 velocities.

    Auditor is faster, just open 16 files and save. That’s a Flexi ready file. A lot faster actually. I wish Auditor could host AUV3 to process the samples, then you could do some very quick variations (clean, distorted, crazy fx) but it doesn’t. In that case you cando it via flexi to flexi in standalone with some AUV3 processing, I use MixBox and Saturn for that.

  • edited December 2020

    Sure an audio editor can be better in many cases, I was just hinting at an on-board solution.

    TwistedWave has AUv3 support, but for chaining clips and AUv3 support, any DAW might be even better?

  • edited December 2020

    The great thing about Auditor in this matter is that you can select straight from the Files app, you just select as many samples as you wish and it lays them one after another perfectly, ready to save for flexi. Literally 5 seconds to do 16 samples.

    If I want to process with AUV3 I can do that in Drambo, from flexi to flexi. Load the file with the concaténate samples from auditor on flexi 1 through some AUV3 modules and into flexi 2. The time consuming part I find is getting 16 hits in a wav. Tried with sampler, different daws... auditor is bar the fastest way. A bit overkill to pay 10€ just for that, but it feels good to not waste time on such a repetitive task.

    I could probably use Sampler with layers instead of flexi and keep the individual samples. But i can’t work with the sampler UI, breaks my nerves. I keep creating empty zones, I can’t select the right layer... it’s too small. If it had some other way of editing, the UI i find unworkable. I’m more comfortable with flexi and like the extra options like speed. What do you think about the sampler UI?.

  • @Tahiche To be honest, I've stopped using the sampler for that reason as well, plus the lack of a few essential sampler features that make it hard to build usable instruments. I might also use Flexi to import multisamples next time...

    I'm doing all the audio processing on desktop btw, still by far the fastest way to do it.

    Concatenate all wave files? I just enter "sox *.wav alltogether.wav". Just did that again to build a new wavetable file from 70 single cycles.

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