44.1kHz sampling frequency

#1

Is the only way to use samples in Axo to convert them to 48kHz or am I missing something fundamental here?

Cheers
/M

#2

From what I know they have to be 48khz. For example the patch "amon is broke" needs a 48khz version of the amen break.

But I think it is possible to use others too, but you probably have to reprogam the Axoloto to be able to do this.

#3

Oops definitely won't reprogram anything at this stage, altho it'd be nice with a down/up-sample-block. ^_^

#4

Before I got it I also thought about making Axoloti 96Khz, but dunno how to do it. Anyway for now there is enough to play around with and I haven't spend a thought on the 96Khz since i got it. Maybe sometime down the road smile

#5

This is so strange, I've converted my samples into 48kHz but they are still playing back with a low pitch, this should mean that the sampling frequency is too low, right? This is very confusing... Comparing a 44.1kHz with a 48kHz of the same sound, the latter is of lower pitch.

I'm using "80808" template but have replaced all the slots with wave/play fn like in the sampling template..

Skärmavbild 2015-09-01 kl. 23.14.27.png831x578 111 KB

#6

Are these mono files with 16 bit/sample?
The files are really played as raw 16bit files.
The information in a .wav header (number of channels, samplerate, format) will also play, as audio samples, resulting in a brief click.

To answer the original question: yes 44.1kHz samplerate is technically possible. Modding the firmware to 44.1kHz is little work, but if you do that, all the units in patches/objects will be wrong. Getting that right is quite a bit more work. This is not on my short list of improvements.

48kHz was originally chosen over 44.1kHz sampling, because 48kHz has a bit more margin to the upper frequency limit of human hearing.

Proper tablet reading for wavetable synths
#7

what did you use to "convert" the samples? Make sure you are "resampling" them (for example in Audacity).

#8

I exported the sampled first in 48kHz from Ableton Live to .wav, failing to understand that there's a difference between that and raw. This produced the clicking sound you described @johannes.
I converted the batch of files using sox and the following command line:
for file in *.wav; do sox -w -c 1 -r 48000 $file basename $file .wav.raw; done
Which produced an output with the same names, only changing the file ending. The files have stopped clicking but are still pitched down..

I realized the syntax wasn't correct in the command line later, so changing it to:
for file in *.wav; do sox $file basename -c 1 -r 48000 $file .wav.raw; done
produces a correct output.

Cheers

#9

I used Sound forge. Exported the wave files to 16 bit 48khz, in normal way. Don't make the files names longer than MAXIMUM 8 characters, then it should work.

#10

I used Audacity , free and cross platform

#11

So is sox. wink
Any maximum length of a sample?

#12

For streaming raw file playback the limit would be the maximum file size on a FAT filesystem. 2GB I believe smile

#13

only 16 bit or also 24 bit files, would be nice if so.

#14

I'm not planning to add 24bit streaming playback support any soon.

Do not overestimate the need for 24 bit in a sample or track. It's nice to have more than 16 bits when capturing material where you need to leave considerable headroom to deal with unpredictable peaks. But once captured, the recorded material can be normalized and reduced to 16 bit (with dither if you like) without significant degradation.

#15

Yes you are right on this, forget my request please :innocent:

#16

hmm, I'm trying to convert a free large waveform library, but I'm not getting the axoloti to play the files..
I've renamed them all to W0XXX.ar (where the XXX are an index number between 000 and 999) and used audacity to convert them to 16bit pcm, 48khz .raw files. Then put the axoloti in cardreader mode and copied the files to the axoloti
Tried the waveplayers and table modules, both nothing.. upper case, lower case pre/suffix combinations, added/removing a dot.. nope.. nothing..

#17

is it 1 cycle waveforms or longer samples? Is it mono files?

ANyway, it works, you are probably doing something wrong in the process. If you are batch processing, maybe skip that step and try manually. Have made 100's of samples and all worked... I think it it is just a small 404 error :wink:

#18

it's all 1 cycle waveforms from AFWK.
I loaded 100 of them into audacity, set them all to 16bit and 48k SR and saved as .raw
I'll try to do 1 in a moment

#19

ehh... huh?!?
I redid one sample, uploaded it, didn't work.. used the normal string/c module to enter the name instead of the index version.. didn't work.. and then a minute later while thinking about what to try next while the patch is running, it suddenly starts playing..... ?? what the...?!?

#20

whhich version of axoloti are you using?

1.08 has got some issues with loading stuff from sd-card.... which I know have been fixed for next release... Go back to 1.06 and it will work.

As I understand it, Axoloti 1.08 has got the feature to copy evrything used in a patch to the trackfolder(created automatically) on the sd-card. But this works ONLY for the table/load objects WITH filename. IF you use the string/c module it wont work, it wont copy the file to the sd-card and therefor it wont play. It ONLY copíes file to sd-card when using the table/load with filename included.

So I think there was a void that hadn't been considered by johannes. But it will probably work in next version. Johannes have implemented "fallback to sd-card" feature. That means if it can not locate the file from harddisc, it will automatically fall back and use sd-card filepath instead. If I understand this correct, it means that Axo will use sd-card as it is now in version 1.06.

But need to get the version when released and test how it works.