Tutorial: Converting samples to Amiga.

[h0ffman]

Hi guys

Someone PM'd me asking about how I do my sample conversion for ProTracker. I ended up going into quite a bit of detail in who to do it trying to retain as much quality as possible. Thought I would post it up here and some peeps could find it useful.

-- PC Preperation of sample (using soundforge or similar)

1. Mono Conversion

Depending on the sound, you can either mix it down to mono or take either left or right channel. The latter is usually better as you can get phasing when mixing stereo to mono.

2. EQ

There's no rule here, just depends on the content you are converting. A rough guide would be to maybe remove some low end with a filter if there is some. Means you can maximise the sound more.

3. Limiting / Loudness

This is a must!. Quiet samples on the amiga sound like shite. If the sample is loud, but you play it quiet on the Amiga, you will retain the sound quality. Either normalise it or put it through a good limiter plugin.

4. Resampling

Make sure you do this while the sample is still 16-bit as it will give greater accuracy for the resampling and better results. My suggestion here is to setup some presets for each note you want to resample too. Use the table below to perform the calculation.

 (For a PAL machine)

                7093789.2
SampleRate = --------------
               Period * 2

Period table:
C-1 to B-1 : 856,808,762,720,678,640,604,570,538,508,480,453
C-2 to B-2 : 428,404,381,360,339,320,302,285,269,254,240,226
C-3 to B-3 : 214,202,190,180,170,160,151,143,135,127,120,113

5. 8-bit and save as WAV

Simple really, you've prepped the audio data, now all you need to do is convert it to 8-bit and save it as a wav. Your audio editing app should then save the sample with the new frequency inside it.

-- Amiga Side (converting to IFF)

Now I think there are programs out there in PC land which do this, but I never found one. So I use SoundBox on the Amiga, its on Aminet and there is a free key for it too. Simply load your newly created Mono wav and re-save as IFF! Done!

BONUS TIPS..

If your samples when on the Amiga need a little hi-end boost, load em up into ProTracker and hit the Boost button one or two times depending. Really good for adding a bit of fake top end to your sample.

If you wanna twist up samples in the Amiga, try Aural Illusion.

[Sektor 83]

Excellent stuff, h0ffman... heard your tune 'Drop The Panic' only just the other day, loved it and wondered how you managed to get all those great-sounding samples

[klx300r]

great info! thanks for posting

[MickGyver]

Resurrecting an old thread here. I'm having issues understanding how to resample samples for ProTracker. I have downloaded the Adventure Kid single cycle waveforms (in 8svx format). Problem is that all samples are very "deep", the highest pitch is very low, so I'm unable to play high notes. How can I resample or play these waveforms at higher octaves? Thanks in advance for any insight!

[Amiga1992]

Originally Posted by witchmaster

the highest pitch is very low, so I'm unable to play high notes. How can I resample or play these waveforms at higher octaves? Thanks in advance for any insight!

Yeah this is a problem with this kit. If you let the Amiga pitch it up, it could bring issues. But I dunno because I never tested them. Have you tried?
Maybe reduce those to less cycles, if I remember correctly, the Adventure Kid waveforms are actually -not- single cycle, not all of them at least, and single cycle would probably the best to start with.

What is it exactly that is happening? The samples should sound, is it that they are going off tune?

[MickGyver]

Thanks for the reply! Most of them are single cycle waveforms. I'm able to use them but with the 3 octave limit on the Amiga I can only play 3 low octaves, making the samples more or less useless. When I load the same samples into MilkyTracker, I'm able to use seven octaves and the samples sound fairly good up to the highest notes. There is some resampling options in MT but I have no idea how to use them. Damn, I have read the tutorial in this thread and tried to find some good info on resampling for the Amiga but haven't found anything I understand, I feel a bit stupid, can it be this hard?

[Tsak]

Open protracker, load your sample, open the sample editor (SAMPLER), press "UPSAMPLE" (lower right corner) and done

[Amiga1992]

Originally Posted by witchmaster

I'm able to use them but with the 3 octave limit on the Amiga I can only play 3 low octaves, making the samples more or less useless.

I see what you mean! Makes total sense.
Yeah PT sucks and it seems you can only downsample, but not upsample.
You could use a PC tool like Wavosaur, or I am sure there's some Amiga tool that could do it.

Originally Posted by Tsak

Open protracker, load your sample, open the sample editor (SAMPLER), press "UPSAMPLE" (lower right corner) and done

Maybe this is PT3.x. PT1.x/2.x does not have this option.

Even though, you'll reach a sample frequency limit for the AMiga pretty soon, so I would recommend using a PC tool, upsample to required pitch, then downsample in fine quality back to original sample rate (8Khz)
Might sound like absolute garbage, though.

[daxb]

Did you resampled your samples? If not you can/need to change the sample rate (see h0ffman`s point 4.). For example if you want to have the result on note F-3 (Protracker) then sample rate is 7093789.2 / (160 * 2) ~= 22168.0913. First make sure to get mono. Saveing to 8svx format is or should be the last option. Sometimes is is good to have one sample resampled to different sample rates / notes but you will notice that if needed.

Protracker itself has up- and downsampling option (octaves) and resample but I guess the quality isn`t so good compared to good pc software use. However, I used it sometimes and maybe the result is good enough for you (depends on sample). Just try it.

Sometimes it is enough to halve sample rate from 44,1kHz to 20050 Hz. On Protracker it is something between E-3 and F-3. Further you can use the finetune option. Octaves change is done with key F1-F3. Press the Help key for Protracker docs.

[MickGyver]

Originally Posted by Akira

I see what you mean! Makes total sense.
Yeah PT sucks and it seems you can only downsample, but not upsample.
You could use a PC tool like Wavosaur, or I am sure there's some Amiga tool that could do it.

Even though, you'll reach a sample frequency limit for the AMiga pretty soon, so I would recommend using a PC tool, upsample to required pitch, then downsample in fine quality back to original sample rate (8Khz)
Might sound like absolute garbage, though.

Originally Posted by daxb

Did you resampled your samples? If not you can/need to change the sample rate (see h0ffman`s point 4.). For example if you want to have the result on note F-3 (Protracker) then sample rate is 7093789.2 / (160 * 2) ~= 22168.0913. First make sure to get mono. Saveing to 8svx format is or should be the last option. Sometimes is is good to have one sample resampled to different sample rates / notes but you will notice that if needed.

Protracker itself has up- and downsampling option (octaves) and resample but I guess the quality isn`t so good compared to good pc software use. However, I used it sometimes and maybe the result is good enough for you (depends on sample). Just try it.

Sometimes it is enough to halve sample rate from 44,1kHz to 20050 Hz. On Protracker it is something between E-3 and F-3. Further you can use the finetune option. Octaves change is done with key F1-F3. Press the Help key for Protracker docs.

Thanks for the input! I tried to resample the original waveform (used the 16bit wavs) in SoundForge to 96000Hz, then pitch it up by 24 semitones. Sounded ok at that point. Then I converted the pitched waveform using sox (sox sample.wav -D -r16754 -b8 sample.8svx). It sounds good by itself but it's a little out of tune to the lower pitched original. Finetuning makes it worse.

Originally Posted by Tsak

Open protracker, load your sample, open the sample editor (SAMPLER), press "UPSAMPLE" (lower right corner) and done

Thanks! I was using PT 2.3 so I didn't have that option, installed 3.62 and tried upsample in that version, seems to sound ok, the tuning might be a little off but I have to test some more! I can always use upsample in 3.62 and use the sample in 2.3, I prefer it's gui.

[Tsak]

Originally Posted by Akira

I see what you mean! Makes total sense.
Yeah PT sucks and it seems you can only downsample, but not upsample.
You could use a PC tool like Wavosaur, or I am sure there's some Amiga tool that could do it.

Personally I wouldn't recommend working on pc if your samples material is already 8bit (is this the case here?). As most decent pc sound etitors (Wavelab, Soundforge e.t.c) work in 16bit mode, everytime you load, process an 8bit sound and save it again has the potencial to harm it's quality by some degree, add unwanted hiss, extra noise floor e.t.c. (due to accumulated quantisation).

Originally Posted by Akira

Maybe this is PT3.x. PT1.x/2.x does not have this option.

Ah, yes. I'm using v3.62.

[daxb]

Originally Posted by witchmaster

Then I converted the pitched waveform using sox (sox sample.wav -D -r16754 -b8 sample.8svx). It sounds good by itself but it's a little out of tune to the lower pitched original. Finetuning makes it worse.

Number turner? 7093789.2 / (214 * 2) ~= 16574.2738. Maybe the reason for out of tune. However, 16kHz is sometimes a bit low (depends on sample). You should at least try 22kHz and higher. If not alread known/noticed, B-3 is near/over hardware limits what may cause noise if played (depends on sample too). There is a thread on this board about converting/resampling samples on PC to Amiga with useful (technical) infromation you should read.

[MickGyver]

Originally Posted by daxb

Number turner? 7093789.2 / (214 * 2) ~= 16574.2738. Maybe the reason for out of tune. However, 16kHz is sometimes a bit low (depends on sample). You should at least try 22kHz and higher. If not alread known/noticed, B-3 is near/over hardware limits what may cause noise if played (depends on sample too). There is a thread on this board about converting/resampling samples on PC to Amiga with useful (technical) infromation you should read.

Thanks! God damn, number turner indeed! When converting the waveform I pitched with -r16574 and the lower original with -r8287 they are both in tune with each other.

[Amiga1992]

Originally Posted by Tsak

Personally I wouldn't recommend working on pc if your samples material is already 8bit (is this the case here?)

It was because witchmaster got the 8svx pack of AKWFs, but you can get the AKWFs in their original form and work from there. It's what I would recommend.
Always work with higher resolution of anything you have and then make your way down.

[mt12345]

Originally Posted by h0ffman

4. Resampling

Make sure you do this while the sample is still 16-bit as it will give greater accuracy for the resampling and better results. My suggestion here is to setup some presets for each note you want to resample too. Use the table below to perform the calculation.

5. 8-bit and save as WAV

Simple really, you've prepped the audio data, now all you need to do is convert it to 8-bit and save it as a wav. Your audio editing app should then save the sample with the new frequency inside it.

-- Amiga Side (converting to IFF)

Now I think there are programs out there in PC land which do this, but I never found one. So I use SoundBox on the Amiga, its on Aminet and there is a free key for it too. Simply load your newly created Mono wav and re-save as IFF! Done!

your wav2amiga app covers the steps above, right?

[no9]

I can add one tip to this:

For slowly decaying sounds (e.g. sustained piano) one can expand quiet part to the maximum volume and recreate original sound dynamics with Axx command in tracker. It is similar to compading function but handmade. It can be achieved with just drawing a volume envelope, but other editing may help reduce unnecessary peaks. Of course editing in 16/32 bit before conversion is a must.

It may sound more or less like here
[ Show youtube player ]

Sounds with more complex dynamics would require more care of course.