Use Lich's CV out for Lofi Audio?

OWL Lich
#1

Hi!

Since I’m already using the two audio outputs of my Lich module, I assume it’s possible to use the CV outputs to output “LOFI” audio. I haven’t tried it yet, but I’m asking here so I don’t waste time if the final quality is too low to be usable.

So, could someone please tell me what the maximum audio quality will be from these CV output channels for an audio signal?

I use PureData, and I’m not particularly good at it, but I manage as best I can. A little explanation on how to do the procedure would be more than welcome. If anyone has already done this, thank you!

Thanks a lot!
Have a good day!

#2

maximum audio quality

What units do you expect to use for counting that? :wink:

Either way, you’ll end up with signal with 1/32 of sample rate of audio, so you won’t be able to send anything over 750 Hz. Also, I think CV outs would be unipolar, so you would have to do something like audio * 2 - 1 in digital domain, than scale it back in analog domain or maybe use an HPF to remove DC offset.

Also, the audio would have 12 bit depth, which is too low for anything made for playing audio unless we’re talking about 30+ years old digital hardware.

I’m sure the results would end up sounding like trash (by which I mean worse than LOFI)

If you absolutely need 4 channel audio, only Befaco ACDC had it, but running patches on it was not trivial as it’s not the device’s main purprose. Also, this can be done on my OWL port to Daisy Patch - this works well in practice.

2 Likes
#3

Thanks!

“What units do you expect to use for counting that? :wink:”

The DAC KHz and bit capability

So, if I understand your answer correctly, the CV DAC is 32kHz and 12-bit?

That should be more than enough for an auxiliary audio output. I had a sampler that was 32kHz and 15-bit, I think, which had enough high frequencies to be usable…

However, 750Hz, if I remember correctly, is well below the capabilities of a 32kHz/12-bit DAC, so there must be something I’ve misunderstood…

In any case, if the DAC can’t go higher than 750Hz, its use for audio seems unfortunately compromised… :frowning:

#4

32kHz

No, it’s outputting data once per block size (I think that would be 32 in recent firmware builds), so you will get 48000 KHz / 32 = 1500 Hz sampling rate. So you can’t send anything more than 750 Hz over that

However, this is a compile time default for block size that you can change over MIDI, possibly even set it to 1 for running at full 48KHz. Setting block size to lower values decreases device latency (which is good, but the latency is already extremely low) and also increases CPU usage.

What you could do is send configuration option with name BS and whatever in Rebeltech web configuration UI . This is in Settings / Set Configuration menu, then press Send. I think it was working for me a long time ago.

#5

Okay, thanks.

I understand better now.

The patch I’m using is quite resource-intensive, so I doubt OWL 2 can handle this modification. Anyway, it’s already impressive for me, a non-coder/programmer, to be able to tinker with Pure Data, but modifying OWL itself is completely beyond my current understanding of what I’m doing… If I mess something up, I won’t know how to fix it… It’s too daunting for me! ^^’

So I’ll leave it at that for now, but if anyone tries it, please feel free to drop by this thread and let me know how it goes!

Thanks again!