I was playing around with the slide effect on the volume for white noise and I realized that there was an awful lot of sputtering while it would ramp up the volume, but not while ramping down. It sounded as if maybe the waveform was being doubled in amplitude and thus clipping, or maybe something was messing up the randomizer. I really don't know. That's for @zep to figure out.

Here's a repro case, seems to work the same on the BBS as it did in the executable.

Pretty sure it's not local to my machine's audio hardware, but I'd appreciate others trying it and saying whether or not they hear the same issue.

Edit: Yeah, just checked out this post on my phone, it does the same thing there too. Definitely a bug.

SFX Slide Bug Repro

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SFX Slide Bug Repro

by Felice

Cart #buwihinuye-0 | 2019-12-26 | Code ▽ | Embed ▽ | License: CC4-BY-NC-SA

2

Happy Holidays, @Felice.

Listening. It makes me wonder if the white noise at a lower level does say random noise between low values, say 0-15.

Raising the volume does not give louder noise, just a wider variance thus increasing the noise and distortion, say 0-255.

Thanks, same to you. 🎄

I'm not talking about the difference between low and high volume white noise, I'm talking about an anomalous artifact caused by employing the slide transition effect on volume between a low volume note and a high volume note, and it only occurs when the transition is from low volume to high volume, not when transitioning from high volume to low volume.

It might be a sign issue when applying a delta volume over time in the mixer.

This is an oddity of instrument 6 that I neglected to add to the manual: Unlike the other instruments, noise volume is also taken to mean 'dirtiness'. This is so that you can get both cleaner brown noise (but only quietly -- for things like rolling waves / wind), and dirty noise (rockets, rock grinding, punchier short sounds).

You can use an SFX instrument to get quiet dirty noise by setting the instrument (e.g. sfx0) loud, and then playing that instrument quietly (e.g. a green 0 in sfx1).

@zep

I'm not sure we're on the same wavelength here.

That doesn't explain why it only gets more sputtery during the ramp-up period. Play the cart, you'll see what I mean.

Like, when the ramp is half-done going up, making it half-volume, it's sputtering much more than it is when it's half-done going down, even though it's also at half-volume at that point.

@zep

Oh wait!

I think I see what the problem is.

Okay, so for other instruments, volume is volume, but for 6, volume is dirtiness, as you said. And yes, it does seem to work that way.

However, the slide effect didn't get the memo. With the slide effect, the dirtiness is still stepping, while the volume interpolates.

I really feel like the dirtiness should interpolate, since it's supposed to be standing in for volume. Don't you?

Ahh.. yes, you're right! The noise osc is just reading the raw note value. Agreed, it should also interpolate, and I don't think the change would be likely to break any existing carts.

Yay!

‹hannibal›
I love it when debugging session comes together!
‹/hannibal›

By the way, that was an interesting choice to make. I approve, because it's much more useful to be able to select white/pink/brown rather than WHITE/White/white, especially now with sfx instruments and the volume trick you described. Nice.