egr wrote:

Paging boaconstructor.

Boa uses GBA, 2.5 i think

Until now.  lol jk

Paging boaconstructor.

Boa uses GBA, 2.5 i think

NITRO2K01 recently showed me how to generate DC levels with ultrasound on a square wave channel and I used this technique for a new kind of sound in nanoloop 1.7.0: A low frequency square wave with slightly inclined edges, which sounds like a low-pass filtered square.

Regular square:

Soft pulse:

The volume is about 3/4 of the regular square, but because of the lowpass, other sounds appear much louder. It can't play arbitrary notes, but only fractions of the tick frequency, so you are limited to a few subharmonics. The tick frequency is tunable by two semitones with fine resolution though. By default, the highest soft pulse tone equals the lowest one of the regular square (C).
It has volume, envelope and panning, other parameters have no effect.

It doesn't work on GBA. GBC, DMG and GBP are fine.

Example

A little track fragment

nanoloop 1.7.0 demo ROM / nanoloop 1.7.0 update ROM (at the bottom of the page)

To try the sound, place a note with B and press B+right 3 times. Adjust the frequency with B+up.

Please keep in mind that it produces strong levels of ultrasound (131 KHz) that are probably not filtered out by the Game Boy and may harm your speakers.

Thanks again to NITRO2K01.