Appendix: Technical data

The numbers behind FRIZZ, for planning a setup. The timings were measured on a CHOMPI.

Audio

• 48 kHz, stereo in and out, through a 24-bit codec. FRIZZ works in floating point, in blocks of 24 samples (0.5 ms).
• The loop: up to 2:45 of stereo, stored at 16 bits in RAM, gone at power-off (see Looper). Live, the input is floating point up to the safety limiter; what goes into the loop is held just under full scale by a limiter of its own, which takes a peak at once and lets go over about 150 ms. Below that it records exactly what came in. A source loud enough to reach it records a little quieter than it sounds live (from about 7 dB below the input’s full scale at input gain 75%).
• The freezer records up to 5 s; the delay holds 10 s, so 2 bars fit at the slowest tempo.
• The tempo: 50-300 BPM, 120 at power-on.
• Every output has a fixed safety limiter after VOLUME (see Master compressor).
• The effects: the shifter lands within about a cent of the interval, its taps lining up within 7.5 ms where they start over. The folder’s sine fold keeps its aliases more than 85 dB down on a sine below about 1.5 kHz at any drive; the triangle’s corners alias, and first-order antialiasing (ADAA) takes 5 to 13 dB off them.

Processing load

Effects that are off cost (almost) no processing time, but the ones that are on do. Some heavy combinations (the shifter and the crusher with a loop playing and the master compressor working hard, for example) can need more time than there is, which is heard as crackles; switching one of them off clears it.

Measured on a build that runs a set of combinations by itself, as a share of the time each block has: FRIZZ alone about 35%, one effect at most about 50%, all the inserts with a loop about 70%, every effect at once about 80%. Every effect at once with a loop, and every effect’s page 2 turned off its defaults (Mix, Band and Level), needs more than there is.

Timing

What	Measured
A quantized loop against the clock it was recorded to, over TRS	0.4 ms a minute at most (1 bar, at 120 and 174 BPM)
The same over USB	4 bars: 0.35 ms a minute at most; 1 bar: from −2.2 to +2.3 ms a minute, depending on the recording
A loop recorded to REAPER over USB (87 BPM, 4 bars)	0.66 ms a minute; every bar within 1.5 ms of the song
The effects’ tempo following a clock that changes	10 BPM within about 0.4 s, 1 BPM within about 2 s
The clock source on Auto, its clock stopping	The other input’s clock counts within about 0.8 s
MIDI clock out over TRS (120 BPM)	Jitter 0.53 ms; 0.64 ms with MIDI feedback sending 1652 CCs meanwhile
MIDI clock out over USB	Its tempo right (120.08 BPM for 120), its ticks less even, bunched while the card is written
A computer’s clock over USB, passed on out of TRS (200 and 300 BPM)	Each tick 0.13-0.16 ms off even on average, 99% within 0.5 ms
MIDI feedback	One CC per value every 10 ms at most
Switching on	Sound about a second after FRIZZ starts

Formats

• The card: microSD, FAT32. FRIZZ’s files are text, in the FRIZZ folder (see Card and files).
• MIDI clock in and out at 24 PPQN. The keys are notes 48 to 72, the knob presses and the other keys below them (see Notes: the keys).
• FRIZZ’s own SysEx starts F0 7D 43 48 (see Remote control).