ABA Pocket Check shows where two performances sit in frequency and in time: where each one owns its space, and where they share it. Shared space is where one performance can hide the other, and your ears decide whether it does.
Pocket Check never lines the files up: when each note starts against the others is part of what it measures.
WAV, FLAC or MP3, stereo or mono.
Drop several files at once and each goes to the performance its name matches (kick, bass, drone…), the rest in order.
Click a performance's name to change it; an added performance asks for its name.
Your audio never leaves your machine. ABA Pocket Check decodes and measures it in your browser, and never transmits it.
The pocket map: where each performance sits in frequency and in time. Time runs across, bands run up; brighter is louder; the color says which performance is louder there, and violet is shared space.
Point at anything on the screen for its numbers. Click the map to listen from that moment. Drag across it to read one stretch of the song.
Each range card reads where that performance's energy sits, band by band. Present means within 40 dB of the performance's own loudest moment, the same rule the map uses, so quiet tails below that do not show, and a loud band spills a little into the band on each side. Bands are a third of an octave wide, so a range reads to the band, not to the hertz. The 25 and 31.5 Hz bands read up to 3 dB low and pick up spill from the notes above them, so a lowest band of 25 Hz can be leakage. The card reports where the energy is; where a filter goes is your call.
Shared space means two performances carry energy in the same band at the same moment, within 6 dB of each other. It is not the same as one performance hiding the other: that depends on the level, the timing and the playback level, and your ears decide it.
The percentages count the map: every band at every moment. Two performances that meet in three bands at once count three times. So they are not seconds.
Present means within 40 dB of that performance's own loudest moment in the song. Moving a level slider never changes whether a performance is present, only who is louder.
Each pair is read as if the two were alone, over the stretch every performance shares. "Most shared band" gives the seconds the two share in that band.
Up to 250 Hz the map listens in windows of about 170 ms (186 ms for a 44.1 kHz file), the shortest that can tell a 41 Hz note from a 50 Hz kick. Closer than that, a kick and a bass note look simultaneous here; the timing lane reads them apart.
Below about 100 Hz that window is wide for the bands, so a steady tone reads up to about 3 dB low (most at 25 and 31.5 Hz, 1 to 2 dB from 40 to 80 Hz), and part of it shows in the band next to it. A tone just above 280 Hz, where the window changes, reads up to about 2 dB low. Every performance is read the same way.
This set has no kick and bass. The timing lane reads where a bass note starts against a kick hit, so there is no lane to read.
Pick Kick and bass, or a set with a drone or percussion added, to see it. Or read any two performances below: the hits of one against the starts of the other.
Each kick hit is paired with the bass note that starts nearest to it, within 60 ms either side. Together means within 5 ms. Pocket Check reports where the bass sits; it does not rate a feel.
Kick hits are read to well under a millisecond. Bass starts are read from the rise in level: the middle of the spread lands within a millisecond or two of a fast-attack performance, but a single low note can read late, by up to about 13 ms, depending on where in its cycle it starts (a 41 Hz note takes 24 ms to complete one). It does not read early. Read the middle of the spread, not one hit.
A slow attack (a soft finger, a swell) reads late, by half to most of its rise.
Hum or a steady buzz in the bass track can read as extra bass starts.
A slurred note, or a hammer-on with no new attack, has no start to find, so its kick hit shows up as "no bass start near it".
Kick bleed in the bass track is mostly ignored when the bass plays; where the bass is silent, it can read as a bass start together with the kick. A DI or a clean bass track reads best.
The record is the report, in the AudioVibes, Phaze Check and Compare look, with the map as it is set now.