groove guru get in

in development · lan-only · open protocol

hear your mix before the room does.

bring your cdjs. learn the path. mix like someone’s listening.

groove guru listens to your cdjs over pro dj link, mirrors the control surface in the browser, and speaks up when you drift — key, phrase, and timing — then gets out of the way. never dj’d? preview the hands-on path here; run it for real on your gear — four-on-the-floor to your first harmonic blend.

start at zero →install the harness

devices requiredpro dj link gear on the booth lan — not a browser toy.

live · udp 50001124 bpm · 4/4
protocol
pro dj link
transport
udp · booth lan
ports
50000–50002
mode
passive listen
licence
mit · self-host

01 / the floor

the booth, mirrored.

groove guru reads play, cue, sync, master and on-air off the wire and draws the control surface in your browser. it sees the same deck state you do — and nothing you haven’t played.

booth.local · groove-gurudemo
demo loop: deck 2 cues, plays, syncs to 124 bpm and goes on air; the crossfader moves across and the coach says: deck 2 locked to 124. phrase turns in 8 — hold the blend till the one.
deck state

read, not guessedplay, cue, sync, master, on-air and pitch come straight off pro dj link status packets.

beat clock

one grid for the boothbeat packets drive the phrase counter, so the coach and the mirror agree with your decks.

any screen

open it in a browserthe mirror runs on the laptop hosting the harness, or anything else on the booth lan.

02 / start at zero

never dj’d? start at zero.

six drills, from four-on-the-floor to your first harmonic blend. this page previews them. the full path runs in-product against live deck state on real pro dj link gear — devices required.

  1. step 01 / 06

    count the bar

    house and techno count in fours. sixteen steps is one bar; light a kick on every beat and you’ve built four-on-the-floor — the grid everything else sits on.

    light steps 1, 5, 9 and 13 — one kick on every beat.

    1 / 6

  2. step 02 / 06

    cue & drop

    a cue is a bookmark you drop from. set it on the one — the first beat of a phrase — and the drop lands exactly where the room expects it.

    bar.beat · the phrase loops every 4 bars

    watch the counter. press cue when it reads 1.1.

    2 / 6

  3. step 03 / 06

    ride the phrase

    tracks move in phrases of 4, 8 or 16 bars. mark each turn as it arrives. the preview runs one bar per beat so you’re not waiting around.

    phrase length in bars
    0 / 3 on time

    mark the turn three times, on time. outlined cells are phrase starts.

    3 / 6

  4. step 04 / 06

    blend on camelot

    keys next to each other on the camelot wheel blend clean: one step round, or straight across between minor and major. pick the outgoing key, then the incoming one.

    1B2B3B4B5B6B7B8B9B10B11B12B1A2A3A4A5A6A7A8A9A10A11A12A
    out 8A
    in 9A

    pick the key that’s playing now.

    4 / 6

  5. step 05 / 06

    the first mix

    put it together. start deck 2 on the one, then ride the crossfader across. phrase-aligned within a beat is good enough to post.

    deck 1 · playing8A · 124.00
    deck 2 · cued9A · 124.00

    start deck 2 on 1.1, then ride the crossfader across.

    5 / 6

  6. step 06 / 06

    take it to gear

    that was the preview. the full path runs in-product against live deck state on your cdjs — same drills, real platters, the coach listening to what you actually play.

    pro dj link cdjsdjm on the same switcha laptop on the booth lan
    install the booth harness →back to step 1

    no account for this preview. the in-product path needs a device session on real gear, not a signup.

    devices required. this page only previews the drills.

    6 / 6

03 / the coach

a calm voice, at the right moment.

the coach waits for something worth saying — a key clash, a missed phrase turn, a deck sliding off the grid — says it once, then gets out of the way. think yoga teacher, not hype man.

deck 1 · 8A · 124.00deck 2 · 9A · 124.50live
coach ›deck 2 is drifting +0.4%. nudge it back before the phrase turns.
phrase in 4 / 8 / 16
32 bars, downbeats outlined. the coach counts them so you can listen instead.
filter · lpf → hpf
it hears the sweep too. a filter held through the turn is a choice; one left on by accident gets a word.

listens first

it only speaks to what it can read off the wire: key, phrase, pitch, sync, on-air. no guessing at vibes.

one note per phrase

a correction, then quiet. no running commentary while you’re mid-blend.

plain words

4A into 11B clashes. 5A sits better.

short enough to hear over the monitors.

04 / keys & phrases

keys tell you what fits. phrases tell you when.

pick a key on the wheel. neighbours light up — one step round, or straight across between minor and major. anything further is a clash the coach will call.

1B2B3B4B5B6B7B8B9B10B11B12B1A2A3A4A5A6A7A8A9A10A11A12A

selected

8Aa minor

blends clean with

7A · d minor9A · e minor8B · c major
  • selected · what’s playing
  • compatible · ±1 or straight across
  • clash · the coach calls it

a clean key change still lands wrong if it arrives mid-phrase. step 3 drills the when; step 4 uses this wheel.

05 / on the wire

it listens. it doesn’t touch.

pro dj link gear talks udp on the booth lan. groove guru sits on the same switch as a passive listener and builds its picture of the mix from what the decks already broadcast. open protocol work, documented in the repo.

cdj-1, cdj-2 and the djm connect to a switch; groove guru’s booth harness listens on udp ports 50000 to 50002.
pro dj link ports groove guru listens on
portcarriesgroove guru uses it for
udp 50000keep-alive and device announcementswho’s on the lan — players, mixer, their numbers
udp 50001beat packets (type 0x28), tempo, master handoffthe phrase clock — bar, beat and drift
udp 50002player status: play, cue, sync, on-air, pitchthe mirror — deck state, drawn live

your gearyour lanno vendor endorsement

06 / get in

practice like someone is watching. because something is.

self-host the booth harness on a machine plugged into the booth switch, open the mirror, and let the coach listen.

booth harness · self-hostin development
# the harness is in development: one rust binary, mit.
# when it ships, on a machine plugged into the booth switch:
$ groove-harness --iface en0
# then open the mirror on booth.local
follow the build →start at zero
harness
freeopen source · mit · self-host
pro
$6.99/moor $49.99/yr · at launch

devices required: pro dj link gear on the booth lan. the cratefield backend runs on cloudflare workers with d1 and durable objects.

companion app

ipad/iphone app — glance the mix from the booth over local wi-fi, or from anywhere over cloudflare. phone is the glance view; desktop stays the power view.

planned