Orra Key Pro: A $19 Plugin That Finds the Right Bass Sample in Seconds

A Plugin That Finds Your Basslines For You (Sort Of)

Orra Audio just launched Key Pro, the advanced version of its recent key-detection plugin, and it's launching at $19 (regular $29) through October 25, 2026, with a 14-day free demo. It's VST3/AU/AAX on Windows and Mac. The headline feature isn't the key detection — plenty of plugins do that now — it's Matchmaker: a built-in sample-library scanner that ranks your own bass loops and one-shots against whatever's playing in your session, by key, tempo, and chord compatibility.

If you've ever dragged six different bass loops into a project before finding one that didn't clash with the chord progression, this is aimed squarely at that problem.

What Key Pro Actually Does

Key Pro is purely analytical — it listens to audio without touching it. Point it at a bass loop, a chord stab, or a full mix, and it reports:

• The detected key and one of seven scales (natural minor, Dorian, and Lydian among them, not just major/minor)
• A bar-by-bar chord progression, with common progressions named outright when it recognizes one
• Seven chord types across six voicings, which you can drag directly into your session as MIDI — either one chord at a time or the whole progression in one go

That last part is the one worth sitting with. Dragging a detected progression out as MIDI means you can route it straight to a bass instrument and have a harmonically-correct skeleton to write a bassline against, instead of guessing at root notes by ear against a reference track.

Matchmaker is the actual new feature over the plain "Orra Key" plugin Orra Audio put out a few weeks earlier (which Key Pro fully absorbs — key detection, chord dragging, and the transpose strip all carry over). Point Matchmaker at a folder of samples, and it analyzes everything in there for key, tempo, and chord content, then ranks the results against your current session. It previews matches already pitched and time-matched to what you're working on, before you ever drag anything onto a track.

Where This Actually Helps on Bass

The obvious use case is sample-based bass production — digging through a folder of bass one-shots, loops, or recorded DI takes and finding the one that's already in the right key instead of pitching three different options and listening for the least-bad fit. Matchmaker doing that ranking automatically is a real time-save if you work with a large sample library, especially for anyone building bass lines from reference audio the way Premix-style workflows encourage (pulling stems or loops from a reference track and needing them to sit in-key with the rest of the arrangement).

The chord-progression-to-MIDI drag has a second, less obvious use: if you're the kind of producer who writes bass first and chords second, you can flip that around. Sketch a rough chord idea, detect it, drag the MIDI to a bass track, and strip it down to root notes and passing tones as a starting skeleton — faster than programming a bassline from nothing, even if you end up rewriting most of it.

Scale detection matters more for bass than most instruments, because a bassline that technically matches the root key but ignores the mode (say, playing a straight natural-minor line under a Dorian progression) tends to clash on exactly the notes a bass sits on — the 6th and 7th scale degrees. Having the plugin flag the mode explicitly, rather than just "C minor," is a genuinely useful detail most competing key-detection tools skip.

The Honest Limitations

Key and chord detection on audio is inference, not certainty — Key Pro is reading harmonic content and guessing at the most likely interpretation, and anything with ambiguous harmony (a sparse bass line with no clear chord content, a heavily distorted or saturated source, atonal or purely rhythmic material) is going to trip up any plugin in this category, not just this one. Treat its output as a strong starting guess you confirm by ear, especially on material with no clean chordal reference to lock onto.

It's also worth being clear about what Matchmaker can and can't do: it's a ranking and preview tool for files already on your drive. It doesn't generate new bass sounds, and it doesn't fix timing or tuning issues in a sample that's already off — it just tells you which of your existing samples are the closest harmonic fit. If your sample library is thin to begin with, a smarter search doesn't solve that.

The 14-day demo is the right way to find out whether the detection is accurate on your own material before paying — key detection plugins vary a lot in how they handle ambiguous audio, and the only real test is running it against the kind of sources you actually work with.

How This Compares to What You're Already Using

If you're an Ableton user, this sits in a different lane than Ableton's own stock tools. Live doesn't have a key-detection device at all — the closest built-in equivalent is manually setting a Scale device and eyeballing MIDI against it, which works fine once you already know the key but does nothing for a sample you haven't identified yet. A plugin like this is filling a real gap rather than duplicating something Ableton ships.

It's also a different tool than the key-aware EQ plugins this site has covered before — KEYCOMB and Scaler EQ Pro both use detected key information to shape frequencies in real time, which is a mixing use case. Key Pro is squarely a writing and sample-selection tool, used before you're mixing anything. If you already own one of those and are tracking key info for mixing purposes, Key Pro's Matchmaker still solves a separate problem: finding the right sample in the first place.

If key and tempo matching across your own sample library sounds like the actual bottleneck in your workflow, our own Key/BPM Finder solves a related piece of this — identifying key and tempo on reference tracks and samples you're pulling in from outside your own library, which is a natural complement to what Matchmaker does with files you already have on disk.

A Practical Workflow to Try First

If you're testing the demo against your own bass library, this is roughly the sequence that gets the most out of Matchmaker rather than just poking at it:

1. Point Key Pro at your reference track or chord progression first, so it has something to rank against — key detection on an empty session has nothing to match to.
2. Run Matchmaker against a folder of bass samples rather than your whole library on the first pass. A smaller, curated folder (your go-to 808s, a specific synth-bass one-shot pack) gives more useful rankings than a few thousand unsorted files.
3. Audition the top two or three matches in context rather than trusting the top rank blindly — the ranking is based on harmonic and tempo fit, not on tone or whether the sample actually works for the track.
4. If nothing ranks well, that's often a sign the detected key or scale itself is off, not that your library lacks a fit. Double-check the detection by ear before reaching for a different sample.
5. For the chord-to-MIDI drag, pull the progression onto a scratch track first rather than directly onto your bass instrument track, so you can strip it down to a skeleton before committing it to the arrangement.

None of this is complicated, but skipping the first step is the most common way to get a useless ranking — Matchmaker can only compare against what it's heard.

The Takeaway

Key Pro isn't reinventing key detection — several plugins already do that reasonably well. What's genuinely new here is treating your own sample library as a searchable, rankable resource instead of something you dig through by memory and ear. For anyone building bass parts from loops or samples rather than programming them from scratch, that's the feature worth the $19 launch price on its own. Run the 14-day demo against your actual sample folder before committing — the real test isn't the feature list, it's whether the detection holds up on the specific material you use every day.