Orbit Bass Cab Builder: free bass cabinet simulator plugin

Why do you need IRs for bass?

Actually, you don't necessarily need them. Sometimes people do without IRs, and it sounds great: for example, the studio Tech 21 SansAmp RBI has no IR at all (it builds the cabinet with an analog circuit), and a lot of wonderful music has been recorded on it.

But we think you do need an IR:

• The bass sits in the mix fast. The cabinet cuts the highs and brings out the mids by itself, so the bass sits in the mix without long EQ work.
• A good filter for overdrive. Overdrive without a cabinet hisses and cuts, and the cabinet removes that grit on top.
• Cutting the sub-lows without losing body.
• You hear the bass on a phone too. The IR moves the focus to the mids, and the listener's brain fills in the low note, even if the phone's speaker cannot play it.

Where does the sound come from?

A mathematical (not AI) model of bass cabinets calculates it. You set the cabinet's configuration and the positions of the mics, and the plugin calculates the IR of that cabinet and plays through it. This is a heavy mathematical operation, so we build an IR that then runs fast: in the plugin itself or in any IR loader.

Are synthetic IRs worse than real ones?

No, not worse. For recording, even better. They don't copy real cabinets perfectly (which matters less for bass than for guitar), but they don't copy their main problems either: the bumps and the dips. You can see this right here, on the frequency response.

Really, really not worse than real ones?

For your recording (unless it's a solo bass album), a synthetic IR will almost certainly be much better than a real one: a synthetic one has no room, no standing waves and no phase problems, and you can see the bumps and dips right here.

But for live playing we strongly recommend a real bass combo or cabinet (not desktop ones!), with a speaker of 8–10″ or bigger. Don't play on desktop amps like the Boss Dual Cube Bass LX, Yamaha THR5 or Positive Grid Spark, even if they sound "like the real thing". On these toys we don't feel that we're playing: we never quite hear ourselves, we turn it up and up, we wear our fingers out and still never quite hear ourselves. And above all, they eat the instrument: we plug in a Fender, an Ibanez or an SG, and nothing changes.

Even the little Ampeg RB-108 with one 8″ speaker can be felt under your fingers in a small room; you can play it in a bedroom. Don't go for desktop ones. Get a real one: an Ampeg RB-110, RB-112, Fender Rumble 40 or, in a pinch, a Harley Benton HB-40B, which is even cheaper. Play on real amps and don't chase "cheap" processors with all the fanciest amps inside. Right now the dam has burst and Chinese NAM processors are flooding in, but they still have no speaker and no air moving. This is advice from people who know what digital is and where its limits are. For playing — no simulation and no desktop amps. A real speaker (8–10″ and bigger) and a real amp.

What goes into the IR calculation?

• the speaker's Thiele/Small parameters (fs, Qts, Vas);
• the box: CLOSED, PORTED, or with an OPEN back;
• a box of several chambers, like an 8x10: each chamber has its own air and its own modes;
• the cabinet's geometry: the size of the front panel, where the speakers, the port and the tweeter sit, the depth of the box;
• the port: at the cone, the mic hears the cone's near field against the port's far field; a port at the back is heard around the box, and quieter;
• each cone as a surface of many patches, each with its own path to the mic; the depth of the cone;
• cone breakup and cone modes, voice coil inductance; after breakup the outer cone lets go first, while the center with the coil and the dust cap keeps moving;
• the speakers in one cabinet differ a little: sensitivity and mode frequencies;
• standing waves inside the box and the modes of its walls;
• the tweeter (HORN): its own crossover, the steps OFF, −12, −6, 0, and a level that depends on where the mic stands;
• all the cones in the cabinet, not just the one nearest the mic;
• diffraction at the edges of the front panel;
• the reflection from the floor;
• the mic's polar pattern, the proximity effect, each model's capsule;
• the mic's position, distance and angle;
• the arrival time (ALIGN), polarity (Ø), shift (TIME) and blend of the second mic;
• EQ: HPF, LPF and three bands, baked into the IR itself.

Not taken into account: the room, reverb, the grille, distortion and the amp.

Why is it slow while the mic moves?

The recalculation is heavy. Basically, there is a lot to calculate: all the reflections, the sum of the sound from all the speakers, and so on. Download the plugin, it is several times faster there: in the browser the same code runs slower and calculates on one core, while the plugin calculates on several, in its own background thread, without getting in the DAW's way.

Can I use these IRs anywhere?

Yes, under CC BY 4.0: in music, in software, in devices, in commercial and closed products too. One condition: credit Darwin's Cat, for example "IR: Darwin's Cat, darwinscat.com". This goes both for the IRs you made here yourself and for the ready-made IRs from the archives.

Your pedal won’t take the downloaded IR?

Choose the format with the arrow next to DOWNLOAD IR: many pedals and processors don't convert the sample rate and expect exactly 44.1 kHz, often 16 bit and 1024 or 2048 samples.

Is it a plugin or an app?

A plugin: in a DAW it sounds like a bass cabinet on its own. An app comes with it too: in the app you can play live through an audio interface, without a DAW, and save IRs as WAV for a processor, a pedal or any IR loader. And on this page you can try the plugin right in your browser.

Where can I download ready-made IRs?

Ready-made IRs of all the factory presets and the typical cabinets, by style and by cabinet size, free, under the CC BY 4.0 license: on the bass cabinet IRs page.

How can I help you? How can I say thanks?

Leave a link to us wherever you can. It helps more people get this cool thing. And feed the cat.