Sending bass from VST to bass amp

Question

Our keyboard player plays bass on keyboard. This is going through MIDI to a Steinberg UR22 interface and is then hooked up with a standard Kontakt 5 libary to create bass sound from the MIDI notes. Finally this is then send out through the UR22's outputs to a bass amp.

Will this work or is it wrong to send proccessed bass sound to an bass amp? Should we use high or low input on the bass amp?

Answer 1

IMO, if the keyboard player fulfills a bassist role, then it is a good idea to use a bass amp! This way, at least on smaller stages you're sure that the bass will be properly present everywhere on stage. With wedge monitors alone, you rely on the mixer to properly distribute to everybody individually. That's not really a standard scenario; you may well end up with either a tinny, unsatisfying in-the-face sound, or just undefined bleed from the PA.

Another advantage of a bass amp is that it will already be connected with a DI, have a channel that's set up for bass, and so on.

If available, using a low impedance input can make sense. High-impedance inputs are a special configuration that only really makes sense for passive instrument pickups, like those on most bass guitars (even more for piëzo double bass pickups).
All active sources like audiointerfaces have low impedance, which basically means they don't care what impedance the input has, so often it just won't matter at all. However, a low impedance input may reject some noise problems.

An audio interface will offer rather more level than a passive bass, but not necessarily more than an active one. If you don't overdo it with the gain, you should be fine, but just try it: a decent bass amp should sound quite nice gritty if you overdrive the preamp a bit.

At any rate, make sure to test it with another bass amp (or at least guitar amp), beforehand! There may very well noise problems, especially if the laptop is fed by a not so good power supply. If you hear an annoying static sound (often, this comes out a bit like weird rattling / drum roll), then a DI is probably the way to go. (Note that you can also go from a DI – with isolated phone output – into a bass amp instead of straight to the PA.)

Software side, I would recommend to make sure you don't have any amp simulation already in the computer. The bass signal should be bright and clear at this point, perhaps even a bit acoustic-guitar like if you listen to it with headphones. You can always reduce treble at the bass amp if necessary, but if the signal is too muffled to begin with then you may get the problem of indistinct rumble with no proper tone definition, when it gets loud on stage.

Answer 2

I would probably go for a combined setup:

1. Get a reamping box (reverse DI) to ensure correct levels and impedance. You can hook up the interface with the box using XLR and continue on to the bass amplifier using standard jack cable. You can test both the Hi and Low input, but using the reamp box, the Low (impedance) input is probably the one to go for.

This will work with any amp.

Alternatively try to use a line input on the amp (or "Power Amp In" input on the back). It will work better with the interface output.

Take a look here for additional info on Hi/Low inputs (leftaroundabout answer is the correct one..): https://music.stackexchange.com/questions/3473/difference-between-hi-and-low-on-amps

2. Use a DI box to get the direct signal to the mixer. You can use another output from the interface, or intercept the amp line somewhere or use the amps DI output. Most likely the engineer simply put it right before the amp - that is standard with conventional basses.

The advantage is that you get a fuller stage sound from the amp (not just the thin indirect monitor bleed).

And the engineer will get a direct signal from the DI/Amp/Interface, which is most likely what he/she wants (as an engineer I would want that instead of micing up the amp).