Ableton Forum

Ok, so I've recorded an album and I'm trying to figure out how to do the bass parts of the songs live. Problem is the bass is processed by some heavy effects on these songs.

What I imagine I need to do is plug my bass into the interface, change the bass tracks output in live to one of the outputs of my interface, then plug that output into the amp, but is that a reasonable signal to send to an amp head? Any latency issues arise from this? Any help would be appreciated, thanks!

That process is known as reamping. The real problem lies in the difference between the low output impedance of the interface sending a signal to the high impedance of an amp head. This reduces the power that can be delivered to the amp because a portion of the signal will be reflected back from the input of the amp and cause cancellation at the source (interface output).

To get around this you need a reamp box http://www.google.com/search?aq=f&sourc ... -8&q=reamp. This is basically a specially wound transformer coil that helps eliminate the above problem as well as ground loop hums which result from differing paths to ground between interface and amp. Effectively isolating their circuits.

Latency is a factor but can be unnoticeable if driver latency compensation is done right in preferences and such.

There are many clever ways to do reamping and using it to record is where it really shines!

Good luck.

Thanks, that's exactly what I needed to know!

actually, that's not exactly reamping. the way you are talking, it's EXACTLY like you plugging into a digital FX box in front of your amp. and that works fine for most people. Instrument level is usually a lot lower than line level, so just turn the output down on the send out of the interface. It may even work as is depending on your setup. If your amp has an FX loop, you probably want to send the FX send into the interface input, and the output of the interface back into the FX return, that might be more useful.

You'll still have an impedance matching problem that way. The output of a digital interface (~50 Ohms) will have a much much lower output impedance than that of a powered digital fx pedal (~1000 Ohms) where the input impedance of a guitar amp is typically ~100 KOhm. It might not be extremely noticeable but it will reduce delivered power.

maybe... not sure (the guys next door do all the signal integrity stuff - good reminder to go back and redo my training, forgot nearly all of it by now...)

but the output impedance of my emu 0404 usb is listed as 560 ohms, whereas my X3 live (in amp mode?) someone tested as 680 ohms. not enough to even worry about.

General rule I always heard is just to make sure the input impedance is at least 10x the output impedance.