Using busses but getting distorted audio

[ianstonehouse]

System spec:
ProTools HD2 Accel + 192 hardware; ProTools 7.4 software; Apple Mac G5 1.8GHz dual core, Mac OS 10.4.11, 1.2Gb RAM; 3 x external firewire 400 drives; Yamaha 02R mixer (optical link to 192).

Issue:
In the current session there are several tracks with recordings of a vibraphone on (i.e. 6 x stereo tracks). When these all play directly out through Channel 1 and 2 on the system it's all fine. However, as soon as we send these tracks all to a stereo bus the audio sounds distorted at some points when the level is high but none of the levels are peaking. We've tried using other buses and the problem remains.

Any ideas?

[Bentley Ferrari]

Try using a Master Fader track for your stereo bus if you're not already. A master fader can control clipping at the input from your summed vibraphone track outputs. If your stereo bus is, say, an Aux track presently, it can and will be clipped on the way in.

[crizdee]

Originally Posted by ianstonehouse

Issue:
In the current session there are several tracks with recordings of a vibraphone on (i.e. 6 x stereo tracks). When these all play directly out through Channel 1 and 2 on the system it's all fine. However, as soon as we send these tracks all to a stereo bus the audio sounds distorted at some points when the level is high but none of the levels are peaking. We've tried using other buses and the problem remains.

Any ideas?

Hi,

is your master fader definitely set at -0dbfs?

placing a bus inline shouldn't make any level change!!

Chris

[Bentley Ferrari]

You might benefit from taking a look at this brief thread:

A DUC Distortion Thread

There are a number of possibilities here for why you're hearing distortion, but without any more info from you, my guess is that it's the combined track outputs clipping the inputs of your stereo bus. You can avoid this by either lowering the track levels on the way in to the stereo bus or by making your stereo bus with a master fader. The latter works best IMO....mainly because you get the benefit of 48bit headroom as opposed to 24bit on a "normal" stereo bus. There's no law against more than one master fader in a session, and a good number of us use them liberally for submixing etc., because they're ideal for it.