As Lou points out, the distortion almost certainly occured in the mike preamp.  Trumpets and Trombones, especially when muted, have a significantly larger positive excursion in the waveform compared to the negative half, perhaps as much as 20 dB, (an announcer's voice exhibits the same characteristic to a lesser degree).  A mike, (or an ear), placed close to brass often just snips these spikes off but miked from a distance these spikes give the brass a presence which is very attractive on orchestral recordings, big band recordings or even jazz solo recordings.


On Tuesday, September 30, 2014 10:07 AM, Bruce Whisler <[log in to unmask]> wrote:

I am working with an old tape recording that has several instances of distortion that sound like clipping.  When I view the waveform in my DAW, I see two things that are puzzling:

1.       The waveform in the distorted areas is not at a higher amplitude than other undistorted sections.

2.       The waveform amplitude appears to be attenuated on the negative side of the waveform, but not on the positive side.

The distorted sections usually last only about a second and do coincide with loud high notes from a trumpet soloist.  The recordings are from live performances in the 1970s.

Any thoughts on what I am dealing with?  I have Izotope RX 3 Advanced, and have had little success in repairing this particular problem with the Declip, Decrackle, or Declick modules.  I don't think there is enough tone left under the distortion to effectively repair it.

Bruce Whisler