LISTSERV mailing list manager LISTSERV 16.0

Help for ARSCLIST Archives


ARSCLIST Archives

ARSCLIST Archives


ARSCLIST@LISTSERV.LOC.GOV


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

ARSCLIST Home

ARSCLIST Home

ARSCLIST  September 2014

ARSCLIST September 2014

Subject:

Re: Distortion question

From:

"John K. Chester" <[log in to unmask]>

Reply-To:

Association for Recorded Sound Discussion List <[log in to unmask]>

Date:

Tue, 30 Sep 2014 10:50:45 -0400

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (40 lines)

At 10:07 AM 9/30/2014, Bruce Whisler 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?

The first thought that comes to my mind is slew rate limiting (aka 
transient intermodulation distortion).  For those who don't know what slew 
rate limiting is, good explanation here:
http://ethanwiner.com/slew_rate.htm
It sounds like distortion, but reduces the waveform amplitude of high level 
high frequency components compared to lower frequencies, so the distorted 
waveform looks quite different from simple clipping.  Some audio equipment 
built in the 1970's used early IC op amps which had slew rate too slow for 
audio.

Trumpet is a very asymmetrical waveform.  When you look at undistorted 
sections of the trumpet waveform, are the fastest-moving portions on the 
negative side, or the positive side?  If negative, that supports this 
theory.  If positive, this theory is almost certainly wrong.

>  I have Izotope RX 3 Advanced, and have had little success in repairing 
> this particular problem with the Declip, Decrackle, or Declick modules.

I've never tried to use digital tools to repair slew rate limiting, but it 
doesn't surprise me that those tools won't do it.

-- John Chester

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003
October 2003
September 2003
August 2003
July 2003
June 2003
May 2003
April 2003
March 2003
February 2003
January 2003

ATOM RSS1 RSS2



LISTSERV.LOC.GOV

CataList Email List Search Powered by the LISTSERV Email List Manager