From: Patent Tactics, George Brock-Nannestad
Paul Turney asks the very reasonable question whether Chandra Lynn's original
posting was merely a veiled advertisement. I do think it is. However, I shall
come to the rescue by referring readers to 25 June 2005 and 24 July 2005,
where Plangent Processes were indeed discussed on ARSCLIST. Further dates are
2 February 2008 and 8 November 2008, where I mentioned it in connection with
many other non-intended signals that would be thrown out if the tapes were
merely used as land-fill subsequent to ordinary transfer to digital.
I an under the impression that I have also contributed more, but on other,
probably mis-named threads.
The essential feature of the process is that the bias information is picked
up as close to the payload signal as possible, eliminating the variable
influence of the lengthwise elasticity of the tape. Having a separate tone-
head further along and merely compensating for the time delay is flawed and
caused some investigators to erroneously accusing Plangent Processes of not
As to bias drift, this is usually a long-term effect, once the temperature of
the original recorder has settled.
And I should note that the process is not dependent on the use of ATR
A completely different approach is very well described in the following
reference, which at least I found on the web:
P. Maziewski: "Wow defect reduction based on interpolation techniques",
Bulletin of the Polish Academy of Sciences, Technical Sciences, Vol. 54, No.
This approach may be similar to the software used by Ward Marston in cleaning
up the Paris piano recordings.
> Chandra Lynn [mailto:[log in to unmask]]
> Sent: Thursday, April 29, 2010
> 02:12 AM
> To: [log in to unmask]
> Subject: [ARSCLIST]
> Airshow Mastering & Plangent Processes
> I noticed some earlier postings about Plangent Processes. It eliminates
> wow,flutter and speed aberrations from analog masters. They are now working
> withAirshow Mastering to offer optimized tape transfers.
> The announcement is onAirshow¹s site at
> lHave any of you worked with Airshow or Plangent?
> If so, what has been your experience?
> One of GlowMarketing.com's clients is ... Airshow Mastering.Is this a wholly
> justifiable posting asking for experiences not by the company or engineer
> but by their PR company?
> Which postings did Chandra Lynn notice about Plangent Processes?
> -----Original Message-----
> From: Andrew Hamilton [mailto:[log in to unmask]]
> Sent: Thursday, April 29, 2010 09:24 AM
> To: [log in to unmask]
> Subject: Re: [ARSCLIST] Airshow Mastering & Plangent Processes
> There are other forensic time stamp signals besides bias which would allow
> for an ATR-100-recorded tape to be de-fluttered by the PP DSP. However, even
> though a tape may be played back by the Airshow ATR-100, it's entirely
> possible that the tape was recorded elsewhere by a different machine (having
> a much lower bias f). I believe that Airshow are offering this service with
> PP for already-existing analog tapes, rather than for creative layback
> transfers.David Glasser is chief engineer at Airshow and he has mastered a
> huge amount of audiophile CDs, DVDs, and SACDs. Great ear; great rooms;
> great gear. From the PP website:"software algorithm, developed with
> researchers at Cambridge University in England, which identifies a
> steady-state ultrasonic reference tone (such as tape bias or logic control)
> embedded within the original analog signal and then performs continuous
> high- resolution pitch correction in order to keep the reference tone at a
> fixed frequency..."AndrewOn Apr 29, 2010, at 4:15 AM, Shai Drori wrote:> My
> experience with the ATR is just the opposite. I have tested > various
> transport and some tapes were handled only by the ATR. Does > the system
> figure out bias frequency automatically. What does it do > with tapes
> recorded on the atr where the frequency is so high it > doesn't show up on
> playback (400kHz+)?> Shai>> On 4/29/2010 8:54 AM, Paul G Turney wrote:>>
> Well they only use ATR 102 machines which are notoriously rough >> tape
> handlers....>>>> They use software to track and maintain a bias frequency so
> that >> any speed anomolies are and wow and flutter are reduced by >>
> maintaining perfect pitch with this tone.>> Not worked with Airshow
> mastering.>>>> It appears to be a monopoly on the software so Airshow would
> be >> subbing the work out to PP.>>>> PT>>>> -----Original Message----->>
> From: Chandra Lynn [mailto:[log in to unmask]]>> Sent: Thursday,
> April 29, 2010 02:12 AM>> To: [log in to unmask]>> Subject:
> [ARSCLIST] Airshow Mastering& Plangent Processes>>>> I noticed some earlier
> postings about Plangent Processes. It >> eliminates wow,flutter and speed
> aberrations from analog masters. >> They are now working withAirshow
> Mastering to offer optimized tape >> transfers. The announcement is
> onAirshow¹s site at http:// >> www.airshowmastering.com/plangent.htmlHave
> any of you worked with >> Airshow or Plangent? If so, what has been