I had the distinct pleasure of working on project with Bruce Springsteen’s engineer Toby Scott a little over a year ago. Toby (not “Tony” as the USA Today article incorrectly named him) told me about a process developed by Jamie Howarth (USA Today misspelled his name too!) called “The Plangent Processes Playback System”. In the world of transferring analog tapes to high-resolution PCM digital copies, this process has been widely praised.<\/p>\n
From the Plangent Processes website:<\/p>\n
“The Plangent Processes software, developed with researchers at Cambridge University in England, is proprietary UNIX-based, and is non-realtime. It runs at 768 kHz with 32-bit double precision internally, ensuring scrupulous audio fidelity with little or no artifacts. The basic function of the software is to identify a steady-state ultrasonic reference tone (such as tape bias or logic control) embedded within the original analog signal and then perform continuous high-resolution pitch correction in order to keep the reference tone at a fixed frequency. For transfer, we maintain a fleet of analog ATR102 tape machines rebuilt by ATR Services, along with custom headstacks and preamps, as well as ancillary electronics and most popular A\/D converters. Conversion resolution is minimum 96 kHz \/ 24-bit, though 192\/24 is preferred. A 44.1 kHz version of the process is also available with slightly diminished performance.”<\/p>\n
In simple terms, what Jamie and the brainiacs at Cambridge University have done is remove or reduce the macro and micro speed fluctuations that invariably occur during analog tape recording and playback. Everything from “wow & flutter” to “scrap flutter” is diminished resulting in “near perfect” playback. This is the ideal way to do a tape transfer. The use of ATR 102 tape machines and custom electronics doesn’t hurt but the essence is in the proper alignment of timing…something that a very well clocked PCM digital system has going for it as well.<\/p>\n
But what else are they doing? The spectrogram below shows areas of a song before the Plangent Process was done and the original. The Red plot line is 5 dB lower in amplitude than the processed version. As we’ve come to expect, the best way to make something “sound better” is to turn it up. Louder is always better, right? It becomes really apparent when you look at the amplitude vs. time plot on the left hand side of the illustration. The area inside of the GREEN line is the original. The beginning and the end are the PP [Plangent Processes] sections. The amplitude has been juiced and the result is a narrowing of the dynamic range of the tune.<\/p>\n
![\"Plangent_Comparison\"](\"http:\/\/www.realhd-audio.com\/wp-content\/uploads\/2014\/02\/Plangent_Comparison.jpg\")
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