[Dtb-talk] A question about preferred book formatting

[Tim Gillett]

Greg, 

That's great there's  indexing tone detection software available. From memory I think it was usually about a 50hz sinewave.

If it's any help,  ABWA's inhouse productions from about the early 90's to 2007
 when they changed to digital recording would be unlikely to contain index tones.

There may however be tones on some inhouse titles recorded from about 1987 to the early 90's.
I remember at that time sourcing some Australian made add-on tone indexing units
 and installing them into at least some of the 4 recording studios. 
 
As well, some  study materials recorded by volunteers at home in this period were recorded on the APH GE type
cassette recorders which had a built in tone index recording facility which the vollies were trained to use. 
These titles would be on a mixture of 2 track and 4 track cassette formats. 

Also, I seem to recall productions ordered from fellow Australian producers RBS and RVIB (now Vision Australia)
contained tone indexing, as well as fast wind voiced chapter indexing. 
It may however be difficult to outwardly identify these as RBS or RVIB productions if they were "rebadged".
But I guess if the tones are there the software will pick them up.

On a slightly more technical note, it may in some cases be necessary to play around 
with the tone detection software's "threshold" settings so as to avoid the problem of tones
 that are too quiet for the detector and get missed, or on the other hand, avoiding false triggering due to studio noises,
  microphone "plosives" etc fooling the software into thinking they are actually index tones.

The same might apply for the software's "tolerance" for tones that were not quite standard in  frequency. 
Analog tape's time domain (and therefore frequency) accuracy was not nearly as stable as digital's. 

These days, with the benefit of sophisticated error correction software, 
we just take it for granted a digital copy will be essentially a perfect replica of the original. 

Nowadays, all the fun's been taken out of it!  (joke)  

Cheers, Tim

Tim Gillett
Audio/Electronics Technician
Perth, Western Australia