This is topic Stereo synthesizers in forum Film-Yak at Film-Tech Forum ARCHIVE.
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Posted by Stephen Furley (Member # 1277) on 10-13-2002, 07:30 AM:
There used to be available devices which were generally known as 'Stereo synthesizers', which claimed to produce a stereo effect, when fed with a standard Academy mono optical track. What did these devices actually do, and what did the final result sound like? Did they send the same sound to each channel, but at different levels, like Perspecta, or did they attempt to somehow separate different components of the track and send them to different channels? In either case, how did they decide what to send where? I am extremely doubtful about the claims which were made for these things, but someone who ran the British Transport film 'Elizabethan Express' through one of these devices built into a Kintek processor said that it sounded good. Was it purely luck that it happened to produce something from this particular film, or did these things actually work?
Posted by Ken Layton (Member # 133) on 10-13-2002, 11:01 AM:
The Kintek units seemed to do a good job.
Posted by David Stambaugh (Member # 1102) on 10-13-2002, 11:35 AM:
It doesn't exactly qualify as a "stereo synthesizer", but back around 1985 one of the Dolby Stereo houses at the now-closed Edwards El Toro 5 had a "surround synthesizer" for use with mono soundtracks. If the overall sustained audio level exceeded a certain threshold, it would feed some signal to the surrounds. Sometimes it was effective, but most of the time it drew attention to the surrounds at inappropriate times. It was all-or-nothing too, so sometimes dialog would start coming from the surrounds for no apparent reason.
Posted by Dave Williams (Member # 299) on 10-13-2002, 02:00 PM:
In theory, a stereo synthesiser should if you are sending it to lets say 5.1, take the sub levels and send it to the subs, take the low levels and send them to the woofer cones, and take the high levels, take one side and put it a few milliseconds behind the other side, and the other side a few milliseconds ahead of the other side, with the center carefully separated from the other two. The three channels now have different sounds, and they can modulated to produce different effects from each other. Really there is no way to separate voices, effects, etc, on the fly.As for surrounds, a mixture of low and high end levels fed through, avoiding mid range frequencies, produce a pretty decent effect.
Now this is in my theory, and could be put into practice. In fact I have done this in practice, and it works quite well on mono soundtracks. Well at home anyway.
As for cinema applications, who knows.
Dave
Posted by Gordon McLeod (Member # 33) on 10-13-2002, 04:59 PM:
The Kintek and most others worked on the following scheme
They used comb filters (30 in the Sart and Kintek) to produce set of peaked and lowered bands that had phase shifts at the ends of each
These were usually subtracted from each other and in some cases passed through a multi band expander so the widening of the image spread was proportonal to levelTHe surround channel was usually a multi band threshold detector again with an expander
In the case of the Kintek it also had a sub harmonic synthesizer (disco box) that was used to take the bottom octave of the track and create a duplicate one octave lower for extra bass effects
Some mono films sounded very good with it and others didn't
One nice feature of the kintek was it featured a 3 band dynamic range expander that resotred some of the dynamics of many compressed mono tracks
Posted by John Pytlak (Member # 331) on 10-18-2002, 03:30 PM:
At ShowEast, I talked to Dan Taylor (formerly of Kintek and Sony), who is now Vice President and General Sales Manager of Theatrical Entertainment Services Worldwide (TES), a theatre checking and polling service company.His e-mail address is dtaylor@tesonline.com
------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
Posted by Brad Miller (Member # 2) on 10-18-2002, 03:42 PM:
Calling that company "Theatrical Entertainment Services Worldwide" probably wasn't the smartest idea. 