Official DataSat RS20i thread. (Setup Tips, Questions,General Info, etc) - Page 81 - AVS | Home Theater Discussions And Reviews
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post #2401 of 2406 Old Today, 05:20 AM
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Fully understand the scepticism and I am not advocating it as the best way, simply that it sounds good to me. I expect I have adjusted to this approach and may have a go at removing the additional delay to check whether it is better.

Hopefully if Carl is about he can chime in.
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post #2402 of 2406 Old Today, 07:39 AM
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I thought that sort of delay was used in something like prologic when upmixing stereo to surround (so you send a decorrelated delayed copy of the LR to each surround channel).
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post #2403 of 2406 Old Today, 08:09 AM
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Originally Posted by 3ll3d00d View Post
I thought that sort of delay was used in something like prologic when upmixing stereo to surround (so you send a decorrelated delayed copy of the LR to each surround channel).
Pro Logic matrix decoding couldn't prevent dialogue from leaking into the surrounds, so delaying the surrounds invoked the precedence effect (hearing the dialogue from the centre channel made your brain ignore the leakage from the surrounds a few milliseconds later).

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post #2404 of 2406 Unread Today, 12:53 PM
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Originally Posted by Wookii View Post
I must admit, I'm struggling to understand the 20ms surround delay approach. Don't get me wrong, I'm happy to give it a try, but surely in a properly calibrated room with a single seat, all speaker should be calibrated such that a impulse test tone reaches the listening position at the same time from all speakers.

I understand the point that in a commercial cinema with such a huge amount of seats, and the necessity to calibrate for all seats, or at least for a very wide sweet spot, and prevent rear speaker information reaching the rear most seats before the front speaker information, thus resulting in a sizable delay of the arrival of rear channel information when sitting in other seats. But why perpetuate that inaccuracy in the home where the goal is surely to exceed the reproduction quality that can be achieved in the commercial cinema?

I'm not arguing against it here, I'm just trying to understand the concept - I may well have missed something?
I just did it and applied 20ms to all channel delays except LCR and Subs. I do find the result quite pleasing. I don't have much space to the side and back and have the feeling now of a much bigger room towards the back. It sonehow increased the back soundstage.
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post #2405 of 2406 Unread Today, 01:28 PM
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Quote:
Originally Posted by Wookii View Post
I must admit, I'm struggling to understand the 20ms surround delay approach. Don't get me wrong, I'm happy to give it a try, but surely in a properly calibrated room with a single seat, all speaker should be calibrated such that a impulse test tone reaches the listening position at the same time from all speakers.
I am triple-checking with Datasat engineering, but I think this is an error in the manual, based on someone's misunderstanding of an old DTS theatrical fix to an unexpected problem. The short version is: cinema processors (for commercial movie theaters) had adjustable delay for the mono (and later, stereo) surround channels, for the same reasons that we do today for home theatre - to time align the surround arrays. You needed a surround delay for the whole array so that you could adjust based on the size of the room.

When DTS launched in the 1990s, by far the most common system configuration was to go analog out of the DTS player into the analog inputs on the cinema processor. It was discovered that many cinema processors did not apply their configured surround delay to the analog inputs, which really muddied things up - audiences were hearing the surround channels early. So very early on in the company history a 20ms delay was added to the surrounds upon disc encoding, 20ms having been calculated to be the average delay needed in an average sized auditorium.

It sounds to me as though in a game of telephone this got translated into "surround channels should always be delayed 20ms", which makes no sense to me. Hopefully Carl can weigh in with his take, though.
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post #2406 of 2406 Unread Today, 07:22 PM
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I rechecked Carl's advice to me and I misrepresented that advice (apologies to all, particularly Carl - this is my second salutary lesson in 24 hours). The key points of Carl's advice are:
- condition 1, if the 'surround to listening position' is less that the 'mains to listening position then set the surround levels to -3dB relative to the mains (ie 82dB) and add 23ms delay to the surround channels


- condition 2, if the 'surround to listening position is equal to or greater than the 'mains to listening position' then set them equal to the mains without adding delay.


Carl's intent is an attempt to recreate the 'acoustic room scale' of a commercial theatre.














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