2020-10-25, 07:55 PM
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Dolby SDU4 Hardware Dolby Stereo/Surround decoding
Dolby SDU4 Hardware Dolby Stereo/Surround decoding
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Dolby SDU4 Hardware Dolby Stereo/Surround decoding
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2020-10-25, 08:26 PM
(2020-10-25, 07:47 PM)pipefan413 Wrote: No, I got it for LaserDisc captures *and* recording SDU4 (because of the crapload of analogue inputs). If you have some time, take a look at this post I wrote quite some time ago, but still good today: https://fanrestore.com/thread-1107.html
2020-10-25, 09:12 PM
(2020-10-25, 07:55 PM)pipefan413 Wrote:(2020-10-25, 07:53 PM)TomArrow Wrote: Couldn't find any specs or tests. They might be in the manual but I couldn't find a pdf of it. You could of course just do an RMAA test yourself since you already own it.  Would only work if it also has an output though.Alternatively, you could try to just record silence at 24 bit, that would at least give you the noise floor. Thanks given by: pipefan413
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2020-10-25, 10:21 PM
(2020-10-25, 09:12 PM)TomArrow Wrote:(2020-10-25, 07:55 PM)pipefan413 Wrote:(2020-10-25, 07:53 PM)TomArrow Wrote: Couldn't find any specs or tests. They might be in the manual but I couldn't find a pdf of it. Yeah, it has plenty of outputs. The breakout connector is a hilarious Lovecraftian affair. You're right, yeah, I could just see what silence sounds like; it'd be interesting to run a full assessment at some point, but I've got so many other things I want to get done I dunno whether I'll be prioritising that for a while. One of the things I'm going to have to work out soon, on a semi-related note, is how to mix the noise floor from an LD recording done on the Decklink (dual mono, analogue, no CX) into a cleaner LD capture (Dolby). Which I think is going to tax my software skills, frankly...
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2020-10-25, 11:20 PM
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2020-10-26, 12:13 AM
(2020-10-25, 11:20 PM)spoRv Wrote:(2020-10-25, 10:21 PM)pipefan413 Wrote: how to mix the noise floor from an LD recording done on the Decklink (dual mono, analogue, no CX) into a cleaner LD capture (Dolby). Which I think is going to tax my software skills, frankly... Basically for the mono track on The Exorcist, which is missing massive chunks of the soundtrack due to missing frames (like, hundreds), I'm going to need to patch the gaps from another source. But there is no other mono source. So I'll have to make a custom "mono" track from another soundtrack, which is Dolby Stereo/Surround and therefore has Dolby noise reduction and an extremely low noise floor compared to the noisy optical mono. Sooo it'd sound really stupid when it suddenly cuts to the Dolby. So, plan is, use some "noise floor" of the mono track (a moment where there's "silence", so noise floor only) and mix that into the Dolby track to make it sound at least a little closer to the mono (so that the background noise doesn't abruptly disappear when it cuts to the Dolby). But how to get just the right amount of noise mixed in etc. is beyond me because it's years since I mixed audio in a DAW. Not looking forward to it frankly!
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2020-10-26, 01:11 AM
I'm not a great sound editor at all, but my advices would be these:
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2020-10-26, 02:01 AM
(2020-10-26, 01:11 AM)spoRv Wrote: I'm not a great sound editor at all, but my advices would be these: Well the trouble is there *is* no other mono source besides maybe VHS but even then it's same master I think. The US mono LD is time-compressed which further limits its usefulness, though it will at best have differently located side changes; the much larger problem however is massive chunks of missing frames in the source, which will have been used for all transfers at that time, methinks. I already captured the US Dolby Stereo LD, the JP "stereo" (note: no mention of Dolby) LD, and both JP mono LDs, but the two mono ones are identical (it's just a reissue) and the JP stereo has side changes in exactly the same places so may not be as useful as I'd hoped. See this post (and earlier ones in the thread) for more info: https://fanrestore.com/thread-3504-post-...l#pid66400 Re. the downmix, my plan was to simply downmix the stereo to mono as is, not decode it at all: straight stereo -> mono. Then, duplicate that back up to get dual mono, and then mix the noise floor from my 2.0 mono into that for the short sections I'd use for the patches (no point mixing it into the entire thing). So I wouldn't need to loop anything, which is nice: just sample a big enough chunk to mix in. The trouble though is the gain of the noise floor relative to the gain of everything else; my understanding of mixing these days is crappy so I'm not sure if I can simply gain match the prepped stereo->mono downmix to the gain of the mono target track and then mix in the noise floor, or if that will mess with the levels and push the gain of the output track up. As in, will the noise floor being mixed in increase the total gain of the track, or not? But we're out of scope for this thread now so I guess maybe reply in the thread I just linked if you know! It doesn't have to do with the SDU4 really, I'm using that for something entirely different (just the chat about checking the noise floor reminded me I'm going to have to figure out the thing about mixing it in and what it'll do to gain).
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2021-07-27, 04:24 PM
Just found a post from the unforgotten expert Disclord:
Quote:the CAT-150E board used the Sanyo Pro-Logic chip but didn't use the built-in VCA's - instead, Dolby used very high-quality outboard VCA's on the E board and it has the best performance of any 150, with more headroom and dynamic range the CAT-150E was used in the Dolby SDU4 decoder, hence it should be considered an high quality one - and, most important, as it was used inside a cinema Dolby Surround decoder, it was one of the more faithful IMHO. 
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2021-09-02, 08:10 PM
So I just picked up an SDU4. I've never captured analogue audio before, but what I was thinking was to use my USB sound card with RCA to XLR cables as the input, and then capturing it with XLR to USB cables. Would this work well enough? I'd rather not spend a bunch on expensive capture equipment yet because I'm not 100% sure the thing even works yet.
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