Quick Tip: Suffering Individual Disc Playback Freezes? Clean The Disc!

When you try to play your latest, smash hit, movie disc, does your player "freeze up" part way through?  Does this always seem to happen just as the movie gets to the GOOD part?  Does it then ignore all your desperate efforts to get it playing again?

And are your friends and family now judging you; given all the money you've spent on your Home Theater system, only to have THIS happen?

Is that your problem, Bunky?

Well take heart old chum!  Your problem may have an easy fix:  Clean The Disc!

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Understanding DSD to LPCM Conversion, OR SACD "Noise Shaping" for Fun & Profit!

In my prior post on Digital Audio, I introduced two, "simple", Digital Audio formats:  LPCM (Linear Pulse Code Modulation) and DSD (Direct Stream Digital).  These are "simple" in the sense that each stream of LPCM or DSD contains the audio for just one speaker channel -- as compared to the more complex, Bitstream formats which combine multiple channels into a single stream.

However, there is one huge, practical difference between them.  DSD Digital Audio can not be "processed"!  If you have DSD content, and want to convert it directly to Analog audio for your speakers, without any other format fiddling in between, you most forego all types of Digital Audio processing.  So, no Crossover (bass steering).  No Down-mixing.  No Surround Sound processing.  No Speaker Distance adjustments.  No Room Correction.  NOTHING, except for Volume control.

If you WANT any such processing, you must first convert the DSD Digital Audio into a different Digital Audio format which CAN be processed.  I.e., into LPCM.

Which of course raises the question, "Is that SAFE?"  Can you DO that without screwing up the quality of the DSD original?  Or must you give up quality to gain access to that processing?

The short answer is, Yes, it is safe, given properly engineered gear.  Let's take a deeper look at what's going on!

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Calibration Discs <-- You NEED These!

EVERYONE interested in Home Theater should have a few Calibration Discs in their collection. This is true even if you intend to hire a professional to come in and set up your system for you. Professionals will bring tools and computer programs which are both expensive to buy and daunting to learn. But even though you can't fully match their professional results, you should STILL have calibration discs handy to confirm there are no silly setup errors in your system, and to check whether any problems you spot while playing real content are due to oddities in that content, as opposed to something you've overlooked in your system setup. Calibration Discs provide you with content of known "correctness" which you can use for this.

There are LOTS of different calibration discs out there at this point, and more likely to come out over the next year or so as UHD (4K) video becomes more mainstream. Some of them are pretty specialized. Some require you also have those professional tools mentioned above. Some are hard to find, or even out of print. The most sensitive test I know of to confirm that Speaker Distance Correction is happening properly, is found in the Avia Pro SD-DVD multi-disc set, which is long out of print. And even in that case, this particular test was included in an add-on disc to that set, which only appeared several years after the set first shipped! Try getting your hands on THAT one!

In this post I'm going to discuss two, generally useful Calibration Blu-ray Discs. And also, one specialized disc -- in this case an SACD disc -- to give you a flavor of what's out there if you go looking for such specialized, test content.

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