Author Topic: Why are these players so good?  (Read 5311 times)

Offline Carlman

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Why are these players so good?
« on: February 05, 2007, 12:59:33 PM »
What makes the Squeezeboxes and other players so good?
I know part of it is that the jitter-free production of bits off a hard drive seems to get rid of a 'digital hash' for me....
Is this the main reason?  Are there others?  I'm going to do a comparo soon (see: http://www.audionervosa.com/phpbb2/viewtopic.php?t=119)
and I'll get some results... but likely not many answers as to why...

Just curious what others think.

-C
I really enjoy listening to music.

miklorsmith

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Why are these players so good?
« Reply #1 on: February 05, 2007, 01:13:15 PM »
I think one of the issues CDPs have is the real-time optical interface.  The cutting process is flawed, which is why copies have potential to be better.  Then the transmission rates off the laser to the buffer and from the buffer to the output + clocking from these functions makes it pretty easy to see why jitter can be such a problem.

Some really high end CDPs seem to be taking this into account and are doing different things with much bigger buffers.  One player I saw (at about $10k) plays straight from RAM (not a hard drive) to avoid jitter creation problems.

The fact that computer-based systems are so good so early on is a serious indicator that this is the future.  Let a ROM drive collect the data, then "pure" bits are available.  The only thing left to do is deliver them accurately timed.

mgalusha

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Why are these players so good?
« Reply #2 on: February 08, 2007, 01:51:56 PM »
I think Mike is on the right track with this in that pulling the bits off on a PC using error recovery produces an output that has all the bits which can easily be buffered into memory. Normal CDP's have error correction and interpolation and they will guess at the missing bits and insert them into the data stream if the laser doesn't pick them up.

In addition, even though the circuitry may be relatively jitter free and reclock the data it seems to me that having the laser pickup constantly hunting for the track when the disk is spinning at 500 RPM would generate timing errors pretty easily and being that Red Book CD's have no error correction codes as part of the data it doesn't take much to make the interpolation mechanism kick in. 'course I could be full of hot air, that wouldn't be the fist time.

Now, if they would put in large enough buffers on CDP's and use an algorithm that reread sectors when an error was detected there should be little or no difference between the data stream from a stand alone machine vs the data stream from a computer. Of course most folks don't want to wait 30 seconds for a song to start after they hit play. ;)

Offline bpape

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Why are these players so good?
« Reply #3 on: February 09, 2007, 07:14:07 PM »
Add in the fact that the transmission medium (PC Networking) is another layer of inherent error correction.  

I also agree that the magnetic retrieval from the disk is superior to the optical retrieval from a CD.  Even though one must read it to get it onto the HD, EAC does a great job of doing multiple reads and providing correction on the fly during the copy stage.

Bryan
I am serious... and don't call me Shirley

Offline Carlman

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Why are these players so good?
« Reply #4 on: February 10, 2007, 04:59:25 AM »
Quote from: "bpape"
Add in the fact that the transmission medium (PC Networking) is another layer of inherent error correction.  
Bryan

Ah, now that's an interesting one... I've often wondered about how having a central server with a PC in a different room would sound compared to having one right next to the DAC.

I will find out today! :)  I'll put the same music on a hard drive in my office (central computer, shared) and access the songs from Foobar on my soundroom's PC... then compare it to the same song played from the soundroom PC's hard drive.  

That's one of a few comparisons I'm doing today.

-C
I really enjoy listening to music.

miklorsmith

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Why are these players so good?
« Reply #5 on: February 10, 2007, 08:12:42 AM »
I've heard USB-connected streams are very dependent on the quality of the soundcard.  Because of this digital path, I also have the impression that USB streaming has other obstacles to overcome to achieve greatness.  It can be done cheaper though.

And, I might be full of hot air.  I only sort of understand how my SB works and my technical understanding drops sharply from there.

Offline bpape

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Why are these players so good?
« Reply #6 on: February 11, 2007, 12:05:43 PM »
Look at it this way - the audio digital transmission methods are one way only.  PC networking is a 2 way communication method where each and every packet is checked and verified at the other end to be the same as what was sent.  If it's not, it's resent.

That mininmizes the issues to getting a bit perfect copy on the hard disk, and getting it from the hard disk to the network card - and then of course decoding it at the other end.

While the error correction in audio is pretty decent, it's far from perfect. It's really just very very good at guessing.  I don't want my audio equipment or my doctors guessing...  :lol:

Bryan
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Dougie085

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Re: Why are these players so good?
« Reply #7 on: April 18, 2008, 05:26:07 PM »
Music played from a hard drive is still not 100% jitter free. Currently I use my HTPC with a USB DAC I built and the sound is far better then any CD player I could possibly afford in my life time. Sounds better then my friends Cambridge Audio Azur 640c as much as I can remember anyways. And definitely kills any sound card I've used. Of course I've never used any of the high dollar sound cards but my DAC has only costed me about 350 bucks so far and I would put it against the Benchmark DAC1 any day.