Things have changed ....

[maxg]

About 6 or 7 years ago I bought a Denon 3000 DVD player that has been with me ever since.

It was a Generation 1 player that pre-dated DTS and such like but it played both DVD and CD well enough for me at the time.

Since that time a Sony NS900V has been and gone, through a brief flirtation with SACD, and I have settled into vinyl now and potentially forever.

This morning I was in one of those hardware hypermarket things that sell everything except food it seems.

Sitting in the middle of the electronics section was a huge pile of various DVD players - all from manufacturers I had never heard of. The thing that got me was the prices - they started at just over $70!!!

Now when I bought the Denon, if memory serves it was nearer $1000. Things have definitely changed.

Anyway I browsed through the various models at this cheapest of all pricepoints. Most were obviously limited in one way or another - no optical out, no decoder, nasty connectors and so on.

One, however, did not appear to be missing anything. Full DD5.1, DTS, Optical and Coax output, plays every kind of disc on earth bar DVDa and SACD (more on this later) and at the same price point of around $70.

For reference the make is "Comet"???!!!

What the hell I thought - how bad can it be?

So I bought it and installed it in place of the Denon.

I am amazed. Cd playback is eminently acceptable. A bit softer than the Marantz CD6000 but not massively inferior. DVD seems fine (although I have no way of testing out the optical and Coaxial connectors). It does sport the full compliment of outputs so I could connect to to a couple of other amps I suppose (for rear and centre), but in 2 channel mode it is fine.

Reading the somewhat hilarious manual - obvously written by someone with English as a third language at best - it seems the unit will play a lot of stuff.

Having tried DVD and music CD I then tried a Video Cd and it worked very well, then I tried a CD with about 4 hours of MP3 and that too, worked well (quality not near as bad as I was expecting either...).

To my amazement it even reads CD's with photo's on them. I put in a CD with a fairly complex directory structure with long file names and varying resolutions from 3.3 Mpixel down to about 800*600. The unit flicked through them with an admirable nonchalance.

Of course they dont look at their best on a TV but you can see them perfectly clearly enough.

It even found some MPEG 1 files (movies) I had taken on my digital camera (not digital video camera) and played those too.

Hell - for all I know this thing will read word documents.

Not bad for $70....

[itsmyforte]

what store was this at? I would like to see this model for myself. you said the maker was COMET?

[justin_tx_16]

He is in Greece (right?) so if you are not, that may be a problem.

SACD/CD/DVD/DVD-A/PCD wow!

[maxg]

Yes - I am in Athens Greece so I dont know how much use the store will be to you. For what it is worth the store is called Praktika and is, I think German owned.

One thing from Justin's comment - it does not play SACD or DVDa - just everyting else seemingly on earth that comes on a little shiney disc.

BTW - how much music can you get on a single CD in MP3 format???

I reckon I have got about 5 hours (126 songs) - this is going to be great for parties - and tantric tricks.....

[eq_shadimar]

For those of you in the US looking for something like this try an APEX unit. I have one in my bedroom that does it all too (no DVD-A or SACD). MP3's, JPEG, Kodak Photo CD's, MEPG 1, Music CD's etc.. Cost was $55.00 at Circuit City. I don't have a system in my bedroom yet so I use it to play CD's and MP3's through my TV speakers. The drawer and remote are kindda clunky but work.

Funny thing was that they wanted to sell me a 3 year service plan for $90. I said no I would just buy another one if this broke.

Laters,

[Deang]

I thought the same thing. The Comet sounds like the Greek version of the Apex.

[justin_tx_16]

"One, however, did not appear to be missing anything. Full DD5.1, DTS, Optical and Coax output, plays every kind of disc on earth bar DVDa and SACD (more on this later) and at the same price point of around $70."

I thought that meant is played DVD-A and SACD. Oops.

You can get that amount on there easily (mp3 cd). But it really depends on the quality of the MP3 as far as how many you can fit. Most all of mine are 320kbps, if not then no lower than 160 with the vast majority <320 at 192.

[maxg]

320??? Isnt that higher than native CD? I seem to remember that CD is rated at 300kb/s...

I think that these are at 128 Kb but I cant be sure..

[ben.]

I'd rather watch S-VHS than the crap picture Apex puts out. Then again, my VCR cost a lot more than $50!!

[Ray Garrison]

RE CD data rate (courtesy of MAC Audio News No. 159, March 1988, pp 16-17)

Data is recorded on the disc as the presence or absence of "bumps" along the continuous spiral track. This binary information is serially read from the disc in groups of 17 bits. Run-Length-Limited encoding requires that the binary state transitions can only occur every 3 to 11 bits. This lowers the maximum recorded frequency and eases the tolerances required for the playback hardware.

Some numbers: The basic bit rate is 4.3218 MHz or 231.4 ns. The highest recorded frequency, with a minimum period of 6 bits, or a transition every 3 bits, equates to about 720 KHz. Likewise, the lowest frequency is about 196 KHz.

Of the 17 bits, 14 contain meaningful data. Given the transition period constraint, there are only 267 binary data patterns of the possible 16384 that are usable. 256 of these have been chosen to correspond to each combination of an 8 bit byte. This is where the term EFM (Eight-to- Fourteen-Modulation) comes from.

To simplify the design of the data separator, the average DC content of the signal is kept to zero. Behold the purpose of the remaining 3 bits. This period may or may not contain a transition, to restore the DC balance of the recorded signal up to that time.

So, every 17 bits recorded generates an 8 bit byte of decoded data. This is a data bit rate of 4.3218 x 8 / 17 = 2034 KHz. Not bad, considering the range of actual recorded frequencies stated earlier!

The 17 bit symbols are grouped in blocks of 33. To enable the player to synchronise and read the symbols, each block is preceeded by 3 transitions separated by 2 periods of 11 bits. This unique header pattern cannot appear as data within a block. This makes a total block length of 588 bits, lasting 136 us, or 7350 per second, and uses about 0.2 mm of a track.

In each block, the 33 data bytes of 8 bits each are broken up as 1 sub- code, 12 odd-audio, 4 Q-redundancy, 12 even-audio and 4 P-redundancy. As a quick check, there are 2 x 12 x 8 = 192 audio bits in each block, or 6 stereo samples of 16 bits. Multiply 6 by the block rate of 7350 and you get 44100. The magic sample rate! You should now all be able to go away and start decoding the data bytes of your favourite CD under any handy electron microscope.

The real-time audio samples are not stored in blocks in the order they occur. All the sample bytes are convoluted in a complicated interleave algorithm that takes 6 stereo samples of 24 bytes and spreads them over 109 blocks. This is a period of about 15 ms, or about 18 mm of track.

The interleave algorithm also generates two types of redundancy information, called P and Q. They are used to detect and correct both random bit errors in data bytes and burst errors of hundreds of successive bits.

When recording the CD master, the 24 data bytes that make up the 6 stereo samples are fed in parallel to the algorithm at the block rate. The 12 bytes of the even samples are first delayed for processing by 2 blocks. The "C2 encoder" then produces 4 extra bytes of Q-redundancy, making a total of 28 bytes. The 28 bytes are then each given unequal delays, ranging from 0 to 108 blocks, in multiples of 4. The "C1 encoder" then produces 4 extra bytes of P-redundancy from the 28 bytes. Because of the unequal delay before the "C1 encoder", the 28 bytes used are actually from 28 different "C2 encoder" generated byte sets.

There is now a total of 32 bytes; the next step merely delays alternate bytes by one block. The final step inverts the 8 P and Q redundancy bytes, so that these will be non-zero when the audio samples are zero. The resulting 32 bytes, plus 1 sub-code byte, neatly fit into the 33 byte block.

[itsmyforte]

well i was wanting a cheap DVD/CD player with an optical output. I am going to build a super quality DAC to use with a digital output. i don't care about picture quality, this will be audio only. When you described the COMET unit, it sounded like an Apex unit, and probably is the same thing. anyone have any bad experiences wiht apex units?

[Gregorius]

My brother bought an Apex DVD at Walmart, and it died after a year. He had to take it apart to get the DVD out. My Toshiba cost $150 @ BestBuy and is still going strong almost 3 years later. Of course it sounds like crap on CD's.

Greg

[Deang]

Ray -- I hereby Christen you "Walking Encyclopedia". Please change your moniker at your earliest convenience.

I feel my brain shrinking and expanding.

[J M O N]

You can get a Toshiba at Sam's Club for something like $67. Probably not the greatest in the world, but I'd bet it'd be better than the APEX. I have the 5-disc version that now sells for around $99, and I've been quite pleased with it for both movies and music.

[maxg]

I dont know the Apex unit so I cant tell you if the Comet is the same or not. Comet do have a site (www.comet.gr) but they do not have an upto date picture of the DVD player - mine looks nothing like the one shown.

I will try to snap some pics of the thing so you can all see. In the meantime I can tell you that is does have a rather cool drawer for the disk. Instead of the front section that slides out being part of the drawer it is a separate little door that drops down for the tray to slide out. I have no idea if this is better or worse or simply different from the norm but it looks pretty cool to me.

One other clever thing. the numbers on the remote control are shaped like numbers - makes it mush easier to find them in the dark.

Oh yes - I think I underestimated how much music I have got on one disk in MP3 format. I played 4 hours yesterday and as on track 55 out of 120. This could take some time.