Help me understand the CD Player

 

New member
Username: Crl21

Ann Arbor, Michigan USA

Post Number: 8
Registered: Mar-04
I'm new to hifi and I'm trying to understand why the CD player in the system would make a big difference. It is very clear to me why the receiver and speakers would impact the quality of the system, but I can't quite understand the CD player. Here's my thought process. If a CD player is hooked up with a coaxial cable or optic cable, the CD player is simply sending the receiver 1's and 0's. If a CD player can do that, then anything above that is just bells and whistles right? Help me understand this. Thanks.
 

Bronze Member
Username: Two_cents

Post Number: 24
Registered: Feb-04
Chad,

I can't give you the scientific explanation as to why CD players make a difference but they certainly do. I think the quality of the Digital-Analog Convertor and the disk transport among other things will affect the sound that is ultimately produced. When I started getting interested in hi-fi, I used to think that there couldn't be that much of a difference between low-end and high-end cd players for the reason you stated. But then I went to a stereo shop and listened to a NAD cd player and it was definitely better than the Sony player I had been using. Then I compared the NAD and a California Audio Labs player and found the CAL player to be even better. It produced a warmer, more musical sound to my ears. The old Sony was harsh, brittle and cold compared to this. I ended up getting the CAL player for more money than I expected to spend (a common occurrence in the hi-fi world). I'm pretty excited for you because you're just starting out on your hi-fi adventure. There's a lot of fun to be had as long as you don't get obsessed.

BTW I would use rca audio cables to connect the cd player to the receiver, not digital coax or optical.
 

Bronze Member
Username: Invierno

Post Number: 12
Registered: Feb-04
What would be the reason to use the analog audio cables as opposed to a digital coax connection, as long as the receiver has good DAC's? Doesn't it just give you more of a chance to lose information with two analog lines (cd to receiver, receiver to speakers) instead of just the speaker wire?

I ask because I'll have a NAD T533 DVD player hooked up to a NAD T773 -- both have good DAC's, and I was considering only using a digital connection.

Does the CD player do something else before creating the analog signal in these cases?
 

Silver Member
Username: John_a

Post Number: 343
Registered: Dec-03
The tracks on a CD or DVD contain information stored in digital form - 1s and 0s. Sound is analogue. So at some stage there has to be a DAC - a digital-to-analogue converter. If you connect your CD/DVD player to a receiver with digital connections, the player is working as a "transport" and digital readout device, and the D-to-A is happening in the receiver. If, however, you connect with analogue connections, the D-to-A is happening in the player.

What difference does it make? For stereo, in most cases, none. Unless one unit has DACs that are markedly inferior to the other. In that case, use the better DACs to get better sound.

Now, for multichannel sound, such as 5.1, in DTS or Dolby Digital AC-3, there is a DSP (digital signal processor) in the path, somewhere, too. It works only on a digital signal. The T533, for example, has a DSP for DD AC-3 but not for DTS. So you still have the choice of digital or analogue interconnects for DD AC-3. But DTS has to be handled by the DSP in the receiver, so digital interconnect is the only way to get DTS.

For DVD-Audio, the DSP has to be in the player, not for technical reasons but for "format rights agreements" or something. So you have to use the analogue connections to get DVD-A.

If you use surround formats such as Dolby Prologic or NAD "EARS", these take place in the receiver, and also require a DSP that needs a digital signal to work on. If you give the receiver an analogue signal, it first has to make it digital with an analogue-to-digital (ADC) converter. After processing, the signal has to be made analogue again, using a DAC, for subsequent amplification. So you will notice a better sound if you miss out that ADC stage and use only the digital signal from the player. Try it!

The basic approach is to use the smallest number of ADC and DAC steps you can get away with. Each step degrades the sound. If the quality of the converters is really high, and, say, the speakers are not so good, then you may not notice.

Chad, you are correct, but even when the CD player is used just as a transport and digital readout, there are quality issues in how well the player can do that, and the bandwidth of the digital signal it can reproduce.

Invierno, I have my eye on a T533, to replace my T532, and get true DVD-A. How is it?
 

Bronze Member
Username: Invierno

Post Number: 13
Registered: Feb-04
John A,

The T533 is showing up this week. I'll be comparing some existing recent CD's with their (supposedly well done) DVD-A counterparts and a mix of DVD-A classical. I'll post my comments on it once I get a chance to listen for a little while.

BTW, from the T533 manual, they do have bass management for DVD-A, with speaker size, distance, and channel controls, which is great. However, the manual states (well, strongly implies) that 100Hz is the non-changeable cutoff for the sub, which isn't so great.
 

Silver Member
Username: John_a

Post Number: 347
Registered: Dec-03
Invierno,

Thanks.

I listen to DVD-A discs in DTS mode at the moment. The ones I have sound really fantastic. I recommend the Naxos DVD-A classical releases, about 10 so far, see e.g. March 13 post on SACD or DVD-A - which way will the industry go.

Yes, I saw the T733 has its own Dolby AC-3 and DVD-A processing and settings. Really speaking, with DVD-A, like DTS, you do not need a sub crossover, because the five main channels are ideally full-range, and then the sub just reproduces whatever the recording engineers decided put on the ".1" track. If, however, you choose to redirect the main and/or surround LF to the sub, then, yes, it is maybe good to have some control over the frequency at which that happens. But 100 Hz is not a bad shot in most cases. That fixed figure would not disappoint or deter me. What I could do with is channel delays for DTS. I have to sit equi-distant from all speakers. My wife thinks I am crazy, and it is not very sociable, but it hugely improves the 5.1 sound.

Yes, please post back with your impressions. Where I am, the T533 is the same price the T512 was a year ago: I doubt if I'll get much for my nearly-new T532!
 

Bronze Member
Username: Invierno

Post Number: 14
Registered: Feb-04
BTW, any suggestions for good (without being insanely pricey) analog interconnects for the 5.1 connection from the T533 DVD-A player to receiver? It's amazing how expensive some of the interconnects are and I would expect some manufacturers to start carying SACD/DVD-A bundles for somewhat better prices.
 

Silver Member
Username: John_a

Post Number: 350
Registered: Dec-03
Invierno,

All you need is a secure electrical connection between 6 pairs of RCA terminals. That is three stereo pairs. The cables should be as short as possible. 0.5 meter or 1.5 foot. 1 meter/3 foot is the longest you will need for a normal set-up. The best place to buy cables is a "hobby" electrical and electronic shop (e.g. in US "Radio Shack" or equivalent), where you can usually buy the cheapest line with confidence. Step up from the cheapest, to ones a bit thicker with gold-plated RCAs, and they may make more secure contact with the terminals, but still should still not cost more than a few dollars/euros per pair, and they won't sound any different. Specialist Hi-fi dealers and even domestic electrical/electronic retailers sell insanely over-priced interconnects, that are unnecessarily long. They never improve the sound. This is controversial point of view, as you will see from other threads. But not with electronics engineers, all of whom regard "audiophile" cables as a complete waste of money.
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