Getting The Most From My Current System
Dear Gary: I was just reading Richard Hardesty’s article about DVD-Audio and am interested in getting some answers to some questions. I was hoping you or someone from your staff could help. The questions aren’t necessarily DVD-Audio related, but the article got me thinking about several questions that have been in my head for some time that I can’t seem to get answers to. I don't consider myself an audiophile—just an enthusiast, but I want to get the most out of what I have and am willing to spend some money on upgrades that make sense. What I’m looking for is practical advice as to how to get the most out of my current equipment, and if considering an upgrade, what makes the most sense. Now that I have upgraded my speakers all around, I’ve been thinking about how I would upgrade my receiver to either 1) a new receiver or 2) separates. I’ve struggled with determining what the best choices would be in the $5,000 range or less. As I think about each, I have some questions and so far have had difficulty getting any answers. If CDs are encoded in 16-bit, 44.1kHz resolution, can a receiver that has better DACs upconvert the signal to a better quality? I understand I would have to use a digital connection between the CD or DVD player to access the DACs in the receiver. I really didn’t want to replace my current $250 CD player with an expensive CD player that has good DACs (especially with DVD-Audio and SACD on the horizon). Instead, I was thinking about getting a processor that has good processing and conversion capability (certainly better than my current Harman Kardon). Denon talks about their AVP-5800 with its 16 DAC channels, two DACs per channel for surround modes, reconfigureable to 4 DACs per channel in “pure-direct” mode. They claim the DACs are 24-bit, 192kHz capable, but I’m not sure what this all means. Does this mean that the signal coming from my CD player is 16-bit, 44.1kHz and gets some benefit from the DACs in the Denon? Or am I limited to the digital signal resolution coming from the CD player? Similarly, the DVD player is 24-bit/96kHz capable, but is it doing anything different than the CD player if they are both connected to the receiver via a coax connection? Some people say the Denon can upconvert the incoming digital signal, and others say the source component sending the signal is the limiting factor. Does new conversion technology (i.e. 24-bit/192kHz) help older encoded CDs, or do I have to purchase CDs, DVD Audio and Video discs, etc. that are encoded in higher bits and resolutions? I know I've asked for a lot in this e-mail. I certainly appreciate any time you or others in your group can take to help me sort through some of this. I would like to upgrade to a new receiver or separates that would do a better job of processing and amplifying than my Harman Kardon, but I need to know, technically, if I can expect to see much improvement over what I currently have. Answers to the questions above should help me understand what I need to do to get the most out of any potential upgrade, or should I wait to do anything because what I have now is pretty good? I only want to spend money if I can get a real improvement over what I currently have. And I would love to know if there is anything I should do to get more out of my current setup.
Chris Gough,
Audio Equipment Review Editor Richard Hardesty Comments:
There aren’t any simple answers to your questions, and you’ll have to do a lot more reading to fully understand the complete picture. I’d suggest that you read my digital controller series in WSR for a start. Here is some information that may be of help: The sample rate of the LPCM digital data on a CD is 44.1kHZ and the sample size is 16 bits. Playback fidelity can be substantially improved by using digital-to-analog converters (DACs) with resolution exceeding 16 bits, but an explanation of why this is true is complicated. (You’ll hear the difference.) LPCM data on DVD-Video discs can have sample rates of 48kHz or 96kHz, but multichannel soundtracks are encoded in a compressed [data reduced—Editor] format—Dolby Digital or DTS. Dolby Digital and DTS bitstreams must first be decoded and then converted to analog, and the quality and resolution of the DACs that perform this conversion will affect sound quality. You can read about this in the controller series. Sample rate conversion is possible, but none of the products you mentioned in your letter perform sample rate conversion. A receiver or controller that can accept sample rates up to 96kHz will not necessarily convert a lower sample rate to a higher one. 96kHz-capable means just that. Capable of accepting sample rates up to 96kHz. Some newer DVD players, like the CAL CL2500 DVD, upsample digital data recorded at 44kHz or 48kHz sample rates. Many earlier DVD players downsample higher sample rates to 48kHz. Sample rate conversion has no affect on Dolby Digital or DTS bitstreams. Amplifiers are important and you need one that can comfortably drive your speakers, but no amplifier can replace information that the source component didn’t retrieve from the recording, and no loudspeaker can reproduce information that was lost in the processor. All components in your system must be of comparable quality for the best results.
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