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I appreciate the questions, but I apologize in advance if I can't answer them all in a timely manner.
USB vs. TRANSPORT: Its a broad comparison, but it really depends on which transport, which USB audio device, and which DAC. If we're talking about the DAC1 USB, they will all perform equally well. A high quality transport will induce less jitter (notice I said 'high quality', not 'expensive'), but the DAC1 is truely immune to jitter. When it was designed, a test signal with TONS of jitter purposely added was used to really test the limits of the DAC1. And, quite literally, there was no performance degradation. With all that being said, a high quality transport will offer better error correction for disc errors. If the DAC1 is used, the only reason to spend money on a high quality transport is for better error correction. The USB solution, however, should be every bit (excuse the pun) as stable as a good transport, provided the harddrive isn't too fragmented, etc, etc.
SPDIF vs. OPTICAL: This is also a broad comparison, and I would say it depends on which interface you are using. I wouldn't say that one is universally superior to to the other. However, with regards to the jitter with these interfaces, as mentioned before, it is not a concern with the DAC1.
I do most (98%) of my listening through studio monitors (JBL 6332, Tannoy Reveal 6, and K&H 4-ways). I hope my lack of headphone experience doesn't disqualify me from this forum .
The headphones we have here at Benchmark are the Sennheiser 650 and 600's, as well as a few different Ultrasone's. At the recording studio where I work, we have the AKG K 240's and Sony MDR7509HD's.
SPDIF vs. OPTICAL: This is also a broad comparison, and I would say it depends on which interface you are using. I wouldn't say that one is universally superior to to the other. However, with regards to the jitter with these interfaces, as mentioned before, it is not a concern with the DAC1.
Can you give us any recomendations about which USB interface we should use. (SPDIF and/or Optical)
I think this is the key question and we end users get very limited reliable information.
Can you give us any recomendations about which USB interface we should use. (SPDIF and/or Optical)
I think this is the key question and we end users get very limited reliable information.
As for a specific product, I don't feel comfortable recommending one because I'm not sure what our company policy is with that regard. It's a fair question, but its one I don't know how to answer fairly. Please forgive me.
As for a specific product, I don't feel comfortable recommending one because I'm not sure what our company policy is with that regard. It's a fair question, but its one I don't know how to answer fairly. Please forgive me.
What I understood from your postings are, we should choose the interfaces that uses native usb drivers.
This is theoretically true, but USB wasn't really built for steady streaming, even in Isochronous. When you watch the stream on a bus analyzer, it becomes apparent.
I think what happens is...USB activity is sort of a queued process, and follows the queue with relative prorioty, etc. Therefore, when other activity takes priority, USB activity is compromised.
I wish I knew with certainty, but even the most official publications on this will disagree with each other!!
Nonetheless, USB audio does suffer from 'ticks' and drop outs, which, for whatever reason, is due to insufficient streaming capabilities. When developing the DAC1 USB, we put several "checks" and buffers into place to monitor the stream and prevent these errors from occuring. We played audio through the DAC1 USB while taxing the processor of the computer with other apps, etc, and we couldn't get the DAC1 USB to tick or pop.
Does this mean that you are using asynchronous USB protocol for Win2000, XP and Vista?
It's always great to have a company stand behinds it products but some of what you posted here differs a bit from my experiences. So let me question some of the statements you made in order to avoid any confusions on this forum.
1. If your sound card driver uses kmixer than the bits will get altered even if only a single stream is playing. What procedure did you use to test this otherwise? You'd be the first to come to a different conclusion.
2. The Windows standard USB driver uses kmixer and any USB audio device using the standard driver will not work bit perfect unless you use kernel streaming. Vista which does not have kmixer anymore uses a different mixer but is still not bit perfect. Is Benchmark shipping with a different USB driver?
3. I was also intrigued by your statement of a clock recovery system in the DAC1. Is that a new feature in the USB model. As far as I understood up to now, the DAC1 does not use any form of clock recovery at all but is using an AD1896 asynchronous sample rate converter running at a fixed frequency. While that reduces jitter is also changes all the samples in the process and therefore the DAC1 never actually plays bit perfect. Is that not correct?
I do most (98%) of my listening through studio monitors (JBL 6332, Tannoy Reveal 6, and K&H 4-ways). I hope my lack of headphone experience doesn't disqualify me from this forum .
The headphones we have here at Benchmark are the Sennheiser 650 and 600's, as well as a few different Ultrasone's. At the recording studio where I work, we have the AKG K 240's and Sony MDR7509HD's.
Since you guys primarily use Senns, you obviously have a good ear and taste Must be why I like the DAC-1 with my Senns. Grados aren't so bad either As a Benchmark owner, this is proving a gread thread to read. You're certainly more then welcome here to provide insight on the specifications of Benchmark products. Welcome to the forum, Elias!
Dave
__________________ Home Rig/ Digital: Music Hall Maverick SACD>Benchmark DAC1>SinglePower PPX3 SLAM Home Rig/ analog: Music Hall MMF-5>NAD PP-2>SinglePower PPX3 SLAM Portable Rig: Sony D-555 Discman>HeadRoom Microamp Photo-Fi: Canon 5D, Canon 135mm 2.0L, Canon 70-200mm 2.8L, Canon 100mm 2.8 macro, Canon 50mm 1.4, Tamron 28-75mm 2.8, Canon 580EX flash Headphones: HD650(silver dragon), SR325i, HD595, HD580 (modded), k501:Sold....just not into AKG
With all that being said, a high quality transport will offer better error correction for disc errors. If the DAC1 is used, the only reason to spend money on a high quality transport is for better error correction. The USB solution, however, should be every bit (excuse the pun) as stable as a good transport, provided the harddrive isn't too fragmented, etc, etc.
an option is to play your music from the RAM rather than from the HDD. Foobar can do it: buffering option
and of course rip your file with EAC in secure mode to a lossless format.
if you do it this way I doubt a CD transport would be better.
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Linear Mode
