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In Reply to: Re: Lynx and RME cards. posted by Dawnrazor on April 17, 2007 at 13:59:22:
Dawnrazor:I spent $80 on a Dynex 7.1 Channel soundcard based on the C-Media 8768. No ASIO at all, of course.
I spent $125 on a M-Audio Revolution 7.1 based on the Envy24HT chipset. No digital out under ASIO but WAY better DAC sound than the Dynex. The AK4358 8 channel DAC
2-channel DAC (fronts)- AKM AK4381 24-bit 192 kHz (THD+N -94 dB, DR 108 dB)
6-channel DAC (surround)- AKM AK4355 24-bit 192 kHz (THD+N -90 dB, DR 106 dB)
I then spent $125 on a Creative X-Fi because it had ASIO SPDIF. I gotta admit, I got this card because I truthfully though I was going to return it like I did the Audigy 2ZS (resampling issue). I was actually kind of shocked. I am really impressed with this card. In Audio Creation Mode / ASIO mode, this card really sounds good and the ASIO drivers work really good too. Channel mapping is very flexible.
The CD4382 8 channel DAC gets (THD+N: -100dB DR: 114dB)
>>>Enter Lynx: (THD+N: -104dB DR: 117dB) [Boo-ya!]
And we all know that DAC specs are just that: DAC specs. Build quality, OP amps, cap quality and board layout all contribute to the final sound.
I would like to get the Lynx 2B as a "long term stopping point" until I can afford to put together my "extreme" digital front end with all this "studio grade stuff operating in synchronous mode".
I am still using a decent (but admittedly upper-mid-fi) HT receiver for my "6 equal channels" of amp power. I only have high-end stuff (SET 300B, 6L6 tube amps etc) for two channel. But multi-way is just so much of an addiction for me right now, especially now that I am getting the hang of DSP room correction (DRC) and Thuneau's Allocator and Arbitrator. I'm running some JBL2441's as mids right now, and after some digital EQ, they sound pretty darned good - and quick too. They keep up to tweeters quite nicely. You can't use just any woofs with these - they need to be able to reach up and past the 600Hz lower usable limit of the 2380 lense. It's amazing the PRAT you can get when you digitally time align and do some EQ. That's why I like the Thuneau Allocator/Arbitrator - it has crossover functions, EQ functions and phase correction all in one VST plugin.
I guess I am afraid to get the Lynx2B because I might end up stopping there like so many Lynx 2B owners have. Then again, what's wrong with that?
Follow Ups:
Presto,You are way smarter, so I don't know if you can say I am so lucky. I WILL be calling on you one day to help me with DRC. I had planed to use the ACXO player's built in DRC, but it is really hard to have a player that can't do playlists and even fast forward...
The Lynx is goood, and I think it is the knee of the curve. I don't doubt that it can be bettered, but I think you have to spend significantly more money as your list proves. ( Hey, you could take Christine's recommendation for the Emu and get 3 for a similiar price of the 2b, buying them one by one when you can afford it.)
But I do wonder if the $1800 might be better spent on speakers or amps, etc.
In my case it most definately would be better spent in speakers and amplificaton, or a pc that can upsample with SRC higher than 44.1....Please tell me that upsampling is unecessary and that Gordon is right on this!
I'm just tenacious and persistent to a fault! ;o)I did dozens of iterations of the DRC process only to find out I was doing it wrong. Now I am slowly trudging up the learning curve of how to understand it enough to make good use of it.
Christine and others make good points. Clocks are a P.I.T.A. It seems that the best way still might be to have the clock really close to the transport, and slave the transport to the DAC clock, which is in close proximity to the DAC. She also makes a good point about sync lines, and whether or not they employ a PLL. If they do, the only advantage to running the clock in a separate wire would be for distribution purposes. Since we're only going from a to b, this is not an advantage, and the clock can remain imbedded in the data stream.
I really need to do a lot more "learning" and reading about digital audio to understand all this stuff.
I also want to read up on the Lynz "syncro-lock" and what that is all about. Maybe there *is* no advantage (with the Lynx AES16 to Aurora 8) to run a independent sync line and slave the AES16.
Seemed like a good idea. Oh well.
I'll talk to this Tuckers fellow as well. He apparently owns both products!! :o)
The *less* circuitry and wires that you have, the better the end result. Complicated design just adds more opportunity to introduce jitter.What I'm looking for (which I haven't found yet) is an external multichannel DAC that has the following features:
- MUST use a *current generation*, flagship DAC chip (ie. BB PCM1794, AKM4396 or CS4398) capable of exceeding 120dB
- dedicated and switchable 44.1 and 48 clocks (NO PLL)
- located as close to the DAC chips as possible (to minimise EMI sensitivity)
- no upsampling
- The digital signal comes in ASYNCHRONOUSLY (ie. "unclocked") and gets clocked by the DAC itself - this can be a simple memory buffer but care must be taken that the wait states are consistent and predictable - static RAM would probably be betterUnfortunately, that rules out just about every DAC unit out there on the market today. Can't use Firewire - too much jitter. The only interfaces I can think of that supports asynchronous (other than proprietary ones) are USB and Ethernet. USB async mode is buggy in Windows XP, and Ethernet introduces too much latency.
So far, the only device that come anywhere close to the ideal (but still not perfect) is the E-MU 1820M, which uses a proprietary shielded (STP) cable to communicate asynchronously between the 1010 PCI card and the external AudioDock. Unfortunately the external unit also draws power from the PC via the STP (but I suspect E-MU wanted to minimise ground loop issues - as far as I can tell from looking at the board layout these guys are pretty smart and know what they are doing)
The only USB async device I've found is the Edirol SD-90, which uses a proprietary asynchronous USB driver written by Edirol (unfortunately, the unit only supports 44.1 and 48kHz sampling rates, and requires a "reboot" to change sampling rates). ThomasPf says the Audigy NX also supports async, but not sure whether Creative has written a proprietary async driver. Neither of those contain flagship DAC chips.
I would also include the Slim Devices Transporter (Ethernet connection, proprietary protocol) but only 2ch.
I'm thinking it should be possible to produce something similar to the 1820M, but using USB2 async and a proprietary driver (or the standard driver in Vista), and preferably using BB PCM 1794 in differential mode (or AKM4396). And externally powered. Such a unit should not cost much more than an 1820M, in fact potentially should be cheaper than a 1820M (if it is a DAC only and doesn't include ADC).
If you know of something like this, let me know. I think the problem is very few people (apart from myself) would buy such a unit. The market is obviously selling overpriced and overengineered SPDIF DACs to well heeled audiophiles. :-)
If I have spare time on my hands, I would build it myself. Unfortunately, I don't, so I keep hoping someone else would do it for me.
Chrstine,the Edirol UA101 is using USB2 and their own driver (at least on Mac), I am using it (and sometimes a TCElectronic Konnekt as well) with my Macbook and Altmann DAC, and it is as good as it gets. I do not remember exactly on what forum, but on one of the professional forums I read it is using async USB2 communication.
Most of the pro audio interfaces, eg. Digidesign Pro Tools, Lynx, RME, uses a voltage controlled oscillator (VCO) as a clock, rather than fixed frequency crystal oscillators (XO).The reason for doing this is so that sampling rates can be easily changed "on the fly" - a pretty essential requirement for pro audio.
However, VCOs are inherently more susceptible to jitter than XOs. They are very sensitive to logic induced modulation, and "drift" over time unless controlled using a PLL.
A device that accepts word clock in is effectively using the clock input to drive a VCO, and using PLL to compare the output with the input. This is less effective than syncing a VCO to an XO (which is what the "internal" clock does).
But using XO driving a DAC directly delivers better results than VCO.
Another technique is to use a "clock divider". This is common with DVD players, which generate a 44.1 or 48 audio clock based on the 27MHz master video clock. This is also not as effective as using fixed frequency XO.
XOs are also unstable (can drift based on temperature) but less so than VCOs. The main disadvantage is that they are fixed frequency, which means to change between 44.1 to 48 for example requires switching to a different XO.
This is not as easy as it sounds, because the DAC effectively needs to be "rebooted" when the XO is switched. This is why most devices that uses switchable XO requires a power cycle to change sampling rates (eg. my Edirol SD-90).
The E-MU 1820M is one of very few devices out there that uses switchable XOs but allow sampling rates to be switched on the fly. E-MU does this through very clever design, but even so it's rather cumbersome (effectively, they do a reboot of the DSP - they also mute audio outputs during the process so that you don't get a "screech" as the DAC resets).
So I should probably clarify, I'm really looking for a DAC with switchable XO rather than VCO. Unfortunately, that eliminates most of the DACs on the market.
nt
Uhmm, you *can't* get 3 1820Ms for the price of a 2B.First of all, it's discontinued. Secondly, it was retailing for $499, and i've never seen it substantially discounted.
And i'm not sure why you would want *3*, since a single 1820M has 6 channels analog in, and 8 channels analog out. In any case, you can't use all 3 in the one PC.
If you are thinking of the 1212M, you can't use more than 1 in a PC either. In any case, there's not enough slots (each 1212M consists of 2 cards, so 3 would require 6 slots).
Hey Christine,I was thinking of the 1212, but forgot about the daughter card. Thanks for keeping me straight.
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