on audio conversion and converters

Hi

First of all a question...

I understand monitor latency when i am recording as the time it takes to make the whole AD DA process (I am monitoring through patchmix dsp not through the daw). but i dont understan really well what latency is about when i am just playing back recorded tracks... i mean, then latency is the time between what events?

second, what others high end converters are there? I know about lavry... why do you think they dont get as much buzz as apogee? are they more expensive? how do they compare to apogee?

In addition to your hardware (AD/DA converters) which has i/o buffers that may or may not be adjustable, your DAW software has buffers as well. Set to the tightest tolerances, your software's buffers will likely match tht of your hardware.

BUT there are many times we want to increase the buffering in our software -- say when there are demanding plug ins, a whole lot of tracks, CPU-sucking virtual instruments, etc, that can slow down the through the CPU journey [waiting for plug-delay compensated plugs and VIs, or just dealing with processing a huge amount of tracks. Increasing DAW buffer size can keep your system from "running out" of data feeding the DA converters at the appropriate data rate to "keep up" with the digital audio -- resulting in the infamous "clicks and pops" that occasionally plague so many of us.

With re high end converters, there are a number of outfits out there in the tier around Apogee.

You hear about Apogee because they spend a lot of money on marketing.

You hear about Dan Lavry because he is a living legend -- not to mention someone who does not shy away from controversy when people and companies make marketing claims that defy science -- and because his VERY EXPENSIVE converters are favored by some VERY high end facitilities.

But since Lavry's converters can cost as much as ten times what Apogee's converters do... not to many of us Joe Sixpack types typically lay hands on his top end stuff.

I won't weigh in on who's got the best converters because while I've heard my share of Apogees I've never sat down for a good listen to Lavry's.

But I will say this, when Apogee was just a filter designer looking to get into digital audio, Lavry was one of the people they went to design their first converter products. There was a subsequent falling out and it's VERY safe to say there is just about ZERO love lost between the two companies.

It seems to be that in Lavry's view -- and the view of a number of other scientifically grounded observers -- Apogee walks a thin line (or crosses it) when making certain claims about some of their products.

You may have noticed that in the latest Apogee Big Ben (external clock) adverts that they have "celebrity endorsers" making some very unscientific claims for the "benefits" of using an external clock source with AD converters.

Science dictates that a single modern, professional grade converter will have the least jitter when working from its own internal clock. Using an external clock source in a star topology MAY well be more convenient than the sometimes tricky business of getting a daisy-chain of converters working properly together, but it will likely mean MORE jitter than the same converters running from the lead converter's internal clock (in a properly set up system).

Now -- what about those celebrity endorsers in the magazine adverts or all those proud Big Ben owners who gush about their "enhanced definition and stereo soundstage, depth of field," etc?

Both Lavry and a recent whitepaper from Digidesign have laid out very straightforward factual arguments putting the lie to any claim that an external clock on a modern, pro-grade converter will "improve accuracy."

And both of them have gone on to wonder -- not necessarily with tongue in cheek, either -- if perhaps the people who claim such noticeable subjective improvement simply LIKE the sound of increased jitter.

As Lavry often says: if you talk about sampling accuracy that is a scientifically measurable proposition and science has weighed in on the side of internal clocking with regards to maximizing accuracy.

OTOH, if you say you LIKE a given sound -- who CAN argue with what you like?

Yeah... some other feel silly after spending more than a grand in a device that "just" sends ticks to their gear, and they dont hear nothing... so they have to claim the do