[geezer]

Like you, I am using only the MAM-A gold for all masters and anything else I want to have listened to by critical ears. I have purchased and used the MAM-A silver for some other uses and tests.

One curious, but powerful, set of facts came to light after I did all the dither testing. I spent some time testing various types of media stock burning at various speeds in my Yamaha IDE burner from approx. 2000....The number of variables during this test were huge, and, I'm sure would show different results with a different burner, program or computer.

I started these tests after receiving some table-top duplicated discs from masters I had heard before, and found them to sound quite different than the masters.....I would stress that, although I did do some file-matching tests, all of my media and speed tests were LISTENING tests done in real time on my reference player monitoring via the digial output into my reference monitoring setup. I was testing the way things sound on playback, with the ultimate concern being client auditions and duplication quality as I was considering buying a duplicator.

I don't think errors, in the normal sense, were ever the issue, and here is why: Before I performed the extensive tests using mixes that I know intimately, I took these bad-sounding table-top duplicated CDRs (collapsed image, loss of depth, shift of apparent frequency response), copied them into my Wavelab computer and simply burned them again at the standard speed I use (4X)(no additional dithering) onto the MAM-A gold discs, and all the imagery and depth were restored! (in real-time playback, that is). I would also stress that all of these real-time playback tests provided readily audible results even in my awful sounding car system and my $100 Teac "real world" bookshelf system. Absolute repeatability of the effect on all systems.

What I found ultimately through a very lengthy test process was this: 1)Every piece of media sounded different (real-time playback) at every different burn speed. 2)Only the MAM-A gold was capable of the real-time quality on playback that I am looking for, though the silver came moderately close. 3)With my burner, only the one speed (4x) produced the desired result. Both slower and faster speeds were different, and, in my oprion, degraded.

I had a long talk with MAM-A's main engineer-tech guy about this at a duplication seminar I attended, and he said he had heard of this issue from some mastering engineers, but had never seen any scientific analysis of it. I was going to send him some examples, but had a serious health issue invade my life a couple of weeks later and have not gotten back to it.....He said that his company's tests showed that their discs tended to produce the best results when run at speeds in the middle of their range (i.e.- a 56x disc would do the best around 28x), but the burners themselves responded differently to different media and speeds.

So, I guess this means that when I upgrade my burner I will have to go through this process all over again....I am sure that I will have to revisit all the dithering (I also use Waves, by the way) as well if I ever change anything else- including software.....I just changed cards in my computer, which has changed my perspective yet again, though I think the change was positive and easy to hear, so I have not gone through any further tests around this so far.