I am a proud owner of a RME Multiface card and one of the reasons I bought
this card was due to RME's reputations for quality converters.
However, this begs the question - what makes a converter high quality in
the first place? I know that soundblaster have cards that get up to
"192Khz" but obviously that is low quality all around.
The RME Multiface has a Dynamic AD ratio of 105dBA
Does a higher number here ALWAYS mean better quality? Or are there other
factors involved?
Also, is it correct to assume that the more Dynamic Ratio that there is,
the more exact the waveform is? What is it that used to cause the "tin"
sound of digital?
Very curious... thanks in advance for your answers!
Robert
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Robert,
The numbers totally don't tell the whole story at all. Yes, RME is well
known for getting a lot of bang out of the converters that they use. And
they do that like this.....
The converter itself is only partly responsible for the sound quality of a
complete a/d or d/a solution. One cannot ignore the signal conditioning
that happens before the converters and those component chosen to do that
job. And in fact, RME seems to pay particular attention to that as well as
other areas. The other areas???? The clock and the power supply. You can
imagine of course that none of your electronic equipment would work well (at
peak spec levels) if the power feeding the circuits is uncertain and not
well conditioned. Furthermore, if the clock that runs all of the digital
circuitry does not tick at very precise intervals, the whole a/d and d/a
conversion process is compromised (this is known as jitter..... the
variation of the clock tick intervals). RME has a really nice clock for the
money.
So what does all this mean. It means that if you put the same chip in RME's
hands and some other manufacturer's hands at the same price point, RME seems
to get more out of the chip than others. And if you do a search on the net
you can find this topic in other places (two manfacturers using the same
chip and not getting the same performance). Now, RME is not alone. There
are other manufacturers who get all that they can out of an a/d/a conversion
system but not very many seem to do it near the cost / performance ration
that RME does.
Dynamic range can also be considered your noise floor. In other words,
sgnals recorded at 105 dba would be indistingquishable from the noise
because thats where the noise in the system is (natural electronic
uncertainty). Why should anyone strive for lower noise floor? Let's say
you want to record a violin. But it's a really delicate part with a lot of
very soft parts and then loud swells. If your noise floor is close the
level of your low level violin part, when you go to compress the part (to
reduce the dynamic range.... essentially squishing down the loud parts a
little so that you can raise the volume of the whole track and there by
raise the volume of the soft parts), you will be raising the volume of the
soft parts as well as the noise that you recorded down there. So if your
noise floor is lower (that's relative) you will hear less of it (the noise)
when you go to boost up soft signals. This is not so much of an issue for
studios that record punk pop bands. So, is a lower noise floor, higher
dynamic range always better. Well, yes, but that's not the right question.
The bettter question is.... do you need a higher dynamic range for the work
that you do? I have not been able to outperform my multiface yet with the
work that I do. But, I can see the next time that I do an accoustic
recording thing for a guy that I know, I will likely need a better noise
floor.
Dynamic range does not give you a more exact approximation of the wave form.
Better clocks, signal conditioning circuits, and higher sampling rate give
you better approximation of the wave form.
Does that answer your questions?
Hope this helps...
Rob Kress
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Hello Rob,
Thanks for the phenomenal response. That really clears a lot up for me!!
I'm also not very concerned about the noise floor at all right now, because
anything that I throw into the mix, I try to get pretty close to the 0DB
(without any clipping) when recording, for maximum quality.
Question: Is there anything that will really increase the quality of the
A/D even more?
An external clock source? Or is the internal one going to be just fine?
Robert
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Robert,
I'm sorry that I sent you a direct response. I tried to post it on the
group and must have hit the wrong button. Anyway, yes, you can imporve your
A/D conversion by the use of an external clock that has a lower jitter spec
than the internal clock in the multiface. But, like I said earlier, RME's
clock is pretty good for the money and a really good clock would cost as
much (actually more) than the multiface / PCI combo. The folks who make a
really good clock (the industry standard) evidently is Aardvark. I think
the Lucid clock has also gotten some good press and is less than half the
cost of the Aardvark. Passed that, the only other thing you can do is to
keep your multiface and cables away from crazy electronic noise makers (cell
phones and other RF signal producers and parallel 110 vac lines).
On a final note..... be careful recording so close to digital full scale.
There really is no need. Especially if you are doing rock or something like
that. Besides, you should be leaving yourself some room for processing
after tracking. With everthing crammed up at digital full scale, how do you
do any eq or compression?
Good luck and enjoy your multiface
Rob Kress