PCM91 vs 90:Aren't the converters different also?
lex...@my-deja.com
24 or 32 bit internal operation with 20 bit A/D/A, whereas the 91 has
32 or 48 bit internal math with 24 bit A/D/A? I ask because the only
response I get is that only the presets are different.
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Before you buy.
Monte P McGuire
>Just curious on the difference between the two, doesnt the PCM 90 have
>24 or 32 bit internal operation with 20 bit A/D/A, whereas the 91 has
>32 or 48 bit internal math with 24 bit A/D/A? I ask because the only
>response I get is that only the presets are different.
My recollection is that the 90/91/300/480/NuVerb all use the same
Lexichip II DSP chips and those are 20 bit chips. They probably use
different converters for each model, if only because of the large
timespan among all of these models, but the Lexichip II is definitely
a 20 bit box and it's common to all the models I mentioned. I have no
idea what resolution the Lexichip II uses internally, but since it's a
custom chip, I wouldn't make any assumptions based on what other DSP
chips do. It was designed to do reverb, not FIR filters, so I'm not
so sure it even has a wide accumulator.
The only important thing you need to know is that if you use one of
these models with digital IO, you should dither the send to 20 bit.
Other than that, the internal operations and word widths are
engineering trivia; either you like the reverbs or not. Some people
love Lexicons, some hate them. I think they're fine things when you
want a high density reverb with somewhat vague imaging and depth, and
that's great sometimes and miserable other times. As to your original
question, I haven't spent any time comparing the 90 vs. 91, but I bet
they're very similar.
Have fun,
Monte McGuire
mcg...@world.std.com
cat
> My recollection is that the 90/91/300/480/NuVerb all use the same
> Lexichip II DSP chips and those are 20 bit chips. They probably use
> different converters for each model, if only because of the large
> timespan among all of these models, but the Lexichip II is definitely
> a 20 bit box and it's common to all the models I mentioned. I have no
> idea what resolution the Lexichip II uses internally, but since it's a
> custom chip, I wouldn't make any assumptions based on what other DSP
> chips do. It was designed to do reverb, not FIR filters, so I'm not
> so sure it even has a wide accumulator.
>
> The only important thing you need to know is that if you use one of
> these models with digital IO, you should dither the send to 20 bit.
> Other than that, the internal operations and word widths are
> engineering trivia; either you like the reverbs or not. Some people
> love Lexicons, some hate them. I think they're fine things when you
> want a high density reverb with somewhat vague imaging and depth, and
> that's great sometimes and miserable other times. As to your original
> question, I haven't spent any time comparing the 90 vs. 91, but I bet
> they're very similar.
>
> Have fun,
>
> Monte McGuire
> mcg...@world.std.com
Could you please elaborate a bit on imaging quality in reverb? There
have been times when I've wanted a more palpable or defined reverb
image, and haven't quite gotten what I was looking for.(With the 80/90,
vocals for example) Lower diffusion seems to help. Seems like I'm
looking for more or different early reflections qualities.? A bit hard
to describe I'm afraid.
Thanks
Wayne
Monte P McGuire
>Could you please elaborate a bit on imaging quality in reverb? There
>have been times when I've wanted a more palpable or defined reverb
>image, and haven't quite gotten what I was looking for.(With the 80/90,
>vocals for example) Lower diffusion seems to help. Seems like I'm
>looking for more or different early reflections qualities.? A bit hard
>to describe I'm afraid.
Lower diffusion can definitely help. The basic problem is that the
reverb is too dense, and reducing diffusion will help that. But
still, it's hard to get that sound with a Lexicon. The Random
Ambience algorithm (at least that's what it's called on the NuVerb)
lets you choose the ratio of diffused reverb to early reflections so
it might be a better one to try. I'm not sure that the other high end
Lexicon algorithms even do early reflections, but the Ambience
algo. does provide them and they'll do more of what you want.
The Shape and Spread parameters can also help with this too. Try
turning them down all the way so that you get some reverb in the early
part of the decay. One client who's a Lexicon hater wasn't so ticked
off when I removed all Shape and Spread, so maybe this will help out.
You could also try some of the simpler algorithms. Either the 80 or
the 90 has some old 224 / PCM70 algorithms available and those will be
a lot less dense than their moden, dual chip algorithms. If you don't
know for sure which to try, try any sort of algorithm that can share
the machine with another algorithm and bypass that other algorithm.
Another solution is to use something like a TC M3000. The reverbs
there are very wide and deep sounding, but they will be useless on
anything percussive because they are not nearly dense enough.
However, for vocals and guitars and other non percussive instruments,
a low density reverb is generally the best answer.
You've definitely hit the nail on the head though - Lexicon reverbs do
have some weaknesses in the imaging department and these stem from the
very things that make them nice to use on other signals like drums.
It seems impossible to have a reverb that does both, so you might as
well add a TC to the mix and use some of each. They complement each
other nicely IMHO...
Best of luck,
Monte McGuire
mcg...@world.std.com
David Chertock
> I find it interesting that given a sharp transient, digital reverb will
> sound like bee-bees hitting metal plate, except at the highest
> densities or rolloff. Never hear that in natural settings. It's as if
> the individual reflections are too discrete.
Just yestarday I was carefully comparing my BX20E1 torsion bar (big
giant spring) reverb to a DP/4. The BX20 is very smooth, whereas with
the DP/4, "the individual reflections are too discrete".
--
David
Venice, CA
cat
mcg...@world.std.com (Monte P McGuire) wrote:
> In article <8d8ptl$2k3$1...@nnrp1.deja.com>, cat <smithwayne@my-
sound like bee-bees hitting metal plate, except at the highest
densities or rolloff. Never hear that in natural settings. It's as if
delays as an alternative, but there are far to few to pass as early
reflections. Another approach was to reduce the r/t way down so the
reflections are exposed in time. (A learning experemetnt, never used in
a mix.) Were some of the earlier Lex better at 'imaging'? The 300
manual refers to using size as a method of controling density, but
shape is definitely a loaded gun the way it jumps from normal liniar
decay to 200ms groups with a setting of one' or more. Never understood
why they did that. Seems like they sort of mucked that particular tool
up. Thank you for the ideas, I need to go poke around in there some
more.
Christian Andersch
> sound like bee-bees hitting metal plate, except at the highest
> densities or rolloff. Never hear that in natural settings. It's as if
> the individual reflections are too discrete. I've tried the diffused
> delays as an alternative, but there are far to few to pass as early
> reflections. Another approach was to reduce the r/t way down so the
> reflections are exposed in time. (A learning experemetnt, never used in
> a mix.) Were some of the earlier Lex better at 'imaging'? The 300
> manual refers to using size as a method of controling density, but
> shape is definitely a loaded gun the way it jumps from normal liniar
> decay to 200ms groups with a setting of one' or more. Never understood
> why they did that. Seems like they sort of mucked that particular tool
> up. Thank you for the ideas, I need to go poke around in there some
> more.
> Wayne
what about quantec?
christian
cat
(in my limited experience). It was at a gig near a small redwood grove
north of Napa. Ever get caught yelling and claping at a bunch of trees?
I doubt there is a cure for this.
It does seem to make a case for moderate density with lots of roll-off.
I appreciate the help.