Yamaha REV7 Digital Reverb?
kir...@sjuvax.uucp
>Does anyone out there have any experience with the Yamaha REV-7 digital
>reverb? I'm seriously thinking of getting one, and it looks great, but $900
>is a lot of money.
>
>How about any other reverbs that compare with it? I've looked at the Alesis
>XT:c, which isn't really versatile enough, and doesn't have stereo. And the
>new Roland has synthsized stereo (mono in, stereo out).
>
>--
>John Labovitz ..!{rlgvax,seismo}!bdmrrr!potomac!jsl
>--
>Don't act so embarrassed
>It's a family trait
> -- Robyn Hitchcock
I have used the Yamaha in a studio and it was really amazing. I can't tell
you much about any other units but, if you can afford it, the Yamaha is
definitely worth it.
--
"Honesty Ain't All that Hard,
Just Put Rambo Back Inside your Pants"
-Jello Biafra
Paul Kirsch
St. Joseph's University
Philadelphia, Pa
{ astrovax | allegra | bpa | burdvax } !sjuvax!kirsch
Robert Sloan
The SPX90 lists for $699. and is the best bang for the buck of any
effects processor.
The SPX90 has Reverb, Early reflection, Delay, Echo, Modulation,
Auto Pan, Vibrato, Freeze (half second sampling),
ADSR gate, Compression and Parametric
Equilization, Pitch change.
There are 30 Preset programs and 60 user definable programs. Single
channel in, Stereo out.
Preset programs include stereo flange, chorus, Reverb HALL, ROOM,
PLATE etc...
Optional Remote and footswitch. It includes MIDI.
31.25 kHZ A/D D/A sampling rate 16 bit linear
20 Hz to 12 kHz
There are some drawbacks;
12 kHz is a bit low.
MIDI effects only program change. Note on/off is recognized
for pitch change and freeze (sampling to change pitch). No dynamic
MIDI controler effects. Also only one program can be used at a time
no combining phase and echo.
Compared with the Lexicon PCM 70 which has extensive MIDI
implementation which can change many of the parameters real time
( ie room size ). The PCM 70 also combines in one program, early
reflections with reverb for a realistic audio space. But the list on
the PCM 70 is $2000. Buy two SPX90's for that price.
The SPX90 is comming out this month.
lp10...@sjuvax.uucp
...I know this is gonna sound like a stupid question,but hey!!!,
stupidity is a virtue.What is *digital* about digital delays??
Do they sample the delayed signal,or use microprocessors
to control feedback,or both??...
...also,why has mechanical (ie. spring-controlled) reverb died??
Was it particularly prone to failure? I have a Fender-Twin (circa.
'69) with mechanical that doesn't work,but when it did I thought
it was *fantastic*,super-genuine!!...
Larry Palena
PS- ...and what exactly *was* the story behind net.music.guitar??
kir...@sjuvax.uucp
Larry, I think the big advantage to the digital reverb is the cleaner sound.
Some people don't like the extra bit of treble/tinniness that you get from
the spring reverb. I guess it's the same as all other analog vs. digital
arguments--with the digital you can get a cleaner sound--which really gets
some people off-though others still like the analog sound.
Nate Stelton
> stupidity is a virtue.What is *digital* about digital delays??
> Do they sample the delayed signal,or use microprocessors
> to control feedback,or both??...
I'm no expert, but my understanding of DDL's is that the sound is sampled
much the same way that digital recorders, digital phone lines, and sampling
keyboards perform this task. The information is stored in RAM, and released
at the end of it's sample duration (set by the 'delay' knob). DDL's are
functionally the same as an echoplex. I believe microprocessors are used to
control the management of the memory in terms of how long to sample, when to
write over what parts of memory, and more recently, extensive MIDI and user
interface.
> ...also,why has mechanical (ie. spring-controlled) reverb died??
> Was it particularly prone to failure? I have a Fender-Twin (circa.
> '69) with mechanical that doesn't work,but when it did I thought
> it was *fantastic*,super-genuine!!...
I wouldn't say it's died yet, but eventually... The main problems with
spring reverbs are the "boing" (try mixing drum tracks through one), and the
physical sensitivity (don't bump it with the amp cranked, and don't drop it
while moving the equipment). As far as mechanical reverbs go, plate reverbs
out-perform the springs for sound quality, but they haven't figured out how
to put them in guitar amps yet.
I am curious about how digital reverbs work. how do they produce the smear?
How many samples are taken, played back, and heard at a given point in time?
Anyone care to expound?
-etan
Gregory Smith
(3) analogue
(1) Is the old spring-reverb that goes 'Pow' when you bump your amp - just
a bunch of springs stretched between two bars with a tiny 'speaker' thing
at one end and a mike-thing at the other. Different sized springs are
used in the same unit to avoid strong resonances. There is also a 'plate'
reverb - using a large metal plate instead of springs - that I have
heard of. It apparently sounds much better but its size and cost limit
its use to large studios.
(2) Digital reverbs. As has been said, these 'sample' the incoming sound,
store it in RAM, and haul it out later to be converted back to audio.
To get a better reverb sound (rather than a clean echo ) some other
things are done. First, the delayed sound is re-mixed with the incoming
sound to get regeneration. Second, the delayed sound is actually
'smeared' to get a less 'wired' sound. Suppose d(10) means 10ms-old
sound. Then a 10-ms delay might actually be done by:
delayed signal = .1*d(9.5) + .2*d(9.8) + .4*d(10) + .2*d(10.2) + .1*d(10.5)
I think more than 5 'taps' need to be used in practice, though.
Thirdly, the regenerated ( fed-back ) sound can be filtered, so
that the sound becomes 'duller' as it fades out ( or whatever effect
you want). Of course, the 'smearing' is in effect a digital filter,
as z-transform buffs will recognize.
(3) Analogue reverbs use CCD's - charge-coupled devices, also known as
'Bucket-Brigade' devices. This is an integrated circuit with a long
line of 'charge buckets'. A clock signal causes each bucket to be
emptied into the next, so that the charges in the buckets propogate
along the line. The charges are created at the input end in such a
way that the amount of charge in each created bucket is proportional
to the input signal at the time of creation. This charge will later
show up at the output end, and be transformed into a signal again
( sorry if this isn't very clear - I need pictures :-) ).
Thus the signal is still *sampled*, but the samples are stored as
charges instead of a memory word. The same things can be done here
as with the digital delay - the output can be fed back, and the
delay can be 'smeared' by using several taps near the end of the
delay line and mixing them. This type of reverb is cheaper than an
equivalent digital delay, but in general much less versatile. Also,
charges will 'leak' as they pass along the line, resulting in a
noise level much higher than that possible with a digital unit.
--
"No eternal reward will forgive us now for wasting the dawn" -J. Morrison
----------------------------------------------------------------------
Greg Smith University of Toronto ..!decvax!utzoo!utcsri!greg