BBds, was Re: [sdiy] digital delay

[john mahoney]

I know we're mostly just playing around with these BBD ideas, but in fact
much work has been done in attempts to make BBDs sound better (e.g.,
companding).

I will say the naughty word, now: "Digital." A digital delay line can
produce high fidelity sound, and pretty cheaply these days. Normally, hi-fi
is a great thing! (Except when you want a lo-fi sound ;-) But seriously,
some people will say the DDL sounds dry or cold or sterile, whereas a BBD is
warm or has character or something.

In other words, DDLs do not change the sound in a noticable way, aside from
the intentional, delay-based effects. Again, that is normally a good thing.
However, some people like the way a BBD messes up the sound. Can't these
sound effects be replicated in a digital system, and with greater control? I
am not talking about digital modeling (leave that to Line 6, Roland, etc.).

I'm talking, for example, about bandwidth controls on the inputs. Go wild
and use a tube-based input preamp with tone controls! Even more can be done
by playing with the signal in the feedback (regeneration) loop. Again, some
bandwidth limiting controls, normally known as "EQ."  :-) How about
controllable distortion, using tubes if you like? Or a way to mix in some
noise (or another sound, like fake clock noise, ha ha!), and you could use
an envelope follower to dynamically add an amount proportional to the signal
level.

A DDL provides many more options for control than a BBD, such as multiple
taps without redundant circuitry, ultra-long delay times if that's your
game, and much, Much MORE! (Oops! I've heard too many adverts on TV.) So
there is a lot to like about digital delays.

I know the analog vs. digital debate will rage on (I still have a working
turntable, thank you very much), and I don't mean this to be part of that.
Besides, this is different from the argument that analog is more accurate
than digital. It's more like the tubes vs solid state thing.

It all comes down to this:
Can we reasonably replicate the desirable BBD distortions in other ways? If
so, we don't need a delay line that adds its own sound; instead, we can use
a clean, hi-fi delay that will do what *we* want it to. This is much more
flexible because you are not stuck with that certain sound.

Using science, I am sure that we can figure out those qualities that we like
about BBDs. Then we can say goodbye to their bad side effects.
--
john


----- Original Message ----- 
From: "Harry Bissell Jr" <harrybissell at prodigy.net>


> Ahhh this is excellent !!! This is my main complaint
> with the BBD in the first place... It doesn't stand
> a "snowflake's chance in hell unless it has a ton of
> refrigeration equipment alongside it".
> (from "The Subways of Tazoo" by Colin Capp - 1965)