Bi-amp rig question

[M. Dittman]

I just received the Seymour Duncan amp I bought on ebay and have a question
about bi-amping. The amp is 400 watts a side. I am using a Carvin 1-18" 800
watt cab on the bottom end and a Carvin 2-10" with tweeter 400 watt cab on
the upper end. The knob for ajusting the crossover freq. on the amp goes
from 100Hz to 1K. What freq. do you recommand as a crossover and why. I am
using mainly Fender 4-strings for now but am thinking of stepping up to a
five in the near future. Any other thoughts on using this setup would be
appreciated, thanks!

[Steve]

It seems to me there are two considerations in the use of a biamped rig:

1) You want to avoid intermodulation distortion caused by inter-mixing of high
and low frequencies in the amp and in the speaker drivers by separating those
frequencies into the two separate channels, and

2) You want a distribution of the power between the two power amps and speaker
systems so that the load is more or less balanced between them in proportion to
their respective power-handling capacities

In your case you have two power amps capable of handling the same power load,
so you want the power more or less evenly divided between them, I would
think.This is true of most biamp rigs I have seen--SWR and Peavey Megabass, for
example. And any rig that uses a bass preamp and a two-channel power amp. The
exception is Gallien Krueger, whose biamp bass amps typically have a 4-to-1
ratio between the power capacities of the low and high channels.

I had a Peavey bass righ that consisted of a Peavey Bassist preamp and a 225W
per channel power amp (also Peavey), with a Peavey 1820 cabinet (1 x 18" and 2
x 10). I used to have the crossover on set to 1K hz, and it seemed like the
low channel was doing most of the work. A friend ( a more experienced bassist
than I am) told me that you get a better balance with the crossover set to 400
to 500 hz.

Hope this helps!

---Steve

[Art Blegen]

I personally like to run the top cabinet as close to full range as it will
handle, and leave only the "Thump" in the bottom cab. With your crossover,
I would probably start with the X frequency at the 100Hz point, and work it
slowly higher only if needed. Of course everyone has a different technique
that they like to use so YMMV.

"M. Dittman" <mdit...@cts.com> wrote in message
news:sssS9.381$F9.1...@dca1-nnrp1.news.algx.net...

[ovid]

100 - 160HZ if yyou want the 18" to function like a subwoofer. The best
judge is your ears, and you can disconnect the 18" fiddle with the freq.
and see how much work you want the 2 X 10 to do. Any crossover freq
above 250Hz is going to sound like most of the work is done by the 18".
There is no 'best' in this - the freq. cross is up to our ears for the
character ou want.

Having said that, the 2 X 10 working harder may sound less loud than the
18"working harder depending on efficiceincy and cab resonance.

[Parke J. Shissler]

Hi

I ran a MegaBass biamped into a custom 15" cab and a Carvin 2X10 for a
few years. In some rooms it was great with the crossover around 100Hz,
but most of the time I found that running it crossed at 200 reduced room
boominess and gave better projection.
A lot depends on frequency response of the stage/room you're playing.

[TDodge]

"ovid" <ov...@nospam.net> wrote in message
news:3E1AD492...@nospam.net...

> The best
> judge is your ears, and you can disconnect the 18" fiddle with the >freq.

big agreement on that. Don't look for a number, find
a sound.

[Brian Running]

Here's my thought: Don't bi-amp at all. I've tried it, a number of times,
and I keep coming back to the same conclusion.

Your 18" cab might have slightly greater low-end extension than your 2x12.
Let's say it can get down to 32 Hz, just for the sake of discussion. And,
let's say your 2x12 can get down to 48 Hz. These are realistic figures, and
they're close enough for this example. Both of those cabs are fully capable
of handling the very highest fundamentals your basses can produce, which are
in the neighborhood of 300 Hz. The vast majority of your playing will be
between 41 Hz (low E) and 160 Hz (E, 9th fret on the G string). These are
fundamentals, even the second, third and fourth harmonics are well within
the range of either the 18 or the 2x12 -- your tweeter will handle anything
above that, and doesn't enter into the equation.

Now, say you took the advice of several people here, and set your crossover
at 100 Hz. You have now eliminated the 2x12 from producing the vast
majority of your fundamentals, it will only be producing the fundamentals of
the highest octave you play in -- even though it is capable of producing
several octaves of sound below that. And, you have placed all the
responsibility for producing the entire range of 32 Hz (low B) to 100 Hz
(roughly, the open G string) on the 18 -- virtually everyone in this
newsgroup will agree that an 18 is not the ideal driver for producing clean,
articulate and "punchy" bass, which is what most bass players are looking
for.

If a bass cab is designed to produce the full range of bass guitar
frequencies, then bi-amping it simply cripples its ability to do what it's
designed to do. Let both your cabs run full-range, and produce all the
sound they're capable of doing. The only time bi-amping is appropriate is
when you have multiple cabinets that are specifically designed to produce a
certain frequency band -- in that case, it makes a lot of sense to dedicate
a separate amp to each frequency band. But not when you're using full-range
cabs.

And, as for being concerned about intermodulation distortion, well, you'll
get a lot more improvement in your sound by practicing a half-hour each day
than by attempting to reduce intermodulation distortion.

[M. Dittman]

Thanks for the advice. I'll try your suggestion and see how it sounds. After
all, as some others have pointed out the ears should always be the final
judge.
"Brian Running" <brun...@XXameritechXX.net> wrote in message
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