Biamp different loads??

[hawkan2580]

(before someone say search the forum, I did )

I have a Seymour Duncan Biamp 8000 that is able to run in a few combinations, bridged giving 600w @ 8 ohms, dual mono giving 2x400w @ 4 Ohms or in Biamp mode sending high frequencies to one cab and low to another (also optimal load being 2x400w @ 4 ohm..)... if running in biamp you can set the cross over point at anything from 100hz to 1khz...

You also than have 2 separate volume knobs for high and low...

Ok, here's the thing, I got a 410 cab that is rated 240w @ 8ohm (original hartke xl) but I was toying with the idea of getting 15" extension cab and would like to run that in 4ohms.. (and have a bit more watt on tap with the 15" cab not yet acquired, so maybe looking at a 3-500w @ 4ohm 15" cab??

My reasoning behind this is, I like the hartke's "snap" and top end clarity but want more power and warmth in the low end. So by feeding the low end cab the 4 ohm that'll give it more volume then what I'm "serving" up to the hartke cab with 8 ohm, right?

IE, using the 15" for the fundamental bass sound and just topping up the tops clarity with the hartke cab and letting that cab take care of things at the say over 600hz or so...

Here's my questions: Am I missing something fundamental in my reasoning? And, as the biamp 8000 manual states that it's optimal load is 2 x 4ohms, the way I understand it, it would be perfectly safe to run 1 4ohm 15" cab and 1 8ohm 410 cab in biamp mode and I should be able to use the volume knobs to balance sound (being fully aware that the 410 cab would get less watt... but since it only has to deal with "easier" frequencies and won't have to deal with the duties of the low end, it should be plenty enough ???

Anyone with knowledge are free to theories with me here even if you don't have experience with that sort of set up..

If I don't make any sense, it might be to the fact that English isn't my first language but I'm more then happy to further explain what I want to achieve.

[bongomania]

The only serious flaw there is in thinking a 15 will have more low-end capability than a 410.

[Selta]

Originally Posted by bongomania

The only serious flaw there is in thinking a 15 will have more low-end capability than a 410.

I really, really wish that somehow more people would know that. Mostly, I wish it was people in marketing/PR who put this in ads, on stages etc. Maybe someday...

[Plstrns]

Add another identical 410, or 210.
The only good biamp option with that 410 would be a real sub crossed over at 100hz or lower.

[hawkan2580]

I hear you guys about the low end capability.. and I am aware that a 15" doesn't go lower per say, it was more a tonal difference .. I find the hartke a tad "cold" but excellent in the upper register..

The main question however is the 4 ohm and 8 ohm being an issue or not? ( As stated, I believe it is safe for the amp as it is optimal load on one and less load on the other side of it)..

But keep telling me opinions and views
Another identical cab would be 2 x 8ohms which I feel would waste a bit of the power in the amp's capability, and the only reason I don't (for now) go for the 2x 4 ohms is limited funds and an existing 8ohm cab

[Floyd Eye]

Why not feed more power to the 15'' via the 2 separate volume knobs? Planning on running them dimed all the time?

[hawkan2580]

Originally Posted by Floyd Eye

Why not feed more power to the 15'' via the 2 separate volume knobs? Planning on running them dimed all the time?

Well, in my view, it would automatically get more juice by being 4 ohm and if I wanted to balance the two cabs, it would be the about bringing them into line either by bringing up the 410 or down the 15...

We don't play hugely loud anyhow so it isn't so much a matter of overall power and volume, it is more a matter of tonal quality and building for the future in terms of ohms on the new cab ...

I purchased the 8ohm cab to go with another amp that since been replaced with this amp that seems to be better paired with 4 ohms ... and since I can't afford 2 new cabs, I wanted to get one new 4 ohm and replace the 410 with another 410 at 4 ohm later on....

[lbwdog]

First, your reference crossover point of 600 Hz is not a good choice. A single (or two) 8" driver or one ten would handle the mid/highs, and you would be wasting a lot of bottom end capability from the 410. Why haul that heavy cab around for that? A lower xover point of 200-300 would be better (if using the 410 as a mid/high cab), as long as the 15" cab had a very stout driver in it. Look at the fEarful 15/6 as a model. It has the wonderful Kappalite 3015LF crossed over at 500Hz, to one 18SOUND 8", and blows most other single cabs away.

As far as the amp goes, I'm not familiar with that model, but most amps that are set up that way have two discrete power amps that can handle different impedances. Personally, if i were going with your desired cab configuration, I would get another 8 Ohm cab so I could use them both in a full-range application without going below 4 Ohms combined.

[BassmanPaul]

Trying to get more lows out of a 15 by boosting the power to it will eventually be fatal to the 15. It will never be able to keep up with a 4x10 in any regard.