Biamp or Triamp for 4628b's

[mrmuse]

Feeling foolish here. Have had my 4628b's for 5 years. Noticed the low input and the high input and naturally ASSumed that the 3rd was a mid input....Now it looks as though they are two way...

I read up on them and all it says is "biamp", now here is the question???

Can a four way Ashley crossover be used 2 way for this????

The Ashley's have mono sum, low, low-mid, mid, and high....

I always wanted to triamp the JBL's with a sub for 4way now I have everything and it doesn't look like it will work.....

Thanks

mrmuse

[johnaec]

If you use the bi-amp inputs on the 4628B's that means one input drives the E145 LF and the HF input drives the 8" and horn HF. I don't see why you couldn't use the Ashley crossover, though I'm not sure right now what the correct crossover frequency should be...

Just be sure not to do what I did, and run 900 watts at 40 hz into the HF input by mistake - the 2118H got rather smoked... :p

John

[mrmuse]

According to specs they cross at 800 and 3k. Right now I'm pushing 450 watts to the lows. Cutoff at 40 since I have 2225's in, instead of the E145's.

But having 4 outputs is the problem. What should I send to the lows and highs. I've not that much experience with the "overlapping" of the crossover....

mrmuse

[johnaec]

Why is 4 outputs a problem? Just don't use 2 of them, (or is it not possible to have the Ashley cover full bandwidth with only 2 outputs?).

John

[mrmuse]

Not sure. Always used the Ashley 4 way. I'm tinkering with it now. But it raised another question.....

Why the two low outs (left and right) AND the sum out???

Couldn't the crossover be bypassed??? I could just make another input plate to use in place of the crossover. If I ever sell them (which I doubt) I could reinstall the crossover......

mrmuse

[grumpy]

Might be worth finding a manual for your Ashley crossover. Should answer quite a few of
these questions. Bypassing the internal crossover (4628) leaves you open to easily
blowing a driver. Do you have the 4628 schematic?

http://www.jblproservice.com/navigation/Network%20Schematics.html

-grumpy

[johnaec]

I agree - get the manual for the Ashley. The sum LF out is probably in addition to the L-R.

You could bypass the internal crossover in the 4628's but you'll really have to be careful, especially with the 2404H-1's.

John

[mrmuse]

I have the ashley manual and it doesn't give a clue as to using it that way.

I tried every combo last night using the crossover but always heard something missing.

I was going to bypass the crossover using Soundcraftsmen for the LF, MF, (250 wpc, and 150 wpc) and a Crown D60 for the tweets. Didn't think the Crown would blow them?????

What do you guys think??? I could always use the sum out, or just the low out for the subs, and run the 4628b's full range, or just replace the Ashleys...

mrmuse

[johnaec]

What model Ashley? Do you have subs to go with the 4628's? Which ones?
John

[mrmuse]

XR88/12 (1) 4 way stereo
SC80 (2) 4 way mono

(2) JBL K151's in 30x24x18 (2) enclosure.....

mrmuse

[Mike Caldwell]

Hello
I take it you have a Ashly 4001 crossover. You can use it as a stereo two way crossover. You will use the high mid output as low and the high out as your highs. Put the low to high mid frequency selection into the divide by 10 mode and turn that all the way down, that will give you an automatic high pass filter for the system of 40hz. If you need 800hz to go to the mids and highs you will also need to put the high mid to high frequency selection into divide by 10 mode and turn it to the 8k setting that will actually be 800hz. If you want to tri amp you do the same thing just move down one set of outputs. Low mid out will be lows, high mid will act as mids and highs will still be highs.

Just be sure to double check everything is going to the correct drivers and the frequency selections are in the correct modes.

Mike Caldwell

[mrmuse]

No it is the XR88/12 and is not the same as the 4001. I will take a pic and post it here..

Give me 5 minutes...

mrmuse

[mrmuse]

Here are the pix...

mrmuse

[Mike Caldwell]

Hello
Ah...old school Ashly, I'll dig on the Ashly website and see if there are any internal divide by 10 options. From looking at what is available on the front and back my guess is that it's not going to be able to do a bi-amp set up or for that matter a tri amp operation.

Mike Caldwell

[mrmuse]

Yeah, now ya got it. I was going nutz..The SC80's I have are the 4 way mono version of this.....

I used to run the 4699 and the 4695 4 way, and the 4628's and 4612 were fill monitors.....

You really have to dig on their website. All I could find was a brochure...

Thanks for trying...Maybe a simple two or 3 way would be better....What are your thoughts....

mrmuse

[Tom Loizeaux]

My sense is that bi-amping, where you seperate the woofer from the rest of the drivers, is the most important thing to do. You get the greatest benefit from driveing trhese two parts of the frequency band seperatly. I think that's what JBL intended for most of their "bi-ampable" configurations.
After that, further splitting of the upper frequencies will benefit - but not as much as the low end division.

Tom

[johnaec]

OK - what I'd do with that crossover is run the K-151's crossed over at 60hz stereo, then use the next band for an 800hz crossover with lows to the LF input on the 4628's, skip the 3rd band, and use the last band crossed over at 800hz to the HF input on the 4628's, with it shelved off all the way to the top. At lease it looks like that should work, but it'd be nice to see what the outputs on the back are to be sure...

Edit - it looks like there's no way to do a simple 3-way with that crossover. But let me look some more... OK - maybe you could "cheat" and fudge it as a 3-way by setting both lo-mid and hi-mid frequencies to 800hz, and skip the use of the hi-mid output. That way, lo band is set to to 60hz, so lo output below 60hz goes to K-151's, lo-mid is set to 800, so the lo-mid output would go to the LF input on the 4628's with 60hz to 800hz, skip the hi-mid output, and use the high output for the HF input on the 4628's, covering 800hz- all the way out to the top. At least that way, you wouldn't have to rewire the 4628's. Obviously, if you wanted to rewire them, a 4-way would be easy, with the hi-mid crossed over somewhere around 3-4K.

John

[mrmuse]

Isn't there a picture of the back of the Ashley???

I thought so...

mrmuse

[johnaec]

Isn't there a picture of the back of the Ashley???

I thought so...

mrmuseMy mistake - I edited my reply.

John

[mrmuse]

I'll give that a try. If not, I'll have 3 Ashleys for sale.

mrmuse

[Akira]

4way cross over units, popular in that era had a dedicated 2 way stereo switch on the back. Without that option, you can not run stereo.

[Akira]

trying to bypass the mid twice at 800Hz is a bad idea...BUT: Bypassing the bass if it goes low enough, say 30Hz, then running 3 way should work fine.

OK - maybe you could "cheat" and fudge it as a 3-way by setting both lo-mid and hi-mid frequencies to 800hz, and skip the use of the hi-mid output, and use the high output for the HF input on the 4628's, covering 800hz- all the way out to the top.

John

[johnaec]

trying to bypass the mid twice at 800Hz is a bad idea...Actually, if you check again, the way I listed only bypasses 800hz once - I was just leaving out an extra 800hz by bypassing one filter. I *think* it should work...

John

[mrmuse]

Sorry about the delay. Couple days of "flu like" symptoms, but I finally tried all your suggestions and YES it works....BUT....It's hard to describe.

I ran a Biamp CPA 650 to the 18's, a Soundcraftsmen 450x2 to the 15's and tried my (apology in advance) Peavey m2600 for the highs, then slapped myself and put a Crown D-60 on the highs. It works, but when you run them full range, and just the subs of the Ashley you get a much more "3 dimensional", or spatial feeling. Running the Ashley, something is missing, but I can't figure out what it is....
What I've decided to do is this.

K151's for the subs
E145's (originally from 4628b's) bass
E110's for mids
2425h's for highs. I just picked up a set of Altec Lansing metal horns.

I was going to go vertical on a cab for the E145, E110 and 2425 but have to come up with a design for the box.

If anyone has suggestions. Please feel free...

mrmuse