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Biamping ADS L1230s?

BmWr75

BmWr75

Top octave? pfffffftttttt
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I've got a bi-amp rig already set up using a Behringer CX3400 active crossover. The ADS 1230 can be biamped, but the owners manual talks about using an ADS C2000 bi-amplifier controller. Can the CX3400 be used instead of hte C2000? If yes, does anyone know the suggested crossover point between the woofers and the mid/tweeter? I can balance the levels between the two sets of drivers in each speaker using other equipment I have.
 
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Well....that didn't go so well. Flipped the switches on back of the speakers to the bi-amp mode. Hooked them up to my bi-amp set up and proceeded with RTA and active crossover to set the crossover point and amp levels. They sounded OK at first, but then the sound started deteriorating and got noisy (clicks and pops every once in a while). I quickly turned everything off and unhooked the speakers from the amps. Hooked them back up to a single amp set-up, flipped the bi-amp switch back to the single amp position and anxiously waited to see what they sounded like. I think the speakers are probably OK.

WTF???? Could there be something bad in the bi-amp switch or speaker crossovers that are still in the circuit in the bi-amp mode?

FYI, this bi-amp set up worked fine with my other set of biampable speakers.
 
Hooked my other Zilch/Heath AS-10 speakers back up to the bi-amp set up. They sound fine. Something apparently is not right in the ADS L1230 biamp switch and associated circuits.

The ADS L1230s sound fine too now that they are hooked back up in single amp mode. Whew!!!!!!
 
Once again....it's Deoxit time!!!

Howdy, BmWr75. Yes, the title says it all.....but first.... Have you ever bi-amped these ADS before? If not, you probably just found out they need a little TLC, .....and Deoxit hosedown.

Don't have a clue as to the internal config here, but I'd start with the switches......I'm betting that's all it is!!!

Here's hoping.......willhowl:yes:
 
I'm "think" the biamp switch separates the woofers from the crossover meaning you have not disengaged the mid/high crossover but the woofs are then run full range until controlled via outboard means. Least that's how the 1290 is. The problem may be that you have not disengaged the mid high crossover.
 
Hate to even admit this, but after reading the owner's manual section on biamping, I figured out the problem. Had hooked the mid/high speaker cable to the woofer 5-way plugs and the woofer cable to the mid/high 5-way plugs. Will give biampling another shot with the correct connections to the speakers later this week.
 
The Bulb Lights Up!!!!

A-Ha! Voila! Good deal, BmWr75!!

No surgery required!

On the other hand.................:D....willhowl
 
soundmotor said:
I would check the crossovers and inspect for signs of heat damage.
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Only had them in the bi-amp mode for a couple of minutes.

Already tested them back in the single amp mode. They sound fine. Will do a more scientific test with an RTA to make sure everything is OK later this week.
 
please post your hookup in full detail if you don't mind- I was under the assumption you couldn't do this without the module.

I have L1230s and am interested in doing this.

Cheers,

Paul
 
thedelihaus said:
please post your hookup in full detail if you don't mind- I was under the assumption you couldn't do this without the module.

I have L1230s and am interested in doing this.

Cheers,

Paul
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Preamp L/R outputs to Behringer CX-3400 active crossver inputs (need RCA to XLR cables for this connection). The crossover has two sets of L/R outputs (need two sets of XLR to RCA cables for this connection). One set goes to the amp for the tweeters/midranges. One set goes to the amp for the woofers. Of course then wire the amp outputs to the CORRECT sets of inputs on the 1230s.

The CX-3400 crossover has controls for the crossover point and ouput levels to each amp so you can match the tweeter/midrange volume to the woofer volume.

It will be later this week before I have a chance to try this again with the amp outputs connected to the CORRECT 1230 inputs. Will post the results then.
 
You should be fine. I did the same thing with my 1530's one afternoon. I was using a JBL crossover @ 500 hz / 12db/octave slope. Pink Floyd's "Welcome to the Machine" never sounded so good :)
 
soundmotor said:
Will it be as entertaining as your attempt at L1230 biamping?

:D
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Depends what you find funny.......

Anywho.....I was able to successfully bi-amp the L1230s today using a Behringer CX-3400 active crossover feeding two amps. Then RTAed the system using a Behringer DEQ2496, the AutoEQ function using a ECM8000 mic resulted in the attached GEQ curve.

The tweeter amp is 70 watts RMS/channel and the woofer amp is 150 watts RMS/channel. I had to set the crossover output level for the mids/highs to +6 (-6 to +6 scale) and at -4 on the woofer amp. The Behringer crossover is set at 600 Hz. The 1230 owner's manual says the internal crossover is set at 400 Hz. The crossover point can be played with to suite you own ears.

The biamp set up sounds great to me, but honestly so did the single amp set up with these speakers using two 120 watt tube monoblocks.
 
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BmWr75 said:
Depends what you find funny.......

Anywho.....I was able to successfully bi-amp the L1230s today using a Behringer CX-3400 active crossover feeding two amps. Then RTAed the system using a Behringer DEQ2496, the AutoEQ function using a ECM8000 mic resulted in the attached GEQ curve.

The tweeter amp is 70 watts RMS/channel and the woofer amp is 150 watts RMS/channel. I had to set the crossover output level for the mids/highs to +6 (-6 to +6 scale) and at -4 on the woofer amp. The Behringer crossover is set at 600 Hz. The 1230 owner's manual says the internal crossover is set at 400 Hz. The crossover point can be played with to suite you own ears.

The biamp set up sounds great to me, but honestly so did the single amp set up with these speakers using two 120 watt tube monoblocks.
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That was funny, but not likely to result in damage for the brief time engaged. The MF/HF section of the crossover has an HP built-in. It remains in place when you switch to biamp mode whereas the LP section is switched out completely. The most noticeable result should be better bass definition with any of the ADS models allowing this. At least, that was the general customer feedback. The trick with the C2000 however was that it was designed to work in conjunction with the passive crossovers in the speakers. In other words, the combination together gave the desired results. That isn't saying another crossover would not work, only that it required some tweaking and you seem to be well on your way.

For the Behringer, what is the HP crossover slope you are using? The general recommendation was even order HP slope (12dB & later 24dB) & not odd order (6dB & 18dB) if someone was trying to biamp using something other than a C2000. What's interesting from your measurement is the high-Q peak centered at ~630Hz with the suck-out below it. It could be an artifact of your miking or a reflection of something close by. It could also be an interaction of the Behringer & the ADS crossover right at the midrange HP because of the crossover slope or the Q of the HP slope itself. I realize you are above the factory crossover point and I would think none of this should matter except for the peak. You might also try reversing the phase of the amp driving the L1230 HP & see how it measures. Further, have you measured the system in normal mode, i.e. not biamping? It would be interesting to see if that peak is still there. The bottom line is that is sounds good and that is the main thing. The rest is idle curiosity or, further tweaking may result in even better performance.

attachment.php
 
The Behringer CX-3400 documentation says this about the crossover slopes:

24 dB/octave, state-variable Linkwitz-Riley filters for precise frequency separation

Switchable 25 Hz subsonic filter per input (12 dB/octave) activated by engaging Low Cut filter


Here's a link to what the GEQ curve looks like after AutoEQ when the speakers are single amped.

http://www.audiokarma.org/forums/showpost.php?p=2500223&postcount=19
 
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BmWr75 said:
Here's a link to what the GEQ curve looks like after AutoEQ when the speakers are single amped.]
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I understand the above to mean the measurement shown has a corrected EQ curve or equalization applied to get the response that flat.

Is that correct? If it is, do you have a dry measurement, no EQ applied image?

attachment.php
 
I understand your question and have attached the RTA curves using a Behringer mic and the DEQ2496. The first pic is the ADS L1230s with no EQ. The second pic is after running the AutoEQ function with adjusts the EQ to a flat response, which will results in the GEQ picture in my earlier post show how each filter was adjusted +/- dB.
 
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