Advice needed to build new 3 way active system

[Zeverin]

Hi.
I'm planning my new system. I want to build a 3 way active system (front speakers).
My current ideia is to use the ULTRADRIVE PRO DCX2496 as the crossover. The amplifiers will be 3 A500 also from behringer (one for each channel).
The drivers configuration will be MTMWW. The tweeter is the Seas 27TBFC/G, the midwoofers Dayton RS180 and the woofers RS270. The box will be sealed because I want the most clean and "fast" sound I can achive. The midwoofers and woofers will be wired in parallel (4 ohm load on the amplifier). I would like to add a third woofer (MTMWWW), but that would have a dificult impedance for the amplifier. Why another 3rd woofer? Because of the added dinamics and lower distortion numbers at a given listening level. Any solutions?
I currently have a TC 2000 15" subwoofer in a sealed box with 110 L crossed over at 60Hz.

Please post your comment and sugestions. Keep in mind that budget is a constraint.
Thanks in advance.

[stickinsect]

Dont forget to budget for some means of 6 channel volume control and you might want to get the input and outputs modified at some stage.

[Zeverin]

Originally Posted by stickinsect

Dont forget to budget for some means of 6 channel volume control and you might want to get the input and outputs modified at some stage.

I think I didn't understood your point. Do you mean that I need to control the 6 channel volume after the crossover? My idea is to get the signal from the pre-amplifier (2 ch) send it to the crossover and then to those 3 amplifiers. One for the low freq, one for mid and the other for highs. This way I can adjust sensitivity differences between drivers. If I want to bring the volume up, I will do it in the pre-amplifier? Do I need something else?

The crossover points aren't set yet, but might be something like 250 Hz (4rd) and 1800 (4rd).

Please comment.

[5th element]

You start losing resolution when you attenuate a digital signal, hence you don't want to use the Behringer as a primary volume control. You're not anyway, so this isn't a concern.

However I'm sure the same is true in reverse. The Behringer digitises the analogue signal coming into it and I'm sure you want to keep this unattenuated also for the same reason.

This being stickinsects recommendation to have a 6 way volume control to adjust the level after all the digital manipulation has taken place.

[Zeverin]

Do you have any recommendations to adjust the signal level after all the digital manipulation has taken place?

[Thebrain]

hence you don't want to use the Behringer as a primary volume control

you should fix it to don't use Behringer at all...

if you still wanna use a digital XO, the best way to control the overall volume is to control the input GAIN.
hence the signal coming from the source before the XO.
this can be done by using a small mixer.

neither if you are budget tight or not i would recommend using analog crossover.
since you don't need a compressor and EQ and you are not gonna use the system as PA.
analog XO are cheaper and the audio signal is not converted twice

[Zeverin]

Originally Posted by Thebrain

you should fix it to don't use Behringer at all...

if you still wanna use a digital XO, the best way to control the overall volume is to control the input GAIN.
hence the signal coming from the source before the XO.
this can be done by using a small mixer.

neither if you are budget tight or not i would recommend using analog crossover.
since you don't need a compressor and EQ and you are not gonna use the system as PA.
analog XO are cheaper and the audio signal is not converted twice

Yes, analog XO are cheaper, but they are also more limited, at least the models that I know. I think that I will need EQ. My budget is 2000€, for crossover, drivers, amplifiers, and enclouser.

And about the drivers choices? Any comments or observations?

[Zeverin]

I'm getting other sugestions that the RS150 might be a better midrange, that way I would crossover at 2100 Hz. What do you think?

[Dr.EM]

I'm going to be using PGA2310 chips for 6 channel attenuation on my 3 way tri-amplified setup. That is in conjunction with analogue filters, but it's still good to keep the signal level through them constant and of moderate level I feel. There are alternative chips, like those by Wolfson (if still available?), the PGA's at least are easily daisy chained for multi-channel control

[5th element]

Originally Posted by Dr.EM

But it's still good to keep the signal level through them constant and of moderate level I feel.

That hasn't been my experience. Mine sound great with small signals too. Of course attenuating the signal coming out of the active crossover, rather then before it, does offer in an extra level of protection for your drivers. As it is, if something goes wrong in the active crossover a huge and ugly signal could be amplified and blow up a driver. This hasn't happened to me yet and I've been using analogue active crossovers for almost 10 years.

And about the drivers choices? Any comments or observations?

The only thing I'd say is do you really need the MTM part? The only reason you'd want to add in the other mid is if you really need that extra 6dB, if you don't leave it out.