Home Theater Forum and Systems banner

Advice needed to build new 3 way active system

16760 Views 53 Replies 14 Participants Last post by  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.
1 - 2 of 54 Posts
Just a few random thoughts...I'll confess I didn't read every post in its entirety.

I want to build a 3 way active system (front speakers).
Any particular reason you want to go 3-way and not 2-way?

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).
If you're gonna go that route, then you might consider going with 3x Crown XTi:
http://www.crownaudio.com/amp_htm/xti.htm
It has a DSP built into the amplifier. They can easily be found for $300 each on the used/b-stock market.

I want the most clean and "fast" sound I can achive.
Have you thought about building some horns? It should be cheaper to achieve a cleaner/faster sound with a single driver bass horn than it would an array of four direct radiators. You get the added benefit of more control over the polar response too.

The trade off is a larger cabinet...

Why another 3rd woofer? Because of the added dinamics and lower distortion numbers at a given listening level. Any solutions?
You can always wire the woofer in series if you're worried about low impedance. When using an active crossover, you don't take any efficiency hit to balance the drivers with each other.

Btw, if you have a sub covering 60Hz and below, then I would highly recommend going 2-way.

I want to achieve 110 db (continuous) at 2 meters listening position from 30 Hz to 20KHz.
Keep in mind that 110dB continuous A-weighted still involves 20dB of crest factor in the music. If you don't want any clipping or compression, then your system will need to be capable of 130dB peaks (yikes).

A 93dB tweeter would need a 5000W peak power handling to achieve that (not gonna happen).

Btw, 110dB continuous is rock concert loud...is that really how loud you plan on listening?
See less See more
Yes I can. But that way I'm not extracting all power from the amplifier, and in this particular case, instead of 220 W I would have something around 100 W. Did I miss something?:innocent:
You don't lose any SPL since doubling up on drivers halves the acoustic space that each is firing into. What you gain is extra headroom in the drivers.

You're just shifting the impedance matching around. Essentially, the amplifier is doing half the power but the drivers are doing effectively twice the power so it ends up a wash.

Have you done any thinking about polar response? Dual 6" drivers can't get any closer than 12" center-to-center which is going to start beaming above 1kHz. The beaming will create on-axis boost, but reduce the amount of output in the off-axis. You're gonna end up in a compromise between dialing in the direct sound that follows precedence effects against dialing in the off-axis "reverberation" of the room. The ideal world would be one where the off-axis energy and on-axis energy have the same tonal balance (flat power response).

The B&W 802D seems like a very similar speaker to what it seems like you're aiming for and it very closely approximates a flat power response:
http://www.bowers-wilkins.com/display.aspx?infid=1157&terid=1305&sc=hf
Notice the single 6" midrange. There's no need to go all crazy style with the woodworking, but I would recommend a similar baffle arrangement.

If nothing else, I would try to find ways of making the polar response between the various sections try to line up at the xover frequencies. The difficult part about direct radiators is they tend to be very wide at the low end of their response and very narrow at the top end of the response. This is where MTM arrangements can be beneficial, but they need to be carefully thought out with respect to the xover frequencies you plan to implement.
See less See more
1 - 2 of 54 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top