HELP!! Creating 3 way with woofer being powered

[JohnnyP00]

Hello All,

I'm looking at creating a new design using a tweeter and mid as passive with a powered subwoofer. The speaks I'll be using is the Vifa XT(HF), Vifal PL11MH(MF) and the PL26(LF). My inspiration is the Verity Parsifal.
Parsifal ovation
The idea I was going for is to have the tweeter and mid passive going into the powered woofer. I want to try to connect the sub through speaker wire.
I've dsigned passive three ways but wanted to try a powered woofer. Ideally I would like the following attachment: int. amplifier > mid/tweet > powered subwoofer. Is this possible without damaging the mid/tweet? Would this affect the impedance/phase etc.
I'm a noob when it comes to powered subs. Ive seen sub amps with speaker wire in and outs. Should I connect the speaker wire into the sub amp and use the outs to the mid/tweet? My amp doesn't have sub outs plus I wanted to simplify the connections using only speaker wire.

Thanks for all your help in advance.. JohnnyP.

[Cal Weldon]

Hi Johnny I have done something similar but mine are 4 ways. The woofer and amp are on the rear and the mid-bass, midrange and tweeter on the front. I found it was easier that way as the woofer on the rear only goes up to 80 Hz so I needed something to take over at that point.

[DougL]

Off the top of my head, wiring the mod/tweeter to the amp, then the plate amp / woffer to that defeats many of the benefits of going active.

1. You probably need a high pass on the mid XO. With a real electronic XO, the mid high pass would be handled in the electronics.
2. You are forcing the power amp to output full range. You miss out on the lower IM and extra headroom of a true bi-amped design.

YMMV.

Doug

[Cal Weldon]

Yes Doug there are real advantages to going fully active but sometimes for whatever the reason you can't. I have enjoyed the results of my endeavours. So much so that I did it a second time, equally satisfying.

[JohnnyP00]

Hi Doug,
Full electronic crossover would be ideal but well beyond my application here and my knowledge. I'm looking to release the need for the amp to have to power the subwoofer without having to change my setup too much.

Hi Cal,
Thanks for the info. Like the speaks. Did your application cause any change to the passive section. I'm not to sure how attaching the subwoofer amp through the speaker wire effects it. I'm looking to crossover around 250hz so I'm probably going with the woofer on the front. Did you connect through the upper passive section first and then connect to the subwoofer or vice vera?

Which amp did you try out for the sub section. How much wattage would you think I would need to be able to mesh with the mid/tweet section?

Thanks JohnnyP.

[Cal Weldon]

Hi Johnny,

First off do they make a woofer plate amp that goes to 250 Hz?
In mine the main amp is connected via the speaker level inputs on the plate and I don't know what the difference would be as to get any sound from the plate amp speaker outputs, you have to connect to the speaker level inputs. And it allows you to make use of the built in 6dB high pass on the speaker outs. I forget which amps they are, the speakers are in my other place so it won't be till tomorrow but I think the smaller speaker is a 70 watt amp and the larger is the 100 w both are sold under the Dayton Name from Parts Express. I can't really tell you what's right for your set up but I always believe in using an amp that is rated at least as high as the driver.

I think these are them:

http://www.parts-express.com/pe/show...number=300-784 running the TB W1139

http://www.parts-express.com/pe/show...number=300-802 running the TB W740

[JohnnyP00]

Thanks for the link. 180 hz it is then Didn't know they only went that low. It should still work out. The 100 amp sub plate looks like a good option.

Was there any phase or impedence changes connecting it through the amp first? I'm a little clueless when it comes to subs.
Have you tried connecting your amp directly to the passive speakers and then use speaker wire as a jumper to the speaker level inputs on the plate amp?

[Cal Weldon]

Hi Johnny, You simply run the speaker wires to the plate amp ins, use the wires that come off the back of the amp to run the woofers and use also the speaker level outs to the passive part of your system. On one of the speakers I think I also used a 200mfd cap on the passive part for the mid basses. Don't remember if that was in addition to the built in high pass or that was an amp that didn't have the high pass.

EDIT: Now that I look at it, the 70 watt amp is a straight pass through so I added the caps to high pass.

EDIT2: I also notice the 100 watt amp I have is not quite the same as mine is an open back where you can see the high pass caps. The one in the link is closed in the back.