HI-VI B3S Center - Bipole or baffle step compensation?

[owdi]

(disclaimer)My first DIY project above 100hz(/disclaimer)

After reading about the HI-VI B3S driver at www.zaphaudio.com I decided to try a center channel using this driver. I've always wanted to try a single speaker center, since it seems like the most natural way to reproduce the human voice.

The B3S is so cheap that the price of a baffle step compensation circuit is almost half the price of a second driver. Would going bipole with drivers facing opposite directions be beneficial in a center channel?

My concern is the finished speaker will sit on top of the TV. Would there be a midbass bump if I do go with a bipole configuration?

The other concern is my receiver is rated only for 8ohms. An old roommate of mine ran a 3 ohm subwoofer with this receiver, and nothing blew up, so I think it can handle two drivers in parallel.

Hi-Vi T/S Parameters from www.zaphaudio.com

Qts 0.998
Qes 1.24
Qms 5.08
Vas 0.79
Fs 105 hz
Re 6.4 ohms
Le 0.43 mH
Eff 79.2 dB

http://www.zaphaudio.com/audio-speaker18.html

Dan

[westend]

Couldn't you wire the speakers in series-parallel to achieve an 8 ohm load? Or, since the Hi-Vi's take such little wattage to bottom out, wire them in series to achieve a 16 ohm load. I was looking at these for HT satellites or the Aurasound 3's. I have yet to enclose the FR-125's but they could be a great canidate for satellites or center, too.

[Landroval]

Originally posted by westend
Couldn't you wire the speakers in series-parallel to achieve an 8 ohm load?

What's series-parallel?

[bobhayes]

Series/ Parallel is for connecting multiple drivers.

Example with basic four speaker arrangement is to connect two speakers in series, another two speakers in series, and then connect the two resulting chains in parallel. For four 8 ohm drivers, this would present a load of 8 ohms.

You need at least four speakers for this arrangement.

I would not use bipole for centre channel as the rear facing speaker would create a heavy reflected delayed image of the original signal.

Did you ever see anyone talking out of their.....??!

[owdi]

Originally posted by bobhayes
Series/ Parallel is for connecting multiple drivers.
Did you ever see anyone talking out of their.....??!

LOL Good point. Maybe I could put a 1.5mH coil on the back woofer. Or move the back woofer to the front and keep the coil. Hmm...

Edit: nevermind, I forgot to take the change in phase into account

Dan

[Landroval]

Originally posted by bobhayes
I would not use bipole for centre channel as the rear facing speaker would create a heavy reflected delayed image of the original signal.

Did you ever see anyone talking out of their.....??!

I dont think that's exactly how bipoles sound. Stereo bipoles dont have a very heavy reflected and delayed image, nor do they sound like singing out of @55.

You can of cource add a coil to the back woofer if you want it only for BSC.

[owdi]

I've ordered all the parts to build both a single speaker center w/ baffle step compensation, a bipole, and a bipole with the back speaker rolled off. Can't wait to get them, this will be my first time measuring T/S parameters.

Now to find the time to build the box.

Dan