****EDIT - See post 13 for crossover revision
I got another of my many half finished projects wrapped up. This is a center channel that I originally built about a year ago, but never truly completed until now. I needed a new center that was lower so the tv remote would work without having to point it at the ceiling.
Madtown was clearancing out the Aura NS3-193-8A drivers for about $12 each, so I grabbed four of them. They fit the height requirement, four gave me an 8ohm nominal load, and I thought four of them would look kind of tough arrayed across the front of the tv. I sit pretty close to on-axis , so the horizontal dispersion issues this caused wouldn't affect me too much.
Each driver has about 2 liters, originally vented. I wasn't worried about LF excursion issues below tuning as the NS3's have a fair amount of xmech. The cabinet is constructed of braced 1/2" ACX ply, with a lacquer finish.
I wasn't super thrilled with the sound of just the drivers and no eq, so I had added a notch to deal with the resonance breakup and that made a big difference. Much more listenable.
As time went on, I decided I wanted a tweeter, but still wanted to be simple and budget friendly. I saw the new cheap Dayton PTMini6 planar ribbon and wanted to use it in a project, and this was perfect. It even fit nicely between the current driver layout.
I determined that a sealed enclosure of the same volume would also work decent with the NS3s, So I made removable foam port plugs (and have them in and plan to keep them there).
The NS3 crossover consists of a small inductor with a tank and zobel, to knock down the upper response and deal with breakup, and the tweeter filter is simply a first order; a cap plus a couple resistors. All the parts fit nicely on the back of the terminal cup. I could have done a lot more with the crossover, but this sounds good and was simple and cheap, with few enough parts to remain compact.
I am very pleased with the sound (and look) after the revision with the tweeter. Off-axis seems improved, and it sounds decent and pleasant to listen to. A quick rta check with my iphone and imm6 looks to show a surprisingly flat response. I think the yellow planar on the glossy black gives it a high end look.
I have been using it alone (in 5ch stereo with the amps to fronts and rears off) to listen to while doing things around the house and it works well for that duty as well. I didn't have a chance to watch an action movie with it yet, but am looking forward to it.
Thanks for looking!
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