A/V-3's: Offsetting drivers, Ribbon Tweeters,...

0 Members and 1 Guest are viewing this topic. Read 1444 times.

volleynbike

  • Jr. Member
  • Posts: 5
A/V-3's: Offsetting drivers, Ribbon Tweeters,...
« on: 19 Jul 2007, 02:41 am »
Danny (or anyone else who'd like to comment),

I'm planning up my A/V-3's.  I remember reading, years ago in some mfr's interview (Proac?), about the idea of offsetting drivers on the front baffle so they are not equidistant from the sides.  Especially higher frequency drivers.  The idea being to spread out the reflection effect through the spectrum instead of reinforcing at one set of frequencies (if the drivers are in the middle).  Any comments or experience with this?

Also noticed that you mentioned that the ribbon tweeters are a direct drop in for the domes that come with your std kit.  Do they require a different hole?  Do you sell them?  Can i substitute them in the kit?  Any comments about them?

Thanks,
Marvin

Vapor Audio

  • Industry Participant
  • Posts: 2023
  • Building Audio Bling since 2007
    • Vapor Audio
Re: A/V-3's: Offsetting drivers, Ribbon Tweeters,...
« Reply #1 on: 19 Jul 2007, 03:31 am »
If you start changing baffle dimensions and layout, then you potentially have to redesign the crossover network to accomodate the different actual response.  The tweeters will respond differently on a different baffle than designed by Danny. 

That's the perfectionist way of thinking.

The truth is, there are variances in drivers from kit to kit, and those will likely be greater than the .5db or so diffraction ripples.  Unless all you care about is a ruler flat response curve, you could probably offset the tweeters without it doing any harm, whether it does any good or not you wouldn't know without measuring. 

My opinion, it'll look funny with an offset tweeter in an MTM with the flush mount mids designed to overlap the tweeter.  What would do more good for sure rather than offsetting the tweeter would be to make a double thick front baffle and put a bigger roundover, like 1" or more on it.  You could also put a felt ring around the tweeter if you're worried about diffraction - but then again, the shape of the T2 tweeter faceplate does a lot to negate the effects of baffle edge diffractions.

About the ribbon, it's not a drop in.  It'll fit a 104.5mm cutout, that's where the drop-in ends :)  It will take a totally new tweeter crossover network, and the shape of the cutout is different behind the flange.  They do sound nice, but honestly the T2 is a pretty nice sounding tweeter as well. 

If you want to improve on an A/V3 kit, I'd say the best way to do it would be with robust cabinet construction.  If you have all the measurement gear and know-how, you could tweak the crossover to your taste, and to accomodate variances in the drivers, but that's a whole new level :)

Danny Richie

Re: A/V-3's: Offsetting drivers, Ribbon Tweeters,...
« Reply #2 on: 19 Jul 2007, 02:12 pm »
Quote
Any comments or experience with this?

Differences on a baffle this small is minor. If it was a larger baffle it would be a bigger deal.

Quote
Also noticed that you mentioned that the ribbon tweeters are a direct drop in for the domes that come with your std kit.  Do they require a different hole?  Do you sell them?  Can i substitute them in the kit?  Any comments about them?

The ribbons require a larger rectangular whole in the center to pass through but they do have the same sized face plate.

Raw Acoustics sells them.

They will require a completely different network. As of yet, I have not designed a network for that design.