BG Neo 8 PDR vertical dispersion... is this a solution ?

[Jvsantosmd]

Hello everybody. I've read that the BG Neo 8PDR has very good horizontal dispersion but lacks in vertical dispersion. That is, a person sitting may hear something different from a person standing in front of the same speaker. (I read this somewhere, I'm not making this up...)
I've managed to build 2 small enclosures that will place 2 BG Neo8 in each main cabinet, one aimed slightly upward, the other slightly downward in relation to each other. Maybe 170-175 *. (think of a > with the sides nearly horizontal to the front baffle). The front baffle could also be slightly tilted as needed to help dispersion.
While we're at this, if I use 2 Neo8 PDR drivers, how would you recommend I wire them to stay in phase?
Kindly remember this is a simple question from a begginner, good advice is welcome, the others will have pins stuck onto the ears of my voodoo doll.

 

[båndsei]

I use amt´s DIY with 170*
I am very satisfied with the dispertion now.

Bernt

 

[Jvsantosmd]

Thanks for your prompt reply.
Can you please provide me with the wiring diagram you're using? I'm still in doubt on how to wire them to maintain them in phase... or should I purposefully wire them out of phase?
Do you use a notch fliter? I know the BG Neo8 PDR should use a notch filter for a 10,000 Hz horrific spike, maybe this does not apply to your drivers.
And lastly, could you PLEASE post a picture of your speakers ?
QUITE IMPRESSIVE !!

 

[Eldam]

hi

What is the reason please of the 90° titled mid-bass? Narrower directivity ? Less power or side walls reflexions ?

each AMT has the same frequency range ?

regards
Eldam

 

[båndsei]

I am not using notch filter for the Amt´s.
Wiring: + O - +O - to keep them in fase.
Here a tread about my Pluto clones incl. sub:http://www.diyaudio.com/forums/multi-way/207478-pluto-clone-incl-sub.html
I did´t use 2 amts at first models.
The bas/mid is tilted to get omnidirektional dispertion.
Each Amt covers the same frequency range:from 1200hz .

Bernt

 

[Jvsantosmd]

I realize the tread specifies top/bottom alignment on the BG Neo 8's.
I've seen several speakers that have them side by side.
As I understand, they have very good lateral dispersion, so to me side by side may not be the most practical.
Is there a "better way" that's been tested ?

 

[Jvsantosmd]

Also dear friend bandsei, I can deduct that you wire your amt in parallel, + to +,
neg to neg. Is this correct ?

 

[båndsei]

No ,it is in serie + speaker - +speaker -

Bernt

 

[Sonce]

BG Neo 8PDR has very good horizontal dispersion but lacks in vertical dispersion.
I've managed to build 2 small enclosures that will place 2 BG Neo8 in each main cabinet, one aimed slightly upward, the other slightly downward in relation to each other.
if I use 2 Neo8 PDR drivers, how would you recommend I wire them to stay in phase?

Narrow vertical dispersion can be an advantage...
Otherwise, your solution is good, but bottom Neo should be almost vertically oriented and aiming at head level while sitting (nobody listens laying on the floor) and top Neo slightly upward.
You must connect serially two Neos and in phase, + from amp/crossover to the first Neo's +, than it's - to + from the second Neo. Neo 8 PDR impedance is about 5.2 ohm, so parallel connection will be unacceptably low at 2.6 ohm.

 

[Jvsantosmd]

I have since decided to place them both flat against the front baffle.
The front baffle is going to be 7 inches wide with both sides cut at 45* corners.
Still crunching numbers as to the best crossover frequency for a series type wiring.
Any help here is appreciated.

 

[Jvsantosmd]

Well, the angled enclosure didn't make it past the design stages. I decided to go with a flat front baffle where the 2 BG Neo8 and the Dayton PC-2 ribbon tweter will be mounted. To my surprise and advantage, they're both the same width, which means I can play around with a MTM or a TMM design.
My questions are now... any difference benefits in either arrangements?
Should I stick to a vertical speaker placement or can I place them sideways?

 

[Sonce]

Go for a vertical placement, it has smooth horizontal coverage.

 

[Jvsantosmd]

Thanks!
Having solved that part... MTM or TMM placement ?
Having two of them wired in series, what would the xover freq be ?
I have been going CRAZY n some of these free xover and enclosure design programs and the only thing I've been able to come close is somewhere around 700-800Hz.
However, I'm still doubtful about something:
Can I use a 6 db attenuation on the low-mid and a 12 db slope on the mid-high transition?
If I can, what would the low/high xover points be?

I have promised to myself there will be a next time... in the distant future...
This is very time consuming ! But so much fun !!

 

[a.wayne]

I use amt´s DIY with 170*
I am very satisfied with the dispertion now.

Bernt

Can we see a direct picture of your AMT...?

 

[båndsei]

Here is a Picture :

And another:

Much more in my tread:http://www.diyaudio.com/forums/planars-exotics/218549-diy-amt.html

Bernt