OB vs. IB

[fatawan]

Hello Thomas.

I wonder if you could comment on a design I saw on the GR Research Audio Circle. It's here www.audiocircle.com/circles/index.php?topic=54875.0

I was most interested in the 3 driver/one servo amp design seen on page 4 of that thread. The drivers are www.gr-research.com/index.asp?PageAction=VIEWPROD&ProdID=141
and amp www.gr-research.com/index.asp?PageAction=VIEWPROD&ProdID=142

Is this a different idea than an infinite baffle sub? I am just curious how you think it would work. Any and all thoughts appreciated!

Thanks.

[ThomasW]

Hi,

Having used 12" or larger drivers in a dipole (OB) application for the last 10 yrs, I can comment about them.

Anyone claiming reference level output to 20Hz or below from 3- 12" dipole mounted drivers is ....

1) wearing them as headphones
2) smoking something illegal
3) lying

At one point I had 8-12" dipole mounted drivers in the same room as a 4-12" driver IB. As would be expected, in the passband where woofers operate the dipole mounted units played much louder than the IB. In the passband where subs operate the IB had significantly more low bass output.

If you want to see how a driver or drivers operate in a dipole you can model the behavior using programs like 'The Edge' or 'ABC Dipole' A google search will take you to these programs.

As for plate amps I consider them to be poor long term investment.

From your IP address it appears you live in or near Centennial, CO. If so, you're invited over to my house to hear a pair of dipole (OB) main speakers paired with an IB sub. I live just off the intersection of I-25 and Hampden.

Hope this helps....

Regards
ThomasW

[fatawan]

Thank you very much Thomas--you saved me from another "project" that would likely disappoint! Thanks also for the offer, but CO is not my homebase, and I just happened to be passing through. If I am coming back this way, I will certainly take you up on that very gracious offer!