Question regarding peak in the first maximum of the dipole effect

[mazeroth]

I'm ready to order the parts for Monte Kay's RS dipole speaker and was taking a look at his Behringer DCX2496 file. I have no doubts this speaker is set up correctly but was shocked at the -9db notch he has at 478hz (see photo below). Does this seem correct? I know a lot of people that run dipole mids that don't use a notch on the mid and think it sounds just fine.

Also, I'll be using the new Dayton RS subwoofers instead of the 10" Dayton RS woofers Monte went with. As far as the transfer function do you feel much will need to change, since they're both the same size woofers and the box won't be changing? I will measure the output and adjust the gain on the DCX2496 accordingly, but I don't "think" I'll need to alter the crossover much, if at all.

Any input on these matters is greatly appreciated!

http://www.mfk-projects.com/rs_dipole.htm

[Davey]

The notch filter looks reasonable to me. I think you'll find that a notch filter similar to this is required on most all open-baffle mid panels. It depends largely on the shape of the basket/magnet assembly on the mid driver and how the mid-panel is shaped.

I'm sure you know this.....but visit Linkwitz' webpage and all aspects of these designs are explained.

http://www.linkwitzlab.com/models.htm

I think you're probably correct with regard to the woofers. Unless there's a significant difference in the Qts of the newer drivers the same 6db/octave dipole correction should be okay. Level shifting notwithstanding.

Cheers,

Davey.

[mazeroth]

The model Monte used has a Qts of 0.35. The new RS subs have a Qts of 0.39 for the high fidelity version and 0.33 for the high output version. I was going to use the high fidelity (2mm more xmax and lower Fs) sub, which has a Qts 0.4 higher than the 10" version in the design. I don't think that should affect it much, do you?

Also, do you feel going with the RS subs will buy me much more performance? They have 2x the xmax, but being 10" woofers, how low do you feel I'll be able to go? Monte uses a 24/db butterworth on the sub at 25hz, but I doubt they can dig that deep.

Thanks for any input, as always!