Mark K's Speaker Site

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Oh, it's coming...

The graphs above are from John K's dipole design spreadsheet. This is a very comprehensive spreadsheet and supporting set of documents that helps design the proper equalization. It's well worth the money. The result shown above is a preliminary result. The woofers are configured in a series parallel configuration, with a 3mH coil on the outer pair. So that would be a 2.5 way as it extends to an MMTMM configuration. An ~8-9ms gated outdoor measurement was spliced to a nearfield summed estimate of the dipole curve below 150 Hz. The unequalized and equalized curves are above in the lower curve. As you can see, it looks pretty promising from 45Hz to 1.5kHz. The actual circuit is not shown. It's only preliminary. Besides, I'll have to ask John K whether or not I can make the actual schematic public since it flows from a proprietary worksheet. I'm sure we'll figure something out...

Before I import it into Soundeasy, I'm going to play around with the MMTMM 2.5 configuration. I'd like to look a little bit at the vertical and horizontal polar response with 2, 3, 5, and 7.5mH coils, as well as a shunt cap (i.e. parallel outer pair has a shunt cap). Why? Same reason I'm doing a .5 way as opposed to a straight MMTMM configuration. I want to make sure the vertical response is acceptable. Too small of an inductor won't attenuate the outer woofer pair soon enough and the vertical polar response may be compromised.

Hopefully over the next month I can finish this, then reimport another set of final outside curves into John's spreadsheets, then into SE. Another month or so to have a working single prototype. Hopefully by New Year's I'll have a working single prototype to evaluate. Of course, that's assuming I make up my mind about the actual midwoofer-tweeter cross topology.