compund motor subwoofer

[muddasirwaheedmalik]

what you mean by "difference in excursionbetween the two drivers in the standard isobaric configuration " ??? Thats what we want to explore here

I think even the most rigit isobarik cannot substitute a mechanical coupling especially when you are pulling the cone out, i mean the foam surrounds are porous, the air is non-linear, at best its thress resonating springs with 2 weights in isobarik as compared to one weight between two springs. easy to predict and work around mor elinearity less surprises.

The objective is learning... and possible some very good SQ out of ordinary drivers. i hope i will have support here.
Any ideas what to measure, THD ? SPL, Qtc, Fs etc???/

Basically as i see most SQ drivers have low Fs usually and low senisitivy, a trade off for more low ouput than higher bands, but having greater MMS and needing greater BL, more magnets for keeping the coil in linear region, and over heating ..........list goes on so for even modest improvement in SQ and motor control over a heavy cone we need a way tooo huge motor and cost.........hence the approach. two motors doing the work of one cone with each coil in different relative position to field force they almost would be linear.... better than stacking 3 magnets why not two magnets doing pull-push in tandem. At least theoretically.

regards

[Don Hills]

For any practical isobaric configuration, even face to face for minimum volume, the excursion of the two drivers differs significantly. Rigidly coupling the two drivers reduces the excursion difference to zero, but doesn't significantly affect the overall response. My original reason for simulating it was to look at what would happen if the enclosure between the drivers was the same volume as the "rear" enclosure. I was surprised to see how even a small volume between the drivers made a significant difference.

As for your thoughts on having the coupled coils in different positions to improve linearity, this will only work if the BL product of each coil is non-linear through its travel, so that the combined force is linear. I believe there is a patented system that does this with a single motor/coil assembly, "Alpine X2" or some similar name.