Push/Pull Slot Loaded

Knocked this up today after much reading of djk's past posts, loaded with a pair of 1550's...



Only had a few minutes to test it out but sounds quite punchy and appears to exhibit a bandpass effect, rolling off around 300hz, presumably because of the slot. However it doesn't appear to play as low as simmed. Will give it a better work out, and take some measurements, on Sunday!

The effective vb is 130l tuned to 38hz, filter assisted (thanks to teslaman for that one) to keep size down as the extra volume of the slot is around 30l and the ports another 25l.


Edited by mikey bear - 05 July 2011 at 11:19pm

Thanks for the info Tony. Will have another look at it. I only used the 1550's as they were available to borrow. I have a pair of JBL 2206 here which might do well above my bandpass sub in this PPSL loading.
Now lets see if I can get one built before sunday .


EDIT: Just to add, gave the cab some juice on Sunday...It appeared to play much better at low volume than when I tested in my garage. However it became apparant as volume was increased that one of the cones had a  torn surround causing some very strange noises and stopping any further testing. I'm unable to draw any conclusions about the design at this stage but it  certainly looks promising.


Edited by mikey bear - 05 July 2011 at 11:32pm

ok, im going to ask a stupid question, i have been trying to figure this out for a while.

Mautopsy wrote: ok, im going to ask a stupid question, i have been trying to figure this out for a while. are the drivers firing together? (are the cones moving towards each other) or are they wired in parallel? And how are they simmed?

one of the drivers is wired opposite polarity. simmed as a reflex cabinet.


Edited by mikey bear - 03 July 2011 at 11:09pm

mikey bear wrote: Mautopsy wrote: ok, im going to ask a stupid question, i have been trying to figure this out for a while. are the drivers firing together? (are the cones moving towards each other) or are they wired in parallel? And how are they simmed? one of the drivers is wired opposite polarity. simmed as a reflex cabinet.

Probably a stupid question and im guessing the answer will be no but

Would it work if i flipped a driver round in my G-sub and swapped the polarity on the driver?

this is the best info i have been able to find with regard to deriving lms  settings from high pass filters with a particular q...
 

i am yet to fully put this info into practice but will be using the 40hz alignment on my mk2 ppsl cab.