Hi Wayne
At the risk of triggering even more promotional posts, I hesitate to reply, guessing (based on past exchanges) you will not read with a mind towards understanding but only towards crafting another torrent of such replies.
I found it interesting you chose to respond so extensively to the poster who’s first hand experience with both, led him to say “I've owned both and i would take the LABs any day. They are smaller, put out the same SPL (Honestly can't notice a difference) and they are cheaper to make.”
Well lets see what the jist is here, I mean aside from his feelings that you try to talk him out of in several following posts.
The Lab IS the truck pack size the group (Here) picked and has the low cutoff the group (Here) picked.
Get the picture, it IS the size it is because that is what people wanted, it also has the low cutoff it has for the same reason and for use in a group.
I did not pick these things and it was not because I was limited to the driver at hand, I derived the parameters, specified the driver remember.
You (at the same point in time) argued against the idea of the heavy / strong driver on the AA forums.
Later, you find the LAB sub approach actually does work, but has fatal flaws that can be resolved simply by throwing away one of the main criteria and make it bigger.
You take the driver made for this job, take the same folding arrangement (with more kinks than needed) and increase its cubic Volume.
You find with the increased size at one Watt you can get what, a dB more in some places, dang, that is like… radical dude.
With your plugs you claim to raise the power handing 225%
You might have been able to find a condition where this might be true, to suggest that this is true in use with music or in general use is disingenuous as I would bet you did not measure the electro acoustic efficiency of a group of labs to a group of Pi’s or under power with music in actual use.
You larger compliance volume (which I see you have addressed with a retro fit filler plug) did smooth the response for one box, at the cost of more excursion for a given power.
Under the right conditions, your plugs would help too, but so do the aluminum plates already used in the lab sub, those get hot too. Unlike your plugs, there was no claim made about how much the unusual aluminum cover plates helped, only that they do a little compared to wood.
While the aluminum cover plates transfer heat out of the chamber and driver, to the out side world, that is conditional on how they are used and most sound folks know you can still blow a driver even with a cool magnet
The more dynamic the source, the less likely the magnet temperature will reflect the instantaneous VC temp.
Heck, on most of my Tapped horns, the drivers are fully out in the open, mounted “where the air is really moving” but I don’t claim any increase in PHC over normal.
So far as the push pull part, it is generally not considered worth the effort and other things are so much stronger factors in measured results.
In particular, the lab sub’s “strong heavy driver” in a small back volume (ala Servodrive alignment) which at the time was fully contrary to the “W bin” light cone / big volume horn lore of the day, when combined with a linear motor, produces much less distortion and much more acoustic power than those “old school” horn driver alignments.
Here too, I would bet you did not actually measure a group of LABs side by side with your Pi’s. You might well be pleased with how low in distortion your Pi’s measure, but so are the owners of the Labs subs, they are also lower than most everything out there.
Lastly since your spinning your pitch off the lab sub as the main reference, build, instrument and (fairly) measure a few side by side.
Even better, to get an actual perspective, compare it and yours to the big money / big loudspeaker names people have been buying for the last 10 years.
In addition to something cool to build, instead of more W bins, part of the point of the lab sub project was to expose how lame some “well-respected” and costly products actually were, a fact only visible when measured or exposed in side by sides.
While the Lab sub is a mature project now and there are many new subwoofers out there, it still holds up very well.
Cheers,
Tom Danley