I'm not sure where Mark Schifter got the design, Mark Seaton hasn't responded to my query yet but in the end, I like it, I really do. I bought it for the price not expecting much and it sat for years and when I put the parts together and put it with a pair of Elac B6's I was stunned at how tight and dynamic it was.
If I can find out the proper information I would like to put the right amplifier and driver in there eventually.
Hi KH,
When I quickly responded to your thread, in my post-show sleep deprivation I scanned the pics and missed the question about if I had anything to do with the x-plosive design. Yes, this was entirely my design and an outgrowth of the original Terraform prototypes that ended up in the basement of the to-be-founder of iRule/OnControls:
The BMF was designed first, which used a similar 6th order bandpass design but with passive radiators for the high and low frequency tuning.
I grabbed 2 of the prototypes from the liquidation sale and one drives the daily office system while the other has cycled in and out of a system at home for when ever I'm not tinkering with a prototype. At the time only one other company, James Loudspeakers, was doing somewhat similar designs where they offer some 4th order bandpass designs (sealed rear chamber, PR in front of the driver).
The x-plosive was a super-budget alternate to what I was working on getting to production in the massive Terraform XL subs many have seen pictures of:
The first long and low units above did work very well, with the x-plosive also working quite well. The higher density designs were both hugely gratifying to see the designs test out exactly as the multi-part models predicted, and disappointing to find the passive radiators and surrounds available at the time were not quite up to the task of such high output per volume. The x-plosive was the biggest disappointment of the stillborn designs I did for AV123 as this was ready to go with just a few reasonable cost parts to tool up to avoid the issues we found with the big Terraform XL. This was a stellar performer and I had an extremely capable 10" XBL^2 woofer sourced for it. I actually still have a couple more on a shelf here if you are interested. It needed very modest filtering to be very flat from ~18Hz - 120Hz and sounds very clean.
If you missed my response on our forum, I did respond:
It's likely to be a bit peaky in response (with the ULW10 driver) unless you get really lucky with parameters, but it will make sound and is tuned around 18-19Hz. Measure about 1" in front of the PR and then about 12" in front on the floor to see what it's doing.
Alternately you could easily just remove the 10" woofer and install a 12" driver appropriate for the internal volume of the cabinet which you can calc very easily. The vent tuning would shift down a few Hz with the front chamber opened to the driver, and should perform very well. This is basically what I did with the Terraform D18 subs I later offered for sale using the above pictured Terraform XL cabinets.
That quick trip down memory lane certainly gives me some ideas about re-visiting some old design ideas with new suppliers available.
