InDIYana Bare Minimum entry; first attempt DNF…

tajanes

Thought I’d take the InDIYana bare min, cheap driver, two spkrs 1.25cu ft (2.5 total), two ways and min crossover for a roll…

And I came up with a minimalists 1 speaker box idea, with 3 active drivers (with 1 passive radiator) design.  Found a unique, made in Chicago, 8-inch broad range (stated 60 to 12g Hz) dual coil /whizzer driver for a whopping $20.30 (so at that price thinking maybe 8 to 12g top end usable max) regardless that might mate nicely with a couple Dayton Audio AMT minis ($29.40) with a capacitor per tweeter.

That dual coil driver didn’t come with a frequency chart, and for good reason.  I ran a scan and it looked more like the start of a roller coaster ride than a speaker driver’s response.  OK, a notch filter may address that issue, so I started off and built a mini floor stander (pics attached).   Put in a 10 in passive (DAA270-PR  $27.90) and more than a few days of sawdust cutting, and got it upstairs for some testing for the filters.

Ok, while the results of a very broad notch filter weren’t the best, it was beginning to look to be workable (and the dip at 1200 oh well, dips aren’t as noticeable as peaks, so they say). The problem, which has been the killer, is the $20.30 dual coil / whizzer cone special’s output doesn’t really move the passive to support the low end.  Placing an additional very large coil up front tilts the balance of the response down above that level beyond use.  Interestingly when pushed via a low-shelf dsp @ 160Hz it works (flatter albeit not with a whole lot of grunt) down towards 40-60 Hz), but thats not the design objective here..

.  So a fun concept, and coming in at ~$150 parts, but short of showing up in Indy.  On to the next…

tajanes

As previously mentioned, I’m a bit bummed that my $20.30 driver didn’t seem to push the passive driver enough to get a satisfying lower end.  Seems that some of the problem additionally is that ‘high quality’ home depot ply (not sure if its really wood or not) warps when one side gets painted…  so a bit of caulk is helping seal the box, which seems to have been a good portion of the problem.  Just have a small cap on each tweeter, so I’ll continue to play with a notch filters…

Interestingly though, with some help via a low-shelf via a dsp its actually kind-of works (see attached freq chart).  I know the dsp takes it out of contention for the bare min contest (though with the dsp unit and the cost of the drivers / parts still < $300…).

I’m thinking of bringing it anyway as a ‘regular’ speaker entry (albiet non-conforming), or my updated Open Back speakers (I had in Iowa) with a new upper section employing a horn loaded concentric mid/tw (Celestion).  Any thoughts / suggestions? Thx

Looking forward to Indy.

Andy