Build Intention:
A “simple” two way speaker with the advantages of the Econowave, but deeper bass than my current woofers, and more directivity by using a compression driver/waveguide that extends down to a lower frequency.
Eventually building the speakers with “modular” cabinets, to make changing parts easier.

I’ve been enjoying my Econowave speakers but I know the Selenium D220ti is not as good as it gets with compression drivers – plus I’ve been quite impressed with the Crites speakers “Cornscala type D” speakers, a DIY two way variant on Klipsch speakers that use the Faital Pro LTH142 Tractrix horn as one of the variants.
These horns even have published directivity heatmaps (although only to 12.5Khz), quite unusual for info for the manufacturer to publish.

Although the Cornscala uses the HF140 compression driver, I’d read that the HF144 has a similar frequency response (usable from 500hz – 18/20Khz) but smoother sound as it uses a “ketone polymer” (whatever that is 🙂 ) diaphragm material instead of titanium.

So a pair of HF144 compression drivers and LTH142 Tractrix horns purchased from usspeaker.com and eventually arrived..

The compression drivers installed with 66uF protection caps in series, to stop an inadvertant blast of LF signal frying them.

also after getting a bit of hiss from the HF amp I’m using (a hifimediy T2), I added some resistors in an approx 9dB LPAD (using 5.1 and 3.9 ohm resistors)to attenuate the output as well.

initial dissapointment – notch in the HF response

left and right compression drivers, no EQ on miniDSP or crossover:

I was disappointed to see on measuring these they had quite a notch in the HF response.. although above the range I can easily hear (about 15K) it was still disapointing when the compression drivers mention a range up to 18K and the manufacturers graph indicates smooth response in that region (but what level of smoothing have they applied?). In fact I stopped using the drivers and waited until Col came over with his WooferTester3 setup so we could measure the impedance curve so we could get a handle on wether the units were faulty – but they tested electrically as fine anyway. Also one of the units has a bit more of a HF rolloff than the other.
After the shock of my first measurements (with a fairly “zoomed in” and unsmoothed graph, using the same scale as the manufacturers graph, with a bit of smoothing, which Faital appears to have used in their graph, I get something closer to the “factory graph” taking into account low frequency room artifacts and rolloff due to the protection caps, but the HF notch is still there where it isnt on the “factory” graph:

As I know my hearing does not go up to the level where the HF notches are any more the notches are maybe not worth worrying about, but still it’s annoying when something doesn’t literally measure up to it’s promise.

On the other hand the units do sound very good, once I set them up with MiniDSP to flatten the response a bit.

Presently thanks to my MiniDSP setup it was fairly easy to add these with my current Econowave speaker cabinets to get started quickly.
I have tilted the cabinets on their side so I can have the tractrix horn as close to the Delta 12LFA woofer as possible.. it looks a bit awkward, but the sound is very good.
I’ve got it sounding clear and pleasant good with a range of crossover points from 500hz to 900hz, although one problem is room effects kick in below 700hz so below there it becomes guesstimation – until I get an opportunity to take the speaker cabinets outside to measure, which I may not bother with as they are only “temporary” until….

total response of Delta12LFA on its side, plus HF144/LTH141 combo, crossed at 900hz, with miniDSP eq. Gated. Measured @ 1M from WG :

total response of Delta12LFA on its side, plus HF144/LTH141 combo, crossed at 900hz. Smoothed to 1/6 octave. Measured @ 1M from WG – so this shows the room effects as well.

THE NEXT STEP: CHOOSING A NEW WOOFER
I’ve been looking at a range of 12″ and 15″ low frequency drivers to match to the new High Frequency part of the system. I started looking at 12″ drivers such as the Beyma 12B100 but have been convinced (especially as how good the HF144 sounds even crossing over at 500hz) that 15″ drivers are worth seriously looking at.
There are a vast number to check out, and I’m working on a shortlist of candidate woofers, and I’m in no hurry as the current rig with the Faitals sitting on top of the sideways econowave cabinets sound pretty good.