Up next - Dayton Waveguide + Generic Kevlar driver

jr@mac

So here we have the beginnings of what essentially amounts to a "use that shit already" build. The woofer is an unknown beyond the T/S parameters - but it is attractive as far as yellow cones go. Here is a picture of them:



https://www.amazon.com/DROK-Subwoofer-Sensitivity-Loudspeaker-Component/dp/B01N76JL25/ref=sr_1_12?ie=UTF8&qid=1519866370&sr=8-12&keywords=drok+woofer

The ad copy cracks me up, you can't make this shit up:

Impedance：4 ohms; Rated power：35W; Unit diameter：6.5 inches; Sensitivity：88dB.

The speaker cone is made from imported fiberglass to provide high sensitivity and good rigidity of sound.

Adopt high performance ferrite giant magnet to promise sweet alto voice and strong bass compensation.

Bright yellow color demonstrates prime and luxury, drawing more attention.

Note: price for only a single speaker, NOT a pair, you may order 2pcs together if you need a pair of speakers.

So here is what the free-air impedance looks like:



T/S taken after a really fun break-in period:

Fs  = 54.60 Hz

Re  = 3.64 ohms[dc]

Le  = 228.00 uH

L2  = 421.96 uH

R2  = 15.94 ohms

Qt  = 0.51

Qes = 0.60

Qms = 3.41

Mms = 16.40 grams

Rms = 1.649932 kg/s

Cms = 0.000518 m/N

Vas = 12.04 liters

Sd= 128.68 cm^2

Bl  = 5.849851 Tm

ETA = 0.31 %

Lp(2.83V/1m) = 90.51 dB

Added Mass Method:

Added mass = 25.00 grams

Diameter= 12.80 cm

Other than a blip at 650 or so, it looks fairly smooth enough. Models so-so in a medium vented box (0.49L) tuned to 52 Hz:



F3/6/10 of 57/46/38. Not going to really drive the point home the brontosaur stampede in Peter Jackson's "King Kong", but decent enough all things considered. 

Here it is in the box with the Dayton waveguide:



Project #3 in these cabinets. At this time, they will be retired and given to someone else to put in their garage or something. 

Anyways, there ya have it - back to my roots by taking a chance on an unknown driver. In all honesty, this driver should probably cost somewhere south of the Dayton classic - but it is better than I expected. I have bought probably 200+ buyout/unknown drivers in the last 10 or so years - the vast majority have T/S parameters that don't measure up to this guy. If the Fs was lower, it would be a pretty damn nice acoustic suspension woofer. As it is, it should be ok. 

Wifey has dibs on the living room tonight, so hopefully measure tomorrow. 

dynamo

“you can't make this shit up”

some guy managed to!


I see Amazon offers “expert setup” if you need it..

dynamo

What did you paint your baffle with?

jr@mac

That is black Duratex.

jr@mac

I am hoping to get some measurements taken tonight and start the crossover design process. The woofer may prove to be problematic - we'll see. Maybe it will offer a chance to experiment with damping the cone. 

Tweeter should be a piece of cake if there are no glaring off-axis issues due to the offset location on the baffle.

dynamo

I like the fine matte finish. What did you use for a roller. I have never used duratex because I thought it left a coarser finish.

jr@mac

Foam roller from Walmart - but finish is also a function of timing on curing between coats.

Nicholas_23

/\ .... this , JR's pretty good with the dirty tex

jr@mac

Thanks, Nick - I do enjoy working with the stuff.

No measurements yet - wife and I decided to have a date night instead. 

dynamo

jr@mac said:

Foam roller from Walmart - but finish is also a function of timing on curing between coats.

Thanks, looks really good

jr@mac

dynamo said:

jr@mac said:

Foam roller from Walmart - but finish is also a function of timing on curing between coats.

Thanks, looks really good

Thank you, sir.

jr@mac

Took a quickie measurement set today so I could get started on modeling.

Raw frequency response in-box:



The weirdness around 600 is high-probability real - there is a wrinkle in the impedance there as well, both free-air (as seen above) and in-box, as seen below:



An hour with Xsim yielded this:







I might throw these components together and see how it measures up and how it sounds. 

So far, so good. I think the woofer is a prime candidate for some modifications to see if that blippydidodah around 600Hz can be improved. 

The tweeter seemed to really like the notch, will probably keep it right there. Depending on how loud you will want to play it, it can probably safely be crossed as low as 2K IMO. Think a 4" based 2-way. As can be seen here, I am currently at about 2.5K. 

Anyways, not a cheap crossover really - but I have something like 1000 components that need to be used up so I don't really care about that shit. If this was something I was designing to try and pander to the kit crowd - I might do something different, I suppose. 

jr@mac

Oh - I also have a pair of those really cheap 6-1/2" pieces of shit Dayton uses in their B652 system. I might pop them in there and see how they perform. I still have a pair of the Cabrini woofers, as well.

PWRRYD

I really liked that tweeter in the Industrials.  I crossed it over a little higher and therefore didn't need the parallel LCR.

jr@mac

Some progress, finally. Still have to mount the ports, but otherwise just about done. Eliminated the notch across the tweeter terminals after listening demonstrated it was unnecessary. That little Dayton WG tweeter is pretty damn nice, one of my favorites. 



Pretty close to true point-to-point, very arguable on whether that has any merits, and uses some pretty inexpensive components. They all measured within 3% of advertised. The coils are both Dayton, mylar TI caps for the two larger values, and a HiVi branded MPT out of that HiVi kit I wasted my money on. Resistors are marketed by Rival. All 16awg wiring, color coded zippie ties. 

jr@mac

Well, I fucked up one of the four ports, but otherwise I am done. In the image, the left speaker has one port offset too far. I also forgot to sharpie the tweeter cutout so it has the ring of shame there. 



If they are not sold off by Iowa, I'll bring 'em along. Thus endeth the Cabrini Redux cabinet journey. These cabinets have thousands of miles on them. 

jr@mac

DJ Dado peaking at 105db or so, these are totally solid. 

jr@mac

I'll throw some measurements up later. I took my standards - distortion at 90db, horizontals out to 45 degrees, and on-axis FR. 

jr@mac

The Dayton waveguide tweeters are pretty sweet, imnsho. Glad I grabbed a few more when they were on sale - I am thinking with a better midwoofer, a pretty serious design can be had - rethink what it costs to get to the higher end of things. I am thinking that MCM 3669 midwoofer. Hmmm... PE 0.23 flat packs, $18 woofer and $18 tweeter. 

Craig, you did an MTM with the 2669 and this tweeter, correct?