Those speakers I bought...

[johnnyrichards]

Thanks, Bryan. This was a fun "filler" project

[johnnyrichards]

Whitney, it is impossible to compete with most of the comercial guys under $100, and becoming increasingly difficult at the $200 pricepoint.

I just do it for fun anymore.

[michiganpat]

I presume these are the woofers?

http://www.parts-express.com/pe/show...number=299-278

I've been hemming and hawing over picking up a pair of these to use as midranges in a project using some empty AR2ax cabinets I have...overall do you like them, sound quality wise? with the .6mh inductor, where's your woofer low pass rolling off at?

[johnnyrichards]

I presume these are the woofers?

http://www.parts-express.com/pe/show...number=299-278

I've been hemming and hawing over picking up a pair of these to use as midranges in a project using some empty AR2ax cabinets I have...overall do you like them, sound quality wise? with the .6mh inductor, where's your woofer low pass rolling off at?

You presume correctly.

With the small coil, they roll off approximately 2nd order LR at 2500 hz:



SQ wise, they offer some very nice bass. Not in this size cabinet of course, but at lower volume levels they accepted some boost without complaining too much which is why I would recommend going bigger if using them for bass duty. Like pretty much every other 4" woofer I have listened to or used, they go to hell in a hurry when you ask them to act like something bigger.

The midrange is pretty solid IMHO, and the best attribute of this design. I hesitate to say it has a "poly" sound - but that may be the best way to describe it. Kind of warm, maybe a little bit fuzzy and decidedly mid-fi in nature. Definitely a mid for the masses - myself included.

You know, on guitar passages you might not always hear the pick hitting the strings, or pick up on it every time the singer spits in the mic. You might notice a slight emphasis on male vocals from time to time.

I think using it as a dedicated midrange would be a great use for it, if you can keep impedance up. IME, a 4 ohm midrange is usually asking for trouble along those lines. On the other hand, it allowed me to use a small coil for a lowpass so got that going for us.

Also, the poly cone looks like an old 45rpm record. Pictures do not show it on the website. So keep that in mind. Very old school driver. I have no idea when these were made, but not in the last ten years I am guessing.

They are vented under the dustcap and have what appears to be some sort of metal visible through those holes. No idea what it is. No venting or bumping on the backplate. Nice rubber surround and a standard 4" frame so if you do not like how they work, either of the 4" Dayton drivers (DA or DS) would be a drop in.

Honestly, I am on the fence with this driver. I think if a guy is looking for a 4 ohm, 4" driver this is one of the only games in town. Otherwise, I think these offer a much better midrange quality, for just a few more peanuts.

I only used these because I needed something that fit the cabinets. I mean, they are not bad by any means, just... Kind of a weird little driver.

[michiganpat]

well, the one big advantage of it was that the dimensions they give on the website, it would fit in the 2ax's tweeter hole without cutting (and I'd mount the tweet in the original's midrange hole, since it is smaller). I was going to use some ND104's I bought for the mid, but they're a little low in sensitvity, and it seems like a waste of a driver to use one that can reach as low as it can as a midrange.

my thought was to basically take a 1qt yogurt container, hot glue it inside the cabinet, stuff heavily with fiberglass, and run ~ a 60-100uf NPE cap for a high pass on it.

for woofs, I have a pair of these in sitting on the shelf:

http://www.parts-express.com/pe/show...06&FTR=299-106

which yield a predicted F3 of ~ 35hz in the 2ax cab, and using the existing 2ax's 1.88mh coil, should yield a L-R crossover point of about 480hz (using a "cookbook" calculator, since I don't have measurement equipment handy yet)

tweets, I dunno just yet. I had a pair of these earmarked for the project

http://www.parts-express.com/pe/show...38&FTR=299-938

but they were used in a vintage box retrofit I gave my mom as a mother's day gift for her sewing room....

of course, since I started collecting parts for this "hot-rod" project, I have found and bought original woofs and tweets for pretty cheap (less than $60total for all 4 drivers, including refoaming the woofs), and can get a pair of original mids for about $40 if I want to restore back to original....

guess this is quite a tangent. sorry for hijacking your thread.

[jhollander]

Honestly, I am on the fence with this driver. I think if a guy is looking for a 4 ohm, 4" driver this is one of the only games in town. Otherwise, I think these offer a much better midrange quality, for just a few more peanuts.

The 0.5 xmax doesn't scare you off? I like all the TB stuff but it does not seem like you can model the tuning lower than the FS without hitting the x max.

[johnnyrichards]

The 0.5 xmax doesn't scare you off? I like all the TB stuff but it does not seem like you can model the tuning lower than the FS without hitting the x max.

Midrange duty Xmax is irrelevent.

[ROTECH]

Johnny,

Great fun little project you have here. Chipping away at that tinkeritus.

I have a challenge for you!!!!
I have a set of DCM KX-6 rear surround/bookshelf speakers that came as part of a circuit city surround set in like 1991. They have a 6'' woofer and a bullet horn tweeter. Sealed alignment. They have got to be the absolute worst sounding speaker man has ever made. I should ship them out to you and see if you can turn their frown upside down.

[johnnyrichards]

I can give it a shot, Ryan. I think that is where my true "love" (as it were) lies. Modding existing commercial designs. I used to do it all the time way back when.

This little project was such a trip for me - having access to the extensive knowledge base (as compared to twenty years ago when all I had was Radio Shack drivers and books) and modern CAD tools and measurement software really just makes it more interesting - also quicker. Still, much-O fun.

[michiganpat]

Johnny,

Great fun little project you have here. Chipping away at that tinkeritus.

I have a challenge for you!!!!
I have a set of DCM KX-6 rear surround/bookshelf speakers that came as part of a circuit city surround set in like 1991. They have a 6'' woofer and a bullet horn tweeter. Sealed alignment. They have got to be the absolute worst sounding speaker man has ever made. I should ship them out to you and see if you can turn their frown upside down.

what's the internal volume of the enclosure? if they're around .25 cuboc foot, you could always pick this up from madisound

http://www.madisoundspeakerstore.com...er-parts-only/

[espeiffer]

Johnny,
I've been trying to send you a PM with no result. Please PM me so I can send PayPal payment.

Thanks,
-Ted

[ROTECH]

what's the internal volume of the enclosure? if they're around .25 cuboc foot, you could always pick this up from madisound

http://www.madisoundspeakerstore.com...er-parts-only/

THanks for the link! I may have to use that little kit someday.
The challenge to Johnny about the DCM's was just to tinker. The speakers have no use to me except dust collectors. I had no intentions of using them in any way but they came as part of a 5.0 set and all I wanted were the larger kx-12's. got the whole set with center for $100 a while back for a garage system.

Johnny, when I am bored some day I will send em out to you. I would like to see what you can do with the factory drivers though, as it would be a true class in XO design.

[Taterworks]

Johnny, be careful what you say about poly cone drivers around here.



That's poly.



Also poly.

Some of the world's most respected drivers use poly cones. Now, like anything else, a poly cone can be poorly designed, but that's no reason to go grouping drivers into categories like that. I've been very impressed with the Tang Band W6-789 drivers in my Firestorms, and the W4-1052 in my Whetstones (both poly); I'd characterize both drivers as very responsive with excellent microdynamics. They don't sound anything like a Solo cup being tapped on the bottom, even though intuitively that's an easy parallel for the mind to accept. It makes no sense to broadly categorize all poly drivers as 'mid-fi'.

[johnnyrichards]

Rory, you and your poly love affair are sooo cute....

[foxfire3]

Are, as expected, pretty miserable

On Tweeter Axis, 1M, plus impedance:


Both Units:


Distortion @ 90db:


Waterfall @ 90db:


With and without grill:


Raw Drivers:



Download raw in-box driver data here, if you want to play. If used, remember that no need to enter any offsets into PCD as that is contained in the files.

I'll grab some construction pictures and whatnot here in a bit, as well as offer some commentary on the whole shebang.

Johnny, can you please explain how you incorporated offsets into your .frd and .zma files so that no offsets are needed in PCD?

Thank you...