CA15RLY + 27TDC 2-way development

[Jed]

Well, to put it bluntly I got sidetracked from my 3-way design and decided to spend some time working on this little speaker for my sister's B-Day present.


If there is enough interest I'll post my progress on this project. It will use the Seas CA15RLY and Seas 27TDC tweeter. The crossover will be 4th order around 2.1K. So far, the results are looking good. I plan on painting the cabinets in a texture black that I've used before with nice results.

Let me know what you think. I can post FR and crossover when I'm done this next weekend. Well, at least I hope to be done soon so I can focus on my Usher 8955a, Scan Speak 12M, and HDS 1" dome tweeter 3-way. I have been working on the 3-way a little bit too, but I'm excited to get this 2-way done.
Jed

[cobbpa]

If there is enough interest I'll post my progress on this project.
Jed

1 vote for "yes please." :T I always enjoy reading through design / build threads.

[Jed]

This is a Rustoleum Hammered finish. There are a few imperfections that I'll have to finish up with the next paint coat. But I think these are looking interesting- not just a plain old box since there is a large bevel on the top. Front baffle is 1" thick and the sides 3/4". The top is 1.5".



I've also got a few crossover ideas. One series configuration and one parallel configuration. Since I have the parts for the parallel one that's probably what I'll end up doing, but the series design got my interest because it is just different. I'll post the crossover ideas later tonight. FRD files and ZMA files were massaged with baffle simulation software, minimum phase- from actual measurements on a slightly different baffle. I'll take measurements in my box this weekend and tweak the design. At that point, if this design sounds good I'll post more info. I do anticipate this one as a forgiving and pleasing sounding speaker. I think a lot of people cross over the CA15 too high, and 2K is probably still too high, but that's about all the TDC can handle/recommended by SEAS @ LR4.

[Jcake5]

Thank you for shareing your design with us. I look forward to your series crossover to compare it with some of my simulations of the CA15 and 27TDFC. My wife has specified size limits so I am trying to find the right 5- to 6-inch driver and the CA15 is recommended. Right now I am considering one of the Peerless Nomex drivers against the CA15. I have heard the CA15 but not the Peerless drivers.

Kind regards,
Eric

[truckman]

This is an interesting project. A while back I looked at a bunch of the designs over at http://www.murphyblaster.com/, and there are a few that have similar drivers to yours.

• CAOW1 - CA15RLY + OW1
• MBOW1 - GR M130 + OW1
• MB27 - GR M130 + 27TFFC

I bought the parts to build the CAOW1 because it has an extended low end as compared to the designs based on the M130. I think pairing the CA15 with one of the Seas tweeters is a logical combination, especially considering the price difference between the Seas tweeter and the OW1 and how well regarded the Seas tweeters are in this forum.

Now if I could only find some time to make sawdust ...

[Jed]

Note series crossover inspired ala Modula. I'm not sure if you can tell but basically I started with Jon's layout and started removing/changing unnecessary parts as the CA15 doesn't have much of a cone breakup (Just massive energy storage- hehe). In fact, it is pretty flat past 2K from what I have seen in some FRD files. This weekend I'll verify a few things and get a few steps further. I don't know yet, but the series layout looks better to me even though the curves aren't perfect LR4. Pretty close though. I'm not sure if I feel like investing in a lot of crossover variations. We'll see.




And the parallel crossover prototype. Not a final design by any sense of the word. These are some parts that I ordered to experiment with before finalizing the crossover. It'll be interesting to see if the CA15 still has that 1k bump with my baffle.

[Jed]

I'm getting closer to a finished speaker. Today, I have finished up the cabinets and loaded drivers for the test speaker. I'll start taking measurements today and post the results as I get further along with the process of finalizing the design.

[capslock]

It's amazing that the glue joints in your bevelled surface don't show through the paint. Did you use some sort of base or filler?

[Paul W]

Is that the gray or silver Hammered? I really like the way that paint drys so quickly but would like to find an additive to lower the gloss.

[Jed]

I used wood filler on the seams, but I coated the entire edge and didn't sand away too much. Then a few coats of primer with light sanding in between. The Rustoleum is black, and if you find out a way to get rid of the gloss let me know. I sometimes do a light coat after the first thick coat is dry, and this method seems to give an even sheen.

Now for the progress. I've taken measurements and modified the first crossover based on the new results. This pretty much confirms you can't rely on simulations with a complex baffle like the one for this project. The tweeter has a rising response, which might add a sense of false detail, so that is why I used the .15 inductor after the L-pad circuit. I'll listen and measure this first crossover to verify the results.

[cgr]

Those look very similar to some custom panniers available for motorcycles:

http://www.jesseluggage.com/odyssey.html

[Jed]

Well, it has been a busy day. I feel like the speakers are pretty much finalized right now but I'll probably change my mind and keep tweaking. For now, the response is incredibly flat from 600hz to 15K. Below that the room starts to have negative effects. I was suprised to see my samples of the CA15 didn't have the 1.5k dip that earlier units had. Hey, that's a good thing! I'm pleased with the way these turned out.

Note the changes of the crossover after I took measurements. There are some significant differences.



Here's the in-room response. I adjusted the top end a bit by changing the
.15uH to a .12uH. Nice flat tweeter response.



Here's the impedance response. Nice and flat with 4.1ohm dip at 5k.



I've decided to name these the "Kiera K's" after my sister. These after all are for her.

Enjoy!

Jed