The Javelin - 4 way digital active project - diyAudio
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Old 10th September 2014, 05:16 PM   #1
Greggo is offline Greggo  United States
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Join Date: Feb 2004
Location: Minneapolis, MN
Default The Javelin - 4 way digital active project

OK, I have been reading around here for a long time... posting very little and not building much of anything. So against all good advice and common sense, I am going "all in" on my first decent project and attempting to build what will be the ultimate speaker for me, personally.

The long version can be found over here:

Javelin - a high end journey into digital active speaker systems

The short version is that I got inspired by Jeff B's Kairos project and drew inspiration from some of my favorite speakers (AR, Harbeth, AudioPhysic), and then tried to design my own version of a substantial tower speaker with a cool modern design. CNC shop is getting ready to make saw dust over the next few days and I am getting ready for the big assembly, epoxy, sanding and painting exercise to kick off in a couple of weekends.

Please fire away with anything, good or bad, nice or mean... I am a bit bored while I wait for parts, so take me to task on anything you can think of.

Materials:
● Raka marine epoxy
● Baltic Birch plywood (60 x 60 x 3⁄4 sheets, which are actually 18mm but seem to measure
around 0.69 inches thick)
● Duplicolor spray paints and primers:
○ HWP101 Silver, HWP102 Graphite, HWP103 Clear, and CP199 Adhesion Promoter Clear Primer

● Drivers: (with some general crossover targets...not in stone by any stretch)
○ Highs: SB Acoustics Satori TW29R 1” tweeter, 1.8 - 20 kHz
○ Upper Mids: Morel EM1308, 2” mid dome, 800 - 1,800 Hz
○ Lower Mids: SB Acoustics Satori MW16P-4, 6.5” mid-bass, 250 - 800 Hz
○ Bass: Vifa NE315W-08, 12” woofer, 25 - 250 Hz
Attached Images
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File Type: jpg G3 Acoustics v54.jpg (206.4 KB, 378 views)

Last edited by Greggo; 10th September 2014 at 05:21 PM.
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Old 10th September 2014, 05:26 PM   #2
Greggo is offline Greggo  United States
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Join Date: Feb 2004
Location: Minneapolis, MN
I am going to be using a miniDSP 4x10 Hd along with a Dayton MA1260 for crossover and power respectively. I will be just doing the very basic stuff first, then reaching out Charlie Laub for help with the very latest in ACD, and otherwise scouring the net for any and all help in getting the very best out of the 4x10 and my drivers.

Any pointers here are most welcome. I have the mic and REW software from miniDSP as well and will be using a MacBook to get everything configured.
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File Type: jpg J13.jpg (524.3 KB, 89 views)
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Old 10th September 2014, 05:32 PM   #3
Greggo is offline Greggo  United States
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Here is some driver porn for those of you who enjoy it...
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File Type: jpg G324.jpg (841.2 KB, 64 views)
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Old 10th September 2014, 06:50 PM   #4
adason is offline adason  United States
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very nice...
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Old 10th September 2014, 07:38 PM   #5
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I don't see a need for the mid dome with the Satori but hey, that's just me. Your design work is excellent and I have no doubt it will be one hell of a speaker!
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Old 11th September 2014, 12:08 AM   #6
Greggo is offline Greggo  United States
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Thanks guys. Yeah, a fair number of folks have called out the mid dome, and it is a good point. I think another valid angle here is just running the Vifa 12 inch woofer up to 700 Hz and then crossing to the mid dome, and then crossing to a 3/4 inch tweeter rather than something like the Satori.

I can pull the mid dome, move the tweeter up in its place, and then patch things up and re-paint if I find things difficult to manage. I am hoping that the more limited passband for each driver translates to ultra clean sound even at high volume, and that it also translates to extremely consistent directivity and power response.

I didn't want to push the tweeter down below 1.8 kHz, though I do intend to test some options all the way down to 1.2 kHz... but if I wind up at 1.8 kHz, I wanted to have a dome mid come next because 1) I love mid domes, 2) The directivity profile and sonic attributes of the mid dome must, in my mind anyways, more closely track the dome tweeter and thus increase the chances of my transition between these two drivers being as optimum as possible, 3) I had 4 channels of DSP and wanted to get my moneys worth since I have no immediate plans for subs.

Yes, I know the Satori mid-bass is fine up to 3k easily, but I wanted to limit its role to lower mids only despite the great success that Jeff B. and Joachim G. had with blending the two Satori drivers together in their monitor designs.

Not the best defense I know, but I just like the idea of keeping cone drivers under 1.2 kHz if possible. No valid science here, just my own mind games.
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Old 12th September 2014, 08:51 PM   #7
tf1216 is offline tf1216  United States
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Man, it's get cold already in MN. Best of luck to you. This is going to be an awesome winter project.
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Old 12th September 2014, 09:05 PM   #8
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The Satori may be one of the best-performing mid-woofers on the market, but nothing will change the fact that it is only a 6.5" mid-woofer, nothing more, nothing less. You gain on two things by passing at 800 Hz:

1) The well-known dip at 1.3 kHz is not in passband
2) Power response at the crossover is improved since at 1.8 kHz (presumably the crossover point you would use if you did not have the upper mid) the mid-woofer has already started to beam.

I say stay with what you have. Perhaps also review this work, if you haven't already:

Build Thread: Ardor - point source monitor

Just be careful about the comb filtering between the tweeter and the dome since the C-C distance is not insignificant. Consider routing out the sizeable mounting flange(s) of the dome and/or tweeter, to get them as close together as possible.

Last edited by 454Casull; 12th September 2014 at 09:17 PM.
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Old 12th September 2014, 09:16 PM   #9
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Could I possibly interest you in using a different bass driver? Is it possible to return them?

Car Audio | DiyMobileAudio.com | Car Stereo Forum

Different size, but same series. I would hate for you to be disappointed through no fault of your own.
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Old 13th September 2014, 12:42 AM   #10
Greggo is offline Greggo  United States
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Join Date: Feb 2004
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tf1216,
Yeah, what was with this morning? Felt like mid october already, what a bummer.

454Casull,
Thanks for the link and the feedback. It is always interesting to see the different perspectives on C-T-C between drivers and the associated crossover points. I did entertain the idea of cutting into the frames a bit on both mid dome and tweet, but decided in the end that I would prefer to leave them alone and take my chances. I have mounted them about as close as one could, and think that it will be OK. At my crossover point and given the flange of the mid-dome being at 5 inches OD, I am as safe as any small two way monitor out there.

The woofers are not superstars in the low end department, but I wanted my bass response down to 30 Hz to be as tight and tuneful as possible. I thought they would be as seamless a match for the Satori mid-bass as possible. If I decide I want a bit more grunt below 30 Hz then I will build a monster sub, but in general I am not really a fan of subwoofers or high mass / high excursion woofers (edit: OK, these vifa woofers are not exactly low mass either...did I mention they were on sale when I bought them, $175 each). The link you gave me regarding the woofers stopped at a account/login page, so I am curious as to what you were recommending? I do agree though, in terms of pure bass performance there are many better choices out there, but the feedback I found on these were right up my alley and I am hoping that by having two of them per side that I get enough total displacement to keep up with the rest of the system. I am going to put a steep subsonic filter on them starting at 25 Hz so I don't have to worry about them bottoming out when I am watching movies.

Last edited by Greggo; 13th September 2014 at 12:58 AM.
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