4345+- DIY

FWIW,

So I'm not one to post a whole lot as you can see from my post count. Been reading along for a few years. Even got my account deleted because I was a zero poster for so long. :)

Been collecting parts for a few years from folks here on the forum, and thought I'd post what's become of them. Hoping in a few weeks to see what a 4345 (+ anyway, hopefully it's a plus) but the baffle is done as is the box.

Liked the sound of the 2397 years ago so, and the 4345 makes sense and is regarded well here. So, This baffle which has taken me an incredible amount of time to learn how to use a router will be equipped with:

2245
2012
2397 / 2445
Someday probably a 2405, for UHF but don't have 'em now. Major milestone here getting the baffle done, as I'm much more comfortable with a soldering iron than a router. Also cheated on the ports so that I can adjust them....

Probably Tri-Amp them being that I have the amps / crossover to do that, and I want to hear them soon, then will take on the project of a cc: crossover and drop back to bi-amp one day (like next winter). This really has been a slow project.


Anyway, Nice to see the post count increment by one. :applaud:

Any thoughts on the logical name for this modified 4345 ?

Mike

is a step closer to the end result. Looks like a neat project. Keep the pics coming please.:)

Hi Mike

I can see from your posting that you are one of the few brave souls that decided to use the 2012 driver. The 2012 is not a very popular driver around here. And the only reason for this is that it does not have as flat a frequency response as some of the other 10" drivers within the JBL lineup. The 2012 has a rising frequency response, which does require some equalization for it will sound right. As you can see from the first chart pictured below, this driver has a large peak at about 1 KHz. Assuming that you will be crossing over to the 2397/2445 at some point near 1 KHz. then all the other higher frequency peaks are not going to be an issue, because the crossover network will kill them off. But, the 1 KHz peak will present a serious problem, unless some form of equalization is used with the 2012. Since, you are going to tri-amp your system. I can share with you a possible solution. After much trial and error and a lot of testing, I have found a LRC circuit that works really well with my 2012H drivers. Pictured below is a schematic and I have also included a parts list. As you can see from the second chart, the frequency response is a lot flatter with the LRC circuit. And from the LRC circuit's impedance chart, you can see that this circuit does not introduce any large insertion losses, except for where it is really needed. Since this circuit does have very high "Q" value, I would recommend that you use the parts listed and not make too many substitutions. The coil's "Q" value has a huge impact on how much attenuation occurs at the LRC circuit’s resonant frequency.

Parts list (per channel):
1 - 0.30 mH, 0.10 ohm DCR, Erse perfect layer air coil 14 AWG.
1 - 82 uF Solen metallized polypropylene cap.
1 - 0.01 uF Bypass Cap. (It’s wired in parallel with the 82uF cap.)
4 - 40 ohm 10 watt resistors (wired in parallel = 10 ohms @ 40 watts)

With some EQ, I know you like the 2012.

Baron030 :)

Quote:

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Originally Posted by StillUse4560s

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Any thoughts on the logical name for this modified 4345 ?
Mike

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Hi Mike,

a very nice project.....hope to see some more pics.

My idea for the model number is 4397, refering to the used horn.

HP

Quote:

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Originally Posted by Hofmannhp

My idea for the model number is 4397, refering to the used horn.

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I was just going to suggest the same, but you beat me to it... :)

John

Quote:

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Originally Posted by johnaec

I was just going to suggest the same, but you beat me to it... :)

John

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ok John...:D but now you have a new chance.....
Do you have an idea for MY new compact monitors (see thread in DIY) ?

HP