2245H Sub-Woofer

[Val]

In August I bought a new-old-stock 2245H on eBay. I have somehow convinced my wife to let me build a 12 cu ft enclosure for it in the living room. It will compliment my LE15A/375/075 DIY project built with the help of this forum and pictured below.

http://audioheritage.csdco.com/vbull...5A%2F375%2F075.

I plan to use the same construction and finish so the sub will match the mains. Although the rig gets a lot of use as HT, my passion is stereo music especially for dance parties.

Before I finalize my design and submit it here, I have a question on something I can't seem to let go of. With the original S8 component set I am using, JBL has the 375 is driven down to 500Hz. I believe JBL later recommended not going below 1200Hz with the 375 and similar. So here's my question, is it over kill to change my mains to a 4-way rig with a 2123 or similar in the 500Hz to 1200Hz range?

Thanks!

[jerry_rig]

From what I've gathered, lurking on this site for while, is that you could vastly improve your system's imaging and smoothness by pitching the LX5 and N7000 crossovers. The 434x crowd raves about the 2122H as an upper mid bass driver. So if you go that route, you may want to cobble together a charge coupled 3145 crossover network as shown elsewhere on this site. It uses 290 Hz (12dB per octave); 1.3 kHz (12 dB per octave); and 10 kHz (18 dB per octave) as crossover points. The major difference between your setup is the 375 large format driver. But the sensitivity is basically the same as the 2421/LE85 driver used in the 4340 - 45 system. I haven't heard either, so don't put too much weight on my comments!

[Rolf]

No problem with 500Hz for the 375. Ask any Paragon owner. (I had one myself for some years ago).

[yggdrasil]

In a home environment the stress on a 375 should not be an issue. Finding a horn that works well down to 500Hz is more of a problem, but you seem to like the setup you already have....

If you wish to use a 10" mid-bass, I would recommend replacing the LE15 with the 2245, and adjust the crossover frequencies accordingly.

The easy way to go is just to continue with your plan and build a sub with the 2245.

[Val]

Finding a horn that works well down to 500Hz is more of a problem,

I'm using the H93 horn with a knock-off L91 lens.

but you seem to like the setup you already have....

I like many things about these speakers, but, to my ears, they do seem to have difficulties reproducing mid-bass. I've never measured this however.

Thanks

[yggdrasil]

If you want to explore what other horns can do for you there are a few routes to try.

A 500Hz horn will be rather big. Normally it will need to have a cut-off of 250Hz.

The easiest build will be a conical horn with 4 straight sides. This will give you a picture of what you can achieve.

Then you can look into Yuichi, e.g: http://www.geocities.jp/arai401204/H.../A290-S90.html

I have redrawn a tractrix horn in the same form as the Yuichi (without vanes) with great results.

[robertbartsch]

I recently asked about a two-way large format system comprised of an 18" 2245 and a 2445 2" compression driver crossed at 500 here and I was told that it would be a very bad idea.

`

[Val]

Then you can look into Yuichi, e.g: http://www.geocities.jp/arai401204/H.../A290-S90.html

That is quite a horn, beautiful too. Listening carefully to my 375/H93/L91 it has that, well, metal horn sound (for lack of better word). Is that is not the case with hyperbolic horn such as the one you mention?

[Val]

I recently asked about a two-way large format system comprised of an 18" 2245 and a 2445 2" compression driver crossed at 500 here and I was told that it would be a very bad idea.

`

I found and read that thread.

It motivated me to listen carefully to my rig and make up my own mind. I've decided that, one day, I want to improve the mid-bass situation with either another driver or a better horn. Thanks.

[yggdrasil]

That is quite a horn, beautiful too. Listening carefully to my 375/H93/L91 it has that, well, metal horn sound (for lack of better word). Is that is not the case with hyperbolic horn such as the one you mention?

I have the S8R installed in my Sovereign's, so I'm quite familiar with your setup. Since they are in the Sovereign cabinets it is not an option for me to switch horns. The only upgrade route for my Sovereign's would be to make new custom charge coupled crossover networks.

I'm not sure that the horn contour will make as huge an impact on the sound as the difference in size will do. The Yuichi horns are quite big, so WAF is down....

[Val]

I have the S8R installed in my Sovereign's, so I'm quite familiar with your setup. Since they are in the Sovereign cabinets it is not an option for me to switch horns.

I had not heard of the Sovereign cabinets until your post. I just read up on them. Very nice looking. And it is good to know of others with the S8(R) components. I too am not too interested in switching horns either as I like the cabinets I have built.

The only upgrade route for my Sovereign's would be to make new custom charge coupled crossover networks.

Are you still using the stock LX5 and N7000 networks?

[yggdrasil]

The Sovereign cabinets are restored to original. No work have yet been done on the networks, so yes they are stock.

They have replaced my DIY's in our living room. My better half got more than just a little hostile when I started switching horns on the DIY's. Her argumentation was that the living room is not a workshop...

The DIY's are in our family room in the basement. This was actually very good, since the living room is stable and I have no such restrictions in the family room.

Given this, the family room is music room, while the living room is TV room. This has minimized the need to do anything with the Sovereign's, so my priorities are on the DIY's....

Regarding the Sovereign's I have already done some very succesful replacement of electronics. I found them very sensitive to change in electronics. In a few weeks I hope to free up a new power amp to test on the Sovereign's(Nelson Pass - F5, DIY).