L200 DIY Upgrade

[Jange]

Hello!

This is the firs time I write in this forum, first I like to thank You for a very interesting site and I suppose that some of the question I have is there already but I have really tried to find it.

After blowing and burning almost every type of speakers Septon (JBL distributor in Sweden) told me to go with JBL. So in 1977 I decided to build my type of 2-way L300, I am not sure but I think L200 used other element at this time. I used 2231A (136A), 2420 (LE85), 2308 (L91), 2312 (H92) and 3110 (LX13) and bought JBL Enclosure Kit to get help to design the box. I ended up with 4,57 Cubic Feet (128 L) Port 2x3” (2x8 cm) duct 4” (10 cm) tuned for 31 Hz.

In 1992 I had the LF recone with 2235H and last year I had the LE85 diaphrame replaced with D16R2421, I also replaced the caps in the filter.

Problem: I feel that the LF don’t have the same punch and balance any more. To compensate the balance I have to step down the filter to -min and then I lose much HF, I have followed Zlits Quick & Dirty but I am not reedy to change my horn (yet).
Any ideas to go further, there is no short cut to the perfect sound.

Regards

[Zilch]

You are missing the high frequencies.

The common (and, probably, best) upgrade with those components is to add the 2405 UHF driver and three-way N333 equivalent crossover posted in these forums.

You can get somewhat more out of what you have two-way by using the HF boost in the 3110A crossover. Look at the schematics and see if you can add that on to the 3110 that you have.

You'll not get as much benefit as with adding the tweeter, however, in part because your horn/lens vertical beamwidth becomes very narrow at the higher frequencies.

So, my advice is to convert what you have to 4333 by adding 2405 and either build a complete new crossover or use 3105 with your 3110. I recently posted a schematic and parts list here for building a charge-coupled 3105....

[Jange]

Do You think I have the box right tuned for 2235H
Sorry, noticed I spelled Your Name wrong.

Regards

[hjames]

I took an L200 system (Although I plugged a port, the cabinets are the original L200 with two ports, not the later L200B with one port) and extended the high freq end by adding a 2405 like Zilch mentioned. I also built a 4333 type (3 way pro version) crossover network for it.

Link to the L200 hacker thread
http://audioheritage.org/vbulletin/showthread.php?t=15317

Link to the Crossover info
http://audioheritage.org/vbulletin/showthread.php?t=9796&highlight=4320&page=4

[Zilch]

Do You think I have the box right tuned for 2235H
Sorry, noticed I spelled Your Name wrong.

Regards

Bass Box says your two 3" ports should each be 5.67" long for 31 Hz. Longer ducts will tune lower. For 26 Hz (probably too low,) it's 9.6".

I don't know where 4333 or L300 are actually tuned, but that may be found somewhere in these forums. 31 Hz should be fine....

[SMKSoundPro]

I also have the L200b, and I added the 3105 crossover and 2405 slot.

I did not, however, go into the N200b crossover and cut some of the elements.

So, I am using the L200 cabinet with a 2235 as woofer only. Wires directly connected to the woofer inside.

Then placed a 2445 - 2" driver/ 2380 horn on top with a 2405 slot tweeter, and am using an active 3-way crossover. (Use protection caps for the compression driver 25uf, and 2405 3uf.)

Three amplifiers.

and WOW! Get it on!

Now I am making this 2390 horn to sit on top of the L200 cab.

[Rolf]

From my small experience, I believe you have to "play them in". takes about 150 to 200 hours to do that. You can also put a 30Hz tone about 50% of what the woofers can handle, go to work, and do it again the day after.

In this way you only need about 20 hours.

Just my thougts.

[macaroonie]

They should be run in by now or am I missing something

[Jange]

I like to stay with the 2-way for a wile.
I will look in to change the crossover an have seen some different on this site.

3,33mH in 3110

2,60mH in 3110A

2,20mH in Quick and Dirty.

All say 800Hz is the difference Linkwitz-Riley vs. Butterworth.
I have tried some calculating with Micro-Cap but it seems not easy when you working with not only resistive load.

Regards

[Zilch]

Each filter incorporates assumptions (or facts) relating to the drivers used with them. It's the acoustic response which defines the crossover frequency, not the electrical alone. That frequency also shifts with HF driver balancing.

They are also second-order with Zobels. Perhaps someone knows how to calculate all that, but it's not me. LEAP (or similar) will do it, or Model them in SPICE to compare.

Q&D was taken from L200B:

http://manuals.harman.com/JBL/HOM/Technical%20Sheet/L200B%20ts.pdf

[Jange]

Hello!

I have not giving up building a new crossover but I just received a a FMOD that I ordered from Harrison Labs that I will test with my Vincent monoblock to run the 2235H and keep my filter for HF.
The FMOD have both 500Hz and 1000Hz, anyone tried those products.


Regards

[John W]

In 1992 I had the LF recone with 2235H and last year I had the LE85 diaphrame replaced with D16R2421, I also replaced the caps in the filter.


Hi,
Is the LF driver ferrite or alnico. Could it just need a recharge?

[Jange]

It is all alnico both LF och HF

Regards

[Jange]

Hello!

I have been running my speaker with BI-Amp and there is nothing wrong with the LF it has released deep and good punch, I have still some problem in the crossover region.
When I look on filter that have possibility to BI-Amp there is still a Zobel ( conjugate RC) in line, what is the advantage of that.

Regards

[Zilch]

Zobel levels the woofer impedance. Some amps care about that....