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View Full Version : finding a 12dB/Octave Slopes active crossover for 4344



loman69
12-27-2008, 12:46 AM
Dear all,

I am a JBL 4344 user in Hong Kong.
My system is in bi-amp mode with a JBL M552 Xover and i am OK with the performance.
Now i am wondering any 12dB/Octave Slopes active crossover is good for my system because i found the original passive Xover of 4344 is in 12dB/Octave Slopes.......

my current system:
CDP: EMT981
PRE: Revox C298 mixer
Xover: JBL M552
Amp: Dynaudio Acoustics DCA 650(an OEM model of MC2 DCA650, 350Wx 2 in 8 Ohm) x 2

I want an analog Xover, Bryston /Accuphase is far over my budget.....
i tried Urei 525 before but it was not my taste....

your recommendation are highly appreciated:)

joel

http://i139.photobucket.com/albums/q316/Rick-lam/audio/DSC_0232.jpg

loman69
12-27-2008, 12:50 AM
japanese recommendation: 18db octave slope....
http://jbl43.net/JBL43xxlist.html

hjames
12-27-2008, 05:52 AM
japanese recommendation: 18db octave slope....
http://jbl43.net/JBL43xxlist.html

I have a pair of biamped 4341s
(nearly upgraded to 4344 spec - awaiting my 2425s early next year)

I'm using the Ashley XR1001 - 24db slope ...
I found it an improvement on the JBL 552 I used to use ...

Specs and such are here -
http://www.ashly.com/product/xr-series.htm

Robh3606
12-27-2008, 06:56 AM
Well there are a couple of things you could do. You could go for a 5235 and build the cards from the ones you get with it. Problem with that is the elctronics in the 5235 are a bit dated and the M552 should be better. It would however allow you to try the 4344 with the original JBL voltage drives.

I have 4344 clones and have run them with an M552 which I also was happy with but I am using a JBL DX-1 with 12db slopes. The DX-1 sounds better than the M552 so that is what I have stayed with. If you can find a DX-1 grab it as the cards are not all that hard to make and we have several schematics for them.

I really need to make custom cards from the 4344 although they seem to sum properly using the XPL cards I have in there now.

Rob:)

loman69
12-27-2008, 07:27 AM
hi james,
yeah i would like to try Ashly.....because it's easy to find one on ebay....


hi rob,
i also tried urei 525 before......M552 was more clear and transparent.
it's very difficult to find 5234/5235 with proper cards now and i am not a DIY guy:(

Chas
12-28-2008, 06:04 AM
hi james,
yeah i would like to try Ashly.....because it's easy to find one on ebay....


Well, what do you know? Here is a nice one, right here;):

http://www.audioheritage.org/vbulletin/showthread.php?t=23292

loman69
12-29-2008, 11:00 PM
hi chas,

thanks for your offer:)
i will think about it......

joel

Mannermusic
12-31-2008, 02:55 PM
Here's another source for you. Marchand will make any slope you like, solid state or tube-type (valves). Designed primarily for hi fi. In Rochester N.Y., USA.

http://www.marchandelec.com/

Ian Mackenzie
12-31-2008, 10:17 PM
Joel,

Check your pms

loman69
01-02-2009, 11:30 AM
thank you guys!

i would like to know that how to conect my so-called 2 ways 4344 system properly.

Connection 1: all output signal from preamp(left & right channel) go directly into my JBL M552, then the crossover divide it into HF & LF.
HF goes into the passive crossover of 4344
LF goes directly into the the woofer

problem: the HF went through 2 corssovers(both M552 and internal passive crossover of 4344)

Connection 2: my friend gave me a Y cable so the output singal from the preamp can be devided into 2.
Singal 1(from 20-20,000hz) simply goes directly into internal passive crossover of 4344
Singal 2 goes to M552, then the LF(from 20-320hz) goes directly into the woofers

For me, i perfer connection 2 because the coherence and the deeper bass.

Am I doing it right?

Robh3606
01-02-2009, 11:53 AM
What position is the Biamp Switch in??

Rob:)

loman69
01-02-2009, 12:07 PM
What position is the Biamp Switch in??

Rob:)

Hi Rob,

Sorry......i am a little bit confused.
Can you elaborate?


thanks,

joel

Robh3606
01-02-2009, 12:25 PM
On the back of the 4344 there should be a Biamp Switch like on the 4345. What position is it in??

Rob:)

loman69
01-02-2009, 12:51 PM
rob,

for sure they are in "external crossover" position...

Robh3606
01-02-2009, 01:24 PM
The correct way is the feed the LF and HF amps from the outputs of the M553. No Y connectors required. It's the L/R line into the M553 and HF and LF line outs to the amps.

It is supposed to go through the 2 crossovers on the high side.

Rob:)

jbl_daddy
01-02-2009, 02:06 PM
I have been very sucessful with a Crown VFX-1 crossover, it has served me well for over 20 years with my 4340's. The correct crossover point for a 4340 is 300Hz if that helps. Just upgraded my two Crown PSA-2's for a set of K1's my friend had. Crown makes some bullet proof equipment.:barf:

hjames
01-02-2009, 02:41 PM
With my biamped 4341 (4 ways) the woofer takes the low split off the crossover, the high split feeds the passive and the 3 mid/high/UHF drivers.

I take the preamp out from my HK receiver and feed it directly to the Ashly crossover (or to an M552 I was using earlier last year).
The Low side output goes to a 150w/ch power amp that is wired directly to the 2235 woofers.
No switch, no passives, direct wired to the woofers.
On my system I had to flip wiring polarity to the woofers to get the Bass right.
Using a crossover point of 290Hz.


thank you guys!

i would like to know that how to connect my so-called 2 ways 4344 system properly.

Connection 1: all output signal from preamp(left & right channel) go directly into my JBL M552, then the crossover divide it into HF & LF.
HF goes into the passive crossover of 4344
LF goes directly into the the woofer

problem: the HF went through 2 corssovers(both M552 and internal passive crossover of 4344)

Connection 2: my friend gave me a Y cable so the output singal from the preamp can be devided into 2.
Singal 1(from 20-20,000hz) simply goes directly into internal passive crossover of 4344
Singal 2 goes to M552, then the LF(from 20-320hz) goes directly into the woofers

For me, i perfer connection 2 because the coherence and the deeper bass.

Am I doing it right?

loman69
01-02-2009, 11:43 PM
Connection 1: all output signal from preamp(left & right channel) go directly into my JBL M552, then the crossover divide it into HF & LF.
HF goes into the passive crossover of 4344
LF goes directly into the the woofer

problem: the HF went through 2 corssovers(both M552 and internal passive crossover of 4344)

Connection 2: my friend gave me a Y cable so the output singal from the preamp can be devided into 2.
Singal 1(from 20-20,000hz) simply goes directly into internal passive crossover of 4344
Singal 2 goes to M552, then the LF(from 20-320hz) goes directly into the woofers



thank you very much for your reply.....

but i really prefer connection 2 for the coherence and deeper bass in my current system......

i tried Connection 1 before and listened it for years, the mid to mid-low were not cohesive. When i listened to Something from Abbey Road. Sir Paul's melodic bass were very shy and the bass from other R&R album was very "polite"

then i tried Connection 2, Sir Paul's bass sounds clear and the bass of Black Sabbath album become more "forward".....

the trade off is a little bit of transparency.....

loman69
01-03-2009, 12:01 AM
the output from my preamp(mixer)

http://i2.photobucket.com/albums/y1/lo69/DSC_0283.jpg

Robh3606
01-03-2009, 07:43 AM
Singal 1(from 20-20,000hz) simply goes directly into internal passive crossover of 4344

When you switch the biamp switch to External you take out the lower half of the bandpass filter on the 2122. You are driving your 2122 with a full range signal, no roll-off below 300Hz. Definately not desireable or correct but they are your speakers so do what ever you want.

When you tried the M552 did you reverse the phase on the woofer?? Using 24dbL/R slopes the drivers need to be in phase not out of phase like a typical 12db network


Rob:)

http://www.jblproservice.com/pdf/Network%20Schematics/3145%20Network.pdf

loman69
01-03-2009, 10:34 AM
[quote=Robh3606;234163]
When you tried the M552 did you reverse the phase on the woofer?? Using 24dbL/R slopes the drivers need to be in phase not out of phase like a typical 12db network


Rob,

yeah! you are the man....
I already reversed the phase on the woofers and found the bass more "forward"

loman69
01-03-2009, 10:39 AM
http://www.amazon.com/XLO-Reference-Test-Burn-Recordings/dp/B0000015AL/ref=pd_bbs_sr_1?ie=UTF8&s=music&qid=1231007581&sr=8-1

Rob,

I found my bass was Out-Of-Phase because of this CD.....
track 2 and track 3 are very useful(for the newbie like me:)).


Joel

JBL 4645
01-23-2009, 10:19 AM
When you switch the biamp switch to External you take out the lower half of the bandpass filter on the 2122. You are driving your 2122 with a full range signal, no roll-off below 300Hz. Definately not desireable or correct but they are your speakers so do what ever you want.

When you tried the M552 did you reverse the phase on the woofer?? Using 24dbL/R slopes the drivers need to be in phase not out of phase like a typical 12db network


Rob:)

http://www.jblproservice.com/pdf/Network%20Schematics/3145%20Network.pdf

What is the easiest way to evaluate this? With sine wave close to where the crossover starts to roll-off with microphone for RTA pointing horizontality at the speaker and at what distance?

Also an SPL db meter same thing pointing directly?

Then adjust wires or polarity of crossover until the signal goes upwards rather than downwards which would equal out-of-phase.