JBL 4430 Questions, Please.

[cgregory4]

My second pair of JBLs were 4425s. I am still amazed by their sound. BUT, someone on the forum commented to me a couple years ago, "Wait 'til you hear the 4430s!"

Well, 4430s aren't common in the deserts of west Texas. In fact, I'm convinced that if California does slide into the Pacific, 90% of the desirable JBLs on the planet will be under water. I had to drive my pickup to Burbank to get my L300s. The Paragons I want are in LA. :(

However, a pleasant surprise: Some 4430s were offered for sale in the Dallas area. I made a day-trip, and returned with one in the back seat of my diesel crewcab, and one covered with a tarp in the truck bed.

Yes, the initial LH forum comment was 'spot on': The 4430s sound awesome. They need work, but I'm slowly getting it done -- finish, refoam, etc.

My questions:

1. The 4430s will reside on the top of 36" tall cabinets on either side of the room. Does it make sense to place them upside-down, so that the baby-cheeks are closer to the listener ear level?

2. My amps in this particular room are Classe and Accuphase. None of them is rated at less than 200 watts at 8 ohms per channel with low distortion at full loads. Each of them will double that output at 4 ohms -- in other words. well-designed, high-current amps. However, the 4430s have provision for bi-amp mode, which my L300s do not have. I have plenty of amplifiers, so that is not a problem. The problem is my ignorance about the benefits of bi-amping, in general, and on this model 4430, in particular. Will you explain to me the benefits that might come from bi-amping the 4430s? I am assuming this is a question with some subtleties involved, about which I am clueless.

Thank you,

Greg

[DingDing]

Congrats on your 4430's, they were my first pair of JBL about a year ago, they sound fantastic, but wait till you hear the 4343B, lol! :D

But seriously, they are very nice speakers and I still have them around because I can't find it in my heart to sell them. Seeing how you go on about how great they are, I should probably pull of the plastic cover and let them sing. :)

As for your questions:

(1) Yes, that makes sense, but try both positions to see what you prefer. I contemplated having them built into the wall behind my PC-setup/desk and people in here suggested it would be wise to have them horizontally to get them in correct ear height. Be sure the cheecks doesn't reflect directly onto a surface though. Having them in free air is probably going to work better.

(2) Some people say there are benefits, some don't. I never tried biamping my 4430's, but I do biamp 4343B. The result is cleaner and tighter bass.* Right now I'm using MiniDSP 4x10 HD to do the xover, before that I used Ashly XR1001 and before that UREI 5235 with 4343 cards. There are people in here who often say that bypassing the biamp switch is a good thing, and also replacing the terminals with something better than stock. MiniDSP 4x10 HD is a bit complex, but Ashly XR1001 is a very good flexible xover network. Getting the Ashly XR1001 is cheap, and you'll get a chance to try biamping them to see if it works better than the passive xover, so go for it.

* I have 2235h drivers in both speakers, but as you know the driver in 4430 goes all the way up to 1kHz, whereas it only plays from 300 Hz down in 4343B. That might be of significance as to how clean the bass sounds, but I'm not sure.

[speakerdave]

1. The 4430s will reside on the top of 36" tall cabinets on either side of the room. Does it make sense to place them upside-down, so that the baby-cheeks are closer to the listener ear level?

2. My amps in this particular room are Classe and Accuphase. None of them is rated at less than 200 watts at 8 ohms per channel with low distortion at full loads. Each of them will double that output at 4 ohms -- in other words. well-designed, high-current amps. However, the 4430s have provision for bi-amp mode, which my L300s do not have. I have plenty of amplifiers, so that is not a problem. The problem is my ignorance about the benefits of bi-amping, in general, and on this model 4430, in particular. Will you explain to me the benefits that might come from bi-amping the 4430s? I am assuming this is a question with some subtleties involved, about which I am clueless.



I think you may find answers to both of these questions by searching these forums. Trusting to memory:

1. I seem to recall that since JBL's hope was that the speaker would be adopted by recording studios the 4430 was designed for soffit mounting, so upside down is fine.

2. There is at least one thread with a discussion of DIYing and biamping this speaker. As I recall (and you should check this) the upshot of it was that the crossover is fully out of the circuit in biamp mode, and except for a 5235 using the appropriate personality card there is no off-the-shelf external crossover that provides the needed compensation for the horn.

Edit: I see "DingDing" and I were writing at the same time wth very similar answers.

[Crestwood23]

I have new crossovers in my L300s that allow for biamping. Before biamping, I tried them with a Mcintosh MC2105 and found the bass to be pretty good, but the mids and highs were too aggressive and grainy sounding. I went from a SS preamp to a tube preamp, and the harshness improved, but wasn't totally gone. Then I tried a restored Fisher 500C, and found the mids and highs to be liquid and smooth, with a greater sense of realism that gave me goosebumps. The downside was the bass became flabby and turned to mush at higher volumes. Based on this, I figured that biamping would allow for me to get the best of both worlds out of these fantastic speakers. I now bi amp with a Crown Com Tech 800 on the the woofers, a Fisher x101ST (12wpc el84) on the mids and tweets - all through a Juicy Music Xtreme tube preamp. The SS Crown really grips the woofers and provides gobs of clean punchy bass, while the sweet little tube Fisher provides sweetly musical mids and highs - never grainy or abrasive - just spectacular tone and crazy realistic 3d imaging. Both amps as well as the pre have separate level controls so I can really dial in the balance for my room which is another plus.

[cgregory4]

I have new crossovers in my L300s that allow for biamping.

Although my original post involves questions on bi-amping the 4430s, your post is appreciated because I own L300s, as well. They are stock and have no provision for bi-amp operation. I know Nelson Pass did some work on improving the original crossover design, but I don't remember that he used a bi-amp scheme.

If you don't mind sharing, where did you obtain your crossovers/designs for the bi-amping of your L300s. I would like to do some research on that, as well.

Thank you,

Greg

[honkytonkwillie]

Upside down on 36" tall cabinets would be an upside down version of raising them 1-2 feet off the floor (with the ceiling acting as the floor), which many say helps to tame some boominess. I've not tried it.

As far as biamping, you will need an external crossover for the 4430. If you search these forums you'll find several threads with people describing their results. I don't recall specifics, but my general recollection was that the internal crossover left nothing more to be desired, and biamping didn't result in any huge improvement. Myself, I want to re-do the crossover with charge coupling but that might take me a few years. If you have the necessary equipment, by all means give it a shot and let us know what you find.

[Crestwood23]

Although my original post involves questions on bi-amping the 4430s, your post is appreciated because I own L300s, as well. They are stock and have no provision for bi-amp operation. I know Nelson Pass did some work on improving the original crossover design, but I don't remember that he used a bi-amp scheme.

If you don't mind sharing, where did you obtain your crossovers/designs for the bi-amping of your L300s. I would like to do some research on that, as well.

Thank you,

Greg

I think you would achieve similar flexibility and results by biamping the 4430s, and it's easier as the are already set up for biamping. Another benefit I forgot to mention is that the amps don't have to work as hard as they have less drivers to drive, I have noticed as a result there is increased headroom.

As for the L300's, I removed the original crossovers and had LH member "Duanage" (thanks again Duane!) build me a set of the Nelson Pass design as detailed here:

http://www.firstwatt.com/pdf/art_l300.pdf

the only mod to this design was that I had the crossover "split" so that the LF section was independent of the HF section, so each section is wired to their own set of binding posts. Nelson says you don't have to get fancy with the caps, but I found a good deal on used Mundorf silver/oils and silver/gold/oils so I went for it. I still have the option of running a single amp by strapping the binding posts, but the best sound I have gotten out of them has been by biamping. Well worth the effort and expense IMO.

[cgregory4]

I PM'd "Duaneage" and hope to hear back from him soon. Thank you for that valuable referral.

Greg

[Mike F]

I would most certainly invert the cabinet, unless you do your listening standing up :)
IIRC, due to the crossover configuration, the acoustic center of the baffle is tilted a little upward toward the horn, so take that into consideration also.

There was a noticeable improvement when I went from a single amplifier to full biamp, most of my neighbors would also agree.
63000

[cgregory4]

I would most certainly invert the cabinet, unless you do your listening standing up :)
IIRC, due to the crossover configuration, the acoustic center of the baffle is tilted a little upward toward the horn, so take that into consideration also.

There was a noticeable improvement when I went from a single amplifier to full biamp, most of my neighbors would also agree.
63000

Mike,

Did you just switch to the bi-amp position and go from there? Or did you do other modifications? I'm thinking I should eliminate the switch function, as a minimum. Your thoughts?

Greg

[Mike F]

Mike,

Did you just switch to the bi-amp position and go from there? Or did you do other modifications? I'm thinking I should eliminate the switch function, as a minimum. Your thoughts?

Greg

Just switched to biamp mode. There are still some passive components left in the path however.
I believe the ones that are bypassed are no longer needed as the active filters take care of the slopes beforehand.
Not sure what you mean by eliminating the switch function.

[cgregory4]

Just switched to biamp mode. There are still some passive components left in the path however.
I believe the ones that are bypassed are no longer needed as the active filters take care of the slopes beforehand.
Not sure what you mean by eliminating the switch function.

Mike,

I figure the audio has to pass through the switch contacts. I was planning on wiring the LF-to-the-LF & the HF-to-the-HF paths directly. Later if I wanted to restore to 'stock', I would connect the signal paths back through the switch. Does that make sense?

Greg

[Mike F]

Are you having problems with the switches?

[Robh3606]

Hello cgregory4

When you switch to biamp mode in the stock speaker the HF compensation for the horn stays in place. Look at the schematic

http://www.jblproservice.com/pdf/Network%20Schematics/3134%20Network.pdf

You needed a special 18Db network card for the 5235 crossover. It did not include the CD compensation and if you did a DIY version all active the CD compensation available in typical crossovers is not as good as the passive network.

Everything you ever wanted to know about them here. They are designed with the listening axis tilted up so you cn easilly flip them.

http://www.audioheritage.org/vbulletin/showthread.php?7852-Improvements-in-Monitor-Loudspeaker-Systems

Rob:)

[cgregory4]

Hello cgregory4

When you switch to biamp mode in the stock speaker the HF compensation for the horn stays in place. Look at the schematic

http://www.jblproservice.com/pdf/Network Schematics/3134 Network.pdf

You needed a special 18Db network card for the 5235 crossover. It did not include the CD compensation and if you did a DIY version all active the CD compensation available in typical crossovers is not as good as the passive network.

Everything you ever wanted to know about them here. They are designed with the listening axis tilted up so you cn easilly flip them.

http://www.audioheritage.org/vbulletin/showthread.php?7852-Improvements-in-Monitor-Loudspeaker-Systems

Rob:)

"You needed a special 18Db network card for the 5235 crossover. It did not include the CD compensation and if you did a DIY version all active the CD compensation available in typical crossovers is not as good as the passive network."

In plain English, please!

I

[Mike F]

"You needed a special 18Db network card for the 5235 crossover. It did not include the CD compensation and if you did a DIY version all active the CD compensation available in typical crossovers is not as good as the passive network."

In plain English, please!

I
Robh3606: I believe the 4430 specific card (52-5130) has a 12 DB per octave slope.
Greg: CD (Constant Directivity) compensation is a form of high frequency equalization for horns.

[cgregory4]

Robh3606: I believe the 4430 specific card (52-5130) has a 12 DB per octave slope.
Greg: CD (Constant Directivity) compensation is a form of high frequency equalization for horns.

I guess I am so far behind the average 'curve' of this forum, I just need a translator like you sometimes! :crying:

Thank you,

Greg

[subwoof]

the crossover as designed leaves one pole in the hf side to make it an 18db slope even though an external connection is a 12db slope ( using an abbreviated 18db card in the 523X crossover )..

So in my experience biamping is somewhat moot on this system but doing a charge-coupled crossover mod is a BIG change...save the money and get a large amp and a pile of solens..:)

the CD comp IS still in the path if internal crossover is used ( recommended ) - no matter the switch selection. Look at the schematic before posting please.

This system used an old style 1 inch compression driver so that is pushed to it's limit with the network so don't expect stadium levels without distortion..larger format drivers work much better for those SPL's.

But getting them to an acceptable SAF is very difficult.

sub

[cgregory4]

the crossover as designed leaves one pole in the hf side to make it an 18db slope even though an external connection is a 12db slope ( using an abbreviated 18db card in the 523X crossover )..

So in my experience biamping is somewhat moot on this system but doing a charge-coupled crossover mod is a BIG change...save the money and get a large amp and a pile of solens..:)

the CD comp IS still in the path if internal crossover is used ( recommended ) - no matter the switch selection. Look at the schematic before posting please.

This system used an old style 1 inch compression driver so that is pushed to it's limit with the network so don't expect stadium levels without distortion..larger format drivers work much better for those SPL's.

But getting them to an acceptable SAF is very difficult.

sub

sub,

Thank you for your comments.

1. A "large amp and a pile of Solens." Now that's something I can both understand and do! :D

2. What is a "charge-coupled crossover" and where would I find one for the 4430?

3. I am about 12' from the speakers and listen at low SPLs with 250 watts per channel.

4, What driver would you 'sub' (pun intended :)) for the original 1", if you were to upgrade?

Greg

[4343]

...

4, What driver would you 'sub' (pun intended :)) for the original 1", if you were to upgrade?

Greg

The 1" drivers work great, as long as you don't run them too low. The 1KHz crossover is a little low, IMO, as well as being a stretch for the 2235H.

My home builts are now a 3-way, with a 10" mid to take over the parts that the original drivers struggle with, at least at extreme levels. I only had to replace one cap to get the HF to blend with the mid. IIRC, it was a 4.7 uF (or so) that I reduced to around 4.0 uF to raise the HP filter on the 1".

I lifted the mid crossover schematic direct from the 4344MkII L/R, and the 10" driver as well, with the upper crossover @ 1.3KHz. I does not look like much, but that 300 Hz takes the strain off the 1" driver enough that I can drive them fairly loud without hearing the telltale sounds of over excursion, which I've learned to avoid. (I managed to keep a set of 2420's with original style aluminum diaphragms alive for 20 years of dances, PA gigs and parties, so believe me, I know what they sound like when stressed.)

The problem with 2" drivers is that the lose directivity in their upper octave, it's just a matter of physics. Without crossing over to a UHF device, you will get beaming...


...
2. What is a "charge-coupled crossover" and where would I find one for the 4430?
...
Greg

Also know as a "Biased" network, it requires 4 times as much capacitance at each of the original capacitor locations. You can either use 4 caps of the original value in series-parallel or two caps of twice the value in series. (Or two caps of different values that when placed in series result in the original value.) A DC voltage is applied to the center of the series string via a high value resistor (1-3 Meg ohms), which biases the caps. The idea is that the AC waveform does not ever make the caps go through zero volts.

There is no stock crossover for the 4430 that is biased, you will have to build one, or find someone that can do that...


...

4, What driver would you 'sub' (pun intended http://www.audioheritage.org/vbulletin/images/smilies/smile.gif) for the original 1", if you were to upgrade?

Greg

There really is no upgrade path for the 1" drivers that does not involve replacing the horn, which usually means something that won't fit in the cabinet, which is why I just went ahead and built from scratch.

4430's are what they are, which is very good. For me, I tried adding a tweeter to get them to sound more like a big 4-way monitor, but it just wouldn't jell with a 2405, I'd like to try with a 2404, but just the physical placement causes problems. The magic goes away. Part, if not most, of the magic is the wide beamwidth that does not fall of until the UHF level drops.

In the end, I just swapped in Radian aluminum diaphragms and live with the rolled off UHF. I do like the aluminum sound better that the Ti, which can really get irritating if you try to get them the do UHF by playing with the L-pad/Pot. I figured, having some rolloff sounded better, and the aluminum can actually get a bit more top end without the tizzyness taking over...

[cgregory4]

I printed your post out and placed it with some other information from the LH site. I'm beginning to get a grip on the charge-coupled concept.

I think my first try will be to upgrade the crossover caps, place the 4430s upside-down on the cabinets, and then bi-amp them. My preamp will allow me to adjust crossover points for each signal. I'll look for a sweet spot -- using your observations about the limitations inherent in the system components. And go from there.

Thank you again, Mike.

Greg