JBL 4435 Harsh Sounding

[MarioGharios]

I am the new proud owner of a pair of JBL 4435 since last week. I'm planning on using these as listening speakers as well as party PA in my home. Currently, I've got them set up with Technics 1200s, an ARS 9000 DJ mixer and Quad Elite QMP amps.

My first observations have been that the mid range and top end sound particularly harsh. The woofers had been set up incorrectly as well, with the 100Hz placed under the horn. Easy fix.

I'm getting substantial bass when pushing them to party level volumes (102 db at 4 m), but I've been constrained to use the L-pad to make the sound palatable. I'm talking -7 db on the mid range adjustment and -4 db on the high freq adjustment.

A first observation was that the mid range L-pad on one of them was "dropping" when trying to adjust it ie the relevant frequency range was clearing out and I had to wiggle the switch for it to come back on. I'm having my good friend and audiophile/tech over on Saturday and am seeking opinions on working out the L-pad issue.

Another observation was that the mid range woofers were "popping/cracking" when pushed. I'm assuming they might need a recone. They have been refoamed recently, will I have to refoam them again after reconing?

Finally, the sound stage is less impressive than what I've been expecting. I imagine raising them off the floor will improve this issue?

Has anyone encountered the harshness issue? I'm pretty sure I need to replace the caps on the L-pads, but I haven't had the time to open them up (they're in my mountain home). Anyone with a schematic I could use to order parts ahead of time?

I'm also planning on:

1- removing the crossover switch as per Zonker: I'm planning on bi wiring the speakers while using the internal crossover, since im only using a single amp for now. Is the mod similar to the one on the 4430s? Any comment on how that mod could affect the high/mid range? Is bi wiring a good option?

2 - checking the diaphragms for damage and looking at Radian replacements (or alternatives?)

3 - raising them up to 3 feet off the floor

4 - checking the crossover and L pads for leaking caps etc....

5 - looking at a different amp.

Cheers!

 

[Zonker92]

They definitely should not sound harsh. In descending order of priority, here's what I'd do:

• Run a bandwidth-appropriate frequency sweep on each driver to check for spurious noises (smartphone apps are useful).
• Remove the back covers on the L pads, check them for damage and bathe them in Deoxit; cycle them repeatedly. (You may be able to do this through the woofer or horn hole, without removing the L pads.) The L pads do not have capacitors.
• Remove the horns and check the diaphragms and back-cap damping foams. Maybe they have cheap replacement diaphragms, and/or they're damaged. Radians are a great upgrade. I use big felt discs from Home Depot as new damping pads, with some extra adhesive (Amazing GOOP) around the edges.
• Clean or bypass the biamp switches. My 4430 thread on bypassing them has instructions that work the same on the 4435s, as I recall. The PC boards and switches are the same; only the way they're populated is different. This mod opens up the bass by letting the current flow to the mid-bass driver as originally intended, and as I recall it prevents any problems where the switches feeding the horns are oxidized. See http://audiokarma.org/forums/index.php?threads/charge-coupled-jbl-4435-networks.636991/ for the schematic and details.
• Check the woofers for damaged foams or voice coil rubs or any other mechanical problems (damaged spiders, tinsel leads, cones, etc.).
• Check the crossovers for evidence of thermal damage; recap them and upgrade the resistors if you so desire. (If replacing the coils, make sure to use ones with similar DC resistance or use appropriate in-series resistors to match the DCRs.)
• Tighten all fasteners; the driver mounting screws can vibrate loose.
• Check for any loose hardware (like soffit-mounting bolts or T-nuts) inside the cabinets.
• Raising them up may slightly diminish the bass by reducing boundary reinforcement.

 

[toddalin]

To some people's ears, the 2425 driver with titanium diaphragm does have a harsh sound. It may be within spec, and you're not used to it. When I listened to Harbeths, even my quasi-L300s sounded relatively harsh.

Popping/cracking sound may mean that you are bottoming out the cones and they are hitting the pole pieces. If the foams are shot, there is more chance of his happening.

Raising off the floor will help. But recognize that the 4430/4435 are known for their sound stage and imaging.

 

[MarioGharios]

hey Zonker, toddalin, thanks for your answers.

The 4435’s woofers have been refoamed by the seller as per our arrangement. The cracking woofers are the mid range ones, so a hypothesis might be that something’s wrong with the crossover system (switch included) or the amp lacks good control of the woofer (for some strange reason, the Quad website doesn’t mention a damping factor for these amps specifically). I’m hoping that removing the switch should liberate enough low freq and produce a more balanced sound, hence needing less volume to achieve the results I’m after, and maybe solving the harshness issue altogether. Wishful thinking maybe.

Sadly, the harshness I’m talking about doesn’t sound like a property of the speakers, more like something is wrong with them. The lack of soundstage and proper imaging attest to that, I hear the speaker, not the music. Dropping midrange by 7db on the L-pads doesnt feel like a perfectly normal adjustment. My room is fairly good sounding.

Zonker, your crossover switch mod will basically require me to bi wire or bi amp, is that correct?

 

[dezmond76]

Sounds like you might have some Chinese aftermarket diaphragms.

 

[RS Steve]

When I restored my 4435's, I decided to not modify anything initially. All capacitors checked out within specs so I left them alone (a tedious process), the switch on the back had no pitting or serious problems showing. I gave those switches a good cleaning and left them in place. Both sets of woofers I refoamed with correct surrounds, all drivers were checked and proved to be operating within specs. By this approach, it gives me a chance to hear them as stock before doing any modifications. I liked them so much as is that I decided not to do anything else. The one thing that is obvious with these, they do let you hear exactly what you put through them. Some digital tracks played through a bright sounding amp or preamp can be pretty harsh sounding. I run a Conrad Johnson tube preamp that has no tone controls what so ever, and it's paired with my WOPL 700B amplifier. All I can say is, I have stopped looking for something better. I hope you can nail down what is causing your issues, they are truly amazing speakers in my opinion.

 

[Lux Man]

All good advice so far, but my mind immediately went in another direction. Your room... length/width/height? Room treatments are very very important. Carpet? Wall coverings? Dampening at reflection points? My room is pretty dead, among other things I have 8- 4"x 2'x4' Corning 703 acoustic panels. Any system will benefit greatly by appropriate room treatments but the more serious systems need it even more. The 4435's are pretty darn serious! If your room is not treated I can image harshness.

For listening- I'd never raise them 3', maybe 4-6". That odd sound coming from the mid-woofer- yeah...gotta track that down.

 

[1audiohack]

Hello Mario;

Something is wrong for sure.

The miss-wired woofers opens the door for almost any other mistakes or worse to have been done to them.

When you say the woofers make noise when they are pushed, do you mean physically pushed or when you put some power to them? As others have said these woofers have limited excursion and can be over driven with relative ease.

I would have the compression drivers inspected to insure they have the proper diaphragms in them and make sure they are undamaged.

I have 4430's and 4435's and am listening to the 4435's as I type in my office, I know them well.

Let me share this: I am not a rabid fan of the 1" compression drivers for one reason, they run out of gas before they get loud and sound harsh as hell when over driven or driven with an amp without enough head room. The 4435's are also good enough to show you the short comings of the electronics on your system. A Bryston DAC for instance allows me to play them considerably louder without fatigue. This I would have never guessed but it removes a lot of the glare when they're turned up.

I don't know where in the world you are but can you enlist the help of a qualified tech? Getting them right will be worth the effort.

All the best,
Barry.

 

[twiiii]

All JBL's sound a little bright to new owners. When your building a speaker thats flat to 17 KHZ with out any roll off they will sound bright. That said, clean all the controls check connections and be prepared to replace all the caps. Yes the HF driver may have issues and follow others recommendations. Remember they are a monitor speakers, not a PA speaker. They re designed to be listened to in a controlled environment at relatively close distances. When they spread the sound on floors and ceilings before the direct sound gets to your ears the sound is going to be compromised and clarity and imaging lost. You really should have different speakers for your applications. Some thing with very controlled vertical dispersions. Sounds like you would prefer C-V. 4435 is my favorite JBL from the past. They have to be installed at the correct elevation in a controlled environment. If placed on a floor I always recommend Standing them up vertically and rotate the horn 90 degrees.. The center of the horn should be at seated listening ear height. Higher for parties, the center line should be at or around 70 inches to get the sound over most folks heads. Lot of folks have issues with the bi-amp by pass switch. I would choose which application you want and by pass the switch.

Go to Web and down load the owners manual for assistance in proper operation.

 

[Zonker92]

Zonker, your crossover switch mod will basically require me to bi wire or bi amp, is that correct?

Yes; unless you bridge the HF and LF inputs in the crossover internally, you’ll need to jumper them on the back panel, or bi-wire or biamp. If biamping using the BX-63[?], my bypass mod should be revised to use the slightly different biamp circuits of the crossovers. My mod abandons those circuits.

 

[MarioGharios]

First off, I wanna thank you all for getting back to me. Reading threads from a guest point of view was already great, but this is really special )

Sounds like you might have some Chinese aftermarket diaphragms.

will figure this out tomorrow morning. I am expecting the worst, Chinese replacements, cracked diaphragms and what not...

When I restored my 4435's, I decided to not modify anything initially. All capacitors checked out within specs so I left them alone (a tedious process), the switch on the back had no pitting or serious problems showing. I gave those switches a good cleaning and left them in place. Both sets of woofers I refoamed with correct surrounds, all drivers were checked and proved to be operating within specs. By this approach, it gives me a chance to hear them as stock before doing any modifications. I liked them so much as is that I decided not to do anything else. The one thing that is obvious with these, they do let you hear exactly what you put through them. Some digital tracks played through a bright sounding amp or preamp can be pretty harsh sounding. I run a Conrad Johnson tube preamp that has no tone controls what so ever, and it's paired with my WOPL 700B amplifier. All I can say is, I have stopped looking for something better. I hope you can nail down what is causing your issues, they are truly amazing speakers in my opinion.

I'm mainly playing records through an Nagaoka MP110, Technics 1200, hi fi preamp mixer ARS 9000. The mixer is somewhat forward sounding but not to that extent. I left the first listening session with a ring in my ears
I'm always on the look out for possible improvements, for better or worse I'll settle down eventually.

All good advice so far, but my mind immediately went in another direction. Your room... length/width/height? Room treatments are very very important. Carpet? Wall coverings? Dampening at reflection points? My room is pretty dead, among other things I have 8- 4"x 2'x4' Corning 703 acoustic panels. Any system will benefit greatly by appropriate room treatments but the more serious systems need it even more. The 4435's are pretty darn serious! If your room is not treated I can image harshness.

For listening- I'd never raise them 3', maybe 4-6". That odd sound coming from the mid-woofer- yeah...gotta track that down.

Lux Man, my room is 6 x 5.5 meters with a 3.3 m high ceiling. Floors are carpeted, and beams run perpendicularly to the sound wall over the whole ceiling, effectively deadening the ceiling reflections. I'll look into covering the wall with carpet/panels.

About raising them, as said earlier, I need to accommodate for dance parties. Ideally the center of the horn would be at ear level for this application. However, I'll go with a mid height option as I also use these as listening speakers. Unless I find an adjustable height platform that can support the weight without rumbling.

Hello Mario;

Something is wrong for sure.

The miss-wired woofers opens the door for almost any other mistakes or worse to have been done to them.

When you say the woofers make noise when they are pushed, do you mean physically pushed or when you put some power to them? As others have said these woofers have limited excursion and can be over driven with relative ease.

I would have the compression drivers inspected to insure they have the proper diaphragms in them and make sure they are undamaged.

I have 4430's and 4435's and am listening to the 4435's as I type in my office, I know them well.

Let me share this: I am not a rabid fan of the 1" compression drivers for one reason, they run out of gas before they get loud and sound harsh as hell when over driven or driven with an amp without enough head room. The 4435's are also good enough to show you the short comings of the electronics on your system. A Bryston DAC for instance allows me to play them considerably louder without fatigue. This I would have never guessed but it removes a lot of the glare when they're turned up.

I don't know where in the world you are but can you enlist the help of a qualified tech? Getting them right will be worth the effort.

All the best,
Barry.

Hello Barry,

By the woofer being pushed, I mean played to loud levels. I mean being fed a 0dbu output by the preamp into the amps that have a gain factor of 33db. I am wondering if there's a way to know how much power is being fed to the speakers without measuring directly.

What alternative to the 1" compression driver would you suggest? My source isn't the most precise, as I am playing old and used records most of the time. I usually buy mint tho. Still vinyl is vinyl.

I'm based in Beirut, Lebanon, where I'm from. I have good friends in the audiophile community, of whom one is a particularly seasoned tech. We're driving up to my mountain home tomorrow to figure things out.

All JBL's sound a little bright to new owners. When your building a speaker thats flat to 17 KHZ with out any roll off they will sound bright. That said, clean all the controls check connections and be prepared to replace all the caps. Yes the HF driver may have issues and follow others recommendations. Remember they are a monitor speakers, not a PA speaker. They re designed to be listened to in a controlled environment at relatively close distances. When they spread the sound on floors and ceilings before the direct sound gets to your ears the sound is going to be compromised and clarity and imaging lost. You really should have different speakers for your applications. Some thing with very controlled vertical dispersions. Sounds like you would prefer C-V. 4435 is my favorite JBL from the past. They have to be installed at the correct elevation in a controlled environment. If placed on a floor I always recommend Standing them up vertically and rotate the horn 90 degrees.. The center of the horn should be at seated listening ear height. Higher for parties, the center line should be at or around 70 inches to get the sound over most folks heads. Lot of folks have issues with the bi-amp by pass switch. I would choose which application you want and by pass the switch.

Go to Web and down load the owners manual for assistance in proper operation.

Hello twiiii,

what do you mean by C-V? and by standing them up vertically? Pardon my confusion, I'm not sure I understand.

Is it also possible to rotate the horn? I don't have the speakers in front of me as I'm writing. Has anyone tried this configuration?

My room is slightly bigger at 99 m3 vs 85 m3 for the control room that was used to measure 122db (!). We're talking noise, so no transients of course. I care about my fellows so of course no pushing them anywhere close to that.

I'll have a clearer idea as I open them up tomorrow. Most definitely going to by pass the crossover switch.

Yes; unless you bridge the HF and LF inputs in the crossover internally, you’ll need to jumper them on the back panel, or bi-wire or biamp. If biamping using the BX-63[?], my bypass mod should be revised to use the slightly different biamp circuits of the crossovers. My mod abandons those circuits.

hey Zonk,

BX-63?

I'm planning on sticking to the mod you've described in: http://audiokarma.org/forums/index.php?threads/cheap-and-pretty-easy-jbl-4430-upgrade.537606/

and proceed to bi wire the speakers. I hope to be able to bi amp them in the near future. Amp dreams!



Cheers everyone!

 

[Zonker92]

Mario, as far as I know, there's no easy way to put a larger diaphragm horn driver in the 4435, but with Radian diaphragms you should be with happy with the horns as they are. I think you can rotate them but you'd have to change the mounting screw configuration; probably have to drill some new holes. (Not my preference.)

I think the BX63 was a subwoofer crossover, and not what I meant, but there was an external JBL or Urei biamp crossover that was meant to work with the 4430 and 4435 using a particular circuit card.

As I recall, they were not meant to be biamped without that crossover (which is why the stock crossovers have a slightly-different circuit for biamping), although with a modern programmable crossover you could make it work.

 

[dshoaf]

Adding my experiences with a number of big-format monitors (UREI 809/811/813s, etc). These speakers are designed for mixdown and mastering - including the 4435. Most of these monitors should actually sound very similar to each other despite different mixes of drivers. This is the case with the UREI line up. Further, they only really differ in their ability to deliver significant SPL levels before they go into compression. I'd expect similar characteristics for the 4425/4430/4435/ series.

This means they're all quite accurate and they'll allow you to 'listen back' into the audio chain. The fact that our OP reports his ears hurt after a listening session tells me that he may be actually hearing deficiencies in the power amp, preamp or source. Some time spend mixing and matching components and taking notes will help identify if this is the case. Grounding of the gear cannot be overlooked, too.

While there may be a problem with the 4435s, I'd suspect that only one speaker would manifest it - not both. The same problem with both would tend to lead me back into the audio chain.

Just my thoughts......

Cheers,

David

 

[Zonker92]

That all sounds plausible, except a pair of crap horn diaphragms or damaged woofers could do it, too.

Mario, C-V means Cerwin-Vega.

 

[hjames]

I am the new proud owner of a pair of JBL 4435 since last week. I'm planning on using these as listening speakers as well as party PA in my home. Currently, I've got them set up with Technics 1200s, an ARS 9000 DJ mixer and Quad Elite QMP amps.

Yeah, skip the CV speaker recommendation - you have better speakers already!

Zonker meant the JBL/UREI 5235 electronic crossover for biAmping - they came with different plug-in cards to get the crossover effect needed for whatever monitor you were using them with ... Tho they may be a bit old in the tooth at this point.

http://www.jblpro.com/pub/obsolete/5235.pdf

So - you didn't list a location so - roughly, where in the world are you? Maybe another AKer with experience is comewhat local and could give a listen and help you come up with strategies ?-

And - just for grins - one of the Lansing Forum guys built an alternative pair of cabinets for his 4435s ... Used less floor space since they were standing upright!

 

[1audiohack]

"What alternative to the 1" compression driver would you suggest?"

I don't have a suggestion for a replacement for the 4435. It is just a limitation on how loud they will play. The 4350 for example will play much louder while maintaining its composure.

I hope it all checks out OK. It will be interesting to see what you find.

Barry.

 

[toddalin]

That all sounds plausible, except a pair of crap horn diaphragms or damaged woofers could do it, too.

Mario, C-V means Cerwin-Vega.

Are you sure? Maybe he meant contant velocity or C-D (constant directivity), like the later horn offerings. Seems weird to offer up some other manufacturer in relation to a question about directivity.

 

[Lux Man]

Mario-

Your room seems like it is pretty much a square. Personally I don't think those beams are helping you in anyway cut down on reflection. Without seeing the room and whatever else you may have for furniture and such and speaker placement, it pretty hard to conclude much. Certainly a square room with only carpet for dancing( probably not thick and plush) I can imagine a pretty harsh sound. I'm not saying you don't have other issues but I wouldn't ignore the acoustics as an additional source of the problem.

 

[twiiii]

I wouldn't recommend an alternative driver, unless you have the necessary test equipment and can design a new crossover filters to protect and complement the HF drivers response. Of course you could bi amp using a multi channel digital processor and drive the drivers directly and throw away the passive crossover. But you have to remember one woofer is operated full range to the crossover point where the second is added at a lower frequency to increase dynamic range. If run both woofer at full range then destructive inference will be come prevalent as bass frequencies turn into midrange frequencies being produced by two drivers. Personally I'd cross the woofer around 250 Hz to one or more of JBL's 8 or 10 inch mid woofers. But now You need to tri amp and find a single 10 that can keep up with that HF driver or 2 15's is going to be a real challenge. So fix what you have and enjoy. You have two great speakers, except for the damn selector switch. Audio files would be screaming at the thought of that much power going thru a Micky Mouse selector switch.

 

[toddalin]

The only alternative driver I would recommend would be and LE85 with an original aluminum diaphragm.