Bi-amping 4343's

[JBL Dog]

I finally got around to bi-amping the 4343's. WOW! Night and day compared to passive. I'm using JBL 6290 and 6230 amps for power and a JBL 5234A crossover along with factory 4343 cards. Those JBL's are much cleaner sounding than the McIntosh MC7270 I was using (go figure?).

If you own 4343's, bi-amp them. You won't be disappointed!

:D

[RKLee]

Biamping/active crossover, ie using 1 amp per driver will effectively double the amplifier power. Plus any distortions produced by the amplifier driving the LF drivers won't appear in the HF driver(s). The problem with passive crossovers, is that the amplifier sees the various inductors and can't apply full damping to the drivers; whereas in active crossovers, the amplifier is connected directly to the drivers therefore will see the direct damping of the amplifiers. The difference to me is night and day. I am paraphrasing this from an old Altec brochure on this subject for justifying active crossovers.

I couldn't believe how clear the sound was when using an active crossover.

[JBLOG]

JBL Dog,

Wow, The JBL sounded cleaner than the Mac in the biamp mode!
Maybe a big part of the difference you are hearing in due to differences in the ability of the amp to control the driver(s).
I was was surprized to find that the MC 7270 has a damping factor of only 30 while the JBL 6200 series is 200.

http://www.jblpro.com/pub/obsolete/6200ser.pdf
http://www.roger-russell.com/amplif2.htm#mc7270

NuForce amps chime in at 4000!

[RKLee]

JBL Dog,
.
.
I was was surprized to find that the MC 7270 has a damping factor of only 30 while the JBL 6200 series is 200.

http://www.jblpro.com/pub/obsolete/6200ser.pdf
http://www.roger-russell.com/amplif2.htm#mc7270

NuForce amps chime in at 4000!Not too familiar with the Mac amps(they are just way too expensive), but I think the tube ones are pretty low on the damping factor, and also their solid state amps were pretty low also because they used a coupling output transformer in the output stage. Most modern amps don't have transformers in the output stage which is why the JBLs amps are so high.

Bottom line is that you will notice a quantum jump in clarity by taking the trouble to use an active rather passive crossover.

You can also get steeper slopes at crossover. In the typical passive crossover, you can only have 12dB/octave slopes, where with active crossover, in addition to 12, 18, and even 24dB/octave are available. I would told that odd order slope of 18 is the best to get rid of various odd-order distortions.

[timc]

JBL Dog,

Wow, The JBL sounded cleaner than the Mac in the biamp mode!
Maybe a big part of the difference you are hearing in due to differences in the ability of the amp to control the driver(s).
I was was surprized to find that the MC 7270 has a damping factor of only 30 while the JBL 6200 series is 200.

http://www.jblpro.com/pub/obsolete/6200ser.pdf
http://www.roger-russell.com/amplif2.htm#mc7270

NuForce amps chime in at 4000!


Hi.

The factor of 4000 is only in the lower octaves. The number in itself isnt too important. The thing to look for is how well the damping factor holds when moving up the Freq. range.

I tried a amplifier (much like NuForce) with a damping factor of 1000 in the bass region. My amplifier at the time, a McIntosh MC402, had way more controll.

The damping factor of the Class-D amplifier dropped like a stone above a few hundred Hz. Mc rated the damping factor of the 402 to >40. This means it never drops below 40. The Class-D thing surely did. I found measurements on a similar amp on the web and at higher Freq. the damping factor went almost to zero.

I believe it was QSC or LabGruppen who wrote a paper on the subject of damping factor. The stated that the most important thing was not to have the biggest number but the most even number uppwards in Freq.

-Tim

[nrwjbl]

..... If you own 4343's, bi-amp them. You won't be disappointed ...!

:D

I had same experience when I got my 4343's biamped. First tried with crossover Urei 5235 and now I run them with JBL Synthesis SPP-AC1.
Amping I do with Lexicon LX-7- amp.
Bass response is much better and powerful, mids and highs crisp and clear. It paid to do so. Sounds really JBL ...!

Biamping my 4435's was not that successful so I returned to passive mode.

peter

[JBL 4645]

I finally got around to bi-amping the 4343's. WOW! Night and day compared to passive. I'm using JBL 6290 and 6230 amps for power and a JBL 5234A crossover along with factory 4343 cards. Those JBL's are much cleaner sounding than the McIntosh MC7270 I was using (go figure?).

If you own 4343's, bi-amp them. You won't be disappointed!

:D

JBL Dog

Well now that you’re pleased with the active crossover which is so choice can we see some pictures please lots of pictures!:D

:useless:

Found a link to other JBL 4343 under Google image so many enjoy.:)

http://images.google.co.uk/images?svnum=10&um=1&hl=en&q=JBL+4343+&btnG=Search+Images (http://images.google.co.uk/images?svnum=10&um=1&hl=en&q=JBL+4343+&btnG=Search+Images)

[gerard]

Jbl dog

which Crossover do you use .
JBL original ?
Home made ?


Gerard

[Titanium Dome]

Biamping my 4435's was not that successful so I returned to passive mode.

peter

Several members have commented on little success in the attempt to biamp the 4430 and 4435. :)

[Zilch]

Several members have commented on little success in the attempt to biamp the 4430 and 4435. :)It worked when I did it, just no big whoop, is all, so not worth all the gear and effort. :dont-know

[hjames]

I finally got around to bi-amping the 4343's. WOW! Night and day compared to passive. I'm using JBL 6290 and 6230 amps for power and a JBL 5234A crossover along with factory 4343 cards. Those JBL's are much cleaner sounding than the McIntosh MC7270 I was using (go figure?).

If you own 4343's, bi-amp them. You won't be disappointed!

:D

Any of the big 4-ways will benefit from biAmping - made a world of difference in mine (4341), and I've heard folks with the big'uns 4345s say the same thing.
With mine I use a JBL 552 to dial in the lo/hi split, and run the 6230 and 6260 JBL amps.

[Titanium Dome]

It worked when I did it, just no big whoop, is all, so not worth all the gear and effort. :dont-know

If the intended result is a notable improvement in sound, then it doesn't matter if it "works," it's still "little success." :p

[blackwell]

Several members have commented on little success in the attempt to biamp the 4430 and 4435. :)

I wonder if this is because people are bypassing parts in the passive crossover that provide EQ'ing for driver correction? I know they padded down the horn but I suspect that there is probably a litte freq. resp. tailoring in there as well. If you just biamp and don't smooth out the response the way the passive did, then it will never sound right. Just a thought?

[Ian Mackenzie]

There is a specific card used for the 4430/35 in the JBL 5235 active crossover.

The prevailing series capacitor in the 3134/35 networks offered protection for the driver and adds a pole for the final high pass filter. The post passive crossover EQ is always in circuit.

I would suggest anyone considering biamping consider the following:

Re build the crossovers with charge couple topology or use high quality capacitors like Hovlands.

Get the titanium diaphragm dusted or use a Tad driver and get the crossover tweaked for the Tad impediance plot.

Use a Bryston10B active crossover or similar setup for the system

A high quality power amp for the HF driver.

Ian

[Zilch]

I wonder if this is because people are bypassing parts in the passive crossover that provide EQ'ing for driver correction?Not the Zilchster, no:

http://audioheritage.org/vbulletin/showthread.php?t=9901

And not a bunch of others who have tried it, either....

[4313B]

not worth all the gear and effort. :dont-knowMaybe not to you, in your particular environment...

And not a bunch of others who have tried it, either....
Several members have commented on little success in the attempt to biamp the 4430 and 4435. :)One hundred of you could fail and blog about it and it wouldn't change my mind about the benefits of bi-amping, tri-amping, etc.

[4313B]

Not to mention having an area conducive to enjoying the system in the first place.

[John]

Not to mention having an area conducive to enjoying the system in the first place.

That is a fact missed by 99% out there.:(

[hjames]

Not to mention having an area conducive to enjoying the system in the first place.

That is a fact missed by 99% out there.:(


Damn - I don't have the obligatory $4k+ for the Bryston10B active crossover plus a pair of Nelson's Past amps,
nor the space for a proper listening environment where I can truly appreciate this gear.
I better sell my big JBLs to the Japanese (they got the REAL money), then go buy some Blowse or Capehart or something -
I guess the attitude here is thats all most of us are good for!

Forgive me for misunderstanding my station in life - we are not worthy!

[4313B]

What are you talking about Heather? See post #11 above... you're already bi-amping...

[Ian Mackenzie]

Damn - I don't have the obligatory $4k+ for the Bryston10B active crossover plus a pair of Nelson's Past amps,
nor the space for a proper listening environment where I can truly appreciate this gear.
I better sell my big JBLs to the Japanese (they got the REAL money), then go buy some Blowse or Capehart or something -
I guess the attitude here is thats all most of us are good for!

Forgive me for misunderstanding my station in life - we are not worthy!




Heather,

I think you missed the subtle differences here in the application of biamping.

Biamping at 320 hz via a woofer and a mid cone that bypasses the passive crossover used at that frequency is a different kettle of fish to biamping at 1000 hz. What you hear is one hellava difference in bass and midrange clarity. The power split at 320 hz is also benefically to biamping.

Now biamping the 4435 will tighten up the bass a tad but primarily offers protection of the Compression driver in the event the system is being driven hard and the amp clips when used for what they were built for..monitoring.

The signal still runs via a series capacitor and passive Eq shaping elements for the bi radial horn...nothing to loose sleep over if they are hi quality parts. If you plan to biamp do yourself a favour and have Giskard build a charge - coupled network. The difference is quite audible.

A lot of amps tend to dislike a 4 ohm load and will sound less than happy depending on the amp. This is most noticably in the upper midrange if your appreciate hi fidelity rather than a loud noise (ie PA systems are usually biamped by the way). Recording studios playback at horribly loud levels incidentally.

The system may therefore sound cleaner biamping. If you have a very good power amp like Guido's and don't need 120 db in your home biamping is probably not going to help. As a practial matter I have used the Aleph 2 in a 3 way system using the 4435 biradial. It worked wonderfully.

I referred to the better quality active crossover because the old vintage models we see floating around with dated i.cs do intrude on the purity of the audio signal even though there are practical acoustic benefits for the drivers. To wring the last drop of the performance of those compression drivers it important to understand the first watt of power is the most important up at those frequencies where the driver operates. To the initiated this means using a hi quality amplifier that has very good performance at low power levels. It is practical to consider using a class A amplifier in this situation.

As you may now appreciate this has little to do with the sort of attitude you are referring to. Ignorance is bliss for some but we learn to live with that around here.

I mean everyone including Giskard had an opinion or should I say a belief on the fog horn used in the 43XX 4 ways. Now no one can say a really bad thing about them in the likes of the 4344/4345 because a number of people have made the effort to re visit these systems. But you need hands on experience in setting all these system up and an understanding of what's important to get it happening. We've had similar discussions about the use of graphic equalizers.

Its not a topic for an academic arm chair discussion. You learn by doing.

Ian

[jblbgw_man]

Biamping my 4435's was not that successful so I returned to passive mode.

peter

I have played around for many hours with my 4430's and 4435's :banghead: and have run both a BSS FDS360 24dB/ Linkwitz Riely cossover and a 5235 with correct network for 4430/4435, IMHO they do need to be used with the right crossovers with the righ slopes, biggest problem I had was balancing the LF and HF drives without a RTA but once right I think they are chalk and cheese between active and passive.:applaud:

Now I want a pair of 4343's or 4345's to play with.

[hjames]

Heather,

I think you missed the subtle differences here in the application of biamping.

Its not a topic for an academic arm chair discussion. You learn by doing.

Ian

No, I think I understand quite well - as I've read in the upgrade threads (and heard), there's a lot of difference in crossing at 290 or 320 hz vs crossing over more within the human vocal range of 900/1200 Hz. I do get that.

I've read Greg Timber's posts here and know there are many advantages to using cleaner, more modern CC networks as well, and when I choose to put more money into speakers again, no doubt I will pursue that strategy, but at the moment I have other expenses and investments pending. It seems sometimes life intrudes ... ;)

Surprisingly, the 4341s remain quite enjoyable, even if not yet at their ultimate capabilities ... and a definate upgrade from the DIY 4ways that were here before. I am quite capable of enjoying the music at this level, knowing that more improvements and refinements await me.

[Robh3606]

High bucks rule.

Hello Heather

Huh??? What does the benefits of biamping have to do with dollars??? Yeah I know that's a really stupid question with it's own obvious answer but really.

You don't need big bucks to biamp and you don't need $4000 amps to hear the difference. The key is to simply do it right or at least as best you can within your means.

With my gear some high end guy would simply laugh at me. I mean 20 years old Crowns some ancient Urei EQ's and a couple of JBL PA crossovers. My god just running Crowns and JBL together could give some guy a heart attack at the thought.

I don't think anyones saying spend big to get big. It's more like spend wisely and do your homework. I have some money tied up but no where near what " High End" gear would cost. I could sell the whole system off and not be able to get a "decent" set of speakers.

The larger systems are not inexpensive as you know and decent gear isn't cheap either. The larger systems can sound damn nice but that doesn't mean you can't fire up the old Pioneer reciever with L26's and get just as much fun out of it.

It's not the money or the speakers it's the mindset that matters

Rob:)

[Ian Mackenzie]

I agree you can do it all with not too much outlay if you go the diy route.

I did with my diy active crossover and amps.

Getting back to the point which was to an extent off topic biamping the 4430/35 same / better issue I would address upgrading the stock crossovers before getting too concerned about biamping. My pm box suggests most members see that as a logical upgrade path. I will respond to those messages over the weekend.

The appreciation is not in what other people write which happens a lot around here but doing it yourself.

Ian

[hjames]

You've got a piece of my deleted post, and took that out of context ... I'm hardly an advocate of high dollar systems.

I thought I had talked plenty here about the mini rack I built of JBL 6230 amp, JBL 6260 amp and JBL M552 active crossover (total price, under $500 even with XLR cables and adapters) as a low cost way to bi-Amp. Didn't think I'd have to remind anyone here that I am a firm believer in cost-effective DIY.

I guess its hard to get sarcasm unless ...?

And Ian - I'm a web developer, I work on the internet - checking mail before bed, and signing on for work in the morning is normal for me - I get paid for it. Your excuse?



Hello Heather

Huh??? What does the benefits of biamping have to do with dollars???

It's not the money or the speakers it's the mindset that matters

Rob:)

[Ian Mackenzie]

What are you talking about Heather? See post #11 above... you're already bi-amping...

Yeah well at this point we're all wondering .

It may be better in future not to buy your way into a thread where you don't have a point to prove.

Ian

[Ian Mackenzie]

I had same experience when I got my 4343's biamped. First tried with crossover Urei 5235 and now I run them with JBL Synthesis SPP-AC1.
Amping I do with Lexicon LX-7- amp.
Bass response is much better and powerful, mids and highs crisp and clear. It paid to do so. Sounds really JBL ...!

Biamping my 4435's was not that successful so I returned to passive mode.

peter

Hey Peter,

It may pay to write a pm to John Nebel on the subject and get his impressions. I think John has tried and heard it all.

In this pic John has his 4343's and 4435's both running biamped

Ian

[pos]

No, I think I understand quite well - as I've read in the upgrade threads (and heard), there's a lot of difference in crossing at 290 or 320 hz vs crossing over more within the human vocal range of 900/1200 Hz. I do get that.
I think Ian was referring to the fact that a system with a low crossover frequency (eg 434x) benefits more from biamping than one with a higher crossover frequency (eg 443x). I guess this is because passive components needed for such low frequency crossovers are more harmful to the signal ?...

[subwoof]

Essentially the first crossover point is when bi-amping confers the most sonic and distortion advantage and that is more true when the point is low enough that the action eliminates ( or greatly reduces ) the number of large caps and inductors needed. This is ( again ) basic physics and has been extensively written here by many.

Both arguments I have seen posted here have merit:

>The LF to LM transition on the 434X 4 ways make a huge positive effect when biamped but the speaker placement, ambient noise floor and room reflections have MANY MANY orders of magnitude more bearing on the total outcome than the small differences in amplifier performance / specs when decent amps and wiring methods are used.

>Biamping the higher crossover'ed 4430/35 does have an advantage for distortion but does require careful balancing and unless running a system with 12+ horns ( as in the many club installs we did ) is of marginal cost-effectiveness. Remember that these *are* only one inch drivers and you cannot reduce the inherent distortion they have over the newer designs and larger diaphram models. Of the 30+ systems we installed, fewer than 1/2 doz used 1" horns as the full HF.

The difference between .01 and .001 distortion in a properly designed system is about the same as a mouse farting in the hall closet while listening to a volume that would break your lease / marriage. Too many are influenced by hype, obscure "specs" and thatsthewayweallwaysdidit syndrome.

eek.

It's all about enjoyment of your system and the fact that if you can pull off a 500 dollar biamped rig of those quality components, that is a lot more skill than tossing wads of hundreds at a "unobtanium + rarium" importer..:)

:cheers

sub

[timc]

The difference between .01 and .001 distortion in a properly designed system is about the same as a mouse farting in the hall closet while listening to a volume that would break your lease / marriage. Too many are influenced by hype, obscure "specs" and thatsthewayweallwaysdidit syndrome.


Priceless :applaud:

[Ian Mackenzie]

Priceless :applaud:

I agree there are lot of environmental differences and when I discuss the objectivity of doing something a certain way with certain equipment it may be difficult if not impossible for anyone else to appreciate.

I did however prove I am not completely insane by discussing a biamp versus actively driven 4344 comparisons rig with Porschedm.

Ed has reported the details in the 4343-4344 upgrade thread. The results were not as predicable as we have read here.

Its not snake oil or splitting hairs on static distortion tests but essentially as Rob put it earlier. Just spend the money wisely where its going to matter. A chain is only as long as its weakest link after all.

Ian

[timc]

I didn't mean to be a critic Ian. I just found that whole sentence incredibly funny.

I have no experience with the large monitors, but i hope to hear one some day.

-Tim

[Ian Mackenzie]

I did my first biamp about 30 years ago and biamped my 4343's not long after. cc1980.

But the refinement and getting the best out of this gear is a discipline that takes time.

Ian

[subwoof]

Did my first biamp in early '78 when working for a crown/jbl sound contractor. Used a pair ofJBL 2390/2440's on top of a pair of single scoops with 2205's With a Crown 300 / 150 and an old urei 521 crossover.

DAMN it sounded good in that first apartment. Neighbors loved it for the initial "breaking in" party but it lost it's cache when pink floyd's the wall ( helicoptor ) kept appearing at 2AM.

Sadly it went into a small club and it was 10 years before another biamped rig appeared..

They seem to come and go with the seasons and the will / room for the outboard gear.

Now with 2 teenage daughters, they are absolutely SPOILED with the maze of speakers in the living room and 2 other large systems in the den and dining area.

I consider it a PROPER upbringing getting them used to maneating sized speakers so later in life when their husband brings home a set of large speakers they will say...

" That's it? "

:cheers:

sub

[timc]

:thmbsup:

Now with 2 teenage daughters, they are absolutely SPOILED with the maze of speakers in the living room and 2 other large systems in the den and dining area.

I consider it a PROPER upbringing getting them used to maneating sized speakers so later in life when their husband brings home a set of large speakers they will say...

" That's it? "

:cheers:

sub


Hey man, thats how it is supposed to be done! :thmbsup:

[Ian Mackenzie]

Did my first biamp in early '78 when working for a crown/jbl sound contractor. Used a pair ofJBL 2390/2440's on top of a pair of single scoops with 2205's With a Crown 300 / 150 and an old urei 521 crossover.

DAMN it sounded good in that first apartment.

" That's it? "

:cheers:

sub

I dont feel that ol yet.:)

Our first xover was a diy asyammetic 18/12 db diy sub kit . Used it for the 2231A's sub setup. I was still at High School so it was probably more like 78. Those 2231A's were the bee's knees then.:bouncy:

Biamping the 43's will always put a smile on your face.

Ended up using a Nakamichi xover and sub sonic filter block box series. Nice units. Conveniently they were 6 db down at the crossover point.

Tried lots of other analogue stuff over the years before digital arrived incl the Crown. Hated digital and Not fond of anything with 5523's or TL074's or any chip used with 100% feeback buffer. The newer BB chips are better but still not ideal. Kind of killed my interest in biamping for along time. Tried the 5234a which was horrible, the 5235 a bit better and the DX1 was hifi. The DX1 was not a bad unit, shame they got destroyed. Built numerous discrete class A Pass diy active crossovers. Almost valve like qualities and very low noise. If you dont need digital they are the ones. Unfortunately the dual Jfets are NLA.