4345 replicas - can they sound better than originals?

[Cornholio]

I'm offered to make a brand new 4345 replica by a local company (I heard their speakers based on Tannoy SRM and they sound and look real good, so these guys are definetely pros). The questions which bother me are:

1) can a brand new speaker, based on 4345 drivers and schemes yet with modern crossovers and more expensive modern parts and cabinets sound superior to the original? Or are originals the key to THAT sound?

2) I never liked the blue faces, so for me it's either black face or wood veneer a-la Altec or Tannoy. The thing is I never saw 43 series JBLs with wood veneer faces - is there something in their design that prevents it? Sorry for amateurish questions.

[ratitifb]

I never liked the blue faces... :crying::blink::eek::banghead::behead:

[hjames]

I'm offered to make a brand new 4345 replica by a local company (I heard their speakers based on Tannoy SRM and they sound and look real good, so these guys are definetely pros). The questions which bother me are:

1) can a brand new speaker, based on 4345 drivers and schemes yet with modern crossovers and more expensive modern parts and cabinets sound superior to the original? Or are originals the key to THAT sound?

2) I never liked the blue faces, so for me it's either black face or wood veneer a-la Altec or Tannoy. The thing is I never saw 43 series JBLs with wood veneer faces - is there something in their design that prevents it? Sorry for amateurish questions.

Ah - if they use Authentic JBL drivers, refurbed if needed with authentic JBL parts, (fresh recones and diaphragms as needed)
but with late model or newer crossover designs, and the cabinets follow the original design with the 10 in mid bass in a "doghouse" closed off from the main chamber the 18 inch woofer works in, it should sound as good or better.

And although I personally prefer the blue faces monitors,
Mr BMWCCA's 4345 clones with the dark ash baffleboard is quite a nice treatment,
if you like that sort of thing ...

Personally, if I could not have blue, I'd have a nicely grained oak or walnut baffleboard -
something with an attractive, pronounced grain but not too dark (I don't like black ash myself)

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=57536&d=1353859371

[Mannermusic]

You might take a look at Giskard's 4345 thread here in the data base (search). It's a straight-forward upgrade that uses a 2" compression driver (in place of the 1"), a 2123 mid, along with his 3155 DC biased crossover (for bi-amp only). Depends how involved you want to get!

http://www.audioheritage.org/vbulletin/showthread.php?27199-DIY-quot-4345-quot-Project/page8&highlight=4345+Giskard

[Lee in Montreal]

"Sound better"... Ask your supplier what he means by that. Audio being the secong biggest scam on earth, right after the automotive business, "sound better" must be taken with a grain of salt. ;)

[richluvsound]

Yes they can sound better than the originals .... I would have them built by someone thats done it before though . Like Heather suggested .... original spec parts and have the networks built by Guido in Germany or Rick in the states . I have have built and shipped to Moscow , I can only conclude that my client wasn't happy with what was on offer in Russia . Duty on the parts is going to kill your bank account .... They would cost you around 9000 euro . If anyone offers to make them for less you know they have cut a corner somewhere !

[BMWCCA]

Audio being the secong biggest scam on earth, right after the automotive business, "sound better" must be taken with a grain of salt. ;)

Uh-oh, I'm double-cursed! ;)

Having never heard a "real" pair, I can only go by what others have said:

http://www.audioheritage.org/vbulletin/showthread.php?10613-4345-Includes-Designer-s-Post&p=110349&viewfull=1#post110349


You Guys are Amazing
http://www.audioheritage.org/vbulletin/images/misc/quote_icon.png Originally Posted by gtimbers
I can't believe all the interest in this 30 year old system. It was never very successful during its life time primarily due to its size. Most people would get something smaller. It also had a reputation for less than detailed bass, which I have always thought was due to the enclosure not being quite large enough. I haven't thought about these things in years but since I have received a few requests for comments - here goes.

The system was and probably still is a stellar performer if you like the inherent sound of the traditional big JBL 4-ways. There is good news and bad news in the basic design. Good in that they are dynamic as hell and never get confused with intermodulation products of any type. They don't take much power to run and can swallow up a really big amp should you wish to do so. The weak areas of that type of design are several. First, there is a large time off-set between the 10" driver and the HL92 horn. This shows up in both the on-axis response, the directivity pattern and the homogeneity of the driver blending. The second problem is the use of a passive crossover between the top of the woofer and the bottom of the 10". Passive crossovers set to frequencies below about 500 Hz react badly with the motional impedance of the woofer/box combination and give substantial gain around 100 Hz. Gain out of a passive system is generally a bad thing. In the case of the High Pass, we have to work the passive network through a really large motional impedance peak resulting from the 10" fundamental resonance in the sub enclosure. This means that the actual voltage drive that occurs at the terminals of the 10" is less than ideal. There was the added complexity that the Marketing folks of that time required switchable bi-amp capabilities in which the incorrect setting of the switch was not allowed to hurt anything. These little things all add up to additional insertion loss for the woofer and loss of damping control. Now all of this sounds pertty bleak, but as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway.

My sonic memory of the big 4 ways, the last of which was the 4344MkII, is that they are effortless, dynamic, pretty low in coloration and really "alive". They are a little vague by today's standards in terms of precise imaging and although they are very low in intermodulation effects, they are not as detailed as really good lesser way designs. There is no simple answer to any of this and no one design statement that is best. Everything is a series of compromises, and the 4345 has a very good set of complimentary compromises.

I noticed a comment earlier in this string regarding the 2122H. It is a really good voice transducer. It always has been and always will be. Things just sound really natural through it. Another one that might be slightly better is the 2123. It is a little less smooth but perhaps a little more realistic on voice. Either are really good for that critical range from a few hundred Hz to about 1500 Hz.

I imagine you guys have talked about and tried lots of things to get the most out of the system. I will mention a few things that I would do if I had a pair at home for my primary system.

Get rid of the bi-amp switch. Hardwire it in which ever mode you want it. The switch is not that great.
If you can work out bi-amping do so. The difference in the 2245H and 2122H will be amazing. The crossover will have to be non standard. Neither driver is flat around crossover so the voltage drives will need to be adjusted to get proper acoustic bandpasses.
The network components should be updated and this isn't easy. All the capacitors should be polypropylene and you would want to use air core inductors where ever possible. I believe the 4345 used some tapped iron cores. Those are hard to replace with aircores because the surrounding network topology would have to change and all of the values have to be re-engineered. I would suggest leaving them alone unless you are really good at this stuff.
If you can swing it, go to a biased network. The difference is unbelievable.
The ring radiator hates passive networks. A major improvement in the upper range would be to drive the 2405 from its own little amp. You only need 3 or 4 v rms. The 2405 does 110 dB for 2.83v. It is padded way down in the system. There is little real power at those frequencies anyway. You only need to know the voltage output of the amp, power is irrelevant. The 2405 is about 12 ohms and won't draw much current. I would use some little chip amp with a 2nd or 3rd order low level highpass in front of it. Take off the passive network to the ring and just feed it straight. Make sure the amp doesn't make a DC thump on turn on or turn off. That will fatigue the diaphragm. The amp will also have to have really low noise characteristics as any hiss will be really loud directly into the ring. I used to use an old Marantz 1030 integrated amp to run my rings. I could separate out the power amp section and the tweeters always sounded really good.
The L-pads aren't so hot either, particularly after all of these years. Once you have your preferred balance, it is fairly easy to measure each leg of the L-pad and replace it with fixed resistors.
I notice from many of the pictures that the system is elevated on blocks. It is very good to get the 2245 up off of the floor to minimize midbass fatness.
For resale reasons, you should be very careful about doing as much of this as possible reversibly.

Before closing I should comment briefly about the 250 - 4345 comparison. Simply put, I prefer a 250. I like the bass quality of the LE14 woofer. Alway have and always will. The 2245 when used as a dedicated sub is one of the best sounding woofers ever. It has an amazing blend of speed, pitch and punch. So does the 14" but the 18" is better. Unfortunately the 18" dislike for passive networks hurts it more than the 14" is hurt by a passive network. I think the mid and high range on the 250 is smoother and much more open however the 4345 wins by a bunch in terms of effortless dynamic sound. I have made all of the above changes to 250 systems (except for separate amp on UHF) and the improvement is huge. I have not done so on the 4345 but I suspect that that system will benefit from theses changes more than a 250 would. If both systems were tweaked out to about the same level, I suspect it would be very hard to come up with a clear overall winner, but I think I might lean towards the 4345 as having the greater potential.

Thank you all for the interest in my work. I must admit I have been blessed with a really nice profession that has treated me well for a very long time. Remember that sound and music enjoyment are very personal things and that what makes you happy may or may not please others. Screw them. If you are happy and no one is geting hurt then go for it. No loudspeaker system even approaches real life so there is plenty of room for interpretation.

.

[Tweak48]

2ch- JoLida 502, Carver TX2, Oppo DV981HD, JBL L200+


Did you notice that the leading character in the movie "The Mechanic" Jason Statham as Authur Bishop used a JoLida 502? He wouldn't let his supporting character Steve McKenna (Ben Foster) touch his turntable. :applaud:

[ivica]

Uh-oh, I'm double-cursed! ;)

Having never heard a "real" pair, I can only go by what others have said:

http://www.audioheritage.org/vbulletin/showthread.php?10613-4345-Includes-Designer-s-Post&p=110349&viewfull=1#post110349



.

Some question or comments about GT words: ".....The second problem is the use of a passive crossover between the top of the woofer and the bottom of the 10". Passive crossovers set to frequencies below about 500 Hz react badly with the motional impedance of the woofer/box combination and give substantial gain around 100 Hz. Gain out of a passive system is generally a bad thing........"

Why not to put "in-parallel with" the 2245 driver , a kind of notch filter ('Zobel network') consigning of about 20mH ( 8 Ohms) inductivity in series with 470uF (bipolar) capacitor? Owing to some simulation such would flatten the response and the impedance too.
If such large inductivity arranged with the core, may be additional resistor has to be added, in order to reach 8 Ohms total DC resistance.
May be with such application would be helpful for the members under "bi-amplification" solution.

regards
Ivica

[4313B]

I'll be real blunt. A system of this magnitude should have been bi-amp only just like the 4355.

One can create some really interesting conjugates with passive parts that will substantially mitigate the motional impedance. Those parts are invariably quite expensive and can suck the life out of a system.

[Wellsie]

Mr. Timbers suggested making the enclosure larger. I would like to build a pair and have no problem "going up". What would be the ideal cubic feet? Is it based on thiel small numbers for the 2245? Thanks for a great board. Dave

[ivica]

Mr. Timbers suggested making the enclosure larger. I would like to build a pair and have no problem "going up". What would be the ideal cubic feet? Is it based on thiel small numbers for the 2245? Thanks for a great board. Dave
As I have remembered (not sure) about 12 ft3 = 340 Lit
In the attached figures simulated Fr curves are presented for 280Lit and 340Lit boxes, either tuned on 28Hz.
About -3dB points for 340Lit box is around about 30Hz, wihile for the 280lit box is about 35Hz, so 5Hz difference in the LF bandwidth is expectable. But what would be the real results in the room (owing to the reflections) it would be difficult to predict.

regards
ivica

[darkmatter]

As I have remembered (not sure) about 12 ft3 = 340 Lit
In the attached figures simulated Fr curves are presented for 280Lit and 340Lit boxes, either tuned on 28Hz.
About -3dB points for 340Lit box is around about 30Hz, wihile for the 280lit box is about 35Hz, so 5Hz difference in the LF bandwidth is expectable. But what would be the real results in the room (owing to the reflections) it would be difficult to predict.

regards
ivica

Thank you for the graphs, I am considering this project at some point myself. Are the graphs / calcs based on basic TS parameters or have the crossover components been taken into account? :)

[frank23]

Thank you for the graphs, I am considering this project at some point myself. Are the graphs / calcs based on basic TS parameters or have the crossover components been taken into account? :)

Welcome! This is a better place for this subject than the hificritic forum :-)

[ivica]

Thank you for the graphs, I am considering this project at some point myself. Are the graphs / calcs based on basic TS parameters or have the crossover components been taken into account? :)

Hi darkmattter,

Only T/S parameters, but passive networks can produce mid-bass over-shoot (of several dB-s around 100Hz, as Mr. GT has mentioned).
With 5.6mH coil and 90uF is shown on the attached figure

Reagrds
Ivica

[4313B]

Thank you for the graphs, I am considering this project at some point myself. Are the graphs / calcs based on basic TS parameters or have the crossover components been taken into account? :)You don't care about the effects of the passive network components on the 2245H because you are going to want to bi-amp a system of this magnitude anyway. :D