View Full Version : My rant about classic speaker "upgrades" (aka hack-ups, IMHO)...

08-23-2003, 09:31 PM
This has nothing in particular to do with JBL products, but in a "meta" way, has a lot to do with them in general, or more precisely, our "duties" as "caretakers" of history, among other concerns.

The below "essay" was a reply to a message on another board, as a response to someone who was considering sending parts from a pair of the legendary Dahlquist DQ10s to Regnar, for "upgrade" (ie, lots of changes- different crossovers, different wiring, driver changes, etc), that essentially, in MY eyes, result in a speaker that is NOT a Dahlquist anymore, in any functional sense of sound balance, etc.

Here goes. Comments anyone? :duck:

------- start of rant :bash: :D -------

(Please don't take this the wrong way...)

... but to tell the truth, the ONLY repair I am in favor of in a DQ10, is re-foaming (replacing the foam surrounds) the woofer when needed, or replacing anything that is ACTUALLY broken, ie, NOT working as it originally did.

IME, unless the speaker has been abused and things physically damaged or burned out, there is little or nothing in a DQ10 that suddenly quits working properly. Yes, if something is actually damaged, replace/repair it... but all this talk about "upgrading" a DQ10, is IMHO, a big waste of time. Where are you going to start, and where are you going to end? Heck, pretty much ANYTHING in a DQ10 can be "upgraded", technology has given us better drivers, better crossover components, better wiring... but the thing is- IF YOU LIKE THE SOUND OF THE DQ10 NOW, THERE IS NO GUARANTEE YOU WILL LIKE THE SOUND- AT ALL- AFTER ALL THE CHANGES.

Basically, in short, EVERY mod done to the DQ10, CHANGES the sound of the speaker in some way. Usually, it's tonal balance shifts (any driver change or crossover component change is GUARANTEED to do this, in some way, shape or form), sometimes it's change in phase behaviour (crossover mods and changes to driver location/geometry are pretty much guaranteed to do this). Once you've started the "upgrade" path, it's like opening the proverbial Pandora's Box... one "upgrade" upsets the tonal balance in ONE direction, which requires ANOTHER change to try to correct that, which usually requires yet ANOTHER change to offset unintended consequences of the SECOND upgrade... ad infinitum. In a speaker as complex as the DQ10, this can turn into a real quagmire, REAL quick.

The bottom line is, in any case... if you LIKE the DQ10, LISTEN to the DQ10, as it is. If not, for the money you'll spend upgrading EVERYTHING that can be theoretically "upgraded" in a DQ10, you can EASILY build a more modern speaker, with MUCH MORE ADVANTAGEOUS driver layouts, that will KILL the DQ10 baffle/driver layout in EVERY way. The speaker was designed as it was, as a BRILLIANT solution to the rather stark limitations of drivers in its day... limitations that NO LONGER exist, to ANYWHERE NEAR the degree that they did then. We have MUCH higher bandwidth, better behaved drivers, and the capability of designing networks to maximize their performance by computer, to the point where you don't usually NEED a 5-way speaker, to get every driver in its' optimal operating range, unless you want to play 120 dB and actually NEED an 18" woofer to get that loud in the bass(and a 3-way or more to keep up with that on the mids and highs).

Simply put, if it ain't broke, don't fix it. If you want different, buy or build different, it'll be MUCH easier and more time efficient, than flogging this poor 25 year old speaker like the proverbial dead horse...

Sorry if this ruffles feathers here... but IME, this is the stone cold truth. With speakers designed by people as talented as Jon Dahlquist, it's hard to improve them, without going to pretty big measures, because of the deliberate optimization (and inherent inter-dependence of components such optimization introduces) that was so pain-stakingly done in the first place...

Not only that, but there's also the HISTORICAL aspects of this. How many people have seen the automotive equivalent of this- the value of an UN-MODIFIED classic car, vs. that of one that has has "upgrades" (ie, hacked up, non-original parts installed, etc) done to them? In a long-term historical perspective, modified products, with the exception of the cases where by rare good fortune of having a modifier SO compelling, that the mod ITSELF becomes classic), have VERY little value in keeping a record of a time and place. I personally just hate to see legitimate pieces of history, marred beyond recovery...

who's seen more Dynaco and Dahlquist equipment BUTCHERED over the years, sacrificed on the altar of "upgrade"...

08-24-2003, 05:24 PM
Well, they are just loudspeakers and what you or I would consider "classics" others would probably term "special interest".

I hardly consider something like a D130 coupled to an 075 a classic, but I'm sure you could find plenty of people who would.

I do get a bit perturbed when I see a hacked pair of JBL's show up on eBay with their seller trying to dump the abominations on some unsuspecting buyer. I especially love the models where the owner has swapped out JBL transducers with those of other manufacturers with the claim that it "sounds better". :p

08-24-2003, 10:07 PM
Well, I dunno about the 075... but after having a pair of Viscount C36s with D130/077/N7000 setup in them, I can say there is a certain magic about those old systems. There's a immediacy, a quickness, that's just plain entertaining. No, they're not ruler-flat. No, they don't have tons of low bass (but park them on a nice period tube amp-ie, McIntosh, even the old Stromberg-Carlson pieces like the one I'm working with now- and they DO have BASS!), but what they do, they do with a sort of inherent "honesty" from a dynamic standpoint. That can be pretty enticing, sometimes...

And it is amazing, to me at least, from an entirely historical standpoint, that THIS sort of quality stuff existed, as early as it did (1950s!). Makes one wonder sometimes, just exactly what is supposed to be THAT much more advanced about many modern speaker systems (mostly non-JBL, but considered "high end"), that fall flat on their @$$es when driven with a good snare drum hit??


08-24-2003, 10:15 PM
"And it is amazing, to me at least, from an entirely historical standpoint, that THIS sort of quality stuff existed, as early as it did (1950s!)."

Yes, someone had a real love for what they were doing.

"There's a immediacy, a quickness, that's just plain entertaining."

I hear you :)

John Nebel
08-25-2003, 08:43 AM

As another example, take the JBL 4343. Looking through the changes JBL made 4343/4343b/4344:

2231a-2231h-2235h LF

2121-2121h-2122h MF

2420-2420-2421b HF

2405-2405-2405 UHF

3143-3143-3144 (=3145) Crossover

With a bit of thought as to how to execute this it is possible to replicate JBLs improvements non-destructively as all the mountings are the same except the crossover which can be mounted as in the 4345 - thanks to Bo's pictures for that.

I'd argue this is not a butcher job, especially when one has the original components repaired - ie. reconed and remagnetized by JBL and saves them just-in-case.

I agree that considering the time it takes to do this properly something like a used M9500 or 9800 begins to look quite reasonably priced. That is in close agreement with a good part of your point, however, by trying this out one learns quite a lot which has a high value to me.


08-25-2003, 11:13 PM
Oh, I agree about "temporary" (well, in a relative sense :) ) bolt-in replacements, such as substituting a 2235 for a 2231. Anything that you can return to stock, with the turn of a screwdriver, with no lingering effects, is fair game. Especially when the COMPANY themselves did LOTS of the same things! :D

OTOH, there's a lot of speakers out there, that people feel the need to cut new holes in, re-wire and re-configure crossovers, modify boxes in, etc. If we are talking about some "piece of junk", ie, something that didn't work very well in the first place, that's one thing (you won't see me complaining about people modifying old Technics rack system speakers, Acoustic Monitors aka "white van speakers", etc, if they feel the need :D )... but stuff that has bona-fide integrity from a design and execution standpoint, that's another kettle of fish altogether.

You know what's a bit ironic tho? A guy emailed me tonight, from England, having just bought a par of Dahlquist DQ10s, where someone had put in some generic woofer of some sort. The fellow was asking what he should do, since getting the originals is dang near impossible, over there. I replied to him, that he should find a pair of old derilict Large Advents and rob them, since they share a virtually identical woofer. In the strict historical preservation sense, I guess that's like the proverbial "robbing Peter to pay Paul" situation... but I will maintain that at least IMHO, that Dahlquist is more significant (ie, rarer, more sophisticated, etc), than any old Advent. I guess that'd be akin to robbing a nondescript 1969 Pontiac Tempest to get a proper OEM part to complete an otherwise perfect GTO Judge... not the optimal solution, but probably justifiable...


08-26-2003, 12:41 AM
I'm working on some modifications on my original 4343's. I just picked up a set of 136A's freshly reconed with a 2235H kits that I will give a test drive in place of the 2231A's. If that doesn't trip my trigger, I'll demo 136H's or 2235H's. I've tried 2234H's already. Bass was much more intense than the 2231A's! :rockon2:

Any opinions on which drivers will be the best fit? :idea:

My C45 is currently a cluster of pro/consumer parts to come up with an S82 system (LE15/2240/075/H5041/LX5/3105.... JBL calls for LE15A/375/075/H5041/LX5/N7000). I get the result I'm looking for without the expense of the higher priced consumer components. Since I don't plan on selling the unit (pictured in my avatar), what difference does it make? :hmm:

This message comes from JBL Dog :band:

08-26-2003, 05:16 AM
"Any opinions on which drivers will be the best fit?"

A 2234H yields more of the type of response the newest JBL systems do. Another way to view it is that the 2234H will stand greater boundary reinforcement than the 2235H will.

"Since I don't plan on selling the unit (pictured in my avatar), what difference does it make?"


"OTOH, there's a lot of speakers out there, that people feel the need to cut new holes in, re-wire and re-configure crossovers, modify boxes in, etc."

You should see the two pair of 250Ti's G.T. "hacked" up for a couple of friends. OMG :p Those won't be getting sold as originals. ;) But the modifications were well worth it :)

I too have done extensive rewiring of older JBL systems, always at the request or consent of their owners.

Don C
08-26-2003, 09:38 AM
I'd like to see those modified 250TIs.

08-26-2003, 10:21 AM
Both pairs have been modified for charge coupled technology and there are wires everywhere.

I've concluded it would be much easier to start from scratch (that's what I've always done anyway). Besides, I would want to keep the original networks intact.

08-26-2003, 02:54 PM
See, that's my thing... I'd be inclined to just build another crossover, to go entirely bolt-in, in replacement of the original, and keep the originals safe and unmodified, to be reinstalled later, whenever it might be called for.

Again, to draw the car analogy: this is like the guy I knew, who pulled the 327/350HP and M22 out of his '66 Corvette, and put in a mondo motor built from a 400 block, 327 crank, with aluminum heads (making something on the order of 440HP, on pump gas, BEFORE he hits the nitrous button! :eek: ) with a modified 5-speed B/W gearbox. He's got all the original parts safely crated away, and did it in such a way, that he had to cut NOTHING on the car itself... he can, whenever he feels like it, make it completely original again, and that's what matters.


Tom Loizeaux
08-26-2003, 06:17 PM
"I've tried 2234H's already. Bass was much more intense than the 2231A's!"

The 2231s, which have mass rings, are very good, deep woofers. The 2235Hs, with ceramic magnets, are not that differant sounding . The 2234s, however, will have a lighter bass response because of the absence of mass rings, yet their low mids will be nice and "quick". The monitors that I use 2234s in are driven by a bi-amp rack that uses the JBL 5235 crossover. I set the DIP switches to give me a +6dB @ 30 Hz, making up for the 2234s loss of low end.
If you want good low end, either the 2231s or 2235s sould give you some of the best low end available in a 15" speaker.


08-27-2003, 12:26 AM
Good argument!! :)