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DS-21
08-06-2005, 10:21 AM
What's the general opinion of the 2035H? Would a single one per side be a good bottom end for an 8" high-efficiency coax, to be used from 60Hz until ~400Hz (sub crossover is 60Hz, because of room issues more than anything, and the upper crossover will be determined by listening and measuring) and fed a steady diet of Mahler, Shostakovich, and Bruckner in a medium-sized room?

While I've never used any JBL driver, by the numbers the 2035H's seem like nice drivers: Lambda Acoustics-like .25mH inductance, copper sleeve motor, 7mm, 98dB/w/m sensitivity, and a nice F3 for a main speaker in a reasonably-sized box. (For aesthetic reasons I had wanted something narrower than a 15, but there are virtues to 600cc displacement, too...) But searching didn't turn up much information about them beyond the snippets and graphs on the JBL product pages for some cinema systems.

Robh3606
08-06-2005, 07:12 PM
I used them over the same range and they were fine. They sounded very good and can get down to 40Hz with no problems.


Rob:)

DS-21
08-07-2005, 03:17 AM
What kind of box were you using to get 40Hz output? While I haven't done any serious modeling, my rudimentary sims thus far have told me that their effective F3 sealed is around 100Hz and ported is around 60.

Also, I note that you wrote "used" rather than the present tense. Is there another driver I should be looking at instead of the 2035H?

johnaec
08-07-2005, 06:48 AM
Does the 2035H have a 3" or 4" voice coil? I know many of the 20xx speakers use a 3" voice coil.

John

Robh3606
08-07-2005, 09:22 AM
I used them in 5 cuft. ported. as my mains with subs under them. They have a 3 inch coil. I used them mainly before I went active. Once I went active I started swapping out drivers. I use E145-8 now. I changed out the 2035's after I changed out my mids to 2123's. I felt the E-145,2123,2344 was the sound I was looking for and the drivers worked very well together. The E-145 is a unique bass driver not a general purpose 15 and has excellent clarity and dynamics. I like a very quick dynamic sound with no overhang and that combo was the best with the drivers that I tried IMHO.



Should you be looking at another driver??? Hard to say I don’t know what your looking for. There is nothing wrong with the 2035. It is an excellent general purpose 15 I just liked the E-145 better for my application. You could look at a 2234 as an alternative. Basically a 2235 without the mass ring. That's another 15 that could do the job very well and keep the efficiency up at 96db. You doing active or passive crossovers?? Do you need a 98db woofer???



Rob:)

Robh3606
08-07-2005, 09:29 AM
Look here for more info

http://www.jblpro.com/pub/cinema/4638.pdf

Give distortion and what not

http://www.jblpro.com/pub/cinema/3677.pdf

You can run them safely up to 1.2K
Rob:)

DS-21
08-07-2005, 01:07 PM
Should you be looking at another driver??? Hard to say I don’t know what your looking for.

Basically, I'm looking for midbass support for an 8" coax (Tannoy 2046, used in their System 800 monitor and CMS8 in-wall) in a system that will be used for all types of music but must especially sound good on balls-to-the-wall orchestral stuff such as well-recorded Shostakovich, Mahler, Sibelius, etc. (Though they will be connected to HT electronics, all the serious listening will be music.) I'll be doing a passive crossover within the mains, but of course going active to the remotely-located subs.

In 5 cubes tuned low, I can see getting in-room response to 40Hz with these things. I'll have to play some more with the models - and do some mock-ups to see how large my mains are allowed to get :) - to see what the sweet spot for me will be.

I figure a 98dB/w/m midbass will give me a total sensitivity in the 92-93dB/w/m range after considering crossover insertion losses, baffle step compensation, and bandpass gain on the woofer section of the coax. That said, I don't need 98dB/w/m; I'm not running flea-powered amps so if I have to pad the coax down a bit and use less-sensitive drivers I won't really lose anything. However, I expect now that I'll start with the 2035H and see where my system goes from there. Thanks for your help!

PS: The graphs on the 4638 page tell me that for hi-fi use these woofers are much happier being used only up to 300-400Hz or so, and that with fairly steep filters. That's fine for me, though it also tells me that should I ever ditch the coax approach for a Geddes-style horn crossed in where the woofer's directivity matches the horns I'll need a different woofer.

Robh3606
08-07-2005, 02:40 PM
"PS: The graphs on the 4638 page tell me that for hi-fi use these woofers are much happier being used only up to 300-400Hz or so, and that with fairly steep filters. That's fine for me, though it also tells me that should I ever ditch the coax approach for a Geddes-style horn crossed in where the woofer's directivity matches the horns I'll need a different woofer."

Take a look at the other sheet. Those are two closely spaced woofers. That notch at 800Hz is due to spacing and so are the notches in the polar response curves. The driver goes out above 1k just fine so try it first. Which curve are you looking at for distortion?? You are never going to get 100 watt's into them so look at the 10 watt curve. If you want a Geddes-style set up look no further than a 4430/4435. That monitor is the original CD monitor design from the 80's. I have not heard his horn so I can't comment however that is where I would expect an improvement over a 4430/35. Either a 2235 or 2234 would do the trick depending on how high you want to crossover. For the DI to match the 100 x100 of the 2344 they crossed at 1K. They are certainly smooth enough up top hovever I would not bring them up to much higher. It depends on what horn you choose. Have fun and post some pictures when you can.

Rob:)

DS-21
08-07-2005, 03:25 PM
Take a look at the other sheet. Those are two closely spaced woofers. That notch at 800Hz is due to spacing and so are the notches in the polar response curves. The driver goes out above 1k just fine so try it first.

It's not the notch that has me concerned, nor the rising response from ~600Hz (exclusive of interference notch) to ~1.5kHz, but the breakup peak at 1.8kHz. Now, with a super-steep crossover, like a 8th order Cauer-elliptic, that's still doable to 1kHz and maybe higher. However, I like my passive crossovers simpler. I like to keep the high-end breakup a good two octaves from the crossover point if possible. Hence my thoughts of 300-400Hz being a useable maximum. (~450Hz is 2 octaves below the peak, making it down 27dB with a 3rd order crossover of Fc=450.)

Also, the wiggles in the impedance curve at ~600Hz and ~1kHz suggest some energy storage to me, though those could just as likely as not be enclosure-related.


Which curve are you looking at for distortion?? You are never going to get 100 watt's into them so look at the 10 watt curve.

Low distortion + low Le = happy me. :)


Have fun and post some pictures when you can.

Will do. Cabinets are probably a month and change out, and crossover design will be finished....well, it will be finished, someday....

Rudy Kleimann
10-20-2005, 02:06 AM
I too am curious to know more about these woofers. I own three pair of them along with three of the 4508A cabinets they came in as 4638 LF cinema systems. From what I've read, asked, and compared to my others JBL drivers, the following facts and assumptions came about:

I just befriended a recently-retired JBL employee through some ebay auctions, and he said that the 2035H was something JBL developed as a cheap alternative to 2226's during the theatre-building craze of the '90's to compete with the likes of Peavey and others for a lower-priced JBL. I asked him about the 2035"HPL" and aquaplas. He confirmed my suspicion that Aquaplas is used for several things, depending on the application: a stiffener on large cones, notably near the outside edge, a dampener on diaphragms, and a mass increaser. He has offered to try to get me more information about the 2035H(PL) from friends he has in various departments (including Engineering) at JBL. So far, I haven't heard anything yet...

There are apparently two versions of this woofer, a 2035H and a 2035HPL.
I have come to assume that the original 2035H had a copper coil, and the 2035HPL has an aluminum coil and uses aquaplas (hence the HPL designation), My guess is aquaplas is used mainly to add mass to make up for the lighter aluminum coil. Both are rated at 400 Watt AES anywhere they are mentioned on jblpro or jblproservice websites.

However, the JBL Thiele-Small parameters list shows a 2035H, NO 2035HPL, but rather a 2035HPL-1, with slightly different data for the two versions. I have deduced that some of the data is simply expressed in different standards of measurement (like metric vs. english standards), but there are other diffs as well, like efficiency, Qms, PE, and Fs. Go figure... :blink:

The 2035HPL Tech mnl .pdf lists the woofer as rated at 400W AES, and having an aluminum voice coil. There is no tech mnl .pdf on the 2035H or the 2035HPL-1 on their websites. The previously mentioned Theile-Small parameters set the 2035HPL-1 at a 300 Watt rating.:biting:

The "Architectural Specifications" section of the 4638 brochure .pdf states an 800W AES power rating for the cabinet describes the 2035H(no PL) as having a copper voice coil,:wtf:

The 4638 Tech mnl .pdf shows the cabinet having two 2035HPL woofers with a power rating of 800 W AES for the cabinet. The cabinet has no crossover, just input terminals.
the 4638TH tech mnl .pdf lists 2035H and describes it as having an aluminum coil. The "TH" model includes a passive crossover, and the system is rated at 800W AES pink noise for the pair of woofers. AFAIK, pink noise is part of the AES test standard, so this is just a redundant remark, IMHO. :bs:

There is no data on a 2035H on the site anywhere except in the alpha-numeric listing, which says nothing more than 15" woofer, 500W.

The 2035H and 2035HPL are rated at 400W AES everywhere else it is mentioned on the website, save for the 2035HPL-1 in the Thiele-Small parameters list...

I own several versions of the SHG- magnet JBL drivers: 2022H, 2032H, 2035HPL, and 2012H 10" mid. After removing the 2012H magnet cover (a "window dressing" that actually fell off during shipment to me) I made some comparisons to the four drivers' magnets:

All 4 magnets measured exactly the same from the outside. The back plates, the magnet slugs, and the front plates were the same diameter and thickness on all four drivers.

Everything I've turned up about these four drivers suggests that they all use the same aluminum flux stabilizing ring at the rear of the pole piece where it meets the back plate.

Everything I've turned up about the 2012H midrange and the 2035H(PL) suggests that these both use similar, if not identical, copper sleeve flux stabilizers in the voice coil gap region. I don't know about the 2022H or 2032H having copper rings around the pole piece in the magnet gap; I have a couple of 2022H's to recone soon, and will investigate this when I cut the old cones out.

It seems logical that, in order to maintain production costs/efficiency and simplify inventory management, JBL would less rather than more versions of a magnet than necessary. Sincew the 2035H(PL) was designed to work through the critical midrange up to where a horn could take over, I'd bet the magnet is the same one used in the 2012H. After all, movies are mostly dialogue, and JBL was trying to keep the system cost as competitive as possible a la two-way systems; even passive crossover versions were produced and a single 2035HPL with a 2416H/2373 90x40 horn mini-system was sold for small theatres!

The 2035 HPL has a spider with a much larger outside diameter than the other 20xx drivers use to accomodate the much longer excusion than the 2012H,2022H, or 2032H. The maximum linear travel (Xmax) spec of the 2035HPL is identical (.4 inch) to the 600W 15"VGC 2226!

Although the 2035H(PL) doesn't handle quite as much power as a 2226, it is rated as 1 dB more efficient than the 2226, making its' overall output on a par with less power required. The 2226's power compression spec at full power (600 watts) is 4.6 or 4.0 dB, depending on which 2226H brochure you read(older or newer one). By extrapolating the 4638 systems' power compression spec at full power, the 2035HPL is 3.2dB at 400 watts. At half-power, the specs read 2.5 dB at 300W for the 2226, and 1.9dB at 200W for the 2035HPL.

When you compare JBL's published half-space reference efficiency between the the 4638 at 8% to the identical cabinet loaded with 2226's (the 4648) at 7% it seems to confirm this. Also, taking the 4638's maximum acoustical power output (before power compression factored in at 64 acoustical watts, then factor in 3.2 dB of power compression listed next, it adds up almost exactly to the 4648's rated maximum power output of 28 acoustic watts.

Oddly enough, the 4638/2035 cabinet and 4648/2226 cabinet are both rated at 100dB/W/M, even though the 2035HPl is rated at 98dB and the 2226 is rated at 97dB. More contradictory information from our friends at JBL... if the driver SPl specs are accurate, and the power compression specs are accurate, the 2226 will produce no more SPl at its rated power of 600W than the 2035HPL can at its rated power of 400 watts- 50% more power in watts represents a 1.87dB increase.

Comparing the frequency response plots, the 2035HPL/4638 system frequency response is much flatter, without the big hump above 325 Hz that the 2226/4648 exhibits. The notch at 800Hz exists in both systems (although it measures deeper in the 4648) seeming to confirm that it results from comb-fiter effect phase cancellation from two spaced drivers on the same baffle, meaning a single 2035HPl shouldn't exhibit these problems.

The stated harmonic distortion spec on the 4638 (2035HPL) is under 0.8% 2nd, and 1% 3rd from 100-500Hz at 100W, while the 4648 (2226) is stated at less than 2.5% from 40-800Hz at 100W. The distortion plots are debatable as to signicant differences; you be the judge. Could be insignificant; different day, different system -no matter how close a person tries to duplicate the setup, some differences can and will crop up. Ears would have to be the judge here.

All this being said, I see the 2035HPL as no slouch; in fact it may be more efficient and produce the same SPl at 400W as the 2226H with 600W. The 2035HPl also appears to have flatter frequency response, and lower distortion up to 500 Hz than the 2226H. And the bonus is it costs a hell of a lot less than the 2226, and a much smaller amplifier should do the same job. Time will tell if this holds true. The copper should yield sweeter upper mids if you require it, and easier passive crossover design. I just wish I had a pair of 2226H's to put head-to-head with these...

Mr. Widget
10-20-2005, 10:33 AM
There are apparently two versions of this woofer, a 2035H and a 2035HPL.
The HPL designation simply means the woofer's magnet doesn't come with a rubber trim ring and possibly other decorative features. A XXXXH and XXXXHPL are identical drivers.


Widget

Rudy Kleimann
10-20-2005, 10:40 AM
The HPL designation simply means the woofer's magnet doesn't come with a rubber trim ring and possibly other decorative features. A XXXXH and XXXXHPL are identical drivers.


Widget

Well... what about the different T/S parameter differences and the 2035HPL-1? Copper vs. aluminum VC? Other contradictions?

NONE of my other 20xxH drivers have a rubber ring. My 2035HPL's have no rubber ring. My 2012H's have that aluminum magnet cover (window dressing, IMHO). My 2447H's all have rubber rings around their magnets...

Mr. Widget
10-20-2005, 10:57 AM
My 2035HPL's have no rubber ring.
I thought I was clear... the HPL version shouldn't have a rubber ring.

Despite these designations, JBL is amazingly inconsistent within it's own naming schemes.

JBL frequently offers different driver variations designated by a -1, -2 etc.

I have no knowledge specific to the 2035.


Widget