Looky What I just got - Those Darned L200 Cabs (from Aberdeen)

[Zilch]

Very interesting Zilch, I didn't know this. Thanks for the heads up.

Another option, seemingly a good one.

It strips away L200's boomy bass and opens the door for using H91/2307 in a more optimum range. Typically, that's pushed down to 800 Hz in L200 upgrades, and it does sound a bit "horny" down there.

I've been running PT waveguides ~1 kHz, but that's near the limits of both them and 2235H. Heather's reporting here she likes PTH-1010 better run at 1.2 kHz. The smaller "F" versions certainly like a little higher, and LE14H-3's been working nicely at that frequency. This is all with 24 dB/octave active crossovers.

I haven't found the engineering specs for the 2234H if they're posted in these forums, but there are several suggestions by those who know that they'll play higher than 2235H, at some sacrifice of low-end extension, but with more "punchy" bass.

Guess I'll load up some 2234Hs and see how that combination sounds. Not sure exactly where to tune them, tho.

[Ah, well. Research! ]

[grumpy]

did 45deg offset plots, but I won't clutter here. Think I'd stop fooling
with either of these drivers much above 1KHz. I didn't spend a lot of
time trying to optimize mic position to make the plots look "better".

Exponential swept sine using mac/FuzzMeasure.

org/grn is nearfield (~2" from cone and offset from cap ~1")
red/blu is on-axis, ~20" from cab face.

-grumpy

[Zilch]

Thank you, Grumpy.

Well, they certainly go poopy above 1 kHz.

[This would be a preliminarily qualified technical synthesis of measurement results, subject to peer review.... ]

[hjames]

Thanks for the charts AND the info guys ... weird, thats not what I expected - the JBL brochure on the 2235H shows it doing much better than that - thats why I was interested in it over the 2215.
I guess the spec-sheets don't tell the whole story ... sigh!

Link to 2215 at JBL Pro Archives

Link to 2235H at JBL Pro Archives

Thank you, Grumpy.

Well, they certainly go poopy above 1 kHz.

[This would be a qualified technical synthesis of the results.... ]

[Zilch]

Factory curves are done under somewhat different conditions, typically.

The 2235H spec. sheet is in the forum library:

http://www.lansingheritage.org/image...2235/page2.jpg

Looks like they just stopped the 2215 at 1.2 kHz:

http://www.lansingheritage.org/image...2215/page2.jpg

I can dig out a measurable LE15A. Maybe I'll do ground plane and in-box on all three here, as well. Been wanting to try that....

[Robh3606]

I don't see the mystery here. How did JBL use the 2215 and 2234/35??? You have all you need looking at the applications JBL used them in. That should always be the starting point.

The 2234 is a 2235 with less mass. That gives you 3dB more output and a higher FS. That doesn't meant it will do better higher. It's the same exact cone.


Rob

[hjames]

I tried going back to my passives system, but substituting the 2435 instead of the 2405 slot tweeters - you're right - too much attentuation. But Emma and I agree that we missed the bass push of the biamp setup.

This afternoon I ran new lines to the left and right front corners, put the biamp system back together - but tried a few things differently.

I did get a tape out feed to run the Active crossover ...
Low out to the HK and to the 2215s
Hi out to the T-amp and then to my passive crossover
LO there to the 2123
MF there to the 2420/horns
HF there to the 2405 slots

I tried varying the xover freq of the active crossover - I know for a 4345 it would cross at 290 - I'm set on about 400cps with these drivers.

Got to run - but I'll try more when I get back ...

One last comment - the receiver apparently taps the preamp out before the optical inputs for the digital sources (DVD, CATV) so I don't get front Left/Right for those sources - which is a darned shame. I wonder if the newer HK receivers with optical inputs have the same problem ...?

For the money, it seems like some "shimmer" is a small compromise. The chipheads will likely have some good options to offer. Chip amps come with the endorsement of heavyweights; we just need the specifics.

The hookup you propose may work, though there may be too much attenuation and they won't play loud enough. Try it and see.

Yes, you need the compensation filters in line.

Thank you for the "test disc." I'll watch for it!

[Zilch]

I don't see the mystery here. How did JBL use the 2215 and 2234/35??? You have all you need looking at the applications JBL used them in. That should always be the starting point.

Doing that, actually.

Well, more "wishful thinking" than mystery, perhaps, but JBL spec'd 2234H as replacement driver for the 1200 Hz L200, and not for the "boom" or impedance of 2216, I wouldn't think. Perhaps just for the efficiency? It's the only place JBL used 2234H other than 4435 that I'm aware of.

I'm hoping it'll play better up there than 2235H. There's suggestions elsewhere in these forums that it will. The cone mass is less, which might translate to a bit more extension, but Grumpy's measurements certainly don't find it. I'll look at the E140/2235H frankenwoofers, too. More flux may provide more extension....

[Zilch]

I tried varying the xover freq of the active crossover - I know for a 4345 it would cross at 290 - I'm set on about 400cps with these drivers.

First mark below 400 looks to be 300 Hz. 200 would be the first mark above 180, then....

[grumpy]

... but Grumpy's measurements certainly don't find it.

Just to add to the confusion, I had made some earlier measurements
(of a 2234H in the 4430 cabinet)
using a 1m on-axis setup and the 4430/4435 cards in place in a 5235...
This setup ran flat (more or less) to about 1.3KHz before rolling off,
so I wouldn't write the 2234 off as being unusable above 1KHz, just that
there may be some compromises and some required EQ. (graph attached)

Please don't take any of my "hobbyist" plots as being reference material,
but perhaps useful for comparison. I'm still learning how to properly use
and interpret the results from this equipment. Best regards, -grumpy

[Robh3606]

Hello Zilch

Yes your correct but it is not optimal. It is "Use as a last resort".
It will work. There is no reason with a clean slate to be going in that direction. We know a 2234 or 2235 will work up to 1k. Beyond that we are pushing them. They are better yet crossed over lower at 800Hz or at 300Hz like a 4344. Well let's see what Heather finds as she experiments.

Rob

[Zilch]

Heh.

Looks like I been on a CRUSADE.

[Uncle Paul started it. There's the proof.... ]

[hjames]

First mark below 400 looks to be 300 Hz. 200 would be the first mark above 180, then....

Right - thats what I'd figured too.
I've been listening to a variety of music now - currently Shooglenifty - sort of modern Celtic hip-hop very cool thumpy bass stuff with bagpipes and ... well very neat.
But the bass is killing us ... its just way too much hammering bass.
I tried turning the Input level for the 552 to minimum, and turning the Lo Out down as well - but even so - BOOM bitty Boom.
I think I need to attenuate the input to the HK Citation!

Current config:

Tape out from JVC receiver --> JBL M552 active crossover -->
Lo out --> HK Citation 22 200w/ch --> 2215 woofers (in L200 cabinet)
Hi Out --> Sonic Impact Tamp --> Giskard 3133 Equiv -->

LF --> 2123 midbass in upper cabinet
MF --> 2420/horn/lens combo in L200 cabinet
HF --> 2405 slots in upper cabinet

I've been varying the active crosspoint from all the way down to 180cps to about 800cps - I did that just to hear what the differences were.
Best results are between 300-400Hz .

Emma's headed out for the day so I should be able to do some more critical listening from 1PM to around 6 or so.

[Zilch]

But the bass is killing us ... its just way too much hammering bass.

No gain controls on the Citation? Just crank 'em down if they're there. No rule says they hafta be set at 0 dB attenuation....

[hjames]

No gain controls on the Citation? Just crank 'em down if they're there. No rule says they hafta be set at 0 dB attenuation....

Hmm - wish the Citation HAD controls - its just a gainamp - no controls

witness the composite shot below - seems the 552 is the only controls in the system right now - and its cranked WAY down.
Pix courtesy Emma's camera - she borrowed mine today(!)