Null and Void at 630 and it Hertz!

[toddalin]

JBL didn't know everything back then.

Blastphemy!

[Ian Mackenzie]

I edited the last post with the curves.

Okay that explains a lot. I guess they had to work with what they got.

It would be useful to see how the shorter horn works in reality on the baffle and measure it down to 800 hz. Becuse its shorter I would expect the response to tappper off a bit and you may end up with a reasonable transition.

Todd,

Sorry I dont have an answer for your woofer ills.

Do the sine wave sweep and listen carefully as suggested above.

Ian

[4313B]

It would be useful to see how the shorter horn works in reality on the baffle and measure it down to 800 hz.

You can do that with your 4345's.

I guess I could too...

[Ian Mackenzie]

Yeah I thought of that too.

But at any rate Todd's got other issue that make this look like the icing on the cake.

Personally I would get the jigsaw out a cut a hole for the longer horn and make a neato rear housing for the driver hook up a 4333 network .

ian

[toddalin]

Yeah I thought of that too.

But at any rate Todd's got other issue that make this look like the icing on the cake.

Personally I would get the jigsaw out a cut a hole for the longer horn and make a neato rear housing for the driver hook up a 4333 network .

ian

Already been considered and just yesterday had a bid in for a pair of the longer horns (that ended up going for ~$157 with one being cut up and no slant plates included). I was just going to make a hole in the back and glue a large PVC cap over the back. Wife was not in love with that idea.

Anyway, if I recall the 4333 crossover uses a propriatary choke, as do most JBL crossovers, which is a major reason why the N200B was selected.

The hole issue manifests itself even with no crossover or horn connected, so I really don't see how using the 4333 crossover would remedy this anyway.

[Robh3606]

Hello Ian

If you mean the 2307 here's how one measures mounted in my 4344 cabinet with a 2425 driver. No crossovers.

Rob

[toddalin]

Hello Ian

If you mean the 2307 here's how one measures mounted in my 4344 cabinet with a 2425 driver. No crossovers.

Rob

I think the 2307 is the shorter H-91 while the 2312 is the longer H-92. I've no idea which is used in the larger cabinets that have a cone lower mid.

[Robh3606]

Still over a 6 dB change between 700-900 Hz.

So +/- 3 db Yes but look up at 1.2K. That's really as low as you should use them. I know JBL took them down to 500Hz and all but they are starting to unload below about 1k

Rob

[grumpy]

Think it's time for an outside test. ...can also run in-box impedance and individual
driver response curves with no crossover. -grumpy

[Robh3606]

Think it's time for an outside test. ...can also run in-box impedance and individual driver response curves with no crossover. -grumpy

Good idea you should also run the impeadence on the horn and driver mounted to the baffle.

Rob

[Ian Mackenzie]

Hi Rob,

Thanks for posting the 2307 and horn response, the peak at around 1khertz might even fill a few holes.

Looks usable to 800 hz if only for domstic power levels.

I agree, some more impediance runs wioht drivers in the box would prove useful.

Ian

[boputnam]

just for the hell of it did you try to invert the phase on the mids to see how the crossover points react differently. it may be to your advantage. Hey its a shot in the dark but it might work

My favorite post here.

Actually, yes, and I'm finding that things are overall flattest (both to the woofer and tweeter) with the mid inverted. The trough where the woofer meets the mid is about 1 dB deeper this way, but other improvments of over 3 dB are noted just beyond the trough.

Also, the overlap with the tweeter is smoothest like this.

So, why was this abandoned?

Its not pretty.

Yea, and it's right at the crossover points, suggesting to me that something along the lines of pelly3s' idea needs attention.

[Robh3606]

OK here's a 2235 sweep in my box. The 500Hz and up range looks like what you would expect.

Rob

[toddalin]

My favorite post here.

So, why was this abandoned?

Yea, and it's right at the crossover points, suggesting to me that something along the lines of pelly3s' idea needs attention.

Nothing was abandoned! Phase has been inverted every which way, and these result in small changes (ranging from a few tenths of a dB to a few dB at various freqencies), but some of you are missing the BIG PICTURE.

I'm talking about a major suck-out of over 10 dB between about 600-800 Hz on the woofer even with no crossover connected.

The horn is pretty flat down to 900 Hz and down about 5 dB from that at 800 Hz, so the crossover is doing its job in that respect. It is an "800 Hz" crossover.

But if the crossover is supposed to start rolling the woofer off at say ~600-700 Hz..., and the woofer is already down 10 dB at that frequency..., voila a hole in the frequency response!

So the real question is what's making the woofer roll off so early? Recognize that I get the same thing in my center channel and the cabinet is of completely different architecture and I'm even using a different horn.



I just keep coming back to the woofers, but maybe the room could create such a suck out? I have moved furniture around to no real avail. Still, I don't recall seeing it using the W10GTIs/2425s sitting on top of the L200s...

[edgewound]

Todd...

Have you tried a different amp? Maybe the Yamaha that you have has some sort of problem....or just doesn't like the 2205/2235. This is weird.

I highly doubt the room would mess around with that high a frequency...unless the room is really live, reverberant. Does the room "zing" when you clap your hands loud? Corner reflection/bounce?

Just a thought. I'm sure you're really frustrated.