2452H-SL in a 2-way

[Zilch]

I think you might find that you need to run the 2452H-SL down to 1.2kHz to get a good crossover to the woofer - otherwise you are running the woofer up too high. JMO....

We're not doing 1.5 kHz, rather trying to get to 1 kHz, Bo, for 2235H as one option. A major difficulty in accomplishing that passively is the driver/waveguide rolloff below 1.5 kHz....

Two projects are built, and two more are under construction, LE14H-3 being the preferred woofer, with 2235H as alternate, both @ 1kHz. We're presently using my half-ass adaption of N3134 crossovers as I don't have LEAP yet.

We'd like a compensation filter that could be used with 24 dB/octive L/R active as well as a full passive crossover incorporating it, such that a switchable version might be constructed.

What JBL does in that monitor is of some interest, but they are using a different woofer toward a specific, and also different, purpose.

[4313B]

Well I got it to 1kHz as shown in post 33 using a series LCR in parallel with a series resistor and added in two notch filters but the file save didn't do what I intended so I lost the schematic. I was too tired to bother with it further last night.

[Zilch]

Well I got it to 1kHz as shown in post 33 using a series LCR in parallel with a series resistor and added in two notch filters but the file save didn't do what I intended so I lost the schematic. I was too tired to bother with it further last night.

Wouldn't a high Q two-pole highpass as Earl suggests get it at 1 kHz from what I've done? Not sure I consider 60 uF a very practical approach, tho.

It sounds very good on 24 dB L/R active presently, but I want to tweak it using your suggestions above and see if it can be improved, then retest with several drivers here....

[4313B]

I didn't use a 60 uf capacitor anywhere.

If I have time I will look at it further.

[Robh3606]

didn't use a 60 uf capacitor anywhere.

No but I did. Used it as a single pole, in front of the compensation circuit.

That red quide line is for a 1K 24db L/R crossover.

You can get it out to 1K but the slope is screwed up.

Zilch you have a 50uf in front of the compression driver for all the measurements??

You need the real SPL at 1 meter on the wavequide to do the crossover correctly. Anyone know what it is????

Rob

[Zilch]

Zilch you have a 50uf in front of the compression driver for all the measurements??

Yes, a 47 uF protection cap.

You need the real SPL at 1 meter on the wavequide to do the crossover correctly.

Do you know that of 2435HPL on PT-H1010HF or some other driver/horn combo I have?

If so, I can easily measure their relative SPLs and we can come up with something close....

If I have time I will look at it further.

Thank you. As always, I very much appreciate your assistance with this.

There are apparently others interested in using this driver, as well, and they'll be confronting similar issues....

[rs237]

Hello,

Thank rob and zilch for the posts and measurements with the 2452HSL. One question. I am planning a two way speakers with 2234 and 2252HSL, crossover by 800-900Hz. I want a (DIY) oblate waveguide horn. I see a start attenuating around already at 1,5kHZ. Is it the horn or the driver?
It is perhaps better to use the 2435HPL?

regards
juergen

[Robh3606]

Those measurements are specific to the waveguide plus a series capacitor. Really need them with no series cap to see what the loading is.

Rob

[4313B]

We could use the .mls and .sini files from CLIO

*****

Here's what I came up with using the data from #8

[Zilch]

We could use the .mls and .sini files from CLIO

That's a "Do over," and I can certainly do that, but I need to know what, specifically. There's no smoothing or windowing reflected in those, right, it's just the raw acquisition data, so my settings don't matter?

Rob's implying he wants without the protection cap, also. Yes?

[4313B]

That's a "Do over," and I can certainly do that, but I need to know what, specifically. There's no smoothing or windowing reflected in those, right, it's just the raw acquisition data, so my settings don't matter?

Nevermind, I played with it as much as I wanted to using the available data and posted the results above.
I have no idea how it will sound or if you will have enough gain.

*****

If that 20 kHz bump really bothers you then throw in another notch: 0.39 mH, 0.16 uF, 5.6 ohm

[Robh3606]

Rob's implying he wants without the protection cap, also. Yes?

Wondering what it's doing. It may not have a significant effect. If you are concerened about protecting the drivers don't do it or just double them up. Just try one if there is no change then it doesn't matter.

That looks good why not just try it and drop in the attenuation later.

Zilch you don't have any 2425's or 26's laying around??

Rob

[edgewound]

Do we know the crossover point JBLPro uses in the VP7212MDP? I've looked and can't see that you guys have discussed that. Granted, that is a 2-way with an incredible 12-in woofer, but some of the smartest guys I know are doing 12-in 2-ways... Maybe JBL take the 2452H-SL up to 1.5kHz...?

If it helps at all, the 2452H is used passively in the later versions of SRX722 and SRX725

Crossover is listed as 1.2KHz on the spec sheet at 75 watts continuous pink noise.

http://www.jblpro.com/srx700/PDF/JBL.SRX725.pdf

[Zilch]

Here's what I came up with using the data from #8

Thank you again. I believe I have sufficient parts to prototype this.

Zilch you don't have any 2425's or 26's laying around??

Yes. Do we know the SPL on 2370A or 2344A? I guess so, and will look it up.

Wondering what it's doing.

Mr. Widget taught me their value to not blowing up drivers.

My Sonic Impact HF testing amp has a bit of DC, though I've never measured how much.

That looks good why not just try it and drop in the attenuation later.

Yes, the crossover version will certainly require attenuation. I'll probably use a fixed and an adjustable L-pad to do that; not sure where to put them yet, is all. Adjustable at the driver output, probably. Still running just the comp version active here....

[Robh3606]

OK 2426 is about 110db on a 2370

http://www.lansingheritage.org/image...2426/page2.jpg

Rob