2435 HPL- 2 way 750hz

[kartsmart]

I am thinking of doing a 2 way system for home audio use.
Could the 2435 HPL be used down to 750 hz or lower with good results ? If so what horn could be used ?
I will start with these simple questions first to see where it will go.
thanks

[Zilch]

From my experience, 750 Hz is too low, though it might work on some horns, like 2352 or Harman Consumer biradials. Giskard recently suggested the drivers themselves are good down as low as 650 Hz; I just haven't tried that. 4338, for example, is crossed at 750 Hz with 435AL (2431H equivalent).

I'm currently running 2435HPL on PT-H1010 at 800 Hz, and they sound guite nice. At least one other member here is using that combination with good results:

http://audioheritage.org/vbulletin/s...808#post143808

Start with that, perhaps, using the Timbers "Key" compensation filter and a frequency adjustable active crossover. It'll get the answer for you toot sweet.

Those waveguides are inexpensive, $94 apiece. 2352 is $300 list, and you'll pay more like $450 or more each for the Harman Consumer horns, if you can get them at all.

[Robh3606]

Hello Zilch

Gregs filter is tweeked for a particular horn/driver combo. It's not optimized for the PTH1010. It really needs to be fine tuned for the driver horn combo it is used for. It's a great jumping off point however you won't get the best performance out of that combo using it as is. It's not fair to Greg to use it beyond what it was engineered for without pointing this out.

Rob

[spkrman57]

Crossover points are best derived after horn/driver analysis.

Ron

[Zilch]

It's not fair to Greg to use it beyond what it was engineered for without pointing this out.

Thanks, Rob, for reiterating that.

I think it's pretty clearly shown in the link I provided....

[DJ Vincenzo]

wow a lot of peeps have the 2435's. arent they 2 lous for home use?

[Robh3606]

Hello Zilch

I have been playing around with Crossover Shop and working on a crossover for the 2435 with existing horns I have on hand. I am using the PTH1010 in my active set-up so I decided to see what an passive network would look like using Gregs filters and notes I made from Project May. It looks good so far on paper. Could sound like crap so I have to actually build it and get my Le-14H-3'S into cabinets so I can measure them up and see what happens on the other end. I woudn't go to 750Hz on this horn/waveguide that's for sure.

A reference on how these networks are put together from Project May


Rob

[Zilch]

Your green curve and my green curve (Greg's filter) seem well matched. I'd say the sim is good.

What's the AM6212 sim curve look like?

Though I haven't A/B'd them, it may make sonic trouble in the last octave, though it seems to be working in your system.

My experience was that 2435 is not as amenable to compensation up there as is 2431 :dont-know

[Zilch]

Well, we're doing a bit of a semantics dance here. I try to avoid using the word "boost" anymore, because it confuses issues. Yes, as I understand it, AM boosts, in the active sense, above 0 dB, above 20 kHz, which may itself be problematic, since it's additional energy going into the driver outside the operating range, or "out of band," outside the design envelope, assuming source material is provided up there.

But, the issue I'm raising here relates to the total compensation WITHIN the band, achieved via midband attenuation: AM attempts to flatten the last octave with additional compensation via a steepened slope. Timbers lets it roll off. I'm saying I can flatten 2431's last octave response, notwithstanding it's already having more extended VHF, easier than I can 2435's.

And I'm postulating that it's more difficult, i.e., requires more energy, to accomplish that with 2435's beryllium diaphragm than 2431's aluminum, as it requires transitioning and operating the 2435's stiffer diaphragm more from pistonic mode into breakup mode above 15 kHz, as illustrated in Button's 2002 AES Convention Paper:

[Thom]

This isn't sarcastic just in case it sounds like it. When you get through with all your computer simulations and then I'm guessing you probably do tweaking with a mic and analyzer ( actually I see reference to that I just sometimes lose track as to which is which) do you end up with a finished product that's tits or after the equipment is put away, or maybe it's still there do you tweak to make it more "listenable"? I guess I mean do your ears over rule the instruments. I'm not sure if that was clear. If this was the wrong place for this question tutor me, I'm listening.

Also is it easy to tell if my 2435 suspension has been glued?

[kartsmart]

Has any one tried a round tractrix horn on the 2435s ?
Ron do you have any in your collection to try ? A 350 hz horn might be about right, or I could through one together and give it a try ( might take a little time )

[Zilch]

There is a very real and tangible reason why some of us are willing to forgo a few k on the top end with the aluminums and switch over to the berylliums, especially the aquaplased berylliums. I really don't care that my 435Be's are 7 dB down at 20 kHz.

I'm not arguing in favor of one driver over another, or one filter over another, or one horn over another, or being critical of any of it. I'm actually listening to the various combinations here myself, trying to ascertain the differences, sonically, and the reason(s) behind them, i.e., the "real and tangible" you cite.

In asking Rob to post the AM6212 curve, I wanted to point out that there are two fundamentally different approaches to the application of compensation to these drivers illustrated in this work:

1) Apply basically linear CD compensation above mass breakpoint and let the driver roll off "naturally" in the VHF, or,

2) Apply additional compensation at a steeper slope in the VHF region as required to flatten the VHF out to 20 kHz.

Mr. Widget's earlier observations on the sonic consequences of the latter approach are on point:

The plot may show a response out to 20KHz yet it sounds hard and bright with no air, or conversely it may look soft on top yet sound really good.

Clearly, there are limits to how hard particular combinations may be "pushed," and it's important as we work through this, each for ourselves, and together as a group, to understand what those limits are, and why they exist.

Again, it's not intended as criticism; I'm merely submitting my own experience with this for consideration: 2435 doesn't "push" as easily or gracefully as 2431 via compensation contouring....

[Zilch]

This isn't sarcastic just in case it sounds like it. When you get through with all your computer simulations and then I'm guessing you probably do tweaking with a mic and analyzer ( actually I see reference to that I just sometimes lose track as to which is which) do you end up with a finished product that's tits or after the equipment is put away, or maybe it's still there do you tweak to make it more "listenable"?

Yes, all that.

Mostly, it works.

Some of us never put away the gear permanently, is all....

[4313B]

I'm not arguing in favor of one driver over another, or one filter over another, or one horn over another, or being critical of any of it. I'm actually listening to the various combinations here myself, trying to ascertain the differences, sonically, and the reason(s) behind them, i.e., the "real and tangible" you cite.

In asking Rob to post the AM6212 curve, I wanted to point out that there are two fundamentally different approaches to the application of compensation to these drivers illustrated in his work:

1) Apply basically linear CD compensation above mass breakpoint and let the driver roll off "naturally" in the VHF, or,

2) Apply additional compensation at a steeper slope in the VHF region as required to flatten the VHF out to 20 kHz.

Mr. Widget's earlier observations on the sonic consequences of the latter approach are on point. Clearly, there are limits to how hard particular combinations may be "pushed," and it's important as we work through this, each for ourselves, and together as a group, to understand what those limits are, and why they exist.

Again, it's not intended as criticism; I'm merely submitting my own experience with this for consideration: 2435 doesn't "push" as easily or gracefully as 2431 via compensation contouring....

I deleted my post because I went back over the entire thread and realized my post was irrelevent. I simply don't have the time or inclination to get thoroughly involved and/or read all these posts any longer and cannot therefore, add anything of value to them.

This quoted snippet of my post is out of context, as was my entire post with respect to this thread. Basically, wrong thread, and I didn't realize that this was the thread Rob wanted to post one of the Project May schematics in. No biggie.

[Zilch]

The 2435 is pistonic at 15K. The 2431 is not from the graphic you posted. What does that mean??? It's apples and oranges. Do you think that +3dB at 30khz will cause the Be diaphram to break up????

Button's paper states that a primary design objective of 2435 was for it to operate pistonically throughout the audible range, and that was achieved up to 15 kHz. It's also implicit that "pushing" that driver beyond there may be sonically counterproductive.

Giskard repeatedly says the drivers must be used "according to their intended purpose" for successful application. Well, in detail, we're not privy to that, and thus we make the best of what information is availible to us in combination with our own empirical determinations. I THINK that's part of the process, even at JBL....