When compared to CH-3 it seems that it needs less compensation and maybe at a little higher frequency. Actually, my suspicion from looking at JBL's data, is that the slot loaded part makes the 2370 look more like a shelved response, not falling. JBL shows response is roughly flat to 5.5K then drops 4dB, then it is flat to 15K. So when you add the sloped reponse of the cap is this what makes it "splashy"? I have noticed that with PSD 2002 (as opposed to the JBL used for their data) it still falls a little over the top two octaves, but not as quick as on a CH-3. So it still needs a sloped compensation.

My first thought is to try a .33mF bypass on the pad. I know this will make the comp happen higher. In relation to the rest of the HF band, if the comp happens "later" is it also reduced in level due to it's "knee" being further out of band? Also, say I used an LF driver that is more sensitive. (delta pro for instance) This forces me to use less HF padding. would this reduce the effect of the cap without having to raise the frequency of compensation? Would this have the overall effect of making the compensation curve seem shallower, or would it just seem to have moved up in frequency? I think I need shallower compensation, but I dont want it to start too late. I see the comp cap as a first order rising response, but I know it behaves differently as part of the system. I do not have a good handle on all this yet. what is the best approach for a 2370?

Thanks for putting up with us can't leave well enough aloner's,
Thomas

One thing that differentiates the 2370 from the horns I like to use is that it's the only one with a secondary acoustic device in addition to the horn flare. The 2370 has a diffraction slot to increase horizontal dispersion at the highest frequencies. It creates wider dispersion at the expense of an added internal reflection, which causes a slight bit of impedance and response ripple. That's the cause of its "splashy" sound.

You wrote
"The 2370 will sound a bit more "splashy" because of the diffraction slot in its throat. But overall character is very much the same."

Good call! You nailed that one.

I should have remembered that, It took me a few weeks to really listen and see that this is exactly what it is that bugs me about them. I agree that it is not a big deal, and for most people it would be too small an issue to bother with. If I leave it alone this is still the best set of speaks I've ever had by far.

If I just wanted to be obsessive, what might I do to tame it a bit? Can it be done by a change of value in the existing compensation circuit? I think I might get some smaller caps to see what happens. Is that a viable plan for this? Or will it just push my top octave down too far?

I know I am splitting hairs at this point, and I really appreciate all of your help on this. Thanks,
Thomas

The deal with passive compensation is your ability to tailor the curve is somewhat limited. For example, when attenuation requirements are low, that also necessarily means that top octave augmentation ability is also low. You could add notch filters to the RC filter/damper I've employed, but I prefer to keep it simple. There are some limits to this approach, but the horns discussed on this forum are all good canidates for compensation as is used in the π crossover. In fact, I've not seen any CD horns that wouldn't benefit by some amount of this technique.

If you need a lot of augmentation and a little attenuation, your passive network design choices are generally limited. Likewise, if you need attenuation but the augmentation slope deviates from diagonal too much, then your choices are also limited. But really, when used above the frequency where a horn becomes well loaded, it will generally be flat for a while and then enter a couple of octaves of smooth rolloff at a relatively constant rate. This is where the π compensation technique is most beneficial.

oops, you can also "split" the R1 resistance, and only bypass a portion of it, if you really want to tweak it to death:)

Thanks Sam,
Thomas

Thomas