[Occam]

Paul,

As Davey said above, I've no reason to expect linear phase from the coincident driver, but one can only hope. And if linear phase, waveform fidelity, is important, its most so in that 600-4,000kz? range. If anyone expects that linear phase response at more than one, ideal listening position, I believe one must have coincidence, at least with respect to the listening position window. And the typical passive crossover isn't linear unless a 1st order or something involving a filler driver/voicecoil. Regardless, your physical topology really does at least offer the possibliliy of linear phase over a broad frequency range spanning drivers, and over a larger listening window. I wonder what the possibilities might be of applying a DEQX (or equivalent) would be.

If you're feeling masochistic, an oscilloscope picture, miked on the listening axis, of a square wave at 1 octave above the woofer to mid crossover point. Just the mid tweet combo, the woofer could be disconnected if easier. This would give that fundamental and all odd harmonics. Low levels are fine as you don't want to fry your tweeters. (or lowpassed without phase corruption) Same thing for 15 degrees of whatever axis. I don't expect waveform fidelity, but if the signal were the same on and 15 degrees off axis, that would be really cool.

Thanks,
Paul

[OBF]

Additionally, as you are probably aware, when looking at power response I recently realized that a monopole woofer in close proximity to the floor is actually a better power match to a free standing dipole mid.

John,

This is interesting as I'm considering open baffle mids/highs and a pair of small, conventional subs blended with a TacT preamp.  Would you have any opinion on whether the above statement would be true with the woofers corner loaded, or do you think I'd get better results with them next to the mids/highs?

Thanks

[johnk...]

Additionally, as you are probably aware, when looking at power response I recently realized that a monopole woofer in close proximity to the floor is actually a better power match to a free standing dipole mid.

John,

This is interesting as I'm considering open baffle mids/highs and a pair of small, conventional subs blended with a TacT preamp.  Would you have any opinion on whether the above statement would be true with the woofers corner loaded, or do you think I'd get better results with them next to the mids/highs?

Thanks

(JPK)  The free standing dipole has 4.8 dB lower power response than a free standing monopole. Place the monopole woofer near a ground plan (floor) and it radiates 3dB less power for the same on axis level or 1.8dB more than the free standuing dipole. Place it at the intersection fo a wall and floor and it radiates 6dB less power (1.2dB less than the free dipole). In a corner, 9 dB less power (4.2 less than the fre dipole). This doesn't take into account room modes, etc. It is just what the total radiated power into the space would be if the system were driven at a level that would yield constant on axis anehoic SPL.

You might want to look at http://www.musicanddesign.com/PowerMatching.html and http://www.musicanddesign.com/VariabDF.html

[PaulHilgeman]

Great article.  I really enjoyed it, I read it early today.

[OBF]

Yeah, thanks John.  Just read them and very worthwhile.  It seems to me that people putting their subs in corners are increasing their headroom at the expense of even power response.  Point source mains and corner subs is about the worst combination for power response, but I realize there are other considerations.  If you really need the extra headroom, it seems you'd be better off placing the subs on axis at the back wall before going to the corners.

Since I don't want to take this any further off topic, the good part is Paul's system is about as good as you can get for integrated power response without getting into the very extreme methods described in the article.  

[PaulHilgeman]

Sorry I havent gotten to the measurements yet.  Maybe this afternoon or this weekend.

I did do some updates on the website.

-Paul Hilgeman

[PaulHilgeman]

This is a quick snapshot of distortion at 1510Hz.  This is about the worst case for the tweeter.  Even though the crossover is at 1300Hz, the output at that frequency is the combination of the midrange and tweeter, thus a lower output from just the tweeter.  

The red is the Ronin, the black is another tweeter highly regarded for its distortion performance.  As you can see, the 2nd harmonic distortion is significantly lower on the Ronin, 3rd is very slightly lower, and the Ronin has a complete absence of high order products generated with a 1510Hz input.  The other tweeter is a Seas 27TDFC.  The levels were calibrated within .1dB between the two drivers, and the mic was at the same distance within 1/16th of an inch.

If you have any questions, let me know.

-Paul Hilgeman