Sloped baffle

Hi Psag,
What you are quoting makes absolute sense... If you pull the crossovers and make everything perfectly phase and time aligned along with perfect frequency response, then the only difference is sound between speakers is the materials themselves...ie, how does the box sound, what does a Kevlar cone vs a paper or aluminum cone sound like etc.... So you are hearing first hand, (by correction) how important a flat response along with phase and time alignment can be.

Even with DSP, bet there's still a market for $300 Revelators vs. a $20 Silver Flute and vice versa.

Psag ... just took a quick peek at the DEQX web site. Very interesting.

Problem is that it's not cheap and where is the vendor located? What recourse if it doesn't work well.

Also, it obviously entails inserting an artifact into the signal path, presumably between source components (e.g., CDP, DAC and phone pre) and linestage. Oftentimes, not the best thing to do. How does it work if one has an integrated amp with built-in phono section??

Sure wish I could try the device on approval.

Cheers,

BIF

07-08-14: Bifwynne
Bombaywalla, sorry for the confusion. I'm referring to a driver's electrical, not mechanical, attributes. Rather than go off on a tangent, if Al catches these last few posts, he might be able to untangle what I'm trying to say.

Bruce (Bifwynne) raises a good question, to which I suspect there is a good answer, but I don't know precisely what that answer may be :-) But I'll reformulate what I interpret to be the question, and perhaps one of the others who are participating can address it.

Consider a simple two-way speaker having a first order crossover consisting of a capacitor in series with the tweeter, and an inductor in series with the woofer. For each driver that will result in well behaved 6 db/octave rolloff characteristics, which will result in time and phase coherence if other aspects of the design are also supportive, **IF** the impedances of the woofer and tweeter are purely resistive.

However I believe Bruce has been alluding to the fact that the impedances of the drivers are not purely resistive. And it would be more accurate (if still somewhat oversimplified) to electrically model them as consisting of a resistor and an inductor in series.

So the question then becomes: Doesn't the presence of that inductive component of the driver impedance (especially in the case of the tweeter) cause a deviation from first order 6 db/octave behavior? And if so, to a degree that may audibly compromise phase and time coherence? And if so, is that or can that be compensated for in other aspects of the speaker's design?

As I said, I don't know the answers, but those strike me as good questions.

BTW, Tim (Timlub), thanks for providing the link to my post about impedance phase angle.

Best regards,
-- Al

"So the question then becomes: Doesn't the presence of that inductive component of the driver impedance (especially in the case of the tweeter) cause a deviation from first order 6 db/octave behavior? And if so, to a degree that may audibly compromise phase and time coherence? And if so, is that or can that be compensated for in other aspects of the speaker's design?"
ABSOLUTELY, I had stated earlier that a simple cap seldom produces a 6db slope for that exact reason, no speaker that I've seen shows purely resistive(other than a ribbon). In the crossover, we can only lower impedance of a driver with compensation circuitry. A simple pad in series on a tweeter will raise impedance, but also cause you to need a new crossover. All this is the difference between electrical vs acoustical crossovers, cause & effect. 6, 12, 18 or 24 db per octave crossovers on paper, often end up being larger slopes because of the natural inductance, impedance and capacitance of a driver that must be taken into consideration in the design itself. In my experience without impedance compensation work, a driver with 6 db filters are still TYPICALLY 10 to 20 degrees out of phase... Any speaker that is with + or - 15 degrees of phase for its useable response curves in my mind IS phase coherent.