Well, better late than never
You attribute audible sound character/tonality/tone colour to the slope of a curve between 2-3 kHz. Yet claims of audible differences between capacitors is considered hogwash?
There's a lot going on here.
Due to the changes in the crossover for the tweeter, the frequency response curve starts to rise in the 2-3kHz range and remains raised up to 10kHz - provided Danny's measurements are reliable, which I have already written in the previous posts.
These changes in the frequency response curves have caused me to ask if there are any changes in the premium crossover component values. This was confirmed by
@Rick Sykora.
The premium-crossover was recommended to
@Rick Sykora because it would make the speaker sound much more transparent, supposedly because of the better and more expensive crossover components.
If the changes to the premium crossover really do what it says they will, then the speaker will definitely sound significantly different, brighter with more detail - how easily tonal changes are perceived, I tried to show in the previous post
***.
In the case of
@Rick Sykora's DIY loudspeakers, however, the tonal change/improvement(?) is not caused by "better" component quality, but simply by changing the crossover. But it should actually be "proven" that the component quality causes audible differences - with
exactly the same component values.
Here we come full circle to the capacitor tests.
When people claim to notice a significant improvement in high frequency reproduction after replacing capacitors (usually one or two serial capacitors in the high frequency branch of the crossover), the exact capacitance values of the old and new capacitors are never given.
It is then said that the capacitance values before and after the exchange were identical, for example 4.7µF. The tolerances of the capacitor values are not taken into account. With cheap capacitors this can be +-10%, with better +-5% and with the best +-2%.
These tolerances are sufficient to cause audible tonal changes in the speakers.
In
the first part of my capacitor experiments I show that with exactly identical capacitance values there are no significant measurable differences (FR, multiton distortion, impluse response, CSD) at all between a "normal" and a high-end capacitor.
I also show that even small differences in capacitor values (which occur when capacitors are replaced without prior selection regarding the old value, because of the tolerances) cause measurable changes in the frequency response.
In
the third part I show that in a hearing test the claim that there are practically no measurable differences, but clearly audible differences, between a simple crossover version and the premium crossover are simply not true.
Which again shows how important it is that really identical component values (measured and selected) are used in such comparisons.
Therefore
@Rick Sykora's comparison was doomed to fail from the beginning (with a lot of luck the deviations could have been minimal, but we would never have known).
With the changed component values in the premium crossover, two speakers
with different crossover tunings are now compared.
*** (Just to be clear: The audibility of the shown low-Q resonances is of course not directly comparable to a modified Encore crossover, it should only illustrate that tonal changes can be perceived well below the 3dB you mentioned. My own experiences with loudspeaker development, crossover tuning and the audibility of tonal changes would, rightly, be dismissed as anecdotal - hence the various examples).
