napilopez said:
What's weird about it?
Is the phase curve normal? Never seen it before, though to be fair I haven't seen many.
If a measurement is performed "correctly" ("dual-channel measurement"), the phase frequency response provides some information.
It shows the filter order at the crossover frequency and if the crossover frequency is known, you can estimate how good the phase position is at the crossover frequency.
The Klipsch measurement taken at hometheaterhifi.com is not quite optimal. However, you can see a 360° phase shift near the crossover frequency, which suggests a fourth order filter. Or is it just 270° phase shift, which would correspond to a third-order filter - hard to tell.
It looks a bit "wild" due to the missing gate (which would fade out the reflections) and the phase seems to be shifted a bit to low frequencies.
From:
https://hometheaterhifi.com/reviews/speaker/bookshelf/klipsch-rp-600m-loudspeaker-review/
Correctly measured, you can read out a bit more information and as a developer you get more feedback about the quality of the development.
[off-topic]
As an example here the frequency and phase response of a 2-way bookshelf speaker which should show a low tuned BR frequency of third order Quasi-Butterworth and was separated at 1.6 kHz with fourth order LR.
In the low frequencies we expect a phase shift of about 270° due to the quasi third order Butterworth roll-off - check.
Around the crossover frequency we expect a phase shift of 360° due to the fourth order filter - check.
Most of the reviews that I have read/viewed mention that these speakers present a sound stage seemingly originating from up-close, as opposed to coming from the actual distance of the speakers, or even behind the speakers. Is this a thing (is this something that can be read from the measurements) or is this more about room and positioning or just subjective-review quackery?
As others have said, it probably has to do with the narrow radiation pattern.
However, the directional bands according to Blauert should also play a role.
In the median plane the perception of direction is determined by certain frequency bands.
If the sound level of a sound source positioned at the front in one of these bands is raised in relation to other frequency ranges, the auditory system can use this to determine whether the sound is coming virtually from the front, from above or from behind.
vorn = front, hinten = back, oben = top
Unfortunately I did not find an english wikipedia entry.
https://de.wikipedia.org/wiki/Blauertsche_Bänder
So if the sound pressure is reduced in the median plane in the 1-2kHz range and the 3-5kHz range is emphasized, then the perception of direction tends to push the music up-close .
This can be further enhanced in the horizontal plane by manipulating the same frequency bands as the directional perception in the median plane.
The perception of direction "from the front" (median plane) becomes in the horizontal plane a sound that is present, close, direct, superficial.
This can be achieved by raising the frequencies 300 to 600 Hz and 3 to 5 kHz and lowering frequencies by 800-2000 Hz.
So the Klipsch's listening impressions fit quite well with the directional bands of Blauert.
