Its a pair of Seas FA22
H1597-08 FA22RCZ
One of them has a significant dropp in frequency in the upper range.
The measure equal re (Ohm) and le (with a LCR-measurement)
Please look in the link to the forum thread under:
The first measurements is in the cabinet with correction filter (baffle step & notch)
The latter is measured outside the cabinett close to the driver without any component
Noen som vet hvorfor? | Hifisentralen
H1597-08 FA22RCZ
One of them has a significant dropp in frequency in the upper range.
The measure equal re (Ohm) and le (with a LCR-measurement)
Please look in the link to the forum thread under:
The first measurements is in the cabinet with correction filter (baffle step & notch)
The latter is measured outside the cabinett close to the driver without any component
Noen som vet hvorfor? | Hifisentralen
Last edited:
Note: whizzers are primarily a [high] mids BW device to enhance/project vocals, so normally no place to be looking for actual HF [> ~ 6 kHz] anomalies.
The voice coil [Vc] dia. limits point source output to ~34400/pi/2.6 = 4211 Hz, making the whizzer BW going back down to ~600 Hz, ergo something's weird with the dust cap's [dc] output, so apparently something different WRT density and/or stiffness and/or whizzer, dc, Vc connection. Note there could be some HF coming off the diaphragm also, comb filtering with the dc's output.
FWIW, IME and lacking any experience with using a mic to look for such 'needles in a haystack', a mechanic's stethoscope has been my 'best friend'/most used test tool. 😉
The voice coil [Vc] dia. limits point source output to ~34400/pi/2.6 = 4211 Hz, making the whizzer BW going back down to ~600 Hz, ergo something's weird with the dust cap's [dc] output, so apparently something different WRT density and/or stiffness and/or whizzer, dc, Vc connection. Note there could be some HF coming off the diaphragm also, comb filtering with the dc's output.
FWIW, IME and lacking any experience with using a mic to look for such 'needles in a haystack', a mechanic's stethoscope has been my 'best friend'/most used test tool. 😉
Interesting behaviour.
I'd do the following checks:
- Swap speaker cables between one speaker and another - make sure it's not an amplifier or something else acting weird
- Make sure the mic position is perfect each time.
After that, I'd contact Seas and see what they say.
Chris
I'd do the following checks:
- Swap speaker cables between one speaker and another - make sure it's not an amplifier or something else acting weird
- Make sure the mic position is perfect each time.
After that, I'd contact Seas and see what they say.
Chris
I have done that. Double checked!
And also contacted Seas. They are btw located 15 min from my place. I have visited them before 🙂
But they didnt know whats wrong. Maybe someone at R&D should look at the measurements they said.
One guy had an idea that it could be something mechanical. F ex that the magnet got a punch (but i cant see any marks) and then the voicecoil is very little misplaced in the gap? I dont know?
And also contacted Seas. They are btw located 15 min from my place. I have visited them before 🙂
But they didnt know whats wrong. Maybe someone at R&D should look at the measurements they said.
One guy had an idea that it could be something mechanical. F ex that the magnet got a punch (but i cant see any marks) and then the voicecoil is very little misplaced in the gap? I dont know?
Since this is so high up in frequency, this could be anything from even a dab of glue .
You could also measure impedance as well, that will quite often reveal many things.
You could also measure impedance as well, that will quite often reveal many things.
Yep, impedance measurement is a good idea.
I'd also ask Seas about refund or replacement of the faulty driver. It's clearly not performing to spec.
Chris
I'd also ask Seas about refund or replacement of the faulty driver. It's clearly not performing to spec.
Chris
I use Arta.
It seems quite easy to measure impedance with this connection:
https://www.artalabs.hr/AppNotes/AN1-MeasuringBox-Ver2-Rev2Eng.pdf
It seems quite easy to measure impedance with this connection:
https://www.artalabs.hr/AppNotes/AN1-MeasuringBox-Ver2-Rev2Eng.pdf