I think you indetstood what I meant. Gravity is not a fundamental factor here whatever you flip tje driver 90 or 180 degree and more... It is just people usually use their driver at 180 degrees on a front baffle. At most weigth of the voice call + cone are not diqtributing mass on surround when the unit is flipped above horizontally plane.
The pression of air and temperature, altitude , are way more important.
OK gravity is changing with altitude but not enough for you to notice. So imo, just forgett the blah gravity whatever 180 degree. Any way the mass of the cone will act both way or (again) the pressure of air is dense enough to slide out of the cone due to the weigth of oxygen VS when the cone is horizontal seing the sky and all the air above that weigth on it... uh poor cone!
The pression of air and temperature, altitude , are way more important.
OK gravity is changing with altitude but not enough for you to notice. So imo, just forgett the blah gravity whatever 180 degree. Any way the mass of the cone will act both way or (again) the pressure of air is dense enough to slide out of the cone due to the weigth of oxygen VS when the cone is horizontal seing the sky and all the air above that weigth on it... uh poor cone!
I still don't follow.
Gravity is still a major factor when the cone points towards the ceiling.
Any mass-spring (damper) system will move this way. The result is that the motor has to compensate for this additional force. Which will effect the BL of the system as well give an impression of an higher Mms.
Gravity is still a major factor when the cone points towards the ceiling.
Any mass-spring (damper) system will move this way. The result is that the motor has to compensate for this additional force. Which will effect the BL of the system as well give an impression of an higher Mms.
Here (see pgs 10-11) is how you calculate the force of gravity on the mass on the diaphragm:
http://jipihorn.free.fr/Projets en cours/Mesures/dlcpaper.pdf
Excerpt
…with the present equipment, the mass may be added without displacing the suspension.
Gravitational Force Balance.
1 Rotate test chamber axis to vertical upward
2 Select mag-serve to x mode
3 Set x = 0. Note amplifier current
4 Rotate test chamber axis to vertical downward. Note amplifier current. 5 Calculate force of gravity on diaphragm. F ---0.5 BI (Iup- Iaow,)
6 Calculate Mm = F / g. g = 9.8 m/s2
http://jipihorn.free.fr/Projets en cours/Mesures/dlcpaper.pdf
Excerpt
…with the present equipment, the mass may be added without displacing the suspension.
Gravitational Force Balance.
1 Rotate test chamber axis to vertical upward
2 Select mag-serve to x mode
3 Set x = 0. Note amplifier current
4 Rotate test chamber axis to vertical downward. Note amplifier current. 5 Calculate force of gravity on diaphragm. F ---0.5 BI (Iup- Iaow,)
6 Calculate Mm = F / g. g = 9.8 m/s2
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What I meant is the cone is not changing its mass by rotating 90°. The weigth on the voice coil should be the same. Maybe according the stifness of the surround the voice coil may be outcentred. But I assume the main force remain electromagnetic and under playback the difference are not noticeable ?
Are there enough to change the bass result because the T&S are moved enough with the driver positioning in free air?
Are there enough to change the bass result because the T&S are moved enough with the driver positioning in free air?
Depending on the stiffness, that's a wrong assumption.
Btw, nobody said that the mass changed.
The force on this mass changes, which changes the BL
What b_force said (with the possible further clarification that since the voice coil is not magnetized it’s not held in place by the magnet).
Quick update on progress progressing the 10PR320s to stability:
Despite my success getting Fs down close to spec via physical manipulation of the cones, I found this "softening was only transitory and after the drivers sat for a hour or so - even if music was being played through them - they returned back to c 60Hz again when re-testing.
In the meantime I've had a constructive response from Faital which gives me quite a lot of comfort - as follows:
"The Fs pre burn-in is 67Hz, post burn-in is 51Hz. So, we would suggest performing a stronger burn-in.
A signal voltage of 45V at 50Hz for 30 minutes should be adequate.
We measure all the speaker in an IEC Baffle (DIN 45575)."
Hopefully 45V @ 50Hz for 30min will get the drivers closer to a stable state.
cheers Paul.
Despite my success getting Fs down close to spec via physical manipulation of the cones, I found this "softening was only transitory and after the drivers sat for a hour or so - even if music was being played through them - they returned back to c 60Hz again when re-testing.
In the meantime I've had a constructive response from Faital which gives me quite a lot of comfort - as follows:
"The Fs pre burn-in is 67Hz, post burn-in is 51Hz. So, we would suggest performing a stronger burn-in.
A signal voltage of 45V at 50Hz for 30 minutes should be adequate.
We measure all the speaker in an IEC Baffle (DIN 45575)."
Hopefully 45V @ 50Hz for 30min will get the drivers closer to a stable state.
cheers Paul.
