I'm using a TI82 from texas instruments and it seems very flawed in its ability to calculate derivatives of sin functions with small period. I'd guessing it would take probably around 2K for 12"p-p. Ask Dan Wiggins if parthenon can do that and he'll probably laugh at you. Only the $100,000 version that they havent released can do such things. In order to achieve the speed of sound a driver couldnt possibly have a cone. If it had a cone, it would be ripped to shreads before it got halfway to that speed. Not to mention the LOADS of power it would require. Ever heard of a 2000hp subwoofer? Maybe if we used a jet engine to turn a flywheel 18' in diameter at 20+ rpm and then attached a rod to the flywheel's outer edge which would in turn be attached to a piston. Fire that baby up and we'd have a genuine earthquake.
Re: Help
I know,
US$60 SONY SUBWOOFER - 12", 1900w Peak ,etc!
it doesnt take much energy to make loud bass in a car.
Kamikaza said:
I know,
US$60 SONY SUBWOOFER - 12", 1900w Peak ,etc!
it doesnt take much energy to make loud bass in a car.
How can 30Hz be fast? I think 14Khz is fast!
I hope this is not off topic too much. I would like to know how to realize or identify whether the amp has enough damping when driving a subwoofer or the amp is labouring. Are there any tell tale signs?
The Butcher😀
I hope this is not off topic too much. I would like to know how to realize or identify whether the amp has enough damping when driving a subwoofer or the amp is labouring. Are there any tell tale signs?
The Butcher😀
Re: How can 30Hz be fast? I think 14Khz is fast!
Amps are pretty robust these days, so the loss of damping may not come from the amp. If we take a closer look at the resistance on the interface between amps and speakers, the net resistance that determines the overall damping is the sum of the following three components: 1) the ouput resistance of the amp (which is represented by the damping factor), 2) speaker wire, and 3) the voice coil resistance of driver. Among these three variables, 1) is the most stable and voice coil resistance is the one with high variability over temperature. To give you an idea, an amp with damping factor of 100 @4ohms has an output impedance of 0.04ohms. A 4 feet run of 14gauge speaker wire is around 0.1-0.2ohms. The voice coil resistance is 4ohms and 100 degrees temperature rise on the voice voil raises the resistance to 4.8ohms (20% increase). That 0.8ohm increase, by itself is aleady more than the amp damping and speaker wire combined. It is also funny every time I look at this issue, the mother nature does seem to work against us. Wouldn't it be nice if the damping actually improves when VC temperature rises?
Brian Ding
Rythmik Audio
chris ma said:
Amps are pretty robust these days, so the loss of damping may not come from the amp. If we take a closer look at the resistance on the interface between amps and speakers, the net resistance that determines the overall damping is the sum of the following three components: 1) the ouput resistance of the amp (which is represented by the damping factor), 2) speaker wire, and 3) the voice coil resistance of driver. Among these three variables, 1) is the most stable and voice coil resistance is the one with high variability over temperature. To give you an idea, an amp with damping factor of 100 @4ohms has an output impedance of 0.04ohms. A 4 feet run of 14gauge speaker wire is around 0.1-0.2ohms. The voice coil resistance is 4ohms and 100 degrees temperature rise on the voice voil raises the resistance to 4.8ohms (20% increase). That 0.8ohm increase, by itself is aleady more than the amp damping and speaker wire combined. It is also funny every time I look at this issue, the mother nature does seem to work against us. Wouldn't it be nice if the damping actually improves when VC temperature rises?
Brian Ding
Rythmik Audio
You could use a material like on the NTC temperature probes, the resistance reading drop when temperature rises! 😉
But then, you'll get a superb avalanche effect, temperature rises, resistance drop, more current flows, temperature rises, resistance drop, more current flows, amplifier and/or voice coil burn up! 😀
But then, you'll get a superb avalanche effect, temperature rises, resistance drop, more current flows, temperature rises, resistance drop, more current flows, amplifier and/or voice coil burn up! 😀
Hello,
I'm listening to some 15" Magnavox drivers from the 1930's - They use Field Coils for magnets and are very 'fast' - response from the low 30's out to 7K (with beaming of course) - The QTS is variable on the fly with the feild coil power supply. Sensitivity can be varied too (up to around 103 db midband with a watt at 115 VDC) with NO horn..
These are very good - very relaxed and resolving yet big time slam and dynamics. They easily outperforming my Jensen F12 field coils and many other serious woofers I have. (TAD, Altec, JBL, ect - the real stuff)
I'm listening to some 15" Magnavox drivers from the 1930's - They use Field Coils for magnets and are very 'fast' - response from the low 30's out to 7K (with beaming of course) - The QTS is variable on the fly with the feild coil power supply. Sensitivity can be varied too (up to around 103 db midband with a watt at 115 VDC) with NO horn..
These are very good - very relaxed and resolving yet big time slam and dynamics. They easily outperforming my Jensen F12 field coils and many other serious woofers I have. (TAD, Altec, JBL, ect - the real stuff)
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