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MultiWay Conventional loudspeakers with crossovers 

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3rd June 2004, 03:29 PM  #1 
diyAudio Member

voltage or current?
what affects the actual loudness of the music, the vrms, or current?

3rd June 2004, 03:35 PM  #2 
diyAudio Member
Join Date: Jun 2002
Location: Left Coast

Yes.
Whichever you run out of first. But assuming you have more than enough of each at your disposal, it is probably best understood as voltage. Except in the case of the two extremes of infinite impedance or zero impedance, there is no current with out voltage, and no voltage ("potential" is an other mater) without current. 
3rd June 2004, 03:50 PM  #3 
diyAudio Member

The product of voltage and current is what affects the loudness of the reproduced sound.
This is coherent with the forumla where power is equal to voltage X current. In a speaker, the impedance varies with frequency. This means that for a given voltage from the amplifier, the power used will not be the same for all frequencies since the current flowing through the speaker changes for impedance. All amplifiers have a certain limit of voltage swing that they can output. This basically states the possible power output into a certain impedance of speaker as long as the power supply and transistors can handle enough current at that voltage to produce all the power. I hope this clears the ideas a bit.
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4th June 2004, 01:06 AM  #4 
diyAudio Member
Join Date: Jan 2004
Location: Toronto, ON, Canada

SPL is proportional to the acceleration of the cone. The acceleration is equal to the force on the voice coil divided by Mms, or "a" proportional to "F", since mass doesn't change. Force applied on the voice coil is proportional to (equal to?) i*B*L. B and L are constant, and current depends on voltage (I = V/R)  note that impedance isn't constant, but varies with frequency.
So, it's voltage that gives you loudness. EDIT: B is the magnetic field strength that the voice coil is subjected to by the driver motor, and L is the length of the voice coil (between the pole piece and the top plate, I think). 
4th June 2004, 02:14 AM  #5  
Speakerholic
diyAudio Moderator

Quote:
Cal 

4th June 2004, 02:26 AM  #6  
diyAudio Member RIP
Join Date: Nov 2003
Location: Brighton UK

Quote:
the line in each loudspeaker  more power  more volume. Also note 70V rms is just notional maximum voltage for the power settings of each tap, the system can run at any lower level, just the ratio of volumes of the loudspeakers is fixed. And the total of all the power taps should not be larger than the power output of the amplifier. sreten. 

4th June 2004, 02:59 AM  #7 
Speakerholic
diyAudio Moderator

Thank you
Cal 
5th June 2004, 02:16 PM  #8 
diyAudio Member

thx
youve all been extremly helpful!
thank u! 
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