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 Multi-Way Conventional loudspeakers with crossovers

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 27th March 2006, 07:06 PM #1 nikita   diyAudio Member   Join Date: Dec 2004 Location: Montreal, Canada Spl I have a 87.8 dB/1W sub. What is the equivalent dB for 2.83 Volts? Thanks
 27th March 2006, 07:10 PM #2 owdi   diyAudio Member     Join Date: Sep 2003 Location: Bellevue, WA That depends on the impedance of the sub. In general, every time you half the impedance you gain 6db. So the 4ohm would be 93.8db at 2.83v. Dan
e-side
diyAudio Member

Join Date: Jun 2005
Location: The Netherlands
Quote:
 Originally posted by owdi That depends on the impedance of the sub. In general, every time you half the impedance you gain 6db. So the 4ohm would be 93.8db at 2.83v.

2.83 V = 1W @ 8 Ohm;
2.83 V = 2W @ 4 Ohm;
2.83 V = 4W @ 2 Ohm etc.

When you double the number of Watts, SPL increases with 3 dB.

So if your sub has a SPL of 87.8 dB @ 1W and it's impedance is 8 Ohms, then SPL @ 2.83 V (= 1W @ 8 Ohm) = 87.8 dB

If the impedance is 4 Ohms, then the SPL @ 2.83 V (= 2W @ 4 Ohm) = 87.8 + 3 = 90.8 dB (half the impedance means the double of watts at a given voltage level, so +3dB)

 28th March 2006, 01:38 AM #4 Ron E   diyAudio Member     Join Date: Jun 2002 Location: USA, MN As I posted at Parts Express to your question there: Many manufacturers dB/W values are actually 2.83V ratings. Since not all manufacturers rate them the same way, the only good way (short of actually measuring them yourself) to do this comparison is to do a apple/apples comparison using calculated (not rated) values. calculate dB/W as: dB1=112+10*log10(9.614e-10*Fs^3*Vas/Qes) Calculate dB/2.83V as: dB2=dB1+10*log10(8/Re) Vas in liters Re is DC resistance of coil, not the rated ohms. __________________ Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. —Aldous Huxley
 28th March 2006, 01:40 AM #5 David Gatti   diyAudio Member     Join Date: Mar 2004 Location: Melbourne, Australia Why not use something like Unibox?

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