Quote:
Originally Posted by
gogunbaba
Hello Everyone,
Would it be correct to wire 5 Bass shakers using a 200w (4 ohm) subwoofer amp like in the below picture? I found this picture here (I know it is for 6 shakers) and thought it may work with 5 shakers as well. Instead using 3 Aura pros in each row I am planning to have 2 in the first row and 3 in the second row. would each shakers get the same amount of power?
Thanks,
Burak
No, the row with 2 would get more power than the row with three.
Let's assume the amplifier is a constant voltage source (and most are)
Let's assume it is able to output 30 volts (and it is very likely to be able to).
According to Kirchoff's law,
In the row with 2 shakers, each would have 15 volts dropped across it. (half of the 30 volts)
In the row with 3 shakers, each would have 10 volts dropped across it. (one third of the 30 volts)
Power = voltage squared, divided by resistance, so....
( 10 volts * 10 volts ) / 4 ohms = 25 watts to each of the shakers in the string of three
(15 volts * 15 volts ) / 4 ohms = 56.25 watts to each of the shakers in the string of two.
As you can see, two of your shakers each get 56.25 watts, the other three each get 25 watts... It is NOT going to be even shaking.
To prove my numbers...
The total load to the amplifier is:
1 / (( 1 / ( 4 ohms + 4 ohms + 4 ohms ) ) + ( 1 / ( 4 ohms + 4 ohms) ))
or
1 / (( 1 / 12 ) + ( 1 / 8 ))
or
1 / ( .083333 + .125 )
or
1 / .0208333 = 4.8 ohms total load to the amplifier.
Ohms's law says that "voltage / resistance = current"
When the amplifier is outputting 30 volts into 4.8 ohms the current (in amperes) will be
30 volts / 4.8 ohms = 6.25 amperes
The formula for power (in watts) is:
"voltage * current = wattage"
30 volts * 6.25 amperes =
187.5 watts.
Remember earlier I said two of the shakers were going to each get 56.25 watts and the others each get 25. Watch when I add them up.
25 + 25 + 25 + 56.25 + 56.25 =
187.5 watts ... just like I expected, it all adds up, regardless of how you do the math.
Unfortunately, the shaking is nowhere near even...
Joe L.