Series parallel wiring confirmation
Hey guys,
Another bone head question, just verifying that these subwoofers are wired for series/parallel correctly;
Four subwoofers, single 8ohm drivers in each. 2 subwoofer boxes are wired in series, and the other 2 are parallelled to the terminals ( neg to neg, pos to pos ) to the boxes that are wired in series.
Is this correct?
Wiring in series spoils Your driver's Thiele parameters!
A low frequency speaker "sees" a generator impedance of hopefully much less than an Ohm. It consists of:
a) the amplifier's output impedance, e.g. 0.04 Ohm
b) cable resistance, e.g. 0.1 Ohm
c) resistance of series coil in the crossover, e.g. 0.5 Ohm
When using an active crossover You can get rid of "c", and it pays to invest in "b" (thicker cables).
This combined generator resistance determines (together with other things) the Thiele parameter Qt.
When placing another driver in series You add that driver's DC-resistance (e.g. 5 Ohm) to the combined generator resistance. That will spoil any cabinet design which depends on a certain value of Qt. In most cases You will end up with a "boom box".
So don't wire loudspeakers in series if possible.
Ruediger
What is Your configuration?
I searched for "EV 3512" and found "EV TL3512". Are that Your boxes?
The TL3512 are "bass-reflex" or "vented", You (me ?:) 1st need to check what a proper alignment (box tuning) would be for the speakers. 1st of all tell us what boxes You use.
Then use 2 + 2, 2 speakers on the left channel and 2 speakers on the right channel, wire them parallel to get 4 Ohms. Do NOT bridge the amp, connect one speaker pair to the left channel, and one pair to the right channel.
If You want mono-sub, connect left and right by using a proper Y-cable at the amp's input. 1st tell us how You are driving the amp.
Ruediger
Improve cooling to make speakers last longer
There is a datasheet of the speakers on the net. That tells You the low frequency limits and the power handling capacity.
If Your speakers die from over-excursion then You need to change the electronics setup. Don't ask me, see the manuals :)
If Your speakers die from overheating (burned voice coil) then You can do something:
Mount the speakers "reversed", with the diaphragm facing the inner part of the box and the magnet assembly on the outside. That way cooling is improved.
The box's net volume will become larger by this as the driver does not any longer occupy space in the box. That will spoil Your boxes' alignment unless You compensate.
Check the driver's data sheet for "volume displaced by the driver" or so. Put a piece of styrofoam (as big as the displaced volume) into the box to compensate for the missing volume displacement.
Now that You have reversed the drivers YOU MUST REVERSE THE CABLE'S POLARITY. Connect red to where black was and black to where red was.
Ruediger