power of 400w power amplifier...

[juneray]

is 400w power amplifier enough for four 8 ohms, 15 inch 500w speaker?

[glen65]

It should be plenty,
The 500 watt rating on the speaker is probably a
"max" rating.

[Tony]

Originally posted by juneray
is 400w power amplifier enough for four 8 ohms, 15 inch 500w speaker?

YES, if you series connect those 4 speakers, but if you parallel them, make sure your amp has a 2 ohm or lower power rating for you to safely operate those speakers..

[myhrrhleine]

It depends on the rated SPL 1-watt 1-meter and how loud you want it to be.
The wattage rating of a speaker is just the damage-rating not loudness rating

[cled]

the lower the impedance the more chances of distortion.....

[AndrewT]

If you wire the 4drivers in series parallel then the effective impedance is 8ohms.
Each speaker will get an equal share of the power delivered, i.e. a maximum of 100W of unclipped sinewave.

A single driver with 100W of input will produce an SPL figure at the LF you require.
Two speakers each fed with 100W will give SPL + 6dB
Four speakers each fed with 100W will give SPL + 12dB

Your 400W amp feeding 4off 8ohm drivers, wired as an 8ohm load, will sound as loud at LF as a 1600W amplifier driving an 8ohm speaker, if it could survive.


You will be asking each driver to handle a maximum of 100W. They should be reliable and loud.

Personally I would use four amplifiers each rated at 100W or so into 8ohm and power each driver individually. You get the same volume (SPL) of 1600W driving a single 8ohm speaker and you have resilience in your system. If one amp or one speaker breaks you still have three other bass channels working for your audience.