What is a low pass filter?

[Phatmat 10+ year member]

I'm looking to buy the Kenwood KAC-8104D. Does anybody know if this is a good amp?

Though, on the specs list it says:

Variable low-pass filter (50-200 Hz at -24 dB per octave)

What does this mean? Does it mean that I can't run my sub at frequencies lower than 50Hz?

Another question I have is the amp says "Rated Power Output 14.4V". It runs on 12V I'm assuming? And do all subs run on 14.4V or something, or will I have to make sure the sub I'm going to use (Kicker CVR12) allows a 14.4V input?

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[ampjunkielikeme 10+ year member]

no , a low pass variable crossover is made to adjust the frequency that you dont want to play through your subs.....

14 volts means that the amp was tested to make sure how many watts it puts out at 14 volts, and yes, your car is 12 volt but when its running it puts out 14 volts.......

subs do not run on 12 volts . they run on the ac voltage that amplifiers put out..

just make sure your subs rated rms wattage matches your amps rms output at whatever ohm your subs are........so if your 4 ohm kicker sub has a rms wattage of lets say ,250 watts. you will need a amp that puts out 250 watt rms at 4ohms.....

 

[Phatmat 10+ year member]

What if my sub is rated at 400wRMS (4Ohm), and my amp is rated at 300wRMS (4Ohm). Would this work good, or is it going to under power the sub?

 

[Nathan1659]

You should be fine, as long as your not pushing out equal to or more than the rms rating. I dont think you can under power a sub

 

[dman4486 5,000+ posts]

You should be fine, as long as your not pushing out equal to or more than the rms rating. I dont think you can under power a sub

I am running 2 times rated power on my subs:fyi:

O.P.

under powering is fine as long as you don't decide you want more and crank the gain. This scenario can cause the drivers to burn up. I prefer to have more power on tap instead of not enough.

 

[Nathan1659]

That also is a good idea, it would sound cleaner too.

 

[Lakota 5,000+ posts]

Low Pass = "low frequencies pass" Those frequencies that are under what the lpf is set to will tend to pass through better than those that are above the setting of the lpf.

High Pass is just the opposite. High frequencies tend to pass, but the ones under the setting of the hpf will be blocked.

Pretty easy to remember their functions this way.