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sub sonic switch

788 Views 6 Replies 6 Participants Last post by  automaticman
i have an audiobahn amp and there is a switch that says sub sonic on it.. I am wondering how exactly do I use it... If it is on it filters out the sub sonic frequencies.. Of if is off it filters out the sub sonic frequencies??? Then next to the switch there is a 20-50 turnable knob I know this is for the frequencies as well.... BUT do I want this switch in the on or off position?? I know you cant hear sub sonic frequencies so I would like them shut off... I hope this makes since but I just got confused when I saw it...

oh and the directions says it is used to filter out sub sonic frequencies that may damage speakers.. So what does that mean do I want it on of off to filter them out???

sorry just a stereo n00b :)
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The sub-sonic filter will cut out any freq. usually below 20hz. Because we can't hear down that low, but it can damage your equipment very quickly.

It looks like you have an adjustable sub-sonic freq. so if you set that knob at 50, all sounds below 50hz will NOT come out of the speaker. If you set it at 20, nothing below 20hz will come out of the speaker.

I highly suggest turning the filter ON and setting the frequency at about 25. But the frequency is personal choice. But Don't set it at any higher than 40, there is lots of music and bass notes that hit at 40.

Hope that helps!
is my alpine amp the same?
I have this dial with alot of Hz readings all over it.

I dont know what it means but when i turn it up, my subwoofer is louder.
[quote author=kspec link=topic=72114.msg1270215#msg1270215 date=1174007749]
is my alpine amp the same?
I have this dial with alot of Hz readings all over it.

I dont know what it means but when i turn it up, my subwoofer is louder.

It's probably your low frequency crossover. So the higher up it is, the higher the frequencies it allows to get to the sub => louder sub. Mine is set to about 120 and my high freq crossover is set to about 95. Just a little overlap to ensure I get every note!

What size sub are you using, and what type of enclosure is it in?

If you're using a sealed enclosure you can typically set the subsonic filter as low as it will go, if you're using a ported enclosure you will set it ~5 Hz below the tuning frequency of the enclosure.

The subsonic filter is merely a high-pass crossover that you can use to limit the output of your sub at frequencies where it's no longer controlled by the enclosure. This is a larger issue in ported enclosures, and the higher the tuning frequency, the bigger the potential for problems.

The other "benefit" to a subsonic filter is that it limits the amplifier in amplifying extremely low frequencies that you cannot hear. This causes the amplifier to be less of a strain on the electrical system of the car.
my system is not much.. but its way to loud for me, I have it turned down low...

i have:
stock headunit with a LOC
8ga power wire kit
200watt RMS/ 400watt MAX Audiobahn Amp
single 10" Alpine Type S Subwoofer in a sealed box
dehoff is exactly right. Since you're using a sealed box I would turn it on and, if there is an adjustment knob next to the switch, turn it down to its lowest setting.

Subsonic filters are essential if you have a vented enclosure, because below the tuning frequency of the box the air ceases to act as a suspension for the sub.
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