subsonic filter not there.

[ham4864]

hi i just purchased a Aq-200 2 to use in mono mode for my sub stage and come to find out it has no subsonic filter. It would have been the icing on the cake. Now i'm debating if i want to keep it or send it back.

iT performs well but do you think a SSF is that much important

[hazestorm23]

This was from an old thread by beatndown

8o8. If any of this matters to you then maybe you want to send the amp back.

guys Im sure everybody knows what a subsonic filter is but I know not everybody knows how to set it.Ive seen and heard alot of people ask where it should be set at...When I was looking around I found this read on decibel car.com..I thought maybe it could help somebody else out as it did for me!!!..I wasn't sure where to put this so Im sorry if this is in the wrong spot,But here it is an enjoy!!!!.....A subsonic filter is basically a High Pass Filter for very low frequencies, generally 45hz or lower. That is, whatever you set it at; only frequencies above that setting go through. Anything below that setting is attenuated (made quieter).

As only frequencies higher than your setting pass its a high pass filter.

A subsonic frequency is very low, so low the human ear can barely detect it, but your body can feel it. Because you cant hear it, and they're prone to damaging woofers, filtering subsonics is a desirable characteristic in subwoofer amplifiers.

A subsonic filter is used differently in sealed enclosures than in ported.

In a sealed box: The lower the frequency, the more excursion your subwoofer exhibits in order to play it loudly and accurately. A sealed box is tuned by enclosure volume, larger enclosures tune lower, smaller enclosures tune higher.

Subsonic frequencies potentially damage your subwoofer because they make it expend a lot of energy, travel right to the limits of its excursion and play below the enclosures tuning.

So for safety, we want to cut those frequencies out. For a sealed enclosure you adjust the subsonic filter to 25-35 Hz, to filter the extremely low bass frequencies your woofers unable to play.

In a ported box: You tune the port to a certain frequency, the enclosure is then capable of playing all frequencies above that tuning without an issue. The enclosure can also play below that frequency, but only half an octave, before the cone starts over-excurting and there's potential for damage.

So for safety, we set the subsonic to 1/2 an octave below our tuned frequency. Whats half an octave you say ? Lets do some maths ! One octave up is double the frequency, One octave down is half the frequency.

Lets say you are tuned to 45 Hz:

- 45 Hz / 2 = 22.5 Hz (one octave lower)

- 22.5 Hz /2 = 11.25 Hz (half an octave lower)

So we take 45 - 11.25 = 33.75 Hz (rounded up to 34 Hz)

In other words, you set your sub-sonic to 34 hz. So that way, if there's music below the ports frequency, it gets filtered out protecting your woofer.

Always remember the subsonic filter is NOT a cut-off. It has a roll off "slope" where whatever frequency its set to will be attenuated, and the attenuation effect increases as the frequencies get lower. Thus the power to the woofer decreases at filtered fequencies, which reduces the excursion and risk of damage.

As a final note for the audio geeks: Subsonic filters have steep slopes such as 3rd or 4th order(18 or 24dB/Oct) this is so u can set it nice and close to your 1/2 octave frequency, or 25-35 Hz sealed, without losing power in the neighboring frequencies.

[Guest]

learn the music you play and turn the amp down on low notes.

[ham4864]

I like the brand don't get me wrong its a good amp. But had i know it did not have this feature i would have purchased something else.

I think i may use it for my mids.

[ham4864]

I like the brand don't get me wrong its a good amp. But had i know it did not have this feature i would have purchased something else.

I think i may use it for my mids.

[Jessica]

Doesnt that amp have a bandpass feature?

[SnowDrifter]

You don't really need a SSF to be honest... Just don't go full tilt if you know there's a low note

[Jessica]

i havent seen a aq200, but if it has the bandpass feature like the sq200 then put it in bandpass and set the high pass to 30hz or so

[ham4864]

I like the brand don't get me wrong its a good amp. But had i know it did not have this feature i would have purchased something else.

I think i may use it for my mids.

[SnowDrifter]

Might be tough to get any sort of adjustability with it, since the filter goes form 20hz to 5kHz