# setting ssf and lpf?



## 808Munkyeee (Jun 6, 2011)

so my box is tuned to 35 hz do i set my ssf to 30 or 25hz? and set the lpf to 80hz right?

now how do i know it at that exact setting?
can i use this method with the car off or has to be on?

Setting Subsonic Filter (SSF)
Subsonic filter reduces the amplitude of certain frequencies depending on where it's set.
If your using a sealed enclosure, then turn the ssf all the way counter-clockwise.
So your enclosure is ported? Your going to set the ssf to the frequency your box is tuned to.

Let's use 30hz as an example...
disconnect speakers
turn ssf counter-clockwise until it's considered "off"
play 30hz tone at volume 10.
Measure the voltage output
Let y = voltage output * 0.707
turn ssf clockwise until voltage output now matches "y"
Now your ssf is set.


Setting Low Pass Filter (LPF)
LPF does the exact same thing as the ssf but it's reducing higher frequencies that we don't want our speakers to play.
Depending on the speaker your using and it's frequency response you'll want to set the lfp filter higher or lower then others.

For this article were going to be setting it to 80hz for a subwoofer.
disconnect speakers
turn lpf clockwise until it's considered "max"
play 80hz tone at volume 10.
Measure the voltage output
Let y = voltage output / 0.707>
turn lpf counter-clockwise until voltage output now matches "y"
Now your lpf is set


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## zoomer (Aug 2, 2009)

Subsonic filter is to roll off the low frequencies under the resonant frequency of your subwoofer if you are using a ported design because under the port tuned frequency the woofer excursion is no longer controlled and will bottom out very easily. This does not have happen if you have a sealed box as the woofer excursion is always controlled by the air in the box. 

For your sub, 30Hz would be about right but other forum members may have other responses. 
As for th 80 Hz LPF, it depends on how much bass your mids can take. If you have really good mids you can set the LPF 60Hz or so, and then the High Pass Filter for the Mids also at 60Hz. Thats where I set mine. Experiment with yours. The extra bass comming from up front is awesome. I do have very high end mids and 300watts a side however. 

the "turn counterclockwise until voltage is .707 x max voltage" is setting the -3db point 

since power is voltage^2, .707 x.707 =0.5 or half power, the -3db point. 
(.707 = 1/square root of 2) 

So for the LPF example, the procedure sets the -3dB point at 80 Hz. This would be more accurate than looking at the frequency dial on the knob. 

you need to have an AC RMS voltmeter. Most DVMs read AC volts RMS.


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## 808Munkyeee (Jun 6, 2011)

zoomer said:


> Subsonic filter is to roll off the low frequencies under the resonant frequency of your subwoofer if you are using a ported design because under the port tuned frequency the woofer excursion is no longer controlled and will bottom out very easily. This does not have happen if you have a sealed box as the woofer excursion is always controlled by the air in the box.
> 
> For your sub, 30Hz would be about right but other forum members may have other responses.
> As for th 80 Hz HPF, it depends on how much bass your mids can take. Really good mids are great down to 60hz. Thats where I set mine. Experiment with yours. The extra bass comming from up front is awesome. I do have very high end mids and 300watts a side however.
> ...


huh? im lost this is setting for the sub amp only sorry.
So how i set it in lame turns?
i have a dmm


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## zoomer (Aug 2, 2009)

I edited my post to refer only to the LPF for the sub. Keep in mind that you will also set the HPF for the mid at the same frequency.

In lame terms... just use the numbers on the dial...


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## 808Munkyeee (Jun 6, 2011)

yes so what number do i use and read when i am turning the lpf/ssf on the amp?i am still lost


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## zoomer (Aug 2, 2009)

808Munkyeee said:


> yes so what number do i use and read when i am turning the lpf/ssf on the amp?i am still lost


set lpf at 80 and ssf at 30


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## 808Munkyeee (Jun 6, 2011)

yes i know that but how do i get it exactly on the amp? i use a 30 hz for the ssf and read what on the dmm when turning the ssf dial? same for the lpf play a 80hz tone and set the dial to read what on the dmm?


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## zoomer (Aug 2, 2009)

808Munkyeee said:


> yes i know that but how do i get it exactly on the amp? i use a 30 hz for the ssf and read what on the dmm when turning the ssf dial? same for the lpf play a 80hz tone and set the dial to read what on the dmm?


forget the DMM 

are there no numbers on the dial?


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## 808Munkyeee (Jun 6, 2011)

noo it only 25 and 60
35 200 

sundown amp saz1200


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## zoomer (Aug 2, 2009)

808Munkyeee said:


> noo it only 25 and 60
> 35 200
> 
> sundown amp saz1200


 Unless you have a cd or mp3 sinewave source you cannot use the DMM method anyway. So just set it by eye between the dial numbers.


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## hottcakes (Jul 14, 2010)

and yet another thread of this guy and his amp! yes!


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## 808Munkyeee (Jun 6, 2011)

zoomer said:


> Unless you have a cd or mp3 sinewave source you cannot use the DMM method anyway. So just set it by eye between the dial numbers.


yes that what i was using


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## zoomer (Aug 2, 2009)

Great! So to set the lpf at 80hz play a 80hz tone at a moderate listening level. Does not have to be loud. Set the lpf knob fully clockwise to its maximum frequency setting. Meaure the ac voltage at the sub speaker or amp terminals. Record the voltage. Multiply ththis voltage by .707. Write down the result. Then turn the lpf knob counterclockwise untill the dmm reads this voltage. 

For the ssf. Do the same except use a 30hz tone and start with the controll at minimum frequency. Record the voltage, multiply by .707 and turn the knob to a higher frequency untill the dmm reads the new level 
(I don't know if it is clockwise or ccw)


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## 808Munkyeee (Jun 6, 2011)

maybe half way on the deck? or half ways from the deck clip? this can be done with the car off

i forgot to ask do you set the gain first than the ssf/lpf or it doesnt matter?


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## minbari (Mar 3, 2011)

hottcakes said:


> and yet another thread of this guy and his amp! yes!


maybe he is going for a world record!


seriously though. set it for approx 25-30 hz. if you ar eoff by 1 or 2 hz, you arent going to be able to tell anyway.


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## zoomer (Aug 2, 2009)

808Munkyeee said:


> maybe half way on the deck? or half ways from the deck clip? this can be done with the car off
> 
> i forgot to ask do you set the gain first than the ssf/lpf or it doesnt matter?


huh? have no clue what your first sentence is about. 

order does not matter. gain or ssf/lps


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## 808Munkyeee (Jun 6, 2011)

zoomer said:


> Great! So to set the lpf at 80hz play a 80hz tone at a moderate listening level. Does not have to be loud. Set the lpf knob fully clockwise to its maximum frequency setting. Meaure the ac voltage at the sub speaker or amp terminals. Record the voltage. Multiply ththis voltage by .707. Write down the result. Then turn the lpf knob counterclockwise untill the dmm reads this voltage.
> 
> For the ssf. Do the same except use a 30hz tone and start with the controll at minimum frequency. Record the voltage, multiply by .707 and turn the knob to a higher frequency untill the dmm reads the new level
> (I don't know if it is clockwise or ccw)



this.



set the deck half way or you only need to turn it up a lil like 10


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## 808Munkyeee (Jun 6, 2011)

zoomer said:


> Subsonic filter is to roll off the low frequencies under the resonant frequency of your subwoofer if you are using a ported design because under the port tuned frequency the woofer excursion is no longer controlled and will bottom out very easily. This does not have happen if you have a sealed box as the woofer excursion is always controlled by the air in the box.
> 
> For your sub, 30Hz would be about right but other forum members may have other responses.
> As for th 80 Hz LPF, it depends on how much bass your mids can take. If you have really good mids you can set the LPF 60Hz or so, and then the High Pass Filter for the Mids also at 60Hz. Thats where I set mine. Experiment with yours. The extra bass comming from up front is awesome. I do have very high end mids and 300watts a side however.
> ...


I have high end speaker
rainbow germanium 6.5 and a sundown sax 100.4


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