Sub-sonic filter question for the pros

[wlmrs 10+ year member]

Alright I just built my new box tuned @ 30hz and on my bxi2006d the sub-sonic filter range goes from 15-35hz.Question is what is the proper setting I should be using on this filter?Thanks in advance!//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

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[revrider1 5,000+ posts]

I would say about 20hz-25hz

 

[SRim23 5,000+ posts]

i too have had thise question no one can ever give me an answer as to whats the difference between the crossover setting and subsonic filter?

 

[Rich B 5,000+ posts]

i too have had thise question no one can ever give me an answer as to whats the difference between the crossover setting and subsonic filter?

The crossover setting is the top frequency you're allowing the sub to play, the subsonic setting is the lowest frequency you're allowing the sub to play.

Subsonic filters are important in ported sub systems as its used to prevent damage to the sub from trying to play frequencies that are below the port's reponse.

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[SRim23 5,000+ posts]

The crossover setting is the top frequency you're allowing the sub to play, the subsonic setting is the lowest frequency you're allowing the sub to play.
Subsonic filters are important in ported sub systems as its used to prevent damage to the sub from trying to play frequencies that are below the port's reponse.

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ur the coolest kid on the block man makes sense thanks

 

[mlstrass 5,000+ posts]

Same as doing a bandpass setting for your mids if running active. Will save your sub, especially with a high tuned box.

 

[blowthemup 10+ year member]

I have always read it should be adjusted to what your enclosure is tuned too.

 

[wlmrs 10+ year member]

not true!

 

[ngsm13 5,000+ posts]

Half an octave below tuning, which in your case would be 22.5hz

Go with 20hz and call it a day.

nG

 

[wlmrs 10+ year member]

Half an octave below tuning, which in your case would be 22.5hz
Go with 20hz and call it a day.

nG

Thanks!

 

[thch 10+ year member]

yep, (1/2)^(1/2) * 30 = 21.2hz. other common folklore estimates are:

1/4 octave below: (1/2)^(1/4) * 30 = 25.2

1/3 octave below: (1/2)^(1/4) * 30 = 23.8

5hz below tuning: 30-5 = 25

3/4th of tuning (about 2/5th octave down): 0.75*30 = 22.5

notice that all of these fall within a few Hz of each other, and that the pot is probably not labeled enough to tell you what you actually set it to.

not that it matters too much -- all the numbers above are just what other people have tried one other setups that are not the same as yours.

there really isn't too much point in trying to accurately set the SSF to a number that is just a guess. so long as it works, you'll be happy and attribute it to some "proper" setting that you really didn't do. if it doesn't work, you'll just adjust it up a bit until it works, and assume that you didn't set it to the correct value the first time. in the end the result is the same.

edit --

for reference, fractions of an octave follow the same rules as whole octaves. if you go up a half octave, then go up another half octave you reach 1 full octave up from the orignal point. eg:

20hz

1/2 octave up = 20* (2)^(1/2) = 28.28hz

1/2 octave up from 28.28hz = 28.28* (2)^(1/2) = 40hz.

if you use the "aritmetic" fomula 20 + (40-20)/2 for finding half octaves you get:

1/2 octave up = 30hz

1/2 octave up from 30hz = 30 + (60-30)/2 = 45hz

45hz is not 1 octave up from 20hz. 40hz is. for the most part no one deals with quantites below 1 octave, and if they do, they use a look up table and don't ever need to calculate the values for themselves.

 

[sundownz Pro Seller]

Half an octave below tuning, which in your case would be 22.5hz
Go with 20hz and call it a day.

nG

I agree. With a 30 Hz tune it is highly unlikely that you need to even worry about it on music... just put it as low as it goes!