LPF based off Fs

[i2ain2thunder 10+ year member]

Hey guys hope someone can help me. (on this subject my knowledge level is that of a retard so take is slow/easy on me plz)

Anywho looking to find a good xover point for my LPF for my subs. I hear that I might like having a 6db rolloff quarter of an octave above my Fs...so the equation would go ((((Fs*2)+Fs)/2)+Fs)/2 I'm not sure what factor to use for Fs do I just use the specs for the woofer, because mine say their Fs is 21hz. Which would land me at a LPF setting of 26.25 and that doesn't seem remotely close to being a good xover point. Is there some other Fs spec, or does the Fs change based on the enclosure? Or do I simply have no clue what I'm talking about here lol.//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

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[Louisiana_CRX 5,000+ posts]

start with 80hz

 

[i2ain2thunder 10+ year member]

Thanks but I already know the generic LPF settings I'm looking into this basing it off the Fs thing.

 

[subzero 5,000+ posts]

too many variables.... box tuning, box rise, vehical freq response, blah blah. My FS is 39.8. my box is tuned to 43, and my lpf is 100 hz with a 12db slope. and the subsonic is set at 29hz. hmmm. what to change?

 

[Louisiana_CRX 5,000+ posts]

too many variables.... box tuning, box rise, vehical freq response, blah blah. My FS is 39.8. my box is tuned to 43, and my lpf is 100 hz with a 12db slope. and the subsonic is set at 29hz. hmmm. what to change?

lulz

 

[i2ain2thunder 10+ year member]

Well I guess my question is has anyone heard of doing this and if that Fs that I gave sounds right......

 

[subzero 5,000+ posts]

are you making a fart box?

 

[i2ain2thunder 10+ year member]

na man I'm building a 2 sealed wedge enclosures clamshelled. I guess I don't have to ask about the Fs and stuff really I'm just looking to find out what to set my LPF to. I'm going for SQ with a bit of gain down to 56hz but since I am switching to an SQ setup from an SPL I don't know too much about how SQ guys do their thing. Anyways I don't have my midbass drivers installed yet, so I wanted to set my LPF a bit higher to help assist with the midbass frequencies and let my midrange components handle the higher midbass frequencies. Normally I don't set my LPF past 80 or 90, because accoustically the location of the subs becomes ever more present the higher you go past those freqencies, I'm just wondering if it would be a good idea to cover up higher with my subs with this SQ setup, and if so how high abouts to set it.

 

[Louisiana_CRX 5,000+ posts]

na man I'm building a 2 sealed wedge enclosures clamshelled.

that should sound good

 

[subzero 5,000+ posts]

what ate you trying to achieve, if you want a decent well rounded sound, loud, then go meter your car and see what the respons is and see where you need help. then compare to the natural slope of the sub and the peaks. then you can pin point how to set it up and smooth all peaks ... blah blah

 

[i2ain2thunder 10+ year member]

I guess you're right I was just seeing if anyone had starting suggestions or if anyone was really against setting a LPF in the upper 100s to lower 200s. That and meters are few and far between.

 

[i2ain2thunder 10+ year member]

Anyway thanks for slapping me back to the reality that it's better to test, trial, and error in the end.

 

[RAM_Designs 5,000+ posts]

Just play with it until it sounds best to you. It's too hard to predict what frequency and slope is going to work the best with each individual setup...much easier to trial and error, like you said.

 

[brandinooooo 10+ year member]

What sub are you using exactly? Because I hardly ever hear about anyone putting their LPF over 100. Unless I'm reading this wrong.

 

[subzero 5,000+ posts]

I run mine at a 100hz sloped at 12dbs,

When I get some soundstream pro audio mids, I will drop the mids slope to 80hz or so. and drop the lpf to 80hz.

Really it all depend what sounds good to you and how you play your system.