too high fc tuning for 4th order?

[plexlove]

Didnt get much help...any really on my other thread so ive pretty much figured out evertlything on my own. But have one last issue.

I am building a 4th order for 2 18 zv4s. Sealed chamber is 5.5cubes, subs firing into sealed for cooling, ported side is 18cubes with 240 port area. Was gonna tune port to 40hz to get into lows really well but when i ran the numbers for my fc it came out very high. 67.86!

Now im supposed to tune my box to around that!!!??? Theres no freakin way! And also, when computing fc do u need to input both subs or just 1? I did just one.

Either way, i think i messed up because everyone else is gettin round 40to46.

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[plexlove]

And if i was supposed to do both subs its 95.26....never in my life have i heard of anyone tuning that high...i have to be missing something here!?

 

[plexlove]

Also...im now lost on the purpose of fc? I read its the tuning frequency for sealed but how do u tune a sealed?

The also say if u go smaller sealed it raises fc and qts, bigger lowers it...so how many cubes would i need to get mt fc down to 45hz so i can tune at 40?

This crap is driving me crazy...been reasearching NON stop for 29 of the last 35hrs and seem to be back to square one!

Not even sure my box size will work now!

 

[plexlove]

No help??

 

[blazian87 10+ year member]

I think you would be better off paying a professional to design you a 4th. If you want the lows, 45 hz is considered low for a 4th order because most of the lows come from the sealed section, not the port. You get more lows from bigger sealed too. It's a fragile mix of ratios you need to get to sound remotely good on music. Usually its like a 2 to 1 ratio and the sealed section has to be big enough. There's many ways to do this. Ask a professional.

 

[plexlove]

Ive spoke to a lot of people and read close to 400 pages on this....all say the same thing...small sealed, tune to 45hz and u will be between 28 and 55hz...i want between 20 and 50hzish...so i was gonna tune to 40 or 42.

Also 3 to 1 is better for spl than 2 to 1 thats why i chose that. I dont need advice on any of that. My question was stricly about the fc of my sub!

Idk why people feel the need to comment on everything BIT the question asked on these forums. Now i remember why i stopped coming here for advice.

Not trying to be a **** it just doesnt make sense to me....a sit dedicated to helping people yet no one rarely gets helped! Ive yet to get a straight answer from anyone.

Guess ill just wing it and destroy my 1300 dollar subs.

 

[negolien]

And there ya go ...

Well seems like you know it all already.. Not sure why you're coming here.

 

[big scott]

And there ya go ...
Well seems like you know it all already.. Not sure why you're coming here.

thats what i was thinking...

 

[plexlove]

Oh really smart ***!? Both of u idiots statements r exactly what im talkig about. A bunch of amatures whondont know crap just on here to fill space with theirnignorant comments.

If i knew it all i wouldnt have asked the **** question retard!

I said I knew the rest but needed to know about fc....simple **** question but you group of tools do nothing but bash people instead of helping. At least i can say ive never done that...when someone asks a question i either answer it or i dont say anything....maybe u should fo the same and this place would get back to helping peoole instead of being just a place for a bunch of *** hokes to compete!

Dont bother commenting if u cant help...i dont need advice about ANYTHING except the question asked....so it would seem that i dont "know it all" but obviously know more than u since i cant find either of u helping anyone...all u guys do is run ur dong suckers. People like u should be banned.

The PURPOSE of these sites are to HELP people not talk crap on them with absolutely no justification. Grow the hell up and get outta ur moms basements!

 

[plexlove]

I ask a question so I...ME...can LEARN....profesionals r on here and i would gladly pay to be TAUGHT but im not gonna have someone do it for me. I want the knowledge.

So there u go...sorry that i actaully have a passion for car audio and not just lookin for something loud to be tossed in my ride that i know nothing about. I take pride in my work and my knowledge base...u should too and offer it to those willing to accept.