4th order chamber size help

[Artiflex]

Yeah the orange was my first design on another thread on here that you actually also gave me input for.  I began this thread trying to see if I could get the same or better than that from a 4th.

The only thing for me I guess that I cant get ahold of is how low of lows the 4th will play.  The orange slotted @31 will play to 26hz.  Will the 4th reach that low from what I graphed out?  (2.5 sealed 5 ported @45hz)

[Triticum Agricolam]

Try switching the WinISD graph you are looking at from "Transfer Function Magnitude" to "SPL".  The TFM graph is for looking a frequency response, but isn't good for comparing how much output you will get when comparing two enclosures.  

[Artiflex]

I understand how much more output it will give me. That wasn't the question.  I am trying this 4th order design because I know how much more output it will give.  What I was wondering is will the 4th still be able to play down into the 20s like the slotted design will that I posted?  I'm sorry, I probably should have explained that better.

[Triticum Agricolam]

1 hour ago, Artiflex said:

What I was wondering is will the 4th still be able to play down into the 20s like the slotted design will that I posted?

This is exactly what the "SPL" graph with tell you.  

[Artiflex]

Ok one last thing.  If these subs require 80sq in of port area as a pair then would that apply the same to the port on the 4th?  I've seen a lot of setups with big window port openings at like 12 x 20.for example.  Should I still make sure its 80sq in of area or just make it as large as it needs to be tuned at 45hz?  There is obviously no port walls needed but the opening size is what I am referring to.  I hope I am explaining this correct.

Edited April 22, 2019 by Artiflex

[DiBo]

1 hour ago, Artiflex said:

Ok one last thing.  If these subs require 80sq in of port area as a pair then would that apply the same to the port on the 4th?  I've seen a lot of setups with big window port openings at like 12 x 20.for example.  Should I still make sure its 80sq in of area or just make it as large as it needs to be tuned at 45hz?  There is obviously no port walls needed but the opening size is what I am referring to.  I hope I am explaining this correct.

70-80in² would work just fine. Port won't be long either due to higher tuning. Some people like to play with stackable ports to dial it in which is a good idea. This will be pretty straight forward. Not hard to build either. Even a bigger Port area on 4th orders is ok. Maybe... 90+in or so

[Artiflex]

I have read on here that it is recommended to use half the cone area for determining port area.  If I was to do it that way, the port area would then be around 113 not 70-80 and my port would be 10.5 x 10.5 x 20.5 in order to get tuned to 45hz  I got that number from the surface area of 2 12s = 226.19 then divided by 2 = 113.  Is this correct thinking?  I dont know necessarily know if the person who posted that thread knew what they were talking about or not.  It was on this forum though.   Dont remember the exact thread atm.  Been reading a lot the past few days so I can lock down this design.

[DiBo]

You can always shrink it down if you don't like the outcome or output. Give it a shot..I bet you nail it. 

[Shawn holland]

I'm going from flat wall to 4th. Running 6 zv5 18s on 6 synergy 7ks..my resonating freq of my van is 47 I believe..I'm doing 160 now on 4 zv5 18s and 2 synergy 7ks.my goal is 163/164 any design info would help..I also want lows around 28/33 ish..if possible..

[Jjblueiiz89]

Hey what’s up guys , 

 

I have a single ZV6 15 in a ported box. I don’t know much about boxes but I do know when I had my Acendent audio MAYHEM 15 in a 4th order it was way harder more air pressure inside it was insane. Im looking to see if I can find someone who builds 4th order boxes who ships to Miami,Florida. Im willing to pay the price. Anyone? Definitely liked the builds that 

Triticum Agricolam

 

posted. Please respond