4th order box

[Totty2003]

Hello, im building a 4th order box for my edge 12’’ 1500wrms. But need a litle help with what ratio i should have, seen people have 1:1 1:2 and 1:3 and dont know wich one would be better for a single 12 sub.
also im hoping for a 145+ db. You think its posible?

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[Jroo 10+ year member]

no such thing as a standard ratio to point you to. It depends on the sub and the goal of the 4th order. You may want to list the sub and why you want a 4th order, may not work for the sub or the application. In general you may see larger ratios for people trying to get a lot of gain. I sometimes see smaller ratios with people looking to get a more musical sounding 4th but this is not set in stone

 

[Totty2003]

no such thing as a standard ratio to point you to. It depends on the sub and the goal of the 4th order. You may want to list the sub and why you want a 4th order, may not work for the sub or the application. In general you may see larger ratios for people trying to get a lot of gain. I sometimes see smaller ratios with people looking to get a more musical sounding 4th but this is not set in stone

Sub is a Edge EDP122SPL-E6 12" and i wanna build a 4th order cus imma compete with the car so i wanna get the most out of the sub. Its all going in a small ford fiesta 2 door and i only got the trunk so i have a maxim of 145 litres to the box, im gonna compete in 1-1500w class but people thwre are doing 148 db so i wanna try to get as close to that as possible with only 1500watts

 

[hispls 5,000+ posts]

4th order box is absolutely not going to be your silver bullet to be competitive.

First and foremost you will want to buy an SPL meter, then build boxes with large external round/flared port.

 

[Buck 5,000+ posts]

Ratios don't really matter when it comes to 4th order bandpasses. What matters is how much air the sub can use sealed and ported. You need to know how the sub acts in sealed and in ported. Too big or small on either one of those will lead to less than wanted performance.

 

[Bobbytwonames 5,000+ posts]

Ratios don't really matter when it comes to 4th order bandpasses. What matters is how much air the sub can use sealed and ported. You need to know how the sub acts in sealed and in ported. Too big or small on either one of those will lead to less than wanted performance.

So, how do you know that before building the box? Serious question. I've seen most 4th orders around 2:1.

 

[Jroo 10+ year member]

most people model or get someone to model the sub before building. A person like Buck certainly can speak to this. Some subs flat out dont like sealed or ported. On the other end, I have seen subs that excel in that type of box. As far as ratios, I had a 4th order for a Type R 12 and the ratios were literally 1:1 with a high port tuning. The builder made it to play flat from 70 down and be musical vs being loud. I reached out to Buck recently on a 4th order he displayed that was similar.

 

[Buck 5,000+ posts]

most people model or get someone to model the sub before building. A person like Buck certainly can speak to this. Some subs flat out dont like sealed or ported. On the other end, I have seen subs that excel in that type of box. As far as ratios, I had a 4th order for a Type R 12 and the ratios were literally 1:1 with a high port tuning. The builder made it to play flat from 70 down and be musical vs being loud. I reached out to Buck recently on a 4th order he displayed that was similar.

People should also study home audio/theater 4th orders and look at the sealed and ported sizes on those.

Any box should be completely custom to your specific situation. Doing boxes of rules of thumb will only get you so far with performance. IMO, 4th orders aren't really the best for SPL; it depends on the woofer and the goals. If you want to be loud with a bandpass, I usually recommend a series 6th order. The ported box advice given above with the ported boxes with external round ports is solid, for sure. You can get loud with a 4th order bandpass, but I'm not sure it's the best way to do it, usually. 145 db out of a single 1500w 12 is a pretty high goal to have, IMO. I wouldn't expect for a setup like that to be good on music.