6th order designs

[LMJexploder]

im looking to build a 6th order for 2 zv5 12". If anyone has some design plans that they wouldnt mind sharing or giving me some ideas, or if anyone can recommend someone to design me one i would pay if i had to. have no problem building whatever just still not 100% confident on the program numbers that i come up with yet. max dimensions are 41" wide 50" deep 20 " high

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[Buck 5,000+ posts]

What type of 6th?

 

[LMJexploder]

I was thinking series tuned unless you think parallel would be better

 

[Buck 5,000+ posts]

I'd definitely do series with those. It's gonna be a big box.

 

[Boominburban]

I'd definitely do series with those. It's gonna be a big box.

Are you doing designs again Buck??

 

[Buck 5,000+ posts]

Are you doing designs again Buck??

No! I am not able to, don't get excited haha. Still get people asking me, I wish I could though.

 

[LMJexploder]

I know your not design right now but can you give me a rough guess on the size of each chamber and what I should tune them at

 

[Buck 5,000+ posts]

I'd do about 5 cubes rear @ anywhere from 25-32 hz and front 5-8 cubes or so from anywhere like 45-65 hz. These are all rough numbers, with that power level of those subs and them being 12's, you're gonna want decent port area, even in the rear, IMO. Greatly depends on tuning. You could do 35/70 tuning, but usually people don't do series 6th's to play that high.

 

[Buck 5,000+ posts]

If you stay around an octave apart on tuning like 30/60, and just choose a tuning for the rear like you would want from ported, and just match the front with, that's a start. You basically have to add the front port length to the rear, so say your front port is like 5" long, that means your rear port is 5" longer than it structurally is. That's a very great place to start. So say you have 30" long rear port to reach 30 hz, then your front port is 5" long to reach 60 hz, then you'd want something more like 25" rear port for the rear to actually be tuned at 30 hz and not lowered by the front. My first series 6th, years ago, I made this mistake, made the rear way too low not realizing the compounding length of series ports, but that's why it was a test. The math and logic can be made more complicated than that, but that's basically how it works.

If you remove the loading chambers from the 6th and look at the waves traveling through ports only, like one big long port as a tapped transmission line or type of tapped horn, the rear wave from the rear port is feeding into a larger front port and is a similar function to a tapped horn, if you look at both ports combined as singular port structure. If both front and rear ports are the same size in surface area, which can need to happen sometimes, then you're more like a tapped transmission line. Front port adds length to rear port, so start there.

 

[Buck 5,000+ posts]

If you stay around an octave apart on tuning like 30/60, and just choose a tuning for the rear like you would want from ported, and just match the front with, that's a start. You basically have to add the front port length to the rear, so say your front port is like 5" long, that means your rear port is 5" longer than it structurally is. That's a very great place to start. So say you have 30" long rear port to reach 30 hz, then your front port is 5" long to reach 60 hz, then you'd want something more like 25" rear port for the rear to actually be tuned at 30 hz and not lowered by the front. My first series 6th, years ago, I made this mistake, made the rear way too low not realizing the compounding length of series ports, but that's why it was a test. The math and logic can be made more complicated than that, but that's basically how it works.

If you remove the loading chambers from the 6th and look at the waves traveling through ports only, like one big long port as a tapped transmission line or type of tapped horn, the rear wave from the rear port is feeding into a larger front port and is a similar function to a tapped horn, if you look at both ports combined as singular port structure. If both front and rear ports are the same size in surface area, which can need to happen sometimes, then you're more like a tapped transmission line. Front port adds length to rear port, so start there.

So, you have to understand how both of the series 6th ports combined are actually one long port for the rear chamber, despite where the sub introduces its front wave in the line, which it does in the front chamber in a series 6th. It's like adding a chamber to tap the front wave into the port to resonance charge the front chamber at a higher frequency, instead of just letting it exit into the environment, which is how/why you get that savage boost, kinda like 2 boxes in one.

 

[Jimi77 5,000+ posts]

View attachment 56481View attachment 56482

So, you have to understand how both of the series 6th ports combined are actually one long port for the rear chamber, despite where the sub introduces its front wave in the line, which it does in the front chamber in a series 6th. It's like adding a chamber to tap the front wave into the port to resonance charge the front chamber at a higher frequency, instead of just letting it exit into the environment, which is how/why you get that savage boost, kinda like 2 boxes in one.

Never seen anything like that. Looks like a reversed t-line. Maybe a weird folded horn. Is that considered 6th order? What's the advantage/reason to have the sub housed within the line?

 

[Buck 5,000+ posts]

Never seen anything like that. Looks like a reversed t-line. Maybe a weird folded horn. Is that considered 6th order? What's the advantage/reason to have the sub housed within the line?

It's just a tapped horn. It's done to create multiple tunings, with the sub tapped into the line, due to the way that changes phasing interactions in the line between front and rear waves, and there's the distance the front wave has to travel through the line seemingly in both directions. All of that adds different resonances vs just having a simple t line where the sub fires directly into the environment. I think it can be explained extremely complicated, and I haven't gotten deep enough into designing horns to share any examples I have of them. It also causes more overall pressure in the line, where the "front" wave of the sub creates more pressure in the line than it would firing out into the environment, because there's less room for the energy to escape from around the cone of the sub over the same time period due to it being enclosed, which can allow more power to be used before the woofer unloads, possibly allow for higher overall peak pressure like a bandpass can have over a ported box. That's my whole point is tapping a line and doing a compounding/series bandpass have similarities. Idk, there's a lot of explaining always to this stuff. I'm not trained in it, just learned myself.

 

[Jimi77 5,000+ posts]

It's just a tapped horn. It's done to create multiple tunings, with the sub tapped into the line, due to the way that changes phasing interactions in the line between front and rear waves, and there's the distance the front wave has to travel through the line seemingly in both directions. All of that adds different resonances vs just having a simple t line where the sub fires directly into the environment. I think it can be explained extremely complicated, and I haven't gotten deep enough into designing horns to share any examples I have of them. It also causes more overall pressure in the line, where the "front" wave of the sub creates more pressure in the line than it would firing out into the environment, because there's less room for the energy to escape from around the cone of the sub over the same time period due to it being enclosed, which can allow more power to be used before the woofer unloads, possibly allow for higher overall peak pressure like a bandpass can have over a ported box. That's my whole point is tapping a line and doing a compounding/series bandpass have similarities. Idk, there's a lot of explaining always to this stuff. I'm not trained in it, just learned myself.

That kinda makes sense, so it looks to me like you'd have at least 2 tuning frequencies by placing the sub in the line. Never really cared for the sound of higher order enclosures, but they do have the potential to get loud.

 

[Buck 5,000+ posts]

That kinda makes sense, so it looks to me like you'd have at least 2 tuning frequencies by placing the sub in the line. Never really cared for the sound of higher order enclosures, but they do have the potential to get loud.

It's all situation dependent, but I think I know what you mean. There's ways to have higher order enclosures to be designed for more SQ or like realistic sounds where the bandpassing is used to create harder loudness over a wider scale than ported can. I think higher orders with systems with lower chamber and line pressure overall will sound better. That's what makes lines what they are is the line is low pressure compared to a ported chamber, so the roll off is different and seemingly less harsh with lines, so you make multiple orders really potentially play a wider and softer/less peaky bandwidth.

 

[Jimi77 5,000+ posts]

It's all situation dependent, but I think I know what you mean.

Depends on listening preferences too, I prefer something that's ~RTA flat so a 10-12" sealed enclosure with ~500wrms is enough to keep up with most front stages.