Need help designing 1st 4th order

[THATpurpleKUSH 5,000+ posts]

I'd like to try playing around with a 4th order, I have never built one before.

woofer tsp:

Fs: 25hz

Re: 4.06ohms

Qms: 7.04

Qes: .49

Qts: .46

Vas: 114 L

Mms: 143g

Sd: 520 sq/cm

Xmax: 10.5mm

I have played around with win isd and 1.5sealed/1.5 ported tuned to 48-50hz gives me a decent response curve (27/28hz - 77/78hz at -3db)

I want something that will get louder than the ported box I did in the past for this woofer. Ported was 2.07 cu/ft tuned to 35hz with 1 4in pvc pipe port.

I'm not sure if I'm looking for something that will play music or just get loud.

I'd like to use pvc for the ports, I have 17in of 3in pvc and about 5ft of 4inch. I'm not sure if I should use 2 3in or 4in ports.

It will most likely go in the trunk of Ford Contour and will be wired to an amp thats rated for 534wrms.

My car peaks around 42hz all sealed up and 57hz with the passenger door open.

Wanna give me some recommendations for music and/or spl?

I would also be open to doing a t line if one can be adapted to fit my speaker. I don't have enough confidence in my build skills to try a folded horn.

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[Jroo 10+ year member]

Your subs seem close to what I am going to use. I ended up with a 4th order very close to yours. I had a guy talk to me about a tline, but the box was huge. I think he was tuning to my Fs, which are close to yours.

 

[THATpurpleKUSH 5,000+ posts]

What kind of sub did you use? Size isnt an issue for me, so a t line could work but idk how to adapt a t line to this sub because from what I have read you need a sub with qts and qes both under .4. I'm not that far away from that but I just dont know what to do.

 

[THATpurpleKUSH 5,000+ posts]

bump

 

[Flastrongman 10+ year member]

I'd try 1.25 sealed/ 2.5 ported@50hz, 3 4" ports if you want to go with pvc.

 

[THATpurpleKUSH 5,000+ posts]

What would the larger ported chamber do? I heard it was best to stick to a 1:1 ratio.

 

[SicAudio 5,000+ posts]

1:1 who the hell said that? every sub is dif....their is no steadfast rule on it...most ratios are closer to 2:1...not to say 1:1 doesn't work...

last 1 we did just recently ( 3 people helping out plus input from several others including John Hone...)

was 6cf sealed ( fer teh LOWZ...) and 10 ported with 100^2 of port..tuned at 47hz for 2 15" OA subs...

all depends entirely if ya wanna crush the mic or pound the ground...

and tline tuning can be changed //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif ....

 

[THATpurpleKUSH 5,000+ posts]

Well I guess I'm looking for something that will put up the highest possible numbers. I did a 137 @57hz with a door open in the ported box so I'm hoping to do over a 140. The sub is just a little Boston G1, cost me 10 bucks, I figured it would be fun to play around with.

Is win isd at least correct in predicting the shape of the output curve. I know its off on a lot of other things. I put in 1.25 sealed/2.5 ported at 50 and it gave a peaky curve that was above 7db from 43-57hz and maxing out around 48-49hz. I guess that should work pretty well with my cabin gain.

 

[SicAudio 5,000+ posts]

graphing is accurate yes... and that sounds like a perfect option that you listed....that 7db gain is HUGE...

 

[THATpurpleKUSH 5,000+ posts]

At the peak of the curve the gain is 7.94db

 

[Vossy 10+ year member]

IDK 4th orders for crap, but 8db gain seems way too peaky

 

[SicAudio 5,000+ posts]

to crush the mic that peak is ideal imo.. for daily hell no lolz

but he said he wants SPL...

 

[Flastrongman 10+ year member]

It will still sound decent on music. By no means SQ but it should peak quite a bit lower in car than what the graph shows.

 

[SicAudio 5,000+ posts]

true... tuning drops in cabin response by a few hz normally. that alone will help smooth it off to be musical.

 

[05fronty 5,000+ posts]

dude pm ram. he designed me a sick 4th order for my sa's