Preliminary plans - Opti1232d

[n2audio 5,000+ posts]

So I'm planning for a single ported 12" sub enclosure for the trunk of the new contour. Temporarily I'll just use one of my trusty Pyramid 1295US's, but if things go well I'm going to spend a few bux on an Opti1232D so I'm using those T/S numbers. 90sq/10spl

Lanzar's recommendation for "large ported" is 1.8cf, 3" port 6" long with a tuning freq of about 36. Those numbers produce a pretty ugly graph in winISD, and excessive port velocity. There's a +4db peak at 44hz, f3's about 30.

I get a good (close to flat) curve with a 2.2cf net enclosure (~2.6 gross), 2x8" port, 24.74" long, tuned at 26.

26 seems really low - gives me an F3 of about 24 (ssf would be at about 30). I'll rarely listen to anything much below 40, but to get well into the 30's and still have some SPL would definitely do something for the wow factor.

Do the graphs ever match up to the real world? Is there any sort of recipe to get decent sound out of a ported enclosure in a trunk? Should the sub face the backseat or the rear of the car? (the port will fire out the side)

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[DarkFox 10+ year member]

if you know how to read them, I think the graphs show you a pretty good idea of the Enclosure. Some people say that they don't, but they usually use the example of X box showed this plot but gave Y results in (your car here.) Just remember, that winISD shows you what the ENCLOSURE will sound link in a mathematically perfect world, rear results can vary.

 

[DBfan187 5,000+ posts]

That sub is meant for small sealed boxes.

 

[n2audio 5,000+ posts]

its ebp says otherwise

 

[DBfan187 5,000+ posts]

post the specs, I can't open adobe here.

 

[n2audio 5,000+ posts]

 

[DBfan187 5,000+ posts]

I'd still say sealed. EPB around 54-55.

Some sites are saying Fs is 26Hz.

 

[n2audio 5,000+ posts]

I've always thought that just because a sub WILL work well sealed doesn't mean it won't work well ported, but if it's more geared toward a ported setup it probably won't do much sealed.

I've never heard anyone claim an L5 should be used sealed - ebp of 53, or a compVR at 41.

 

[DBfan187 5,000+ posts]

I've never heard anyone claim an L5 should be used sealed - ebp of 53, or a compVR at 41.

I've always thought they sound better sealed. My old 15" RF HE2's had an EBP of 40, I ported them and they got loud, they just didn't sound good doing it.

 

[n2audio 5,000+ posts]

well, the over-riding issue is I'm going from 2 12's to one, and I'd like to get as much out of a single sub as I can - a ported enclosure seems like the logical choice.

you may be right though -- I can always go back to sealed if the SQ isn't what I'm hoping for.

 

[Immacomputer 10+ year member]

You will be fine with that setup and I don't think it will sound too bad. But, I would NOT use a subsonic filter at 30hz. Set the subsonic as low as possible or don't even use one. If you don't listen to much music with a lot of material below 30hz, then you shouldn't bother with a subsonic. Also, with a tuning frequency of 26hz, you shouldn't need one unless you're watching movies at extreme volumes.

 

[n2audio 5,000+ posts]

I listen to all types of rock most of the time, and like a good, tight kick bass (thinking "Saliva - Click Click Boom), but I like the occasional SPL session (Nelly, Lil John, Too Short)

based on these would you say there's an obvious choice?

 

[Immacomputer 10+ year member]

Your original plans of tuning to 26hz are not bad plans. People don't understand what they're not used to seeing. I believe that 2.2 @ 26hz setup will give you much more of what you're looking for -- lower group delay, better transient response, and flatter frequency response.

 

[n2audio 5,000+ posts]

cool --

one other thing -- I'm planning to do something like this with the port...

Do i measure the centerline to get the length I need?

 

[DBfan187 5,000+ posts]

why not just an aero port? it'll save you space.