AB XFL 12" or AB XFL 15 in similar sized box? (+ My WinISD graph)

[akillj 10+ year member]

Okay, so i'm doing another build and i'm struck between the AB XFL 15, and the AB XFL 12. I'd be putting the XFL 12 in a box about 2.25 Cubic ft^3. Or if I got the 15", i'd put it in a box about 2.75 Cubic ft^3.

I wanted to get a basic model, so I modeled the specs on WinISD and this is what I came up with.

I'm pretty sure I modeled this correctly. Is this the correct type of response I'd be getting? It looks to me, that the 15" would yeild similar results at tuning, but be way louder at higher frequency's, and a little louder below tuning. Ideally, i'd like as flat of a response as possible, I wouldn't mind a small or mid sized "bump" of response at tuning, but I'm not really a fan of peaky systems. It seems like the 15" would be a better choice for me. Thoughts?

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[will3 10+ year member]

Win isd can be a bit misleading at times especially when the eff. rating is 4 db higher in the ts parameters on one sub over the other the 12 in 2.25 ft3. Should give you better low end extension and an overall better response try lowering the tuning to around 28-30 and the response should flaten out some

I would match the spl parameter for both subs to try and give a better idea in comparing the 2 subs response to each other

 

[akillj 10+ year member]

Thanks, I did what you said and this is what i got.

It seems that the 12" will have a better response than the 15" in a small enclosure.

 

[will3 10+ year member]

Thats more what I was thinking you will have a small increase around tuning with the 15 because of the increase in cone area

But with that 15 in that small of an enclosure even though you might be tuning at 33 your peak will be closer to 50 than 30

 

[akillj 10+ year member]

Thanks. I'm still messing with it, I think I found something I like.. I'm considering scaling this up a bit and going with a 4 cubic foot box on the XFL 15..

Would you say the XFL in a box of this size and tuning would accurately yield a response like this? If so, I think I know what i'm going to do.

 

[will3 10+ year member]

If you were wanting a flat response that right there looks pretty **** flat to me

 

[akillj 10+ year member]

Yeah, I just wasn't sure if this is what it would actually sound like in my car. (Not accounting for resonance frequencies / placement / ect)

 

[will3 10+ year member]

Just keep in mind the response in car will be different than win isd , it is just a tool to show you response plots where you can compare different enclosures and drivers , I guess what I'm saying its good tool to use but the response in car won't be exactly like what you see on the graph there are too many varibles it doesn't take into account

 

[T3mpest 10+ year member]

cars add a alot of gain from 50 and down in most cases. Smaller cars need more low end to sound good, but they also get more low end cabin gain. Best bet here is to try the 4 cube box and see what a "flat" to 35 out of car response sounds like in your vehicle once cabin gain is applied. Probably going to end up abit bottom heavy, peaking mid 40's and rolling up op top by around 55, and that's pretty normal of most car audio setups, to be fair. Should be decent, much better than the single 12 you were graphing.. Once you build that box you will always have it as a reference when graphing other things, which will make WINISD alot more powerful a tool for you.

One thing to remember and winisd shows you, is that while people like to use a termlab to show that their 12 is just as "loud' as someones 2 15's, that is really only true at a VERY narrow range of frequencies in most cases. (exception to this is small hatchbacks and things like that where cabin gain makes comparisons not very fair). Smaller cone area setups can be loud ,but it's definetly at the expense of any kind of musical linear output.

Also you shouldn't adjust t/s parameters when comparing setups. If one subs is 3db more effecient than another then it's more effecient. It will give you more output up top with the same amount of input power. The first graph you did shows what was REALLY going on. The 12 will have less output up top at power limited frequencies (less cone area) and will fall off faster due to the smaller box, relative to cone area. Your second graph makes the 12 look much better than it is. It won't be just as loud as the 15 except at 30-40 where its louder. It's going to be quieter everywhere, except near 30-40 where it will be too peaky to sound good and ONLY as loud as the 15 would have been.. Falling responses in WINISD is usually a good thing.

 

[akillj 10+ year member]

cars add a alot of gain from 50 and down in most cases. Smaller cars need more low end to sound good, but they also get more low end cabin gain. Best bet here is to try the 4 cube box and see what a "flat" to 35 out of car response sounds like in your vehicle once cabin gain is applied. Probably going to end up abit bottom heavy, peaking mid 40's and rolling up op top by around 55, and that's pretty normal of most car audio setups, to be fair. Should be decent, much better than the single 12 you were graphing.. Once you build that box you will always have it as a reference when graphing other things, which will make WINISD alot more powerful a tool for you.
One thing to remember and winisd shows you, is that while people like to use a termlab to show that their 12 is just as "loud' as someones 2 15's, that is really only true at a VERY narrow range of frequencies in most cases. (exception to this is small hatchbacks and things like that where cabin gain makes comparisons not very fair). Smaller cone area setups can be loud ,but it's definetly at the expense of any kind of musical linear output.

Also you shouldn't adjust t/s parameters when comparing setups. If one subs is 3db more effecient than another then it's more effecient. It will give you more output up top with the same amount of input power. The first graph you did shows what was REALLY going on. The 12 will have less output up top at power limited frequencies (less cone area) and will fall off faster due to the smaller box, relative to cone area. Your second graph makes the 12 look much better than it is. It won't be just as loud as the 15 except at 30-40 where its louder. It's going to be quieter everywhere, except near 30-40 where it will be too peaky to sound good and ONLY as loud as the 15 would have been.. Falling responses in WINISD is usually a good thing.

Very informative buddy, thanks.

 

[rebelfromva 10+ year member]

The 12 in a 2.45 cft box tuned to 33

 

[akillj 10+ year member]

I'm pretty sure for this build i'm going to scale the box size up a bit, and go with the 15" in a 4 cft box, tuned to about 28hz. From the graph, I should be pretty flat down to about 30hz +/- 3db, and have a little extension into 25-30, which would be great.

 

[rebelfromva 10+ year member]

The Xfls liked to be tuned a little bit higher than 30

 

[akillj 10+ year member]

What does that mean exactly?

 

[rebelfromva 10+ year member]

Instead of tuning at 30 tune 33-35