How important is xmax?

[Warbleed 10+ year member]

Correct me if I am wrong, but I believe Mackenzie is right. Sealed can play down to sub-sonic frequencies flat, yet ported will give you a nice boost in the 30-40hz range, but not much below that. Therefore, the sealed box would go lower, but the ported box would be louder in that region.

Yep. You can make ported boxes go very low, but most people who use vented boxes in cars tune in the 30s, and they nearly always have a peak in the response, and of course that's what many of them wanted in the first place.

For musical accuracy, sealed is ideal.

 

[audioholic 5,000+ posts]

5-6mm xmax was pretty common on subs not too many years ago. My old PPI Pro's I have sitting ina closet are right around 6mm. It certainly limits their output capabilities (especially in a sealed system) but you can still have very good sounding subs with low xmax numbers. xmax is much less important in vented systems than in sealed ones (or 6th order bandpass).

What that being said, your seeming desire to not share the actual speaker with us, only the spec, tells me you are looking at a sub you suspect or know to be inferior. Unless you can give us some more details (like the actual speaker, what you want from your system, etc) we're just guessing.

 

[SSS 18734 5,000+ posts]

My 2000SPL's have 12.7mm Xmax and they get really loud...

 

[jujumantb 10+ year member]

Sealed boxes go lower. ported boxes play louder. You may be able to tune a box low, so that it plays lower than a sealed, but generally speaking the optimum sealed box for a sub will play lower than the otimum ported. Some subs perform better in sealed than ported, and vice versa.

By the time a sealed box gets down lower than what a ported box is tuned to, there isnt much output anyways... A ported box will SOUND louder on the lows. Technically it cant play down to 20hz, but a sealed barely can anyways.

I will always say a ported plays lower and louder, because to most people its true.

A sealed plays flatter and sounds better.

 

[T3mpest 10+ year member]

you have to double your excursion to gain 3 decibels, which isn't a huge jump anyway. Overall X-max is most important in sealed applications where the sub won't be getting it's boost from being ported. I don't know what would be the minimum, subs are just getting bigger and louder every year. Too many kids are more concerned with making their cars chest feel funny than actually listening to music. ID had the first real "supersub" with 24 mm of xmax, then their is the brahma which is like 28.5, then the xxx at 32, and their new one is like 50. Where they will stop, I don't know, so I'd say the minimum is definetly a number only limited by the technology at the time.

 

[Justinw303 10+ year member]

5-6mm xmax was pretty common on subs not too many years ago. My old PPI Pro's I have sitting ina closet are right around 6mm. It certainly limits their output capabilities (especially in a sealed system) but you can still have very good sounding subs with low xmax numbers. xmax is much less important in vented systems than in sealed ones (or 6th order bandpass).
What that being said, your seeming desire to not share the actual speaker with us, only the spec, tells me you are looking at a sub you suspect or know to be inferior. Unless you can give us some more details (like the actual speaker, what you want from your system, etc) we're just guessing.

Well, the 12" with the 5.6mm I was looking at is definitely trash. I was thinking about getting it, but because I will be using a small, sealed enclosure (single cab truck), It is out if the question.

The 8" with 5.3mm was an MTX 4500... I won't be getting that either.

Then I saw a RF punch 1 8" with 7mm, and I was thinking "hey, it's a little better and it's a better brand, I want it." Then I saw that the frequency response begins at 40 hz, and I trashed that idea.

So now I think I'm just going to do some serious shopping around and try to find the perfect combination of a sub for my tastes.

 

[Polecat 5,000+ posts]

I wouldn't always base your decision solely off Xmax. If you have a sub that does 20mm of Xmax, and only have 200 watts, forget it...you'll never get that full Xmax. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[klassic 10+ year member]

By the time a sealed box gets down lower than what a ported box is tuned to, there isnt much output anyways... A ported box will SOUND louder on the lows. Technically it cant play down to 20hz, but a sealed barely can anyways. I will always say a ported plays lower and louder, because to most people its true.

A sealed plays flatter and sounds better.

A sealed enclosure with the right sub (low resonant frequency and exursion cababilities) can do alot more than "barely" play down to 20hz. A typical good 10" driver may barely play down to 20hz but the avg good 15" designed for sealed and SQ can easily rumble the car down to 20hz.

a ported enclosure has very poor control below its tuning frequency and rolls off very fast so one tuned around 40hz (like typical over the counter loaded ported enclosures) may flap itself silly (or destroy itself) trying to play 20-30hz freq. Thats reason enough to tune a ported box in the low 30hz. But once you tune it that low you lose SOME of upper range efficiency advantage over sealed enclosure.

I agree though with most music a ported enclosure is louder (I would never tell anybody a ported enclosure plays lower though. even tuned low that typically is just not true) but if you listen to windpipes and atypical shit those 20-30hz frequencies might be useful to you. To most people its not.

 

[jimmyslide 10+ year member]

Specs are for girls...my atomics are rated at 5mm Xmax, but they move a heck of a lot more than that. Look towards the Stroker...one of the smallest Xmaxes out there, but to this day still a potent sub. There are a lot more factors to take into consideration here than just the spec of Xmax. And as above stated, the box design is a big one.

Shawn

 

[squeak9798 5,000+ posts]

Specs are for girls...my atomics are rated at 5mm Xmax, but they move a heck of a lot more than that.

Sure, it can move more.....but is it doing it linearly?? Xmax isn't a limit of how far the sub can move, it's a limit of how far the sub can move while remaining linear. The sub can move beyond well beyond Xmax....it won't, however, be linear (which is what's important in a daily driver sub).

 

[Warbleed 10+ year member]

Specs are for girls...my atomics are rated at 5mm Xmax, but they move a heck of a lot more than that. Look towards the Stroker...one of the smallest Xmaxes out there, but to this day still a potent sub. There are a lot more factors to take into consideration here than just the spec of Xmax. And as above stated, the box design is a big one.
Shawn

No, specs are more for people who actually understand how speakers work. If you think xmax doesn't dictate linear output, you aren't included in the aforementioned group...

 

[Nikuk 5,000+ posts]

No, specs are more for people who actually understand how speakers work. If you think xmax doesn't dictate linear output, you aren't included in the aforementioned group...

buuuuwhhhaaa hahahahahah.

Nicely stated.

-Nick