Can someone explain how the fi bl's would

[moser64 10+ year member]

be louder than the same sized fi q that has 27 mm of xmax compared to the bl's 18 mm. This concept is boggling my mind.

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[Johnny Law.Lulz 5,000+ posts]

xmax is only part of the equation for SPL kid.

 

[KyleBechtold 5,000+ posts]

xmax only goes so far. no pun intended

the fi q can get down lower because that

 

[thericanballer 10+ year member]

wait i thought the q was an sq sub? and the bl was spl? so the q is louder than the bl? wtf lol

 

[KyleBechtold 5,000+ posts]

wait i thought the q was an sq sub? and the bl was spl? so the q is louder than the bl? wtf lol

read.. its good for ya

 

[moser64 10+ year member]

anywhere i could find more details? its interesting cuz it doesn't really make sense at all. it just seems that more air moving would be louder.

 

[Johnny Law.Lulz 5,000+ posts]

wait i thought the q was an sq sub? and the bl was spl? so the q is louder than the bl? wtf lol

The BL is louder and the q has a longer xmax so it can dig down lower and pound the low notes. Reading comprehension > you.

anywhere i could find more details? its interesting cuz it doesn't really make sense at all. it just seems that more air moving would be louder.

Moving more air doesnt really mean louder. And the T/S of the sub would make a huge difference. Xmax is a fraction of the SPL equation

 

[thericanballer 10+ year member]

read.. its good for ya

well i understand the xmax helps with the sub getting lower and moving more air. moving more air = more spl. which now that i think bout it, the q would theoretically would be louder. but everyone says its a sq sub

 

[thericanballer 10+ year member]

The BL is louder and the q has a longer xmax so it can dig down lower and pound the low notes. Reading comprehension > you.


Moving more air doesnt really mean louder. And the T/S of the sub would make a huge difference. Xmax is a fraction of the SPL equation

thanks fore the help, but F U lol

 

[KyleBechtold 5,000+ posts]

well i understand the xmax helps with the sub getting lower and moving more air. moving more air = more spl. which now that i think bout it, the q would theoretically would be louder. but everyone says its a sq sub

moving are and the force behind it are very different.. My fan moves **** tons of air but doesn't doesn't have a high spl..

 

[thericanballer 10+ year member]

moving are and the force behind it are very different.. My fan moves **** tons of air but doesn't doesn't have a high spl..

so farts dont create spl?

 

[moser64 10+ year member]

moving are and the force behind it are very different.. My fan moves **** tons of air but doesn't doesn't have a high spl..

That makes sense.

 

[ahole-ic]

You guys aren't understanding. Lower frequencies require the sub to move more than higher frequencies. High SPL is easier to create at higher frequencies. Moving air is what you're doing but it's not how far you move the air in one direction which is what high xmax allows. It's how violently you shake the particles in the air. That is not simply achieved by xmax. Most people get confused. They think you are simply compressing the air inside of the cabin. You're not. You are moving the air creating a sound wave. If you are metering, you are trying to get the least cancellation possible aka maximizing efficiency and trying your best to focus this wave at the sensor. Most people get louder when they open a door or rolling down a window. If you were compressing air, the more you sealed the cabin the louder you would get.

 

[reclessantics 10+ year member]

light bulb.. it does make sense. the bl pushes harder, so the lack of xmax is made up for? thats how it would get louder?

but the q hits lower? in the right box ect..

 

[T3mpest 10+ year member]

Cars get louder when the window or door is open because it acts as a port. You have a sub firing into closed cabin that then has an opening, you create a bandpass that usually increase scores. Go look at extreme vehicles that have properly designed enclosures, they act as pure pressure vessels, no leaks anywhere. Anyway fans can be used to create very high SPL's down low, you just need it to make it oscillate in another dimsension (pitch), it's been done in home audio, they play flat down 1hz at 120db's or something silly. That being said, you want to pressurize excite the air, not blow it in a single direction as a regular fan does. SPL is always about displacing air, your not creating a "sound wave" in car. A sound wave in the 30-40hz range is many feet longer than a car, you'd need a school bus or bigger to get a full sound wave. Below 200hz your pressurizing the cabin, that's why cabin gain is so apparent whereas in a home breaking a 130 requires alot of equipment and plannning.

The BL is more of an SPL woofer because it has, as it's namesake suggests,more BL. BL is motor force. This allows the cone to move further when playing near tuning, which excites the port. Near tuning the cone is under alot of back pressure from the port, compliance is high and the cone doesn't want to move. A higher BL gets the cone moving further, which lets the port move more air. SPL is always about displacement, SPL can actually be calculated as

SPL = 100.3 + 20log(xmax) + 40log(d) + 40log(f) - 20log®

where: xmax=piston excursion, d=piston diameter, f=frequency, r=distance to driver

units: dB, meters, Hertz

alternatively:

SPL = 102.4 + 20log(Vp) + 40log(f) - 20log®

where : Vp=volume displacement (cubic meters)

For a sealed enclosure this works perfectly. Ported you have to figure out how much air your port can displace as well as what portion of the driver output will couple with the sub, etc. It's the same basic formula, but it gets too complex to put quick numbers on it. However, the idea that SPL subs are magic is a fallacy, which is how alot of people on this forum seem to look at it, even high level competitors. They don't see it as displacement, which it is, so they are left with power handling and BL as being important, which both are, but most don't understand why, again, it's displacement related. Point is, SQ woofers with high XMAX dont' get loud because they don't have enough motor force to move a port when they play a note at tuning. Their 28mm of xmax means nothing when they can only handle 1000 watts of power and will barely move with 1000 watts of power near tuning. A SPL sub with more BL that may only move 15mm cleanly, but can muster 10mm with 1000 watts and can handle 2500 to reach the full 15mm of xmax will own it all day long.

Edit: Just to help show that many of your preconcieved notions are wrong, here is your subwoofer fan. The blades simply need one more degree of freedom while moving in a circle and you have bass. More of it than even many cars can muster, in a room lol! http://www.eminent-tech.com/RWbrochure.htm