Xmax question

[mat3833 10+ year member]

ok, i feel REALLY stupid for asking this, but im trying to figure out how much clearance i will need for my sub. i got 2 ID8 v3s and the listed Xmax is 15mm. but it says "one way linear" next to it. my thought is there is 15mm of "out" and 15mm of "in" movement. is this correct? or am i crazY?

Matt

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[gckless 5,000+ posts]

Yeah Xmax is usually measured for one way travel from rest. So, 15mm Xmax would be 30mm peak-to-peak. Usually.

 

[Phoenix Risen 10+ year member]

thats correct.

but your going to want more space infront of them than 15mm

i have 5" between my sa-8's and the loading wall.

 

[zako 10+ year member]

The maximum excursion is usually way above the xmax. Is it xmag, xmech, or xlim (should be one of these).

 

[THATpurpleKUSH 5,000+ posts]

one important thing about xmax is, it doesnt mean shit if you cant maintain enough force on the coil.

 

[mat3833 10+ year member]

well its a pair of ID8 v3s. im only asking because im playing them on REALLY low power atm(about 15W each) in my livingroom to let the mloosen up while i get a box built. and i had to "stack" the boxes with subs up. so i put 2X4s on top of the first box and there is like an inch of clearance for the bottom sub. i dont have any boxes with 8 inch cuttouts so i used 2 peices of shipping cardboard(that inch thick 8 layer stuff) to make an adapter and just used sheet metal tape to seal the gap so i could play them. honestly i have to say im impressed already. they are in seperate 1.6 cube sealed boxes and even on that little power they are sounding really good. i hope to have the final box designs complete so i can review these bad boys.

but back to the Xmax question. so 30mm would be total travel? or could they theoreticly do more?

Matt

 

[T3mpest 10+ year member]

one important thing about xmax is, it doesnt mean shit if you cant maintain enough force on the coil.

The correct way to measure XMAX is using the 70% Bl method. So when a subwoofers BL is at less than 70% of it's resting value it has passed xmax. So really, if the manufacturer is being honest and using a klippel machine for xmax then that is taken into account.