What exactly does bottoming out a sub mean?

[alec14 10+ year member]

I recently had my friend build me a custom sub box, and he put an aero port in it. I've heard aero ports make it easier for you to bottom out a sub, but that poses the real question: what does bottoming out a sub exactly mean? and how can I prevent it? Any info would be great!

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[goingdef 10+ year member]

when a subs voice coil hits the back plate, caused by the wrong size box or playing below tuning.

 

[quackhead 10+ year member]

I recently had my friend build me a custom sub box, and he put an aero port in it. I've heard aero ports make it easier for you to bottom out a sub, but that poses the real question: what does bottoming out a sub exactly mean? and how can I prevent it? Any info would be great!

this is the sole purpose of a subsonic filter that so many amps are equipped with.

 

[alec14 10+ year member]

when a subs voice coil hits the back plate, caused by the wrong size box or playing below tuning.

can that happen on too much power? and would the box have to be really big?

 

---------- Post added at 07:25 PM ---------- Previous post was at 07:24 PM ----------

 

this is the sole purpose of a subsonic filter that so many amps are equipped with.

really? how does the subsonic filter work?

 

[snoopdan 5,000+ posts]

Some badly designed subs can do this too. Not enough spiders (less voice coil control) can lead to it as well. But i've only seen a few subs do that and they were limited runs of that model.

 

[garretttt4 10+ year member]

really? how does the subsonic filter work?

Keeps from playing too low of frequencies.

 

[Loudmp5 10+ year member]

power is an issue as well but that leads back to the box issue smaller box more power handling box is to big gets my vote any pics? box specs and sub?

 

[alec14 10+ year member]

power is an issue as well but that leads back to the box issue smaller box more power handling box is to big gets my vote any pics? box specs and sub?

well it's a skar vvx 12, and i had my friend make it to the sub specs. the only thing i was worried about was if the aero port might cause it to get too much air back there or something, and cause a problem. like bottoming out

 

---------- Post added at 05:43 AM ---------- Previous post was at 05:42 AM ----------

 

really? how does the subsonic filter work?

Keeps from playing too low of frequencies.

ahh, okay. that's understood now for me, lol

 

[RangerDangerV2 5,000+ posts]

some woofers never bottom out lol.... such as the apxx 18. I had it in a box that didnt build compression until about 37 ( I was experimenting with a higher tuning) and I was playing 27hz down to 12hz full tilt.... it sure did move but never bottomed out lol. but like others have said just set your ssf accordingly and you should be fine.

 

[SPLaudio 5,000+ posts]

it was common back in the 90s when amps didnt have ssf and the motors were greatly limited. you cant bottom the coil out on a skar but you can bottom the spider out.

there is 2 limiting factors on subs thermal or mechy failure.

 

[alec14 10+ year member]

some woofers never bottom out lol.... such as the apxx 18. I had it in a box that didnt build compression until about 37 ( I was experimenting with a higher tuning) and I was playing 27hz down to 12hz full tilt.... it sure did move but never bottomed out lol. but like others have said just set your ssf accordingly and you should be fine.

okay, thanks. I believe it's set right, i just wasn't sure if i ran it on a lot of power, if that would cause it to bottom out with the aero port in it

 

---------- Post added at 04:34 PM ---------- Previous post was at 04:34 PM ----------

 

it was common back in the 90s when amps didnt have ssf and the motors were greatly limited. you cant bottom the coil out on a skar but you can bottom the spider out.
there is 2 limiting factors on subs thermal or mechy failure.

is it pretty hard to bottom the spider out? It's not receiving crazy power, so I'd hope it would be fine

 

[SPLaudio 5,000+ posts]

dont worry just play it...

 

[alec14 10+ year member]

dont worry just play it...

okay, thanks man. I'm a bit of a worrier, I always wanna be informed and safe then sorry. lol

 

[butterMilk 10+ year member]

Not to thread jack. But how could you tell if a sub is bottoming out, would it make a bit of a slap sound? When my sub hits really low it seems to make a weird noise, which I have been told is normal, but I'm thinking the stereo shop might want me to blow it and buy a new sub from them. Its also in a sealed box.

 

[sundownz Pro Seller]

A coil bottoming against the back plate is typically very loud.

As Corey mentioned there is also a spider glue joint vs. top plate bottom as well.