Sub bottoming out?

[AJM511 10+ year member]

i have an mb quart rwe-302 500 rms, with a kenwood excelon 520 watt max amp. Whenever i play a song loud with alot of bass, the sub sometimes sounds like its slapping something, but its not. Like it makes the note but adds a kind of a slapping sound or something....? Is it bottoming out? or something else?

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[TheFiverMan 10+ year member]

Bottoming out. Whats your box tuned to and where is your SSF set at?

 

[AJM511 10+ year member]

box is a sealed groundshaker truck box haha. So i have no clue. And the low pass filter is at 75-85 somewhere

 

[stangman67 10+ year member]

sssf= sub sonic filter. If you do not have it set right (roughly matched to the tuning frequency of the box) , the sub will unload when it tries to play notes below a certain frequency,.

 

[ThatChevyGuy 5,000+ posts]

Amp settings:

Bass boost on?

Whats your gain at?

 

[RAM_Designs 5,000+ posts]

You're pushing the sub too hard trying to get louder than it is capable of doing. If the voice coil former is hitting the back-plate of the motor(which is what it seems like from your description), then you can surely tell by looking at the sub that it is being overworked.

 

[norrizzle90 10+ year member]

i had the same problem with my btl's. my specs were all perfect for the box....but, when a deep low note would hit, it would draw more power than what the fuse is rated for. your prob. simply just drawing too much power for your fuse.

 

[AJM511 10+ year member]

alright the bass boost is on and the gain was set with a multimeter with all the settings on my headunit and remote set to what i would normally have. Should i remove all the settings and try again? The volts going to the sub is around 42 with all the settings. Should i remove all the settings then set the gain? Because it seems the gain would be almost maxed out if i did that. And the "infra" sonic filter is at 15hz.

 

[stangman67 10+ year member]

Bassboost should always be OFF

 

[RAM_Designs 5,000+ posts]

Up the infrasonic frequency to ~25hz, since you're unlikely to see anything below that, and if you do, it'll be phased out to protect your sub. Just watch the sub, see what's going on when you're hearing this odd noise. It sounds like it's just being pushed beyond it's limits...either get a louder setup or back off on your current one.

Is the sub moving quite a bit? Like 2"+?

 

[AJM511 10+ year member]

Yah i'd say 2 inches or so. I'm going to re tune it with the multimeter tomorow with no settings. But the sub is REALLY quiet without some boost. The bass boost is a knob btw. So hopefully if i max out the gain it'll give it the right amount of volts. If not could i mess with the eq settings on my head unit to give it more volts?

 

[stangman67 10+ year member]

Turn the bass boost completely off, and then set the gain with the multimeter. If it isn't loud enough for you, upgrade as Ryan said.

 

[AJM511 10+ year member]

I've been running it with the bass boost on and the head unit eq controls tweaked for about 2 weeks. Could it have damaged my sub by doing that?

 

[Spooney 10+ year member]

If the sub actually bottomed out then you most definitely could have done some damage to it. Bent voice coil formers are not your friend.

 

[hispls 5,000+ posts]

I've been running it with the bass boost on and the head unit eq controls tweaked for about 2 weeks. Could it have damaged my sub by doing that?

Bottoming out a sub will destroy it pretty fast. If it still plays without sounding scratchy at low volumes it's probably OK.

Do turn off "bass boost" and set the infra-sonic to 25hz or so, should prevent over-excursion.