Sub "tapping"?

[Superjay]

could it hurt anything if gone unchecked? bought from a buddy = no warranty

yes. pull the sub, and look at the joint between the former and cone. see if there is a small crack there. if so, use some CA glue or 50/50 to fix it...make it smooth and even all around the joint.

[Superjay]

FYI...clipping doesn't add power, only distortion

[OldsBoomer]

Bottoming out on the lows due to port tuning or area. You need a subsonic filter on that bish. Or what is stated above. 300 rms shouldn't do that.

reading>you...he said it's a sealed enclosure..ergo, no subsonic needed since there is no port to unload

he can still bottom out on a sealed enclosure. Do you have a subsonic filter? also you may be clipping it so its more like 500+watts and if its dirty that can cause issues

Nope. And I don't have an O-scope so no way to tell for sure, but I wouldn't think it would be clipping if its a 500w rms amp wired to only 300w would it? Or can it still clip because of the load present?

it all depends on how far you turned that gain knob up and if it has it the bassboost and the volume knob on the H/U.. if you have a dmm you can sort of check if its clipping by checking the ac voltage leaving the speaker terminals

[Superjay]

clipping won't show on AC...clipping results in DC voltage

[OldsBoomer]

clipping won't show on AC...clipping results in DC voltage

you obviously dont understand what im saying until you do i wouldn't say much i never said anything about being able to see the clipping on a dmm and FYI the signal is a SINE wave which is AC current. you say do the math to set the amp to close to a certain amount of watts by knowing the output ac voltage on the amp

[sundownz]

A squared waveform is still AC -- good explanation of that here :

http://www.allaboutcircuits.com/vol_2/chpt_7/2.html

The integral (area under curve) is higher for a squared AC wave -- it contains more power.

http://en.wikipedia.org/wiki/Clipping_%28audio%29

Typically you won't have a perfect square looking wave, either -- the wiki link has a good illustration of what you might actually see.

[Superjay]

a SINE is AC...clipping that sine wave makes positive and negative DC voltage at the point where the signal is clipped.

Let me briefly explain clipping and why it's bad:

a smooth sine wave allows the piston to move constantly. once clipped the piston pauses at the point of clipping. The means voltage is applied to the voice coil, but it's not moving so it gets hotter. it does not increase power, it decreases the coils ability to dissipate heat, thereby reducing the length of time it can handle power.

[Superjay]

A squared waveform is still AC -- good explanation of that here :

http://www.allaboutcircuits.com/vol_2/chpt_7/2.html

The integral (area under curve) is higher for a squared AC wave -- it contains more power.

http://en.wikipedia.org/wiki/Clipping_%28audio%29

Typically you won't have a perfect square looking wave, either -- the wiki link has a good illustration of what you might actually see.

correct, because it still alternates. a square wave is an alternating signal that contains direct current, at both extremes of positive and negative.

[Sanitarium]

refreshing to see "noobs" getting it right for once. good job superjay.

OP. your low pass setting goes from 50-200 hz on that amp. all the way down isn't something i'd recommend (although it is preference thing, set it by ear while listening to music.)

Make sure you bass boost is OFF ( all the way down, don't thin there's an on/off switch) and there is no subsonic filter on this amp so if the "tapping" you hear is happening on low notes, make note of those songs and stop listening to them or at least turn the volume down on them.

If it's not on the super low notes, then as said, it's likely a mechanical failure and you should get it warrantied

[OldsBoomer]

a SINE is AC...clipping that sine wave makes positive and negative DC voltage at the point where the signal is clipped.

Let me briefly explain clipping and why it's bad:

a smooth sine wave allows the piston to move constantly. once clipped the piston pauses at the point of clipping. The means voltage is applied to the voice coil, but it's not moving so it gets hotter. it does not increase power, it decreases the coils ability to dissipate heat, thereby reducing the length of time it can handle power.

what you think i dno what clipping is? its still an AC current because its alternating DC is either only negative or positive it never crosses the x-axis. so it is AC as Jacob stated. and you can calculate watts with a DMM thank you.

W = V2 / R get the AC votlage leaving your speaker terminals square it and divide it by the measured resistence while the music is playing thus you get watts! you want to continue?