sub on fire, recone?

[Kyblack76]

Well I am not giving up my SP4's because of a little fire

No way.. in fact, im ordering 2 more in time....

[Nikitaaa]

I don't think the cone can brake fast enough to literally just stop in the clipped portion of the signal long enough to make a difference in the cooling theory. . .not to mention 30 Hz literally means the cone is moving in and out 30 times per second, clipped or not.

Mike Edgar did a big test on clipping. Ran square waves into several different drivers at their RMS power rating and did not damage ANY of them.

The issue is that a clipped signal has a higher RMS voltage which means higher average power. If the amp does not self destruct, you could get 2X the rated RMS power with a fully clipped square wave.

while I completely agree an amp has higher input voltage when clipping it makes me wonder why, when it comes to spl, to much clipping brings your score down?

[bkolfo4]

That is easy - once the output hits the rail voltage, it cannot go higher (of course this is why it clips). This means the voltage is maxed on the output, which means cone excursion is maxed. Applying additional input gain only produces more power that is wasted, since the cone is not traveling any further.

In theory, you should come to a maximum SPL and not decrease. The decrease comes from many things, such as additional heat (you are generating more power, it is just being wasted). Amps have a tendency to begin to draw a lot of current, since the output devices are maxed and being asked to do more than they are designed to. With the larger current demands, the electrical system voltage drops, rail voltage drops, output voltage drops, SPL drops. Domino effect. . .

[ncc74656]

having a sub on to high of a cross over point can cause it to burn up?

[CortezDTV]

It will cause the tinsels to have extreme heat and yes they can catch on fire,

It's easy to slinky and break coils by clipping but catch a sub on fire by clipping not so much....

I would put a lot of money on the fire on thoes subs started by the improper tuning and then tinsels

Funny how everyone instantly blames the sub, subs are stupid and play only the signal they are given in these few cases the owner is the true dumbass! And just incase you guys missed the post, I've super heated tinsels and I've burned subs by doing that, but thoes guys must have been playing thru the initial smoking to actually get it to "flame up"

Ie. it's the owners fault 100% pretty obvious if you have done this....

[SnowDrifter]

The decrease in spl from hard clipping comes from the fact that your are feeding the sub more power, but that power isn't necessarily useful power. It takes power to make power so your amp will draw more, increased draw causes more voltage drop, and the voltage drop decreases the voltage on the output rails

[Jessica]

Clipping odes not cause a speaker to reach XMAX (send a 5 watt clipped signal to a sp4 and see how much it moves)

What clipping does is like kranny said, It tries to keep the speaker from moving at the peak of the sine (square in this case)

Voltage from an amplifier is a/c voltage, it rises and falls but in a smooth way, not a on/off way. When you clip, the amplfier rises in it output stays at the peak of the wave and then drops off. Think about it like this, the area under a normal sine wave is far less than a square wave, therefore the average power during the square wave is much higher than the normal wave even if the output at the peak is the same. Plus a clipped signal is more like DC voltage than AC voltage. AC is rise/fall and dc is on or off.

Speakers are designed to work with AC voltage. Also, sending a clean signal to an amplifier and then pushing that to clipping is not nearly as bad as sending a clipped signal to an amplifier.

Here is my theory on how many new guys smoke subs and veterans do not when it come to clipping.

Scenario one: Veteran guy has great electrical, clean signal, no bass boost modifiers enhancers, properly set gains ect. He pushes amp to just into clipping or a bit more and doesn't break anything.

Scenario two: New guy, modest electrical, bass boost on head unit, loudness on. gain cranked on amp, bass boost on amp. Push amp to clipping smokes subs.

I think what happens here is more about what the amp is fed. If you push the inputs of an amp past the input voltage, but the signal is clean then only the output side is really clipping. Yes, we are overdriving the inputs, but we are overdriving them with a clean a/c signal.

Now the second guy is throwing a big fat square wave into the amp, and he is overdriving the inputs past the proper voltage. Now the amp is stupid and it just does what it's told. It amplifies that big DC wave and what you get out is a big fat DC signal.

Hopefully that makes sense.

[ncc74656]

i like to have my subs run 30-120hz if possible. i do not like to have a sub cut out at 80hz. does this mean that when i get my SP4 running again i need to set it to 80? at present i have it in a lower tuned box but i had planned on changing the tuning a bit higher to allow the sub to hit higher frequencies (if i dont go sealed).

now i feel that i have great electrical and i never use loudness or deck do dads to boost stuff. i do use bass boost on teh amp, set the gains, and use part of the EQ on the deck for balancing the front mids/highs.

how do i know if the deck is clipping the signal that goes into the RCA's?

[bkolfo4]

It amplifies that big DC wave and what you get out is a big fat DC signal.

I was following along hoping for a good post until that statement.

It is not DC. If you are playing a 30 Hz clipped wave (even square wave), the signal is still alternating and the cone is still moving in and out 30 times per second.

Like someone else said and like I tried to explain. Once you max the output voltage, the cone does not move any farther. You get more average power, but the same amount of output. The higher average power kills the speaker.

Once again, the theories of 'DC output' or the cone stopping at the top/bottom are people trying to over think the situation. You can clip all day as long as you do not increase the average power beyond the thermal limits of the driver.

[bbeljefe]

i like to have my subs run 30-120hz if possible. i do not like to have a sub cut out at 80hz. does this mean that when i get my SP4 running again i need to set it to 80? at present i have it in a lower tuned box but i had planned on changing the tuning a bit higher to allow the sub to hit higher frequencies (if i dont go sealed).

now i feel that i have great electrical and i never use loudness or deck do dads to boost stuff. i do use bass boost on teh amp, set the gains, and use part of the EQ on the deck for balancing the front mids/highs.

how do i know if the deck is clipping the signal that goes into the RCA's?

A scope or a DD-1 will tell you if the head unit is sending a clipped signal. It works in exactly the same way it works for speaker level outputs with the only difference being the power of the signal.

A 120,000 volt high line (in the US) carries a 60hz signal that can be read by a scope and that can be clipped.... and the same 60hz signal can be read at 1.2 millivolts and can be clipped. The sine waves are identical in shape. Only the power changes.