Why did these speakers blow?

240 watts x 2 channels at 2 ohms is the rating for the Pioneer GM-A5702 amp I have. I have four speakers, each with a 100 watt RMS capacity, that are Kicker 46CSC654. For each channel, I have two of them wired in parallel to produce a load of two ohms. There was no gain set. I’m utilizing the JL Audio MBT-RX to connect over Bluetooth straight to my phone, bypassing the head unit. I had my phone hooked up to 75-watt speakers with a 3.5mm RCA connector before this install, and the sound was excellent with the gain adjusted to roughly 1/4. However, there was enough distortion with the new speakers, the Bluetooth device, and gain at 0 for the speakers to get damaged. Is there anyone who knows why?
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I’ve noticed that the gain is typically set too high when I observe blown speakers. Usually, it’s because most individuals are unaware of the distinction between volume and gain.

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They would have undoubtedly been cutting before releasing the smoke.

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Simple. There is no high pass filter on the amp.
In other words, even if your speakers aren’t designed for sub bass, they still sound good.
The cone must travel farther (Xmax / Xlimit) the lower the notes.

I’m betting that amp really amplified your performance.

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You failed to adjust the gain, which blasted the speakers. The signal voltage that the JL outputs should match the inputs of the amplifiers. With the gain a 0. As soon as volume was upped on the phone. The signal to the amp is more than zero volts. enters clipping mode and sends all of its power to the speakers. If it is more than a speaker can manage. Guess what, though?

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That was unknown to me. The idea that increasing the gain would have stopped this from happening appears illogical. Could you elaborate?

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Use a meter and set your gain correctly.

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Set gain using an oscilloscope

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incorrect gain configuration. You must determine the voltage you want to aim at. I enjoy CD, Bluetooth, and XM, but it takes time. Each have various sound properties. I’ll set switching between the media I want to utilize once I get my target voltage and keep going until I reach it without any clips on the various media. You can detect your clipping if you use Bluetooth and then switch to radio, XM, or CD because those media types usually have higher quality and volume. I hope that’s useful.

When I was a child doing vehicle audio, I used to wonder how I didn’t blow my speakers. I would include everything I could get from friends selling subwoofers or amps that someone was getting rid of. Ended up with an RF 4 channel amp, maybe the quality was why I never blew it up? Not sure. I never knew about the gain issue, but I also never adjusted it all the way in either direction, so I took it quite seriously.