general amp question

[BumpMW 10+ year member]

what is happening when i turn up the bass boost?? am i increasing the wattage to the woofer or what?

i understand the gain and frequency im just tryin to gain some knowledge to help keep me from blowing subs or frying an amp.

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[thch 10+ year member]

to understand this, understand how an amp works.

there is a power converter that takes the existing 12V from the battery, and converts it to something useful, like +40V and -40V (200W* @ 4ohm)

but with no signal, the amp puts out nothing.

the signal is some lower voltage, like 4V* or so.

***edit -- the bass boost is a type of gain, so what I say below about gains is also applicable to bass boost ***

the gain tells the amplifier how to convert the small signal into a large one -- eg, "if i see +4V, then I should put out +40V" would makes sense for someone with 4V preouts*, but someone with 2V preouts would then be limited to a maximum output of +20V, which is less then the amp is capable.

bass boost works by providing more gain to bass frequencies. often WAY too much. eg +20dB on top of the above example would mean "when i see 400mV, output +40V"

well, clearly if you get a strong bass note, which by itself is 4V on the RCA line, then the amp will see 4V and want to output 400V, but that is impossible, so it outputs 40V.

this in itself is not terrible -- the amplifier is fairly robust, and people tend to not care about mild clipping as it does make the music on average. With the ability to get mild clipping, quite notes are loud, and loud notes are still loud.

so yes and no. the amp can't make more then some maximum amount of power, but clipping certainly does make the amp output more power then it otherwise would with music -- possibly a lot more!**

now, from what i've said, its clear why people who turn the gains all the way up can get so loud at some low volume setting on the HU, and have terribly distorted sound before reaching the max setting on the HU -- at low signal levels on the RCAs the amp is already putting out full power. turning it up higher doesn't allow the amp to magically put out more power and clipping occurs. at some point the clipping is so severe that massive distortion is heard!

* These numbers are for demonstration. generally a "4V" HU will have a peak voltage near 6V, and the 200W amp a peak power near 400W. I am trying to reduce confusion by removing the AC-concepts of peak vs RMS.

** there are more advanced sub-topics involving how the speaker handels distortion.