Speaker/Amp power discussion - technical

Just joined the group - should get Trib delivered in about a month?<br><br>I went through the archives, and have found many interesting things - luckily nothing to scare me away yet. This is a great group.<br><br>The math used in previous discussions was somewhat off. Without getting into the math (I will is someone wants), basic car amplifiers - the ones that only use the car's 12V (13.8?) system can't put out much power.<br><br>To get the 25W rating (per channel) of the head unit requires speakers less than 4 ohms (~=3.2). Did the old paper speakers have impedance marked on them?<br><br>For the subwoofer, the amplifier is probably the same configuraton (12V bridged), so to get more power, lower the impedance (i.e 1.6) ohms. This gets you the ~=45W. Have two chanells with two voice coils ~=90W!<br><br>When bridging the OEM amp, not much probably happened. Both outputs are probably already bridged, so the new output is probably the same as using one of the outputs alone. The only way to use the whole amp is to have a dual voice coil speaker.<br><br>The only other way to get more power, is to raise the voltage. The high power amplifiers have a powerful voltage step-up section inside. These are the amps that are more difficult to make stable at low impedances. They are also much more expensive than the 12V bridged amps discussed earlier (you get what you pay for)!<br><br>Let me know if any more details are wanted.