ohms?

[cheapskete OCer]

i dont see much of car audio on here ..but im getting this amp for my car off ebay and it says this on the specs Thunder 204 Amplifier

--------------------------------------------------------------------------------
RMS Power measured at 12.5 Volts DC:
25 Watts x 4 into a 4 Ohm load with less than 0.1% Thd+N
50 Watts x 4 into a 2 Ohm load with less than 0.3% Thd+N
100 Watts x 2 bridged into a 4 Ohm load with less than 0.3% Thd+N

Dynamic Power (IHF-202 Standard) measured at 14.4 Volts DC
65 Watts x 4 into a 4 Ohm load
125 Watts x 4 into a 2 Ohm load
250 Watts x 2 bridged into a 4 Ohm load

Signal to Noise Ratio:
110dB A-Weighted

Damping Factor:
>200

Frequency Response:
20Hz-20kHz±0.25dB

Maximum Input:
8Vrms



i dont know anything about ohms...but how is it i get 125w x4 in 2 ohm versus 65w x 4 in 4 ohm.....and how are you able to choose what ohm you run in.......thanks

 

[Buckeyefan 1]

First off, go by RMS. Dynamic refers to peaks. You want average.

It depends on your speakers. Most door speakers are 4 ohm, and you connect them to your head unit. Everything remains 4 ohms. It gets a little tricky when you start running subs or components in series and parallel.

I run two dual voice coil, 4 ohm subs in parallel, which means my amp is seeing 1 ohm (very hard on an amp). When you parallel speakers, you drop the resistance. When you run speakers in series, you increase the resistance. Lower resistance is harder on your amp, but allows full power/full bore.

The best amplifiers will double down their power as the resistance drops for the same number of channels. Class D amplifiers will stay coolest when introducing difficult loads.