Is it better to go with same ohms as stock and just higher wattage? Any recommendations?
Acura now have 10 speaker 490 watts stock system now with 25 watts 4ohm speakers , would going with 65-100w at same olms and getting better tweeters make it louder and clearer , already added a 500 watt sub .
No, and they will most likely make it quieter. Now stock speakers are generally bare bones garbage, (but they are good enough for most people). They have a little bit to do with factoring into this as far as what you might personally notice, but I'll try explain the theory.
Sensitivity, is a rating which is a measure of volume. The sensitivity rating is measured at RMS wattage. So if you have two speakers that ARE RATED AT THE SAME SENSITIVITY, and one is 30w RMS and one is 100w RMS, (which generally doesn't happen, but the sensitivity will be close).
100w x 4 (ohms) = 400. Square root of 400 is 20 VAC (power supplied to reach wattage).
30w x 4 (ohms) = 120. Square root of 120 is 10.9VAC
25w x 4 (ohms) = 100. Square root of 100 is 10VAC
(here is a video that explain how voltage converts to watts)
You are not adjusting a gain, you're only variable is the volume control, and your output is minimal. So lets say maxed out that head unit/or amp, puts out 25w.
30w RMS speakers that have a sensitivity of 87 are going to get to 10/10.9 = 91% of their voltage needed to make that sensitivity.
If you have 100w RMS speakers have even a sensitivity of 92db, they are only going to get half the voltage they need to make rated sensitivity. Powering 100w speakers with 25w will be the EXACT SAME thing as powering them with 100w, and then turning the volume way down, (the volume isn't evenly spread, but it's about as much as turning the volume down to half if they were powered correctly.
If you want to increase the volume, You're either going to: want a new amp for those speakers, OR you want to find really low wattage speakers with a high sensitivity.
