Hi, i am about to buy the Infinity Reference 6012si (which are two-way) while the peak power is 150 watts. I have a alpine 9857 head unit. Will i need to buy amp for this? thanks in advance!

 

To get the best performance out of the speaker - Yes.

 

nope

 

Basically, your head unit can provide them with 19 watts rms which would most likely be where your head unit distorts. The speakers are capable of 50 watts rms. You have a significant amount of improvement by adding an amp, however it depends on whether or not you need the addition volume. The speakers themselves are capable of running fine without an amp. A good idea would be to install them without the amp and see if you are satisfied. But if you install them and you think you need some more volume then add the amp. I recommend just getting the amp as well, because most of the time people will end up adding in the amp later. Our cars can get pretty noisy, especially with the top down.

 

assuming your HU can push cleanly at 19rms, and that the speakers can handle 50rms well, an amp will give you a bit over 3db of intensity.

if you have a home receiver with digital display ... check the difference in loudness level with 3 additional dB (at any reference volume level.. db increase are perceived constant) ... see if thats worth spending 200$ on an amp