. My plan is just for soft /acoustic kind of music only. I don't intend to use it for say for loud type of music. ParAng nagsayang Lang ako ng speaker if gawin ko man na pang disco young lsi15. Will 70-120 wAtts enough for them? thAnks in advance
It may not need as much current as some people think, but it still needs good current (more than most entry level speakers). Amp selection should not be based largely on rated power output.
What amp are you looking at? A 70 watt amp that's capable of delivering a good amount of current and exhibits a low output impedance would likely suit it just fine. On the other hand, a 120 watt amp with poor damping or current capacity may not do the job well.
Look at the amp's power rating at 8 ohms, at 4 ohms, and at 2 ohms (if any). Unless the maker was fibbing, those amps that nearly double their output at halved impedance would typically be high current amplifiers (not counting amps with multiple taps or speaker impedance switches). Check both continuous and dynamic ratings, as the trend nowadays (at least for entry level and mid-level gear) is to boost the dynamic capability of the amp (aka. instantaneous capacity), allowing it to do tougher loads with "musical material" without building a stronger foundation for continuous output (which could translate to a much higher cost for the maker). Remember that quoted power ratings could be measured very differently between makers and product lines (for both continuous and dynamic ratings).
Amps with high damping factor numbers are those that exhibit low output impedance (granted that you are comparing amps that were measured in a similar manner).
How much are you willing to allocate for the amp, btw?