其實有公式去計
http://www.apexhifi.com/specs.html
In equation form, dBSPL at power P (in milliwatts) is given by: dBSPL = dB(1mW) + 10 * log10 (P)
dBSPL 你你target 個聲壓,我多數用110 dB
dB(1mW) 係sensitivity (@1mW,如果係1mV就要轉單位)
P就係amp 所需power
揾到P, 然後睇下你部amp係個阻抗之下夠唔夠Watt
夠就即係夠推
當然你google headphone power calculator就有好多calculator去做上面嘅計算,唔洗自己計
所以,sensitivity 愈低,P就要高先可以output相同 dBSPL;阻抗愈大,P就愈細,咁你要高sensitivity 先可以出到相同power
一般 sensitivity 低(under 100 for headphone/iem)都比較難推