Side A and B

[MDS]

Unless I misunderstood, if you are comparing SPL, shouldn't it be:
87dB/1W/1M into 8 ohms = 90dB/0.5W/1M at 4 ohms.

You are confused because I'm an idiot. I was thinking '2' and wrote 'twice'. The power is doubled, not the voltage.

1 watt = 2.83 volts into 8 ohms
2 watt = 2.83 volts into 4 ohms

The industry standard is to use 2.83 volts to measure sensitivity, so
87dB/1W/1M into 8 ohms = 90dB/2W/1M into 4 ohms. You have to subtract 3 dB to get the equivalent sensitivity rating for an 8 ohm speaker.

 

[PENG]

You are confused because I'm an idiot. I was thinking '2' and wrote 'twice'. The power is doubled, not the voltage.

1 watt = 2.83 volts into 8 ohms
2 watt = 2.83 volts into 4 ohms

The industry standard is to use 2.83 volts to measure sensitivity, so
87dB/1W/1M into 8 ohms = 90dB/2W/1M into 4 ohms. You have to subtract 3 dB to get the equivalent sensitivity rating for an 8 ohm speaker.

Thanks for a quick response, now I got it.