SPL @ 100 watts/@1 meter

sirogenous

Could someone please tell me what the approximate SPL would be for a speaker that is rated @87dB 1 watt/1 meter and driving that speaker to 100 watts while measuring @ 1 meter. FYI Speaker in question being DX6510

RuSsMaN

Most loudspeaker sensitivity measurements are made at 1 meter distance in an anechoic chamber, not very much like a real listening room (or car for that matter). Better to just use an SPL meter and get a real life measurement at your listening position.

I'm a little rusty on watt/dB calculations, but here goes: As a rule of thumb, every doubling of wattage results in an additional 3dB in output, so the following would be the SPL at various wattages for the speakers, lets say 90db 1w/1m:

1 watt at 1 meter = 90dB
2 watts at 1 meter = 93dB
4 watts at 1 meter = 96dB
8 watts at 1 meter = 99dB
16 watts at 1 meter = 102dB
32 watts at 1 meter = 105dB

SPL drops 6dB for every doubling of distance, so at a listening position of six feet (2 meters), here are the SPL values for the same wattages at a distance of 2 meters:

1 watt at 2 meters = 84dB
2 watts at 2 meters = 87dB
4 watts at 2 meters = 90dB
8 watts at 2 meters = 93dB
16 watts at 2 meters = 96dB
32 watts at 2 meters = 99dB

These are only approximations, you'll need a scientific (logarithmic) calculator to obtain the exact values for a given wattage and distance.

Cheers,
Russ

sirogenous

Thank you very much for answering my question. You answered it exactly as I needed it to be explained.