Steinway Lyngdorf Model D Speaker: 117 dB Sensitivity, dBu Input, and Efficiency Explained

How efficient and powerful are these speakers? http://www.steinwaylyngdorf.com/products/model-d-components/model-d-speaker

Is it 117 dB / 1 watt (1 m) ? How do you convert the dB to dBm to divide by the input wattage?
117 dB - that's super loud right?
What does it mean when a speaker has a 6 dBu/10 kOhm input sensitiviy/impedance? What exactly is dBu?

Thanks

The 117 dB spec is not the efficiency - its the maximum SPL (sound pressure) that the speaker can produce measured at a distance of 1m from the speaker.

dBu = decibel units. As far as I know this is the power measured at an input voltage of 0.775 V(rms). In case of the speaker, I believe it is telling you that it will take a power of (0.772)^2/10k to produce 6dBu of sound. However, I have not seen this sort of speaker specification for efficiency. Speaker efficiency is usually quoted directly as 'x' dB/W/m, or 'x' dB/2.83V for 8 ohms or 'x' dB/2V for 4 ohms speakers.

The speaker spec lists the _maximum_ level as 117 dBA at 1 meter. This is not at 1 watt.

Because the power to produce this level is not specified the 1 watt SPL cannot be calculated.

Hi Anand

Here is a very good site for you regards decibels and acoustice full of usefull information which will porve no end of use to someone like yourself
http://www.engineeringtoolbox.com/acoustics-noise-decibels-t_27.html

Also have a look at this site as well

http://www.acoustics.salford.ac.uk/res/index.php?content=environmental-noise-soundscapes

See upload for ppt format