Pass XA30.5 enough power for Wilson Sophia 2?

According to this list of specifications at the Wilson site the Sophia 2 has a sensitivity of 86db/W/m, rather than the 88 mentioned above.

Al...I got the 88dB sensitivity from John Atkinson's measurements of the Sophia 2 in the Stereophle review. Speaker manufacturer specs often are swayed by marketing considerations (although in this case, his measured sensitivity actually shows the speaker to be more sensitive than their stated specs), so I usually like to refer to measured performance in Stereophile, Hifi Critic, etc...Here is the link to Stereophile measurements section of the Sophia 2 review: http://www.stereophile.com/floorloudspeakers/619/index6.html.

Hello Al,

Wouldn't that be a 6 db gain when you add the presence of the second speaker as well as doubling the power when adding the other channel..

regards,

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06-08-10: Almarg
According to this list of specifications at the Wilson site the Sophia 2 has a sensitivity of 86db/W/m, rather than the 88 mentioned above. Based on the assumptions of 195W max amp power into its 4 ohm nominal impedance, a 4-meter (13 foot) listening distance, a 6db reduction in spl for each doubling of distance, and adding 3db to reflect the presence of 2 speakers, I calculate that maximum spl at the listening position will be 100db.

That is certainly good enough for most music at reasonable listening volumes. But ime it is roughly 5db too low to adequately handle music that has very wide dynamic range, such as a lot of classical symphonic music, if the recording is well engineered and minimally compressed.

Best regards,
-- Al

CMalak -- Thanks. The Stereophile site appears to be down right now. Are you sure, though, that those measurements are for the Sophia 2 and not for the Sophia? I had looked for JA measurements of the Sophia 2 before I posted, but I was only able to find measurements for the Sophia.

Weseixas: Wouldn't that be a 6 db gain when you add the presence of the second speaker as well as doubling the power when adding the other channel

Doubling of power, whether acoustical or electrical, corresponds to a 3db increase. The fact that the additional 195W from the second channel of the amp is applied to a second speaker, as opposed to 390W being applied to a hypothetical single speaker, makes no difference for purposes of this calculation.

You might be thinking of doubling of a voltage, which would be a 6db increase.

Best regards,
-- Al

Addendum to my previous post:

The Stereophile site is up again, and it looks like I was correct that JA's measurements were for the Sophia, and not the Sophia 2. Also, his 88.3db measurement was not based on 1 watt and 1 meter, it was based on 2.83 volts and 1 meter (2.83 volts corresponding to 1 watt into 8 ohms).

2.83 volts into the nominally 4 ohm speaker impedance corresponds to 2 watts. So the 88.3db sensitivity JA indicated for the Sophia would be only 85.3db based on 1 watt into its nominally 4 ohm impedance, fairly close to the Sophia 2's specified 86db/1W/1m.

And I note also that the Sophia's spec is indicated in the Stereophile review as being 89db/2.83V/1m, which corresponds to 86db/1W/1m for its 4 ohm impedance, which is the same as the spec for the Sophia 2 that I used in my earlier calculations.

Best regards,
-- Al