The basic question goes to the understanding of Ohm's Law, V=IR. Where V is voltage, I is current and R is resistance. It should be clear from the formula that, as the impedance of a loudspeaker diminishes, current must increase if voltage is to remain the same. Since the speakers probably do not have a very punishing impedance load, what type and how long are your speaker cables?
Ultimately, your question probably has a more pragmatic answer. Your speakers are probably not very sensitive, which requires more wattage to produce a given sound pressure level. Even though the spec says 89db, which is sensitive, different measurement tecniques yield differet figures. As an example of Spendors optimism, they rate the S5e as being 87db efficient, yet Stereophiles testing shows an extremely low sensitivity of 82.5db. see here, http://stereophile.com/floorloudspeakers/904spendor/index4.html
That 4.5 db does not seem much but it would require over three times the output power to achieve the same volume level. The answer to your question is that more amp power will certainly help if low sensitivity is the issue. But many of these classical British monitors are rather polite and have a lower ultimate loudness level than others, so they just might not play that loudly.
Ultimately, your question probably has a more pragmatic answer. Your speakers are probably not very sensitive, which requires more wattage to produce a given sound pressure level. Even though the spec says 89db, which is sensitive, different measurement tecniques yield differet figures. As an example of Spendors optimism, they rate the S5e as being 87db efficient, yet Stereophiles testing shows an extremely low sensitivity of 82.5db. see here, http://stereophile.com/floorloudspeakers/904spendor/index4.html
That 4.5 db does not seem much but it would require over three times the output power to achieve the same volume level. The answer to your question is that more amp power will certainly help if low sensitivity is the issue. But many of these classical British monitors are rather polite and have a lower ultimate loudness level than others, so they just might not play that loudly.