Current vs. Watts??? Need clarification.

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.

Are you driving one set of speakers or are you driving two sets simultaneously?

Just to add to the mix that pre-amp overload may also play a part. Sometimes some form of attenuation is needed between source and pre. Especially if you are only getting limited volume adjustment.

Gentlemen, That is a great set of answers. Thank you.

To clarify a few things.

1. Beavis - I'm just driving the one pair of speakers. There is only one set of posts on this amp.

2. Viridian - It is interesting that you mention the S5e, as I actually had that speaker in the house for a month or so before trading up to the S8e (not enough bottom on the 5s.)and I did experience the same problem on at least one occasion.

3. Mlsstl - I have to confess that 1/3 is up pretty high on this system. I sometimes - foolishly - try to make up for either ambient noise or lack of detail within the system itself by turning up the volume. Although, as I've lived with the system for a while I learned it's limits better.

Thanks again. G

W = E X I X P.F.

P.F. (Power Factor in %) refers to the phase shift between current and voltage at various frequencies. Some speakers are more prone than others.

So, the more phase shift you have the more current required to achieve the rated watts.

A sufficient power supply will help sustain the voltage during larger phase shifts, and some amps are able to deliver more current.

I guess there are a lot of ways to skin a cat and some amps do it better than others. :-)....?