Efficient speakers v. less efficient speakers

What i am trying to get at is:
will inefficent speakers paired with high powered amp. equal to an efficient speaker paired with a lower powered amp. if the ratio db/wpc are constant, in terms of dynaic, detail, etc...
thx.

You cannot compare efficiency alone without considering speaker/cone size and overall design...it is always a compromise.

The question:

If driven with the appropriate amplifier(s), meaning a higher powered amplifier for a less efficient speaker and a lower powered amplifier for a more efficent speaker, are there any difference?

The speaker design is generally what makes the difference.

An inefficient bookshelf speaker with a big amplifier can be comparable to a full size efficient speaker with a small amplifier when played at acceptable sound levels for both the bookshelf speaker and small amp.

A bigger speaker can ultimately go louder with less distortion particularly when pared with a big amplifier.

On the other hand,

An efficient bookshelf speaker, is rarely comparable to a full size efficient speaker.(Bookshelf being roughly up to 6" woofers, and full size being 12" or larger woofers)

In very general terms:

1) big speakers can be efficient, and play loudest with lowest distortion
2) small speakers tend to be inefficient if they have low distortion.
3) efficient small speakers tend to have the highest distortion even if they can play quite loud with a modest amplifier.

I`m GLAD to hear that! I have Infinity SM-152`s and
2 pairs of SM-155`s. They`re rated at
sensitivity 102db at 1 watt.
My Pioneer Elite C-91 pre-amp volume, sits at
9 o`clock MOST of the time,
that`s about .7-.9 watts per channel.
They DO sound loud.

Sorry I wasn't as clear. I intended my comments to apply to your stated comparison of efficient speaker plus low powered amp versus inefficient speaker plus high powered amp. My experience is that the inefficient speaker plus the high power amp will sound somewhat compressed and lack air and detail. As your original question implies, there is more going on than simple matching of efficiency with power. So, my answer is yes, there is a difference.

Rlew - I intended my reply to be a direct answer to your question. There will be a difference and it is mostly due to the speaker designs being inherently different. The amplifier power level is largely irrelevant assuming you are comparing same sound pressure levels - something your question implies.

Isellstuff - The volume knob position has nothing to do with power output whatsoever. If you used a power meter to calibrate it, ok, but if not, you have no way of telling what the actual power output is in absolute terms. Arthur