mo' better bass: any substitute for watts?

Mapman, no, however the match between the speaker and amplifier is paramount. If the speaker has a low impedance at low frequencies, you are going to have to provide the current that making power into that load demands by law (Ohm's Law- no pun intended). The Ohms were always a difficult load! As you have seen, with less difficult loads the requirement for high power at low impedance is less important.

The flip side of the coin has a question- why go where angels fear to tread? IOW **if** the best sound is your goal, it has been shown that higher impedances favor transistors as well as tubes. A transistor amp driving a 16 ohm speaker will sound better (smoother, more detailed, more impact) than it will driving 4 ohms, all other things being equal. So the argument of current, insofar as the goal of 'best sound' is concerned, would seem to be moot.

Atmaspere ;
In your statement above...

"If the speaker has a low impedance at low frequencies, you are going to have to provide the current that making power into that load demands by law (Ohm's Law- no pun intended)."

Is this opposed to providing voltage , which will also increase the power ?

I went from a 300wpc amp to a 225wpc. The 225wpc had better bass than the "more" powerful amp. So I guess to answer your question, in my experience, watts is not the only game in town!

Saki70, as Bob pointed out above, it takes both voltage and current to make power. The issue is that if we are to make 200 watts into a set of Ohms which might be 3 ohms, the voltage and current can be easily calculated (assuming for the moment that there is no phase angle which there always is in inductive devices).

So you can also look at it as being able to make the Voltage into a load like that- which will only be possible if you can also make the current.

The use of the term 'voltage source' I think can be dangerous without the understanding of the accompanying engineering principles for which the term is a sort of shorthand. You have to keep in mind, IOW, that regardless of the amount of current or voltage that you are making, that the end result is power which is composed of both.

Low impedance amplifiers (Voltage source) *can* make constant voltage with respect to the load. Not all do.

Higher impedance amplifiers (Current source) *can* make constant power with respect to the load. Not all do.

You **must** match such amplifiers with speakers that are designed with intention to work with that particular kind of amplifier that you are using. If you do not tonal aberrations will occur.

It is true that some constant voltage amplifiers can deliver lots of current. It is not true to say that that is the same thing as having lots of bass authority. IOW any kind of amplifier can be perceived as being wimpy in the bass if not set up properly. OTOH, some amps will not play good bass no matter what you do.

In my personal case, because I like amplifiers to be relaxed at all volume levels, I will not use one that has negative feedback, as that design element adds loudness (harshness) cues. So I work with speakers that are designed for amps that have a higher output impedance. So on my speakers there are no 'voltage source' amps that will play the speaker with the authority that my 60 watt triode amps will. But that could be very different on other speakers- my bone of contention is that because the use feedback, as far as I am concerned they will never sound like real music, so who cares :)