What's most important spec(s) for amp driving low efficiency speakers?

That's a loaded question because how "low" efficiency, how low impedance? Room size has a lot to do with it. Type of music and listening habits.
The Polk R200's I use in my office rig are about 86dB efficient, but they also drop down below 4 ohms at certain frequencies. My office/den, etc is a standard 12' x14' room (approx). I use a simple single Pass DIY Minmax amp rated at 15 wpc. It uses a 36V-5 amp switching walwart. I sit 5.5' away and can listen at moderate levels with zero issues.
I can't achieve rock concert levels and I can't shake the foundation. But I don't hear anything missing from the music. The R200's dig as deep as they are capable. But I am limited as to overall SPL. I can listen loud enough to make it impossible to talk over. This is a very simple, small parts count amp with an adequate power supply.
I am not saying to get one of these amps. Just an example of a small, low power, simple circuit amp being more than enough for my needs in my office rig.
Does the DIY First Watt F6 do a better job? Not until a certain volume level is reached.
That's my long winded attempt to give us more info about how the rig will be used and what the more specific inefficiency is.
Big power supplies, many smoothing caps and the simpler the better as far as circuit design will yield a piece if gear that can drive inefficient speakers and low impedance speakers.

I use a Marantz PM6007 for the TV rig running a pair of Polk Elite ES20 speakers. Nice little amp with a built in dac. It does an excellent job and sound very good too.
https://www.crutchfield.com/p_642PM6007/Marantz-PM6007.html
H9

I don't know if this answered the question or was helpful....lol

I still think the recommendations we made the last time are her best bet. Some of those Class D amps we mentioned do great with low efficiency speakers.
Brock did have a good point though. Are we talking 86-89dB low efficiency or something below 85?

motorhead43026 wrote: »

Current aka Amps.

Depends on the impedance curve of the speaker, my apogee duetta 2 speakers are not that hard to drive because the impedance doesn't dip that low, but the sensitivity is only 80db, so they need higher voltage but not a lot of current.

High current (AMPS), with plenty of headroom to spare and a xnsfrmr that can handle it. Final answer.

* In the context of, "Who wants to be a Millionaire" *

Tom

In that sized room with that efficiency, you won't need much. I'd buy a higher quality product with lesser watts over a mediocre product with many watts.

Look at some of the new NAD legacy stuff.
https://www.audioadvisor.com/products/nad-c-316bee-v2-integrated-amplifier-phono-included?variant=45983400362157
Rotel
https://www.audioadvisor.com/products/rotel-a11-mkii-integrated-amplifier-black?variant=45982913986733
Marantz
https://www.audioadvisor.com/products/marantz-pm6007-integrated-amplifier-new?variant=45981818060973
H9

High fi shark has a couple Anthem Integrated 225. Same as I have had in my system for about 8 years. Nothing fancy, straight forward no frills
workhorse. Plenty of good reviews and plenty power and current with lots of headroom. I love the Amthem sound and it’s a quality machine.

And the price is reasonable.

The Emotiva BasX TA2+ is worth a look for this application. The GS60 were considered Monitor Audio's flagship floorstanders 20 years ago. Probably ideally sized for the room. They're 6 ohm nominal so need a high current amp. Although they go to 28Hz by themselves, having the option to easily hook up a subwoofer with analog bass management later is a good idea. Wiim products aren't designed for this type of speaker.

https://emotiva.com/products/basx-ta2-stereo-preamp-dac-tuner-with-integrated-amplifier-1

mantis wrote: »

Dampening factor is a huge one. You don't need massive amount of power or head room especially considering 3 things, the volume that will be the max you ever listen at , the size of the room and the distance your going to sit from the speakers.

Listen , having massive amount of head room or watts if you will does absolutely nothing for you IF your not going to take advance of it. case and point a 200-300- 500 watt amp with massive Capasitors is awesome to have if you have a big room and like to blow your face off. But like HP in a car, if you don't ever use it, it's a total waste to have it unless you like to show all how powerful your amp is.

Most of the time, just about all of the time, we use like 5-30 watts of power as most of us are older, even younger should pay attention, we need to keep our hearing and listening at high SPL will eventually ruin your hearing and the enjoyment you once got, is now damaged.

Having a amp that is high quality , has great control over your speakers, nicely matched to your lifestyle will yield incredible results.

Massive capacitors really doesn't always equate to BIG power. In a push/pull class A/B configuration the amount of FET's really determine how much "power" output there is, usually through many gain stages.
I have many lower power class A amps with 2 gain stages and 2-4 FET's (per channel) that are in the 10-25 watt range with huge capacitor reserves. More for the stout power supply, not necessarily for BIG power output. My DIY First Watt F6 is 25/50 wpc and has 120,000uF of capacitance. Only 2 output transistors per channel, 2 gain stages.
But yes, big power for A/B based circuits, more capacitance is better. For Class D, throw all that information out the window.
Also damping factor isn't as important for a 2 way bookie compared to a floor stander with multiple drivers.
Otherwise I agree.
The last 20+ years of my audio journey has been with 25-30 wpc, class A amps and I've never felt I needed more in any listening situation. And I'm pretty fricking critical and have high expectations for my gear. And listen moderately loud.

H9

For the speakers being used, I suspect speakers in use would benefit a lot with an Emotiva BasX-A2+ with the WiiM Ultra Streamer as the preamp/streamer. The A2L+ may be under powered and only on par with a receiver's amp. Would be fine with a regular pair of bookshelf speakers.

The WiiM products go on sale frequently so some money could be saved there.

I started with the Vibelink and liked that so much with a pair of bookshelf speakers I got an Amp Ultra and an Ultra Streamer too. The Ultra Streamer has a built in MM phono stage, subwoofer output, and HDMI ARC. Pretty cool for what it is. These things have to be used with the app on a phone or tablet though. The touch screen is pretty much useless except for being able to see what's playing and the app for control via a PC is abysmal.

invalid wrote: »

Damping factor is a so overrated spec, it doesn't do much, considering that the cables going to the speaker and the voice coil will pretty much dominate the output impedance of the amplifier, unless the damping factor of the amplifier is really low.

IMO, it's not "overrated" unless it's overstated. Low, like 10-15, can be noticeable compared to 50-100. Once the number gets past about 150 it starts the very rapid slope of diminishing returns.
As stated one of many variables are cables, amplifier topology and the speaker itself, complexity of the cross over, etc.
It is a spec to know, but that number bu itself shouldn't be a sole determining factor about how the amp sounds.

H9