Characteristics of under powered speakers

Are there any tell tale signs of when speakers are not receiving enough power?

 

They aren’t loud enough.

 

Funny but not really true, in my experience. Underpowered means the output is distorted to some degree, which results in a sense of harshness/loudness when you turn up the volume.

Speakers that are driven with ample power, sound simply effortless. Great separation, spacious and solid imaging, and big dynamic swings without any strain. Just like what you hear during a symphonic concert. Headroom rules.

 

I was just being cute. Ample power is acceptable volume without any clipping.

 

Flabby bass response. Amp is also low current output let alone not enough watts.

 

I read on another forum that under powered speakers sound uninvolving, two dimensional, homogenized, textureless.

Would you guys agree with this?

 

It might be the amplifier’s fault, or it might be the speaker’s fault. The only way to know for sure is to crank the music and measure whether the amplifier is clipping. If the amplifier is not clipping, it isn’t because the amplifier is under-powered. If the amplifier IS clipping, you need more power whether you like the sound or not. If you care about the service life of your equipment, you should all ways run your amplifier below clipping.

Bad:

 

Not really. Literally under powered would only apply at very loud volumes. But perhaps what is meant by the phrase is not so literally the amount of watts, but the sound character of the amp. A weaker amp, like a car head unit's built-in little chips, won't have as good a quality even well below clipping. (Though having done some tests in a previous job, you'd be surprised they are not really so terrible).

 

Glad to hear that, as I sometimes get a homogenized sound from my stereo and it's good to know it it isn't likely the amp. Perhaps its just the recording.

By the way, my amp (Yamaha A-S801) has been measured by Audioholics to provide 105 watts into 8 ohms and my speaker manufacturer recommends an amplifier power of 30 watts to 150 watts into 8 ohms for my speakers (B&W 704 S2.)

 

I don't think I have experienced it often, but I did recently and flabby bass is what I heard, as allied mentioned above.

When I tried to run my Quad 12L2 speakers with my Sugden a21, the bass was flabby sounding and I noticed the woofers moving a lot. Seems like the amp didn't have the ability to control the woofers well. With my Classe CAP-80, no issues and the drivers aren't flapping. So perhaps the way the drivers behave is another clue. But yeah, I think the low frequencies provide the best indication, as bass requires more power and current than do mids and highs, so if power is lacking that's where it'll show.

 

I once tried to play one bass heavy track loud with my 25 watts per channel vintage receiver, indeed like other have said, I got flabby bass.

 

I think it's safe to say your Yamaha is not underpowered for the 704s. And yes, you are most likely hearing limitations of the recording.

However, I would like to mention I have personally experienced the Yamaha sound as a bit more homogenized sounding than, say, Naim, Quad or a good tube amp. By homogenized, I mean a presentation that is like a dense cloud of sound versus clearly seperated instruments coming from a black background. Naim is very good at the latter, at the cost (IMO) of a hint of artificiality, tonally.

 

Here are "Head_Unit’s Rules Of Protection":
1) If when things start to sound distorted or odd you TURN IT DOWN, you are unlikely to ever break anything.
2) If you constantly "turn it up to 11" you will break something.
NOTE: the size and power ratings of the speakers and amp do not affect rules 1 and 2. (Specs for amps are often not thorough since they are measured into resistors and speakers are not resistors. Speaker specifications are 92% meaningless (and I say that as a loudspeaker engineer)).

 

the speaker is rated less than 95db1w/1m and your amplifiers give off less heat than a large block V8???

 

IIRC, you already did this, but just in case, are you running the impedance switch at 8 or 4 ohms? If the latter, switch it to 8.

 

Yeah, I have on 8, thanks to the guys at Audioholics.