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A new measurement specification for speakers?

I am a dedicated low volume listener as my ears have become sensitive with age and past youthful abuse. I have been through a number of speakers with mixed results, trying to find one that sounds good at low volumes. Note that this is not my only criteria for speaker choice, but it ranks high. Frequently it is stated that high sensitivity speakers are good for low volume listening, but I feel there is no connection between the sensitivity rating of a speaker and how it plays at low volumes. 

Speaker sensitivity is typically measured in decibels produced with one watt of input using a 1 kHz tone with a microphone positioned at one meter from the speaker. Roughly useful for determining the kind of amplifier that might be required to drive the speaker, but not an indication of of how it will perform across the audible spectrum with one watt of input. 

For those who have owned or demo'ed a number of speakers, I think we are all aware that each speaker "opens up" at a certain level. By open up, I mean the sound becomes fuller across the spectrum. Good low volume listening speakers obviously open up at lower dB levels. 

What would be a proper means of measuring the level at which a speaker a speaker "opens up"? Technically, in my mind, this would be the dB level at which it delivers roughly linear sound across the audible spectrum, or some reasonable sub-range like 40-10,000 Hz. Call it Spectral Sensitivity. If we send a white noise signal using a select range or spectrum, at what dB level does the sound become linear, i.e. a (roughly) flat line on the graph. 

I am aware of Fletcher-Munson curves, but this does not apply, as we are not talking about human perception, only about the dB level at which the speaker produces the full spectrum of sound presented to it. 

I am not a speaker designer, and there are greater minds in this forum. Does something like this make sense?

zlone
Post removed 
larryi
4,568 posts
 

There would be a lot of subjectivity involved in such a “measurement” so the measurement crowd would object.  The its-only-the-sound-that-matters crowd would reject it off-hand too.  If someone made a measurement that correlated with most people’s perception, it would be a first.  I don’t know of any such reliable metric.

bartsw's avatar
bartsw
226 posts
 

@zlone 

Frequently it is stated that high sensitivity speakers are good for low volume listening, but I feel there is no connection between the sensitivity rating of a speaker and how it plays at low volumes.

I think sensitivity rating is from 300Hz to 1 or 3kHz, or something like that. I can't imagine it's going to tell you how much power you need if you use full range. Also if your speaker has low impedance above 3kHz, it might be hard to hear details with a weak amp.

 

It's probably more a function of the amplifier's ability to match the impedance curve of the speaker. I hear Devialet amps do it.

 

There's also noise and distortion spec of the amp, then also the ability of the cables to reject and block interference. I have a good measuring Eversolo streamer and ICEpower amp and with nothing else connected, I can still hear a fair amount of noise with no content playing. The higher you turn it up, the more the noise gets amplified. You might have heard some people doing upgrades to the power supply on the streamer and they heard a more black and clean sound.

 

Maybe look there first before the speaker.

audio_guy_uofw
73 posts
 

I believe what you are talking about is frequency response. In general this does not change with input level, so a speaker has the same frequency response at low or moderate levels. At high levels the limitations of the drivers start to impact the response, with excursion limitations and voice coil heating causing compression of the program material. My suggestion for low level listening would be to recognize that the Fletcher Munson curve indicates that more bass and treble is required to "sound" flat, and apply this equalization via tone controls, equalizer, or loudness controls... not via speaker selection.If a speaker sounds "flat" at low levels (eg 50dB)  it would have far too much bass at higher levels.

oberoniaomnia
344 posts
 

Re "opening up" past certain volume levels, that is precisely Fletcher-Munson, so part of psychoacoustics. That is what the loudness button on older equipment tried to address. 

So you have a choice of a system that sounds full at low levels but excessively polarized at louder levels. OR. A system that sounds flat at low levels but full at louder levels. OR some sort of EQ via various approaches from parametric EQ (digital or analog) to loudness button. 

No metric can parametrize it. 

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