frequency range for instrument vs speaker

I tend to think similar to Drew_eckhardt.

A speaker that is flat and can perform without breakup nor compression at real life volumes best will tend to extend similarly below the frequency range where the lowest and most common fundamentals occur even if not much really occurs down there. Not only does this best cover pretty muchanything we might hear that is there but it also is an insurance policy that the speaker has the bandwidth to deliver as needed where it is most likely to matter.

For lower volume listening, at levels safer to the human ear, this will all tend to matter much less or not at all.

FWIW, Squeezebox touch has a frequency spectrum display mode that can be switched to by touching the display area where album art is displayed by default I believe. Dunno how accurate, but it appears to be somewhat useful to get an idea of what the frequency content of what is playing is. A nice bonus feature! Also has a VU meter display for those that miss those on our modern gear. Very pretty!

Just to be clear, the SB touch frequency spectrum display would indicate the frequency distribution of the signal the touch receives as input. I wonder if it is based on the digital input signal or the analog output of the internal DAC? Dunno.

ANyway, my point is that this is different than the response one would measure with a microphone if one were to do that with another similar device that works with a microphone as input. Furthermore, what the mike would measure would depending on placement location in the room due to room acoustics. The normalized differences between the two at any point if analyzed somehow would tell you the effects of the room acoustics compared to the source music signal.

Probably some good fodder in there for another thread or two on how to quantitatively measure source material quality and/or related system performance. I am not up to date on all the specific devices/programs that can do this but the technology surely exists and could be applied by inquiring minds fairly easily these days I would expect.

Clearly a sub often if not usually makes a big difference but the existence of lower frequencies in the harmonics is not required to explain it.

Often when adding a sub, the difference can be the result of the sub being able to better deliver flat response without compression at louder volumes at even the same frequencies that the mains would have to cover otherwise, along the lines that Drew_Exckhardt explains so nicely in detail in his posts.

The chart indicates "low fundamentals" for several instruments. Not sure what that is or how different from the "fundamental". Could it be the same thing as frogman's "undertones"?

There is [url=http://en.wikipedia.org/wiki/Missing_fundamental]This[/url] that I found which seems relevant to the discussion.

BEtter link:

Missing Fundamental

Or "combination tone"?

From what I read, it would seem to account for hearing frequencies lower than the fundamental but is believed to be most likely due to non linear inter-modulation distortion associated with how we hear more so than an aspect of actual sound per se, an "illusion" per se, so most likely not something that the speaker would play a role in producing assuming the speaker does in fact deliver the real instrument fundamental frequencies up to snuff.

FRogman,

I think we are in agreement save perhaps the technical details.

As I understand it currently from very limited reading on the topic, as long as the recording captures all the real harmonics produced by the instruments accurately, and the system including speakers deliver these up to snuff as well, the lower "difference" tone harmonics can be heard, but they are artifacts most likely produced by our listening senses, not explicitly by the speakers.

We might be saying the same thing, not sure.

I'm no expert but I gather that it is believed most likely the undertones or combination tones, when they exist, are created by our human hearing apparatus. IN that case the speakers do not have to produce the undertone frequency, our ears do that as a result of non linear inter-modulation distortion produced somehow by our ears and the rest of our aural nervous system.

But I gather this process is not really well understood. It could be that the undertones are real and in the recording, though I am not aware of how this could be accounted for scientifically. In that case, the speakers would have to be able to reproduce them in order to be heard.

Its one of those grey areas apparently that most likely is what it is and I personally would not worry about much.

Having said that, ideally, I like my speakers to go flat at lifelike listening volumes down to 20hz or so to the greatest extent possible without sacrificing elsewhere even if just as an insurance policy that I am not likely to miss anything good down there assuming it exists and I am able to hear it.

The reality is though that speakers that can do that and still do all the rest well do not come cheap and are probably the exception and not the rule. I am willing to punt somewhat on that full low end extension if needed in order to get the frequencies above that really matter right. Its a common scenario that applies to many I suspect. One of the many possible practical compromises an audiophile on a budget or with limited space must face. A good sub blended in properly can go a long way to help address the issue for many when needed.