music frequency

Could not agree more with Eldartford. The same can be said of tuned ports to extend frequency range...often the results are less perfect than can be achieved with a separate dedicated driver (usually from a subwoofer) just for the low end. In the end it is often about compromise. Getting transducers to cover a broader frequency range helps in some sense by eliminating the challenges of cross overs but the downside is that the optimum freq range for that particular driver (size/material) may be exceeded and this usually results in more THD/IMD distortion and significantly less dynamic range.

Discrete transducers appropriately sized for their frequency range and precisely integrated using separate active electronics for each transducer is a solution that some speaker manufacturer's have adopted. A system of this type with large dynamic range and low distortion requires a four way system: subwoofer for 20 to 60 Hz, Woofer for 60 to 400 Hz, Mid range from 400 to 3000 Hz and tweeter from 3K to 20K Hz. The drawback of a system using more transducers and discrete active electronics is higher cost. The advantage is relatively low distortion and high dyanmic range (for a speaker). Nevertheless, harmonic distortion is in the 0.3% range, which is still hundreds of times more distortion than typical digital source and SS circuits.

Beware of the Black & White viewpoint that more LF extension is necessarily better....really it is more of a "gray" area. Extreme LF can be better if DONE CORRECTLY AND CAREFULLY using SPL measurements and careful Room design/treatments and a smidgen of EQ, however, in many cases extreme LF may actually be detrimental to the overall sound at LF and may even cloud some of the mid range detail.

See this interesting demonstration about hearing perception at Southhampton University, which should be considered when looking at the chart suggested by Tgrisham.

http://www.isvr.soton.ac.uk/SPCG/Tutorial/Tutorial/Tutorial_files/Web-hearing.htm

It shows how the pitch of an instrument can still be heard even if the loudspeaker lacks the ability to play the fundamental frequency!

The higher harmonics (or partials) allow one to hear the pitch of the played note.

The timbre of the note will, however, be affected by the relative magnitudes of the fundamental AND all the partials and how they decay.

Since room modes (also covered on this website) become severe at very low frequencies (easily up to 15 db boosts and nulls in most cases) then a flat speaker frequency response down to extreme LF may not necessarily be desirable. The room may alter the timbre of low notes more adversely than the loudspeaker response curve....no matter the cost/quality of the loudspeaker!

Therefore, with typical modest room sizes, a well designed speaker with less impressive LF extension can often outperform in LF timbre another speaker with greater LF extension.

There is actually quite a lot on this website that may interest audiogoners.