Musical accuracy in subwoofers

I'm hoping some members who are more musically & technically knowledgeable can answer my questions about subs. While sub shopping, web research and sales people make referrence to subs with accurate timbre. The Linn & REL lines were reported to be more accurate than Sunfires in this respect. After playing my sub at a 45-48 hz. crossover without the main speakers, listening leaves me wondering how timbre ( at this low a crossover point) can be an attribute of a sub when most aspects of timbre are a product of higher frequencies. It seems that pitch accuracy, lack of bloat & "overhang," freedom from cabinet resonance, and the ability to tune crossover, volume, & phase accurately are paramount. But timbre?
Right on Detlof! I was focused on the high notes because of Photon's question. The improvement in the low notes is also worth a listen. On some orchestra recordings I have; what was originally just the strings playing very low, became the Cellos and String Basses playing a very low cord with the sub added. I could hear the separate instruments better with the bottom filled in. If the cord changed slightly, for example the Bass Strings changing slightly from a E natural to an E flat against the cellos, it was much easier to hear clearly with the sub than without it.
Excellent question. It's probably that the timbre issue is the result of semantic confusion. Pitch accuracy coupled with low overhang should result in accurate timbre.
I don't know what "timbre" in a sub is; its just alot of fluffy adjectives the audio world has because the world of mathematics is beyond these forums, its not practical that's for sure. A loudspeaker driver just moves in-and-out to a series of electrical impulses and any non-linearity in that movement is called distortion. The sunfire has quite a bit more than alot of high-end subwoofers, 10% pushing its max. However since its small, it can use the corner of the room as a "horn" and operate more in the 3% range. Its an innovative sub, but giving no consideration to its design, strictly its performance; its just an average high-end sub; i.e. its not that accurate. Not to discredit you question, but I wouldn't worry about the issue of "timbre." You'll know a better sub from another when you here two. Timbre isn't an "attribute of a sub" to sort of use your wording, or any loudspeaker for that matter. All speakers do is reproduce the signal they get. My wording may not be the best. Put maybe another way, What kind of timbre would you want in a sub? None, you'd just want it to reproduce the signal its given. Technically, a phrase like musical accuracy (which I have caught myself typing in other parts of this and having to omit it, so I am guilty too) is redundant- accuracy is musicality so there's no reason to make distinctions in accuracy. Maybe it helped???
Thanks all for your responses. As suggested, I tried disconnecting the mains & listened to the reproduction of various instruments. There are very clear differences between a closely miked electric fender bass, an acoustic bass, & tympani strokes. But so many of the clues we depend on for an instruments unique aural signature are well above the subs range. My initial posts reference to timbre was instigated by quotes from others who said this or that sub is more accurate at reproducing a given instruments timbre. I agree with Ezmeralda11, I don't want any inherent timbre in a speaker. Will.
The distortion figures in a sub effect the timbre of the reproduction more than is often realized due to the Fletcher Munson loudness curves. For a simplfied example: a 30 Hz pure sine wave with 10% second harmonic distortion played at around 70 db SPL (think the fundamental from a double bass or contrabasson) will also produce an additional tone at 60 Hz at about 10 db down. However, at that frequency due to the Fletcher Munson effect, the harmonic will be percieved as equally loud as the fundamental which will seriously distort timbral perception. While the effect flattens out at louder volumes even 3% harmonic distortion can shift the perceived timbres of of lower bass instruments (assuming of course that the room distortions don't swamp the lower bass response).