Ed, I don't understand what you mean by, "By nature, the more specifically a bass enclosure is tuned the more frequency specific it becomes".
To attempt a clarification of my statement; what I mean is the porting in any particular enclosure exists to support the directly radiated sound pressure of its driver(s). Generally ports are used to supplement the sound pressure levels at the lower end of a drivers useful range in a theoretical infinite baffle; i.e. a bass reflex design.
The sage JoeArthur nails it again;
Sure, it is possible to tune a cab to a specific frequency. Yes, it may be somewhat based on the driver you will use. But this is "hi-fi" stuff - where a tuned cab usually means a "bass-reflex" design, and this is the only area where Thiele-Small parameters really mean anything.
In Hi-Fi gear, very specific (to the response characteristics of the driver) cabinet tuning can be utilized to maximize the efficiency of the enclosure to a sometimes very specific range, and it’s my opinion that this overly specific tuning is not conducive to natural sounding musical instrument reproduction.
Hi-Fi normally (don’t tell Dr. Bose) requires a mixture of drivers, each with a specific purpose, or frequency range as its responsibility, 2, 3 even 4 way systems are the norm. I won’t even touch multi-amping, which specifies driver frequency responsibility even more precisely utilizing individual amplifier characteristics as well.
As far as instrument reproduction, I wholeheartedly agree with this Isaacism;
If your 2x12 sounds better with one 12" removed, great. I'm a firm believer that instrument cabinets are for producing sound, not reproducing sound, and whatever sounds best to the musician using it is what sounds best. I might not agree, but it's not my cabinet or my sound.
However I don’t understand the relevance of;
The reason that Thiele-Small parameters are used is that "that looks about right" very often wasn't even close.
Lots of wasted plywood no doubt, I know I’ve wasted my share over the years.
However, as you acknowledge, TS parameters weren’t even recognized by the audio design mainstream until the mid/late 70’s, Richard Small didn’t even publish his series of articles until ’73 or so. What parameters did the designers of early MI or Hi-Fi cabinets
use?
I suspect that with designers such as Mr. Lansing "that looks about right" was in fact very often very close.
According to my ears, it also worked for Mr. Sundholm.
Of course you can measure the “Fb” of a 200S cab. You could measure the “Fb” of an empty beer can; ask Mr Sundholm how much influence the “Fb” had on his 200S cabinet design,
that would be a discussion relevant to the turn this thread has taken.
I guess the question would be the definition of “tuned”. If “tuned” means “on purpose” this won’t hold water, but I think if you want a definition of an untuned cabinet, try any sealed cab. Generally the goal there is to emulate an infinite baffle. The only real influence the cabinet has over its driver(s) other than sound pressure resonation from the cabinet itself is the vacuum/compression damping of the cones excursion.
For bass guitar the directly radiated response of most drivers is subjectively considered to sound better with a little bottom end assist, hence the limited usage of sealed enclosures in a full range application. (I know, I know, the reigning standard is the SVT 8x10) An overly specific tuned reflex port sounds a little too peaky, even boomy to most ears.
In the case of the 200S, there seemed to be a lot more “that looks about right” than actual tuning going on. I think if you cut it in half, you would be closer to an actual tuned reflex cab than with the 2x15 configuration. You definitely get a kick in the bottom end, but I think mainly because not much of the back pressure above 100hz or so can make that turn to get out.
If you pop a 12 out of the closed 2x12, well, it’s tuned (see above) to some resonant frequency. Actually, this missing speaker method is currently in vogue in some boutique circles, and is generally referred to as an “untuned cabinet”. In fact, an amp manufacturer recently recorded demo tracks with one of these “untuned” was a 2x12, uh…now a 112 cabs.
