Having a good knowledge of loudspeaker theory is enough to build an impressive powerful loudspeaker, furthermore - advanced theory will help reduce some of the problems by tuning enclosure, components, and circuitry.
However this is not the way to make a breakthrough in clarity and accuracy!
Being an expert in control theory, computational vibration analysis, fluid mechanics and thermodynamics teaches you; the more complex the system is - the more difficult to isolate problems and improve efficiency -
but after industrial design experience - with all sorts of design and fault-finding methods you realise some things are much more important -
Design out problems at the beginning, and be prepared to start from scratch again and again.
Minimise components which are known to interact with each other
Listen for realism alone, gauging if the performers seem to be in your living room..
Identify improvements with blind substitutional testing - preferably ratified by outsiders.
The Search for the world's best loudspeaker
For decades manufacturers have known that - unless a cone is allowed to move freely it will lose efficiency and distort much more, but in contradiction - if the enclosure is not damped, the enclosure vibrates and
radiates sound from every face, internally reflects the sound back to the cone, goes through the cone, and heavily interferes with the sound, as the damping is increased - so the efficiency decreases, and the
impedance of the loudspeaker distorts - providing an uneven load to the amplifier, thus incurring electronic distortion too.
A very well known suggestion is to use a large enclosure less dense in damping materials but allowing the cone to move more freely. However calculation suggest that to avoid distortion within human hearing (lowest
approx 20hz), the enclosure should ideally gradually dampen the backpressure along its path for at least 16 feet!.
Very few people would purchase such a loudspeaker for obvious reasons, and so to get the loudspeaker into living room acceptability, someone suggested that the 16 foot could be managed as an 8 foot pipe that was
damped twice as dense - that way sound reflected at the end would be damped over a 16 foot length by which time it was so weakened as to be negligible. Further innovations allowed the pipe to be open ended, and bent
and folded into many intricate or simple paths. Eventually the folded transmission line was invented about 1960 which allowed the 8 foot length into a sensible 3 foot high floorstanding size.
Unfortunately folded Transmission Lines (TL) although a good idea tend not to act as an 8 foot
pipe if the bends are poor at reflecting sound waves - so the 8 foot behaves like a 3 foot as it fails at the first bend by reflecting-back and not reflecting-round.
A Few manufacturers persist with TLs today, because of the low distortion even with compromised TL efficiency. It seems most of those manufacturers consequently lost so much bass from the bends that they decide to
vent the open end of the line to the front, and remove some damping - this restores some distorted bass at the low end, but cannot replace what was lost - even worse - the enclosure is now a 'reflex' speaker not a
TL at all, and bass will eminate from bothe the port and the drivers in a superimposed blur!
By spending a lot of time building ceramic & concrete reflectors at each bend in the TL, the losses are largely eliminated, and so the problem is largely solved, but this is unsuitable for mass-production, and
anything but a TL design.
The RESOLUTION uses advanced ceramic and concrete reflectors(5) which are both heavy (approx 4 kg in all) and structually tied to several faces of the enclosure.
The remaining losses are due to vibrations arising from the enclosure material - normally wood (which if grained is too springy, or chipped is too weak). Even thick plywood which is is major improvement is still a
poor absorber of sound compared to many other materials.
-Unfortunately most sound absorbing materials are to weak to use as facets and baffles until recently - a new material is now available which is nearly as strong as wood, but has many more times it's sound absorbence
- however when bonded tightly in a strong co-supporting design, tied at the ends with plywood and concrete, and finally skinned outside with bonded high-strength sheets of laminate - the whole enclosure is stronger
than a hollow wooden alternative!