What matters most in speaker design?

Perhaps the look matters most.

A great paint job or veneer, tall and narrow with sloped baffle and loaded with several mass produced shiny metal drivers and impressive copper phase plugs to boot....all sure to impress. What people see is what they hear - for the most part. So the "Industrial Design" aspect is probably the most crucial - if it is ugly but sounds really good then it won't sell easily when lined up against the beautiful competition.

Shadorne, I suspect you are right assuming the target audience is the general population. No doubt that beauty is the ultimate marketing tool.

Up until the analog signal reaches the loudspeakers, it's a two-dimensional signal: Variations in intensity (voltage) over time. The loudspeaker has to deal with six dimensions: Variations in intensity (SPL) over time, across three dimensions of space (including reflections), and finally the signal processing of the ear/brain system.

Now the ear/brain system does not hear waveforms as such; it deconstructs the waveform into a series of excitations along the cochlea in a manner that is non-intuitive. So waveform preservation is relatively non-critical. In many cases audible benefits attributed to waveform preservation may well be due to other factors that matter more, such as minimizing diffraction or avoiding abrupt changes in the power response. I can explain why these things matter to the ear/brain system if anyone is interested.

Duke

The most important part of a speaker design? Listening to it after fabrication. Voicing it.

What is great sounding speaker? Sound depends on many factors and people have different preferences. Do you prefer speaker with underhung motors (less distortion and less dynamic) or overhung motors(more distortion and more dynamics) . Do you listen soft or loud. Do you listen to Jazz or Organ music? Do you crave for pinpoint imaging or heavy metal punch. Do you care how large sweet spot is. How does it perform in small or large room etc. How easy it is to drive.

Frequency response test is pretty much useless. Bad speakers with horrible phase errors might show with excellent flat frequency response.

I would agree with Shadorne on transducers. If pair of speaker costs for instance $1k then manufacturer sells it to stores for about $500. Components cannot cost more than 1/3 of it (to cover labor, expenses etc). Now we are left with $170. Both cabinets will cost $50 both and we're left with 120$ for let say 6 transducers and crossover components. That's why my speaker had originally $25 Vifa tweeter and Mylar + electrolytic caps in crossover. Good tweeter is 10x this and good cap is $100 (I just replaced $15 caps wit $100 caps of the same value and sound + imaging improved a lot).

There is no universal answer but you won't get very far with cheap transducers (especially tweeters). I don't design speakers but after concept design I would start with the best tweeter I can afford and worked down from it.