That's a question
On a 2-way loudspeaker, the internal volume of the cabinet is essentially for the bass speaker (the treble is a closed unit); so consider it a bit like a subwoofer cabinet.
Based on that - it's generally considered that a larger bass driver will output more lower frequency energy. A sealed cabinet "tunes" the bass driver by acting as an air spring - with smaller volumes generally giving a leaner "tighter" sound, with larger volumes allowing more low frequency extension at the expense of a "looser" sound.
Porting the bass cabinet is more complex, but makes use of the energy coming from the rear of the bass driver to give more output. Depending on the tuning you can get a moderate amount of low bass extension, all the way up to a large spike at a particular low frequency (the kind of "one note" bass you often get in cheap car subwoofer systems).
Audio reviews are like wine reviews frankly (and contain a lot of "plums"), but ported systems are sometimes criticised as sounding "slow" (due to group delay); but there's an argument that it's an invalid perception - just created by the fact there's more low end bass.
The blending of the bass or mid-bass into a treble (for 2-way speakers) is complex; with many different types of filter slope and choice of crossover point. Often one or both drivers will have limitations (e.g. a resonance in the upper part of the mid-bass range) that dictate where you try to blend out one driver in favour of the other. E.g. I'm currently using the sub from this thread with a pair of small bookshelf type speakers - and in reality neither unit is best suited to playing in the 100Hz-200Hz range; so the blending is far from perfect.
The placement of the drivers on the front baffle also matters, as once you get above the lowest bass frequencies the sound energy ceases to radiate all round (like a lightbulb) and starts to beam towards the listener (like a torch). This effect is related to the width of the front baffle, and must be taken into account with baffle step compensation in the crossover - otherwise you'll hear a step up in volume at the baffle step frequency.
As a general rule of thumb; speakers with smaller drivers will produce little low end bass, but with good quality drivers will produce an excellent sound across the midrange to high frequencies. Pushing them hard to create more volume will easily drive them to distortion.
Larger speakers can reach lower (and fill a larger space) but may "boom" in a smaller room.
Cheap drivers tend to produce a lot of distortion - both linear (in that an input frequency sweep at a fixed volume level will produce a varying output volume level at different frequencies) and also non-linear (resonances causing harmonics; e.g. if the driver plays 100Hz there will be some sound produced at 200Hz, 300Hz, 500Hz, etc). Cheap drivers also tend to have very different frequency responses off axis, and because so much of what you hear is sound reflected off walls, floor and ceiling, the quality of the sound produced off axis is really important.
In terms of cost; about 20 years ago I was told (by someone in the industry) that if you saw a £1000 pair of floorstanders in a shop, there would probably be less than £150 in drivers and crossover in the system. The cabinet would also likely be built to a price (using thin chipboard with little bracing).
In theory then, you could increase the retail cost by just a few hundred £ by using a £300 set of drivers and a fairly dense and braced MDF cabinet. However, you wouldn't then sell many of the £1000 speaker, so that better unit would likely be given a wood veneer (for a much more expensive look) and sold for £2000+.
My first set of floorstanding speakers (about 20 years ago) were based on a model from ProAc. All the parts cost around £600, with the ProAc original being in the £3000+ range. Some years ago I spotted a pair of small monitor/bookshelf speakers (at £1000) almost identical (in size and drivers) to a DIY version I'd made for £300.
Down at the budget end it's hard to save money with DIY, as mass produced cheap drivers in little boxes can be made for very little cost, but going up the scale can really save money.
I've barely scratched the surface with that - ignoring passive radiators, 3-way systems, horns, electrostatics, or the single biggest effect on a speaker; the room. But hopefully it was useful.
