Look, I think there are several factors at play here. Certainly, the installation of a speaker will affect the results depending on how it is positioned and whether it is sealed. I have no arguement with that.
However, where I strongly disagree is with the statement "There is no discernible difference between a bass reflex and a properly installed 23mm ESU speaker". This is most definitely not always true (it depends on specific prototypes) and this is where my comment of 'tinny' results comes in because I have heard the differences for myself.
As others have indicated, a larger speaker cone will always produce better results. It's simple fact. What I think is being misunderstood is that the bass-reflex and the 23mm are both designed to handle different frequency ranges - the bass, the lower frequencies and the 23mm, higher frequencies. On their own, a bass sounds 'flat/boomy' and the 23mm sounds 'tinny', however, when you put the two together, you get a cross section of frequencies and a result which sounds much better. Personally, I can't see the point of fitting two identical speakers. All this is going to do is give greater volume, but it isn't going to deliver the frequency range.
Having said that, it also depends on the sound recordings and the prototype being worked with.
For example, I have a Heljan 52 while I have fitted a bass reflex in the fuel tanks and and a 20x40mm inside in the roof. This particular type of loco has lots of low frequency/bass sounds which the 20x40mm cannot reproduce. Originally, I had two 23mm as well. They really didn't do the sound justice. The bass makes a huge difference.
I also put a 20x40mm in a Hornby 50 and think this is acceptable: a 50 doesn't have the low bass sounds which a 52 has and this is why the bass-reflex doesn't make much difference to a 50.
I also disagree strongly with your statement: "At this size and sound quality, forget bass and tweeter installations. There is not the depth of sound in the sound recording to justify really good speakers".
If this was true, why can I hear lots of humming and whiring bass-end sounds (motors, pumps etc) on the 52 with a bass-reflex wired, yet when I have a 23mm connected on its own, none of these sounds can be heard ? I would suggest that the sounds are present in the recording and that it is the speakers which determine whether they can be heard. Sealing a 23mm made very little difference.
So in summary, there are a number of parameters to getting best results. Yes, the technology has some way to go, however, there are a number of steps which we can take which will improve the present situation quite considerably. Simply throwing a LokSound and wiring one or two 23mm speakers to it (sealed or not, positioned correctly or not) isn't going to give the best results on its own.
Looking at Graham Plowman's videos and having played around with these locos myself, in my opinion, the Howes version is a lot better than the SWD version. The SWD has far too much inertia and the engine often idles at times when it should be revving. You can 'clag' the Howes far more reallistically than the SWD.
