If you want to sacrifice a lot of chasis weight, a LokSound micro (or even standard) will fit diagonally in hood units or horizontally in cab and cowl units, and their smallest spealers are narrow enough to fit in the fuel tank area.
I have a few PCM E7's that were factory LokSound units, and they didn't sound too bad. I bought them as factory seconds, and used the decoders and speakers in HO scale switchers, so the N scale spec speakers are fine for me in HO.
The quality of any on-board sound system is contingent upon the size of speaker that can be fit into a model. HO will usually accommodate a 1 inch diameter or oval speaker with appropriate baffle. N scale is very iffy on speaker size and where one can be fit -- usually no larger than 1/2 to 3/4 inch diameter, with weak sound.
You have heard HO scale sound -- now you need to find an N scale club and hear what they sound like.
I've recently been mulling getting back into model railroading from a brief hiatus (military life isn't all that conducive to my hobby I'm afraid) and haven't been able to make up my mind as to whether I'm going to go HO or N scale.
I'm a big fan of long trains with 4 or 5 engines on the front and 2 more cut in, and the scale was tipping towards N scale because of the ability for this kind of operation. However, just when I think my minds been made up I went to a club and saw 2 HO SD45s struggling with a sizeable freight -- or more importantly heard them. I left HO too early to really experience sound in its full glory and it was amazing.
So, basically, my question is, is there N scale sound today that sounds good, and with enough definition to really be able to tell when a locomotive is running fast vs crawling uphill?
Thank you!