I installed a couple of Scale Sound Systems speakers in some locomotives yesterday and have some feedback.
Website here:
https://www.scalesoundsystems.com/I purchased 1 "Coeval" speaker for an Atlas 8-40CW (
https://www.scalesoundsystems.com/product-page/atlas-master-dash-8-40c-1) and 1 "Rectify" speaker for a ScaleTrains ET44C4 (
https://www.scalesoundsystems.com/product-page/scale-trains-sd40-2).
The Coeval speaker comes pre-wired with two speakers, and you can specify it as 16 Ohms (parallel) or 4 Ohms (series). I chose 16 Ohms, as that's how I have all my home built dual speakers wired up. The Rectify speaker is a single speaker rated at 8 Ohms.
The results:
-The Coeval speaker sounds significantly better than any other speaker I have tried. You can hear the low rumble from the prime mover in a way that I've never heard from a model. By far the best low frequency response I've heard.
-16 Ohm load is too quiet when used with Railpro. I recommend the 4 Ohm version.
-Install is simple as can be. A dab of CA glue and put it in place. All their speakers are designed to fit without modification. Solder the two wires to the LM speaker wires.
-The Rectify has volume but lacks the bass of the Coeval.
I think these speakers are a nice upgrade from traditional speakers, and the Coeval even sounds deeper than my locomotives with home-grown 4 speaker set ups. They are expensive though, so that my deter some people. Install is easy, though most are made to fit the factory speaker locations, which in general are lousy positions. Most manufacturers put the stock speaker at the rear of the locomotive....far behind where the prime mover is and where the horn would be. One of the reasons I've built my own speakers is so that I can have one in the front of the locomotive and one in the rear, effectively centering the sound on the exhaust stack and (in my case) horn location. I'm kind of picky when it comes to that. Some locomotives it won't matter on (GP-7 for example), but when you put the speaker in the rear of a ET44C4 you can easily tell that the sound comes from the wrong place.
Anyways, give them a try if you are curious. Get the Coeval if you can, you'll like it.
-Kevin