Higher is usually louder. I haven't seen one yet that the LOWER the value, the LOUDER it gets - that would be against all human nature and maybe even the laws of the universe and any vendor doing that would be laughed out of business.
Somewhere in the manual, or if the decoder manufacturer has a seperate detailed manual, it will list the range. Most go 0-255 but some only go 0-32 or 0-16, and putting say 200 in on one that only goes as high as 32 for max can cause some unpredictable results. It MIGHT simply divide by the max, which in this case 200/32 is 6.25, so it might act like you put 6 out of 32, which is a whole lot quieter than 200 out of 255. Or it might shut off that particualr sound completely. So it's good to know the range for the volume CVs when setting them. If you are trying to reduce one of the volumes, then anythign less than what it currently is will be fine, all the way down to 0 which will shut off that sound completely. If it's already 128 or higher, it's a safe bet it goes to 255. If it's currently 30 and very loud - a good guess would be 32 is the max.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Do note that different decoders, besides different default settings, can have different max settings; i.e., less than the common 255. My LokSound Selects have a master volume range of 0-192, with a default of 180. I'd guess a value over 192 would work, but with no increased volume.
Also, you may want your different decoders in a similar effective volume range. Not the same CV settings, rather reasonably similar actual volume. There are free phone apps (mine is an Android) that can be fun to play with. Surely not exact, especially with different sound files from different locos, but a tool to utilize. OF course, you can get close enough to what you like by ear. Another approach would be to get one loco at volumes you like, then adjust other locos to be reasonable volumes related to the example.
It's good to get the prime mover, bell and horn sounds tweaked to where you like the volumes with relationship to the others, then if you want to change the overall volumes you can just adjust the master volume (if it's not maxed out and you want more) to tweak them all.
It's helpful to take notes, or use a tool such as JMRI Decoder Pro files, in case you need to reset the decoder.
Just some thoughts. I haven;t stayed very consistent about it myself.
Paul
Modeling HO with a transition era UP bent
It tells me the default but not the range but I was asking this as a general question
Joe Staten Island West
I'm no programming expert but that is what I do with the BLI locomotives I have. You need to refer to the manual that comes with the locomotive. It usually tells you I the range as well as the default.
Gary
Is it reasonable to assume that when setting volume CV's such as bell horn etc that the higher the value the louder the sound is?