Speaker size?

Found some at Tonys Train Exchange 

expanding on David's comment: a speaker needs an enclosure to prevent rear sound waves from cancelling front sound waves. for a 1½" speaker, I've used plastic drain pipe as a rear enclosure. if you purchase Soundtraxx high bass speakers you can purchase enclosures made for them.

in addition to the enclosure, sound will be much better if there is also a chamber to amplify and boost mid and low range sounds. a fuel tank won't give you much of a sound chamber, plus the speaker is firing downward, relying on reflected soundwaves to hear it. however if that is your only option, make the best of it.

I had placed speakers in the fuel tanks of a set of MU'ed Weaver FA engines, using SoundTraxx DSX decoders. the sound was OK, but now I am in midst of moving the speakers to the carbody, and moving weight to the tanks. the carbody provides a good sound chamber. it should be noted that the fan grill was routed open and I am etching grills for them.

Dave, Chris; 

Thank you both for the information.  Car body.....hmmm, that would allow for options on speaker size and gives you a premade sound chamber.  

-Mark

My favorite speakers are the QSI High Bass speakers which are available from lots of dealers.  You can read reviews of these at the QSI Solutions website. 

I used an enclosure for my two QSI High Bass speakers in my Sunset brass UP 844 tender and it sounded okay. I removed the enclosure and used the tender as the enclosure and it sounds much better -- fuller, deeper, richer.  But, that only means it works better in this one case.

 think acoustics is at the intersection between art and science.  The theory will only get you only so far and then you gotta do the old "cut and try"   

Thx Bill, I'll look into QSI.

Here is a good video from Model Railroad Hobbyist eZine on describing model railroad DCC speaker principles.

http://youtu.be/j4kgLeDltxg

Scott K.

Austin, TX