Soundbugs have an 8 ohm speaker so there are plenty of options available as far as speakers and enclosures go.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Check with your DCC supplier of choice, there are many speakers on the market. Did you make a sound-box/speaker baffle for the installation? Is that what is fouling the shell? Unless this loco was specifically designed for sound you may have to create space for a speaker by milling out some space within the frame/weights. Anyway, the first step would be to look for a smaller speaker. You will need to know the dimensions with some degree of accuracy.
Remember that the smaller the speaker, the tinnier the sound. So you want the largest that will fit the space. Proper baffle construction, ensuring that the front and rear of the speaker are isolated from each other by the creation of a sound-box is very important to the sound quality and volume.
Simon Modelling CB&Q and Wabash See my slowly evolving layout on my picturetrail site http://www.picturetrail.com/simontrains and our videos at http://www.youtube.com/user/MrCrispybake?feature=mhum
I installed a Digitrax DH165A0 with a Digitrax Soundbug (SFX004) in an HO Atlas AEM SEPTA locomotive, I tested the locomotive everything worked perfectly, lights, sound and motion. I tried to put the shell back on but it won't go all the way in due to the speaker. Is there a smaller speaker that I can use to replace the one on the Digitrax Soundbug with?