Adding a Speaker in a Small Place

Almost a year ago I shared my designs for a 3D printed speaker enclosure which could be built up in sections.  This allowed Zimo speakers to be fitted in even more places.  You can read about it here.  Since then I haven’t had the need for them but just recently I did; and in this week’s post I will share it with you.

Rowa, and later MRC, used to make some wonderful large steam locomotives for N Scale, in particular the 2-8-8-2 Y6b.  When Rivarossi and Con-Cor took over the production they added the 2-8-8-0 EL5 to the lineup.  The EL5 came with a large Vanderbilt tender and it’s one of these I recently added a sound decoder too.

As the shell of this locomotive is full of motor and metal chassis the tender is the obvious place for the decoder and speaker to go.  However, the Con-Cor Vanderbilt tender is a one-piece molding and the body doesn’t separate from the chassis.  To gain access to the inside the back plate has to be removed.  This isthe section between the tender and the locomotive cab just under the coal load.  It’s glued in place but with a gentle bit of pressure it will pop off.  The two metal weights inside the tender will now slide out, giving you full access to the inside.

For this DCC install I am using a Digitrax sound decoder with a Zimo speaker, a LS8x12. This speaker gives much better sound than the standard speaker the decoder comes with.


As you can see the speaker comes with a sound box.  This is an injection-molded box with a recessed lip around the top which the speaker fits into.  However the box is fairly deep.  My intention is to fix the decoder and speaker to the upper metal weight and slide it all into the tender, but the speaker will not pass under the coal load.



To solve this I’ve used two of my 3D printed speaker enclosure sections to form a smaller speaker box. Three sections will make the enclosure the same height as the original.


The two parts have been glued together with a spot of superglue.  Before fixing to the metal weight I did a test to see if it fitted.

speaker-fitting-5 speaker-fitting-6

The back of the tender is slightly higher than the space under the coal load so although the speaker just scrapes through it will be just fine once in the right place.  I again used superglue to fix the sections to the weight.  The speaker has a sticky foam fitting which holds it into the new enclosure.  The decoder was also fixed to the weight as well as the capacitor, you can see it between the speaker and decoder.


This whole assembly then slides into the tender and is prevented from moving by the grooves which hold the weight in place.  The last thing to do is connect up the wires.  For this particular locomotive I cut off the plug and hard-wired it in.  Only four wires need to go to the locomotive, so it made sense.

Once the decoder was tested and renumbered the locomotive was ready for service.


Well, almost ready for service.  The decoder was recycled from another locomotive and, although the sounds work perfectly, they are the sounds for an Alco PA diesel!  This can easily be corrected by uploading some new sounds using Digitrax’s SoundLoader software which is something I will show you how to do in a later post.

For now the speaker enclosure sections should be available by next week and I will share those with you and maybe a video of the EL5 working a train in all its glory.