Anyone willing to yank their ST C39-8/T4 apart?

[daniel_leavitt2000]

I'm looking for photos of the fuel tank, speaker and speaker slot with speaker removed. I tried to remove the speaker on mine, but it is glued/adhered into the slot and may act as a sound baffle.

[Steveruger45]

I'm looking for photos of the fuel tank, speaker and speaker slot with speaker removed. I tried to remove the speaker on mine, but it is glued/adhered into the slot and may act as a sound baffle.

Here is a photo of my dc version with no speaker.
Speaker recess measures 17 x 11.5 x 4mm. The recess/frame is solid metal with only one small hole in the bottom for passing speaker wires through.
Hope this helps [ Guests cannot view attachments ]
See also some ideas I have on post 10 of this thread https://www.therailwire.net/forum/index.php?topic=46527.msg608604#msg608604

[daniel_leavitt2000]

I wonder if that hole is opening up the adhesive seal on the bottom of the speaker. That would account for some of the speaker  issues.

Did you destroy the adhesive when taking the speaker out?

I have two plans of attack for this. One is a speaker that has a pronounced lip with adhesive. This would act like a sound baffle. I would mount the speaker to the tank casting and  use phosphor bronze strips to contact the sprung feet of the speaker. This is essentially how Atlas and IM equip their engines. The advantage to this is the magnet is not held close to the track.

This would be the speaker is use:
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The other option would be to drill a few holes in the fuel tank  bottom where it abuts the speaker top. This would be the easiest solution but I'm not convinced it would do any good. I'm not about to drill into a $230 engine without replacement parts at the ready.

[Steveruger45]

Mine is a dc version.  No speaker.
I’m not sure how the OEM speaker is applied.  It could be stuck, diaphragm side to the frame, with a self adhesive layer I guess. Some speakers do come with that arrangement.
 If that’s the case then the OEM speaker has really no sound enclosure of any meaningful volume and, like you say, could be further undermined by said hole in the frame as well.  That for sure would not be the best for sound.
  It may also be that there is a very very shallow enclosure mounted on the diaphragm side, maybe 1 or 2 mm deep I’m guessing, and that is stuck to the frame which would be better than the former but still have too small an enclosure volume for best sound.

[wmcbride]

Design is a trade-off but I was extremely disappointed with the speaker in the ST Tier 4. It is almost as if ST was kind of oblivious to the issues of speaker enclosure and the speaker was an afterthought -- which I doubt. There certainly was enough room in the Tier 4 and C39 fuel tanks to do it better. The rest of the engines are truly excellent. The speaker design -- meh.

I am not sure if Atlas put more thought into their design but the results are certainly so much better. Also, the fact that the Atlas silver series comes with the speaker installed is a plus and certainly makes it easy to upgrade.

[Jbub]

I've been a little busy with a work trip and train show this week but I did manage to "modify" both engines speakers. To answer a couple of the questions quickly.
The speaker is attached facing up and gently prying the speaker out will not ruin the adhesive backed foam on the speaker. The T4 gevo is a little tricky to make an enclosure for because one side of the "housing" is open due to the air reservoirs being recessed into the fuel tank instead of being cast in place. The c39 did not have this problem.
The t4 sound file for scale trains is horrible. It's over driven and somewhat quiet. Granted the prototype is actually fairly quiet but not silent.
Also if you go with a different size speaker, make sure it's a good one. I've had problems with the replacement speakers I've bought being quiet even with a proper enclosure.
So far my current thought is to enlarge the opening even further to allow for a bigger enclosure