Bad noise from locomotive when increasing speed, noise stops when decreasing speed - ever heard or seen this before?

#1 you have the volume maxed to where it is already crackling in the speaker before you do anything.

#2 When you increase throttle- that's actvating dynachuff- dynamic chuffing increase with more bass to the chuff. When back off the throttle, that decreases the chuff to more of a coasting or drift chuff. Less bass = less speaker cone excursion, thus less or no crackle when not in the hard bass acceleration chuff.

I would replace the blown speaker and then also turn down the volume...

And, being a K-line with cruise that was known to have a potential failure and the fact that cruise board is unique to that engine series to provide the chuff signal -  as discussed right here https://ogrforum.com/...33#81537088427983433

here is that diode install topic https://ogrforum.com/...4-6-6t-diode-install

I'd run it with sounds off, that allows you to determine if it's sound or mechanical.  I'm with Vernon on the speaker, I'd certainly take a close look at that.

@Vernon Barry posted:

And, being a K-line with cruise that was known to have a potential failure and the fact that cruise board is unique to that engine series to provide the chuff signal -  as discussed right here https://ogrforum.com/...33#81537088427983433

here is that diode install topic https://ogrforum.com/...4-6-6t-diode-install

Actually all K-line cruise boards have the ability to provide chuff. The tank engine was the only one that used it from the factory probably because it was the only steam engine to have a fan driven smoke unit. I converted my Hudson to 4 chuffs using the cruise board but it only puffs 2 chuffs.

That's plain old audio distortion and clipping.

Turn the volume down a step or two and see what happens. If that fixes it, you're done.

If it still makes that same noise with the volume reduced a bit, the speaker is bad.

@The TrainBoard It sounds like this could be a mechanical issue with the speaker (hole, tear, or debris inside it)...

OR to my ears it sounds more like something, like maybe a loose screw or something, is vibrating sympathetically when certain bass tones are being reproduced with sufficient volume, enough to overcome the pull of gravity.

What happens if you pick up the locomotive and give it a gentle up-down and/or side to side shake?  Do you hear anything rattling around?

Either way, I'd open it up and look carefully inside for loose parts and physical damage to the speaker or something stuck to it that doesn't belong.

Appreciate all the replies!

I learned that the volume resets to max every time you turn the locomotive on if you lower it with the remote, which is what I was doing.

Turns out if you use the screw under the coal load on the tender to lower the volume, it doesn't reset.

Turned the volume all the way off to confirm that it is indeed sound related, not mechanical.

Even on the lowest volume setting it makes that horrible sound, but much lower.

We took the locomotive apart and don't see any visible damage to the speaker.

I suppose it could be the soundboard itself, but we'll replace the speaker first and see if that helps.

Can anybody recommend a replacement speaker that we could swap out ourselves?