Digitrax SFX volume question...

[mthduggan]

I've recently installed a Digitrax SFX sound bug in an HO scale Bachmann 2-8-0. Not plug and play but still pretty straight forward. Just soldering two wires to the pickups in the tender. I've adjusted the CV 58 (general volume control to max) and the CV 140 (I think that's right for the chuff...that is I did the right one I'm just away from the manual so I don't know if I'm telling you the right one... to the max).

I've used a bottle cap to make the baffle behind the speaker. The speaker is sitting under the "coal" on the tender.

Here's the problem. The loco sounds fine when sitting. It sounds fine when moving slowly. Then when it picks up speed, the mechanical sound of the loco moving down the track drowns out the sound bug. Thoughts? Experience? Fixes?

Thanks in advance for any help.

Cheers,

[vzjtothalo]

I've recently installed a Digitrax SFX sound bug in an HO scale Bachmann 2-8-0. Not plug and play but still pretty straight forward. Just soldering two wires to the pickups in the tender. I've adjusted the CV 58 (general volume control to max) and the CV 140 (I think that's right for the chuff...that is I did the right one I'm just away from the manual so I don't know if I'm telling you the right one... to the max).

I've used a bottle cap to make the baffle behind the speaker. The speaker is sitting under the "coal" on the tender.

Here's the problem. The loco sounds fine when sitting. It sounds fine when moving slowly. Then when it picks up speed, the mechanical sound of the loco moving down the track drowns out the sound bug. Thoughts? Experience? Fixes?

Thanks in advance for any help.

Cheers,

Mike:

While I don't have experience with that particular sound decoder, mechanical noise of the loco should be something that is prevalent without the decoder and should be addressed.


Assuming you have done previous sound installs, you know the basics: baffle, how does the sound get out, can I use more than one speaker, use the largest speaker I can if more than one is not an option, etc.

As far as the baffle goes, the tender of the 2-8-0 would be sufficient so long as the sound from the front of the speaker can't escape to around the back.

Hope this helps, John

[mabloodhound]

Make sure the edges of the speaker are sealed. Also, could the bottle cap be hindering your speaker? Maybe remove it and just use the tender shell as the baffle.

[mthduggan]

Make sure the edges of the speaker are sealed. Also, could the bottle cap be hindering your speaker? Maybe remove it and just use the tender shell as the baffle.

Dave,
Thanks. Definitely louder with the bottle cap baffle though I probably need to seal it better. I've got it in temporarily with a bit of goop from some transfer tape rolled up.
Cheers,

[mthduggan]

I've recently installed a Digitrax SFX sound bug in an HO scale Bachmann 2-8-0. Not plug and play but still pretty straight forward. Just soldering two wires to the pickups in the tender. I've adjusted the CV 58 (general volume control to max) and the CV 140 (I think that's right for the chuff...that is I did the right one I'm just away from the manual so I don't know if I'm telling you the right one... to the max).

I've used a bottle cap to make the baffle behind the speaker. The speaker is sitting under the "coal" on the tender.

Here's the problem. The loco sounds fine when sitting. It sounds fine when moving slowly. Then when it picks up speed, the mechanical sound of the loco moving down the track drowns out the sound bug. Thoughts? Experience? Fixes?

Thanks in advance for any help.

Cheers,

Mike:

While I don't have experience with that particular sound decoder, mechanical noise of the loco should be something that is prevalent without the decoder and should be addressed.


Assuming you have done previous sound installs, you know the basics: baffle, how does the sound get out, can I use more than one speaker, use the largest speaker I can if more than one is not an option, etc.

As far as the baffle goes, the tender of the 2-8-0 would be sufficient so long as the sound from the front of the speaker can't escape to around the back.

Hope this helps, John

John,
Thank you. This is my first go at installing sound. Right now the coal load, a piece of molded plastic, is covering the speaker. At first I thought that it would be muffling the sound; however, the sound is actually better when have the coal load in place than when I remove it. Adding the bottle cap definitely makes the speaker louder though I think that I"ll try some cardboard tubing as a possibility too.

I hadn't considered using an additional speaker or swapping out a larger speaker. Do you have any suggestions on the best place to pick up additional speakers?

Cheers,

[vzjtothalo]

Mike:

Electronics storehouses such as Digikey would be agood starting point. If their SFX product is like their other offerings, it will need a 32 ohm speaker. I would recommend taking some measurements (in mm, as that is how speakers of this size are generally sized) of the area under the coal load. Drill a LOT small holes in the coal load using a no. 78 to 80 bit, the more the merrier, but not so many as to obliterate the coal load.

Since you indicate an increased volume/better sound with the load in place, this says that the bafflling is ok, but has (a) place(s) where the sound is escaping from.

As far as using multiple speakers, check the documentation to see what it says. You'll want to know the output of the SFX is in wattage, and then we get to talk about wiring in series and parallel and which combination won't overload the SFX.

[CN6401]

Mike,
Whether you install the speaker facing in or out of the bottle cap does not matter, but the bottle cap should be fastened solidly in the tender. I use a small bead of silicone bathtub sealer to mount my speakers into the enclosures, in your case the bottle cap.
Next, are the speaker holes in the tender to let the sound out? If there are holes in the bottom then the speaker should be mounted in the bottom. If there are no holes and you say that your speaker is under the coal load the I suggest you take your Dremel tool and add a whole lot if small holes in the coal load to let the sound out. The tender itself becomes an enclosure but it needs to be vented.
Even the cheapest dollar store sound item has holes over the speaker for the sound to get out.
I hope this helps.