speaker enclosure in a Diesel shell

Model Railroader Electronics and DCC
1

[bow]Hi all.

I’m thinking that if I could get a better air flow (sound) out of the loco shell the sound might be louder and you would be able to turn the sound down and get a little better quality. Some time ago I looked in to replacing the solid cooling fans with see through, but as far as I could tell the company recommended, wanted $7.50 for each one plus shipping.
Question: Has anyone tried cutting out the side grills and replacing with some kind of screen? I’m trying not to reinvent the wheel.

Thanks. [bow]

Lee

2

Would help if we knew what locomotive and what scale you are working with.

3

I have found that the shell sort of makes itself into an echo chamber. The test would be to listen to the sound, or maybe even record it, with the shell on. Then do the same test with the shell off. On my locos, I have found that I get better sound and more low frequencies with the shell on. The sound escapes through all the little air spaces around the frame and trucks.

If you think you are having poor sound quality, are you using a speaker enclosure? If not, that is your problem. The size of the speaker also makes a difference as does the sound decoder. I favor the combination of Tsunami sound decoders and the mini oval speaker and enclosure.

4

Most diesel models have so much open space around the trucks from which the sound can escape that there’s usually no need to create openings in the shell. Using a properly bafled speaker is the most critical part of sound installations.

5

[quote user=“wooden”]

Would help if we knew what locomotive and what scale you are working with.

Using an “HO” GP38(?) Athearn with an LL 110 LC and I have a Rail masters Hobbies HI base speaker that is made with it’s own enclosure with a hole facing outward along side the speaker. I assume that relieves the back side pressure. I have several locos that I have installed decoders in. This is a loco that I painted as my first try so while I’m repainting I thought I would experiment with the big speaker to see if there could be improvements to the sound.

Thanks for any help that may you may give.

Lee

6

Well if it were mine I would upgrade to a new Tsunami decoder.

Then mount a 16 X 35 MM speaker over the rear truck and let the sound out throug the truck opeining.

If you mount the speaker face down on the inside of the shell the shell will become the enclosure.

Without a enclosure on the speaker you will have more room.

7

This link to Tony’s web site may help you understand how speaker enclosures work. When you get to the page click on “designing loco acoustics” [PDF] http://www.tonystrains.com/products/pop-speakers.htm

Good luck, Truck.

8

Hey Guys

Here is what I’m using18 X 53 X 14 mm Bass Reflex speaker. The loco that I’m working on is one of the few that this speaker will fit in because of size. This speaker along with the others I have bought and installed seem to have their own speaker enclosure. Do they need something else?
By the way, this speaker is a snug fit in this loco( Atheran GP 38).

Thanks

Lee

http://cs.trains.com/TRCCS/themes/trc/utility/[IMGhttp://i260.photobucket.com/albums/ii34/Yankeeflyer/IMG_0744.jpg[/IMG]:550:0]

9

The speaker you show in your photo is what is called a ported speaker enclosure.

I have not used this speaker as most installs there is not room to fit it into the loco.

I would try to block off the opeinig of the ported outlet. The port is letting the back side of the speaker sound waves out- I would think that this would cancel some of the sound waves coming from the front of the speaker. They are too close together. IMO.

10

I agree.