What speaker is going to work well in an Athearn SD40-2? Do I need to obtain/fabricate a baffle for it, or could it be installed in one of the roof fans (effectively using the entire shell as the baffle)?
I used 4. 1 oval + 1 round + 2 round. That covered all 5 fan vents. The effective resistence was 8 Ohms (2 parallel sets of 8 ohms wired in series)
What brand or model of speakers?
SoâŚhow did it work?
I would have to measure them to be sure the sizes. But the rounds were high-bass.
The high bass plus the oval are available at tonys trains. However a number of vendors now sell them.
I custom cut 3m double sided foam tape to serve as a gasket. It was no louder then a conventional setup but the bass was a little better and the horn wasnât distorted at max volume.
The wiring went like this:
Speaker set 1:
red wire from + speaker terminal decoder to + terminal on oval speaker 1
Black wire from - terminal oval speaker to + terminal round speaker 2
Black wire from - terminal speaker 2 to - speaker terminal on decoder.
Speaker set 2:
red wire from + speaker terminal decoder to + terminal round speaker 3
Black wire from - terminal speaker 3 to + terminal round speaker 4
Black wire from - terminal speaker 4 to - speaker terminal decoder.
When you are done, you will have two red wires on the decoderâs speaker + terminal, and two black wires on the decoders - speaker terminal.
1 Like
This is the brand of speakers I use: Railmaster Hobbies. I have done several SD-40T-2 and GP-40âs. I use the Bass Reflex Speaker -narrow, 8 Ohm for the SD units. It is a really good speaker and fits in the shell very well. It does take a little bit of sanding on the sides to make it fit but it is well worth it. Also it has two mounting lugs on each end. I usually just cut them off. I have used this particular speaker in 5 SD-40T-2 Installs.
The SD-40T-2 is slightly bigger than a SD-40-2 so you may want to use a DS1436-8 instead. It is a slightly smaller speaker enclosure but still gives you a good level of sound. I use this speaker in my GP-40âs which have less space than the SD-40âs.
Both of these speakers come with prefabricated baffles. The bass reflex speaker-narrow is very close to the inside dimension of the Athearn shell. A few swipes across the side with some sand paper makes a perfect friction fit in the shell (no glue needed!)
I have installed both types in Athearn and Atlas Models and have been very pleased with them.
Also I am not affliated with them in any way. I am just a satisfied customer!
I hope this helps.
1 Like
If I can give a more âgenericâ answerâŚin a narrow-hood diesel like a GP, SD, RS etc. type, generally a 1/2" x 1" speaker is the largest that will fit in the body. (Some engines have a pre-built speaker enclosure in the fuel tank between the trucks that can hold a 1" round speaker - I wish they all did!) E, F or FA/PA engines generally will hold a 1" round speaker with ease.
In a tight squeeze, you can get by without an enclosure. That generally works better in a steam loco tender, where the shell is âair tightâ. In a diesel, if you put a speaker in the body facing up so the sound comes up through the radiators, itâs possible some of the sound will escape by going down through the openings around the trucks. Depending on the model, this may or may not be all that noticeable.
Several companies offer speakers either already in enclosures, or with âsnap fitâ separate enclosures. As much as possible, I like to buy speakers now that come with wiring already attached, for me soldering wires to the small pads on the speaker can be a little trying, though eventually I get it done.
Have you looked into the âsugar cubeâ speakerss? They are small and selfcontained (come with an enclosure)> I have not heard any personally except via u-tube videos, but theyâre suposed to sound reallt goood amd have good volume.
Are the ported speaker baffles sold by Digitrax any good?
A port in an enclosure the size we are using in our models isnât even feasable. These little speakers cannot move a sufficient volume of air within the enclosure to even make a port function ! All a port this small is going to accomplish is reduce the any effect backpressure that may exist within the enclosure and weaken the speakerâs effectiveness.
Ports do not function unless there is enough air pressure within the enclosure to utilize one. Even then, the port has to be carefully tuned - the size of the opening and the length of the tube. Even in home stereo speakers, an inproperly tuned port can actually make the sound worse instead of better - but this is utilizing 10 to 15 inch speakers that can actually move some air !
Mark.
Speaker design is a black art. but theres advantages and disadvantages to putting a speaker in a sealed box. If the box were sealed and infinite in size then a sealed box is your best answer. The smaller the box the more frequency you lose. Flanking and reflection cause negative or inverse wave cancelation. Boxes are designed to prevent this from happening. However with speakers properly sealed with a gasket flanking is not an issue when fired through thean grills. The shell prevents the flanking. Reflection from the track bed wont that bad because unlike a normal speaker theres a ton of irregular surfaces and openings that cause cancelation from reflection refraction of the backwave before it can even escape to hit the ballast which will scatter the backwavemore.
1 Like
Theres a you tube vid where a guy test all avalable speakers including sugar cube on a test bench. You might want to try a search under ho speaker test.
Made the link clickable for Donâs video:
https://www.youtube.com/watch?v=UGb4JMct7Tk&feature=youtube_gdata_player
Dave
Holy CARP those sound great! Iâm going to have to revise my opinion on âonboard sound has no bass!â
In the video, 20mm speakers are installed in a Kato SD40-2. Would these also fit in an Athearn SD40-2 or are the shell dimensions different? (the closest measurement I could make is about 19mm, but itâs tough to get in there with the calipers to measure the inside shell precisely)
For Athearn SD40-2, the speaker uses a sealed baffle to produce a natural sound. The sugar cube speaker is a 13x18mm moto speaker with a sealed baffle to produce a good sound. The sound is very good when the shell is properly sealed, the sound is deep and clear. The SD40-2 looks heavy, but the sound is strong and the setup is good. Fix my speaker the speaker is not working properly, the wire connection coil and foam surround are checked