Speaker Comparison: Knowles Fox vs. Star Micronics SCP-08B

[jdcolombo]

Railmaster's stuff is nice, but they don't sell anything that would even come close to fitting in an N-scale diesel - they are really oriented toward HO scale and larger.  I've been looking for a speaker that will fit in the 10mm width we have to work with in N-scale diesels (even my Fox Valley GEVO is 10mm wide for most of the carbody; got plenty of length, though!), and still give a pretty good rendition of a diesel prime mover.  So my cutoff width for these experiments has been 9mm, since you can build an enclosure out of .020 styrene around a 9mm width and still not exceed 10mm overall (.020 is just about 1/2mm in thickness; two sides adds 1mm overall).

If anyone else has suggestions on speakers that are 9mm or narrower, let me know, but the smallest 8-ohm speaker I've found so far is the Star Micronics (which also happens to sound pretty darn good).

John C.

[BCR 570]

Thanks for the reply, Greg - looks like the 8x12s will be difficult to source.

My Knowles Fox speakers arrived from Digi-Key today and I have completed a quick test fit inside the shells of the Atlas/Kato RS-3, RS-11, C-420,, C-630 and Briggs C-425, M-420 and M-630 shells.  I have a ESU Loksound Select Micro on order so I can try this out.

John:  Is there a way to fire up the decoder and speaker without installing it in a locomotive?  If so, how would one go about that?

Tim

[jdcolombo]

My Knowles Fox speakers arrived from Digi-Key today and I have completed a quick test fit inside the shells of the Atlas/Kato RS-3, RS-11, C-420,, C-630 and Briggs C-425, M-420 and M-630 shells.  I have a ESU Loksound Select Micro on order so I can try this out.

John:  Is there a way to fire up the decoder and speaker without installing it in a locomotive?  If so, how would one go about that?

Tim

Hi TIm.

Yes.  The LokSound will arrive with an 8-pin NMRA plug.  Cut this off.  Strip 1/8" or so of the black and red wires (track power) and the two brown wires.  Connect the brown wires to a speaker and the red and black to track power (I use some 6" 22-gauge connector wires with very small alligator clips at each end to do this, but you could just twist some wires together and make it work).   Select DCC address 03 on your throttle, and press F8.  You should hear the prime mover start up.  F1 is the bell; F2 is the whistle.  All of it will work without a motor connected.

Good luck, and feel free to e-mail me directly at jdcolombo@gmail.com with questions.

John

[peteski]

Thanks for the reply, Greg - looks like the 8x12s will be difficult to source.

My Knowles Fox speakers arrived from Digi-Key today and I have completed a quick test fit inside the shells of the Atlas/Kato RS-3, RS-11, C-420,, C-630 and Briggs C-425, M-420 and M-630 shells.  I have a ESU Loksound Select Micro on order so I can try this out.

John:  Is there a way to fire up the decoder and speaker without installing it in a locomotive?  If so, how would one go about that?

Tim

Tim,
just like with any DCC decoder, all you need to do is hook up the red and black wires to the track (DCC power). The speaker and external filter capacitors (if there are any) should also be hooked up. That is all you should need to operate it.

If you want to program it, you might need to hook up a motor (or a dummy resistor) across orange and gray wires to provide enough electrical load needed for programming.

[BCR 570]

Thank you both for your replies.  Sorry for the silly question but I have not operated a decoder outside of a locomotive before and have no experience with sound.  When my LokSound arrives I want to experiment with the different sounds applicable to my fleet and see how good they really are.  I appreciate the clear directions you have provided.

From what you have written, the decoder and speaker connect directly with no resistor in between?  I remember something Greg mentioned years ago about matching impedance of speakers to decoders, but I might be recalling incorrectly.


Tim

[peteski]

The instructions which are included with the sound decoder (or its online downloadable manual) should indicate how the speaker should be hooked up and what impedance it should have (like 4, 8, 16, 32, 100 ohms). Nowadays 8 ohm speakers are pretty much standard.  I think that some really early sound decoders needed a large electrolytic cap installed in series with the speaker (for AC coupling) but nowadays it usually connects directly to the decoder's speaker output leads.  When in doubt, RTFM (read the <insert a 4-letter word like for example "fine" here> manual). 

[jdcolombo]

Thank you both for your replies.  Sorry for the silly question but I have not operated a decoder outside of a locomotive before and have no experience with sound.  When my LokSound arrives I want to experiment with the different sounds applicable to my fleet and see how good they really are.  I appreciate the clear directions you have provided.

From what you have written, the decoder and speaker connect directly with no resistor in between?  I remember something Greg mentioned years ago about matching impedance of speakers to decoders, but I might be recalling incorrectly.


Tim

Hi Tim.

You don't need anything additional - just hook the Fox (in it's enclosure) directly to the two brown wires.

By the way, you can expect the speaker to sound even better inside the shell.  The reason for this is that the Fox in its enclosure will fit snugly inside the shell, with a little air gap at the top.  The snug fit helps control resonances, and the air gap provides just a tiny bit of additional reverberation.  It's not a huge difference, but I've noticed this in my installations, and it is a consistent effect.

John C.