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Sound Only Decoders


rodshaw
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Following on from some ideas in the thread about cheaper and better DCC sound, I've been considering fitting non-sound decoders into my four US HO locos, which are all currently analogue, and using one under-baseboard sound decoder attached to an under-baseboard speaker or two. This would be consisted with whichever loco was operational (there would only be one at a time).

 

Is a sound only decoder worth considering? MRC and Digitrax do them, and they'd save me a bit of money, but I've read fairly negative, or at best lukewarm, comments about them on this forum.

 

I can't seem to find any sound only decoders by Soundtraxx or ESU - do they exist?

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I can't seem to find any sound only decoders by Soundtraxx or ESU - do they exist?

 

No. This is because you can't really do the premium sound performance they are noted for without also controlling the motor. Their decoders all control the motor and the sound and by knowing what the motor is doing they can make the sounds adjust according to if the loco is accelerating, coasting or braking.

 

By an large you get what you pay for

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So does this mean that an under baseboard sound decoder that also has motor control can be synchronised with the loco motor, whereas a sound only decoder can't?

 

No it doesn't.

 

With a sound decoder inside a loco, the decoder can sense the motor revolutions and respond accordingly.  The most obvious illustration of this is making steam chuffs in time with wheel rotation. Many decoders can do this to a high degree of accuracy just by sensing motor revolutions.  It can also be used for other effects, such as making brakes squeal when speed drops below a certain speed, and stopping the squeal when the loco comes to a stop, or altering the sounds from loco working hard (going uphill) and loco coasting (going downhill).

 

With a sound decoder under the baseboard, you loose the connection with the locomotive, so coordination has to be done by setting both decoders to behave in a similar manner, and trusting them to stay in step, or by issuing commands to the sound decoder to change what it is doing.    I doubt you'll get perfect steam "chuff" alignment, but should be able to get acceptable behaviour.    You can do the same setup with both sound_only and sound+motor decoders, so the choice is probably down to the available sound files, and the quality of the sounds generated.   The quality of motor control is irrelevant to under-baseboard use.     You can do it without decoders using a computer or dedicated hardware.   

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  • 5 years later...

MRC do sound only decoders that can be used with whatever your favourite motor control decoder is.

 

They do ones for steam and diesel.  Each can be changed for different sounds by selecting either CV's or Fn buttons.

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Just an idle thought - would the way forward with the 'sound-only' chip be to put it in the appropriate loco (diesel, steam, whatever) let it 'learn' the motorisation and assign a function to that chip to that particular loco. Having done all the sounds wanted one at a time in each loco then put the chip under the board as proposed and then create a 'consist' between the under-board and a loco and then use the assigned function?

 

It would be akin to putting in two chips in the Hornby HST set, the dummy end chip having been first put in the motorised end set up, and then when done, put into the dummy end. The second chip then placed in the motorised unit and 'consist' formed between the two - that's what I did and it worked (though in this instance it was a full-fat chip in each unit, on the move, rather than one being static as proposed).

 

Cheers,

 

Philip

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At one time on the Ingelnook rather than having the chip under the layout I had a steam sound one on top but hidden into a Bachmann pit head gear building.  Not noticeable on a small layout that the sounds are just in one location.

 

Consisting with another is feasible.

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On ‎20‎/‎08‎/‎2019 at 16:55, Richard Croft said:

If I were you I would put the money into one sound decoder and use it in the conventional way, build up your collection of sound decoders over time to spread the cost out.

 

This man is wise.

 

It's what I have done.

I have around 20 locos but only 3 have sound; Class 08, Class 68 and HST.

 

I recently bought a lovely European loco (Taurus), which could have had sound but decided against it as the money I have saved means I can get a Hatton's sound 66, which will be used more than the Taurus.

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Steam loco sound decoders usually use motor bemf to gauge chuffing or coasting, and hence motor speed for which set of chuffs are played (slow, faster, fast), whereas a diesel can be at any notch setting at any speed depending if the loco is driving or coasting, indeed some locos can be run as a stationary generator for trackside tasks.

 

Therefore a sound only loco decoder under board setup may not be what you require. Many would say the sound quality of an MP3 player through decent speakers would be a better bet, especially if coupled to a sequential player that passes sounds around the layout to follow a loco- do not ask me how to do that though as I have not a clue.

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  • 1 month later...
On 20/08/2019 at 14:55, AMJ said:

MRC do sound only decoders that can be used with whatever your favourite motor control decoder is.

 

They do ones for steam and diesel.  Each can be changed for different sounds by selecting either CV's or Fn buttons.

These are indeed what I have used. I bought two MRC diesel sounders and placed them under the layout at opposite ends (it's only four feet long). You can choose between six different US diesel prime movers (four EMD and two Alco). They work perfectly in sync with each other and with the loco, whatever the decoder, as long as they are set to the same address. They have a variety of function options including manual notching, horn, bell, brake squeal, air release etc.. I used them with my previous HO scale locos and now, having gone down to American TT, I can still use them with my new locos. Not quite the same as having each loco fitted with sound but more than good enough for my purposes.

At the lowest volume they are pretty loud at home. At the highest volume they are just about ok at a show.

MRC have produced some new ones now complete with a PC-type speaker housing but I'm not sure they're available yet in the UK.

 

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