DCC sound for a Class 158

[whart57]

I'm building a three car Class 158 set and would like to know if anyone has any advice on the best route to installing DCC sound in it. I use ESU Loksound chips in my locomotives but I have not done a DMU before. Apart from pointers to chip and sound file, do people install speakers in every unit that should have a motor in it?

[SRman]

My two-car 158 has Howes sounds on an older ESU LokSound v3.5. Bryan very kindly added an extra engine start routine for when the decoder eventually gets transferred into a three-car class 159.

I was planning to add connector plugs to operate the lights at each end from the one central decoder, but it would be easier to put separate decoders for each of the dummy cars in the 159, especially as I am working on enhancing the lights to include marker lights as well.

I do like that idea of putting a separate speaker in each car - a two-pin plug and socket would do the job between coaches (as I have done with a pair of class 20s with one sound decoder between the two - one powered the other unmotored). I'm not quite sure if I can do that with a three-car unit as the impedances could be tricky to get right.

[whart57]

Thanks, I'll follow that up.

 

Regarding impedances, if you have three 4 ohm speakers couldn't you wire two in series, one in series with a 4 ohm resistor (of suitable wattage) and then have both lines connected in parallel? If I remember my Ohm's Law correctly:

 

1/(4 + 4) + 1/(4 + 4) = 1/4

 

i.e. overall impedance is still 4 ohm.

[SRman]

That should work, but it does confirm what I said about it being tricky as we have to resort to a resistor in one line, as well as trying to keep them all in phase between three coaches.

[whart57]

Wouldn't it be better if they were not in phase? I remember reading somewhere of a guy who deliberately tweaks the scan or something of loksound chips so that two diesels sound slightly different before putting them in consist

[wiggy1]

Wouldn't it be better if they were not in phase?

 

 

'Phasing' we are referring to is when you have two speakers wired in parallel and if they are not wired up correctly you will get a very poor sound.

I'm not genned up on 'Phasing' but I think they try to cancel each other out, normally wired + to + on the speaker terminals in parallel. 

I think you mean 'in sync' where one engine is either running slightly faster or slower or the pitch has been altered so they don't sound the same in a consist.

Wiggy.

[whart57]

I know, this phasing you can think of one speaker being on "suck" while the other is on "blow".

[wiggy1]

I know, this phasing you can think of one speaker being on "suck" while the other is on "blow".

 

 

Not sure what it would be like in a dummy power car, not tried it yet.

Wiggy.

[Revolution Mike B]

I've used a V4 in my two car 158, running two 4ohm speakers and it's fine. I have some ridiculously small connectors supplied by Charlie at DC Kits (or you can get them from Kevin at Coastal DCC) to connect the wires up via the corridor connectors. I'm not too bothered about the sound of the individual engines firing up separately as the unit is always running. Interestingly enough, if you mount the speakers towards the non driving end of each coach, when you make up a three car unit, it sounds like there's three engines revving away. 

[whart57]

I'll bear that idea of speakers at the inner ends in mind. Seems simpler than trying to balance three speakers