DCC sound question

It is just like any other DCC units. Give each their own address (typically something > 100, usually some 4 digit number). Then you create a consist (with an address

Oh, it is likely that the basic engine rumble of the two units when they are in a consist will be more or less 'in sync'. This would be no different with the prototype with a similar pair of same model engines (the only difference between an A and a B unit is the body -- both would have the same prime mover). Many sound unit have 'random' sound effects: air compressor whine and its presure relief valve, coupler clanking, etc. These sounds are at semi-random intervals and each unit will be different (different states of the random number generators in each decoder's processor). Things like horns and bells would be like the lights -- something you can control by mapping consist functions to unit functions -- this would be part of the consist setup. I would expect that a B unit would not have a 'cab' and thus not have a horn, bell, or headlights (but the decoder might be the same as for an A unit, so it might make sense to disable such functions in the B unit).

Or, you can just give both units the same address and get the same effect.

So long as you're always going to run the units together it saves the time you'd otherwise spend consisting and then de-consisting at the end of each run.

Not really! There are some things that you want to separate out. Since this is an A and B unit, there might not be much, but two hood units (of A units) w/lights and horns there are special considerations that consisting buys you: with two back-to-back A units, you want the headlight of the trailing reverse-facing unit to have its headlight behave like a rear headlight and the individual rear headlights to be always turned off. Units with horns would need to be configured so only the forward facing unit's horn is activated. Ditto for the bell. I don't know if the Broadway Limited E6 B unit's sound system includes either a horn or bell and I don't know if there are any lights on it either, but if there are, then consisting it with the A unit would make better sense than just duplicating the address.

Well, you don't have to ever de-consist them... Presumably the consist related CVs are stored in NV memory just like the other CVs...

On Broadway lImited locos (and most others that I'm aware of) you can program all that stuff into the locos beforehand, and it makes no difference to them whether they're consisted or not. If you turn off the headlight or horn it stays off either way. Only limitations to giving all the units one address are that you always have to run the same A Unit in front and any B units have to be facing in the right direction as well.

Nope. The memory of what's consisted with what is normally stored in the chip in your controller -or on the motherboard of a bigger system- but not in the locos themselves. (At least that's the way it works with the NCE systems that most everyone uses around here.) And that means you have to both consist at the beginning of a session and then de-consist at the end of the day if you're ever going to run your locos on more than one layout- which we do.

Besides which, the guys who own the SD&AE museum layout our club runs on once per month have requested that we clear their motherboard of all consists at the end of an operating session so that it will be empty and ready to go for the next day and a whole new set of operators and locomotives.

That's why circa 80% of our club members prefer to use the same cab address for multiple units (or steam engines when double-heading) rather than consisting.

The other factor to consider is that we've discovered that maybe once per day something in memory will go belly-up and a controller will suddenly forget a consist right in the middle of operations, causing - as you can imagine- some havoc. But this never happens (or at least it never has yet) to units which all have the same address.

~Pete

Actually, to not be 'in sync' would be more prototypical.

Real units are not synchronized and there generally is a low-frequency beat that makes multiple units sound the way they do compared to a single unit, especially from a distance. The next time you are out watching trains, take note of how multiple units can be heard better from a distance than a single unit.

Now, whether the sound that is reproduced by multiple decoders will have the same effect is another issue.

It's called a "low-frequency heterodyne", and if you can get your diesel units a bit out of synch RPM-wise it *will* have the same effect- although nowhere near as ground-shaking. ;-P

~Pete

What *I* meant by 'in sync' was the the appearent diesel revs would be more or less the same, not that they would be exactly syncronized. That is the base frequency of power stokes will be about the same -- both locos will have roughly the same pitch of rumble at a given track speed. It is unlikely that they would be *exactly* in sync, since there would be enough small variations in the timing between the two decoders (small variations in track contact will cause small delays in packet delivery, plus power surges will distort the signal slightly) and I suspect that the sound chips in the decoders are using a randomization function (to add realisim) and the state of the random number generators will not be identical. Plus the various random other noises (air compressor, pressure relief valve, coupler clank, etc.) would not be syncronized at all. I don't believe E's have turbos, so there shouldn't be any turbo whine. And I don't know if the sound decoders will simulate the air hiss when the brakes are applied. (Note that there is only so much low-end possible with a tiny little speaker -- there is a reason woffers are large!)

Hey all!

Many thanks for all of the advice and feedback... I truly appreciate it.

Tom