Hello, I just bought a Bachmann 2-8-0 with a Soundtraxx DSD B280LC decoder inside. It has sound. The chuff sound is not sync with the drivers. In slow speeds, the chuff rate is around 7 chuffs per rotation. At the lower mid range speeds(speed step 40ish out of 127) its synced perfectly. And at higher speeds, the chuff rate it around 2 chuffs per rotation.
You can change CV 116, but there is always a speed(low, mid high) where the chuff is out of sync. Is there a way to fix this without installing a steam cam?Thanks,
Charles
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Modeling the Santa Fe & Pennsylvania in HO
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Charles,
The synthsized chuff lets you move around the "sweet spot" but it will become out of synch gradually as you move away from that setting. Best thing to do is to pick the typicall speed of operation and set the chuff to synch there. I tend to pick toward the slow end of the scale, because it's about narrowgauge here. When things get rolling fast, my eyes aren't going to catch the increasing lack of synch, because it doesnt last long...
If you do want synch over the ful speed range then yes, a cam is the way to go. There are kits that allow this install without pulling the wheels off the axle.
Mike Lehman
Urbana, IL
I understand completely and it's a common issue. I want 4 chuffs per revolution no matter what speed I'm running. The old Tsunami's had a brown wire to use with a sound cam or wiper which would accomodate the proper chuff rate no matter the speed. I understand the Tsunami 2 doesn't have the ability to use a cam. The guy at Soundtrax assured me it would stay in sync with the speed but I have not seen or experianece that and I doubt if it can actually do it. Unfortunately many folks either don't care or don't understand the chuff rate. To me it's as vital as a good whistle!
I think they need to spend more effort getting the chuff rate right than adding radio transmissions to steamers and all the stuff like water sounds when filling the tenders, etc. Get back to the basic stuff!
oldline1
Although it's true it won't be perfectly in synch without a cam, the extremes you describe seem unusual. I have a Bachmann 2-10-0 with the factory Soundtraxx decoder, and I'm able to set it so the chuff rate matches up with the wheel rotation pretty closely across the speed range of the engine. I'd maybe check the CVs (or do a factory re-set) to make sure you don't have a CV that's set incorrectly.
For example, I wonder if you might have accidently set the CV for the type of chuff to the "articulated" setting. That would be most noticeable at slow speeds, because it basically doubles the chuffs. That is, instead of hearing "chuff...chuff...chuff...chuff" every revolution, you'd hear "chuff-chuff...chuff-chuff...chuff-chuff...chuff-chuff". As speed increases, the "chuff-chuff" sound becomes less distinct, making it sound more like a 'normal' chuff.
Also, I've found that sometimes if you set the chuff rate and then change a speed setting (CV 2, 5 or 6) that can knock the chuffs out of synch. Always best to set speed and momentum CVs first, then adjust the chuff rate after.
Keep in mind too that even if you get the chuffs for the engine set up to sound right when the engine is moving by itself, it will be out-of-synch a bit when the engine is pulling a train, because the cars require the engine to use a bit more power to go the same speed...that is, an engine running light at 25 scale MPH is using less power than an engine pulling 10 cars at 25 scale MPH. I usually try to adjust the chuff rate with say 4-5 cars attached, so the chuff rate is pretty close to correct either running light or with a normal (for my layout, 8-10 car) train.
Except for a very early decoder I first used in 2005, a DSD LC variant it happens, and which I ditched because it was a growler (didn't have BEMF and didn't seem to get along well with my DCC system), all my decoders that don't already have connection to a cam (all post 2010 BLI steamers AFAIK) can be surprisingly accurately synched using the appropriate single CV.
Seems to me I recall Tsunami being CV 117, but I may be wrong....it has been three or more years. The advice I followed at the time, already given above, is that you select the typical mainline speed you'll be using, but at least 10 scale mph, and synch the chuff by making it do so when the main crank is at bottom dead center...or forward dead center...whatever, just pick a defined point and ensure the fourth chuff happens very very closely each time the crank meets that point as the wheel turns. From there, a properly working decoder permitting the user to synch using CV XYZ should stay close as you increase speed. Mine were never perfect, but they certainly passed the scrutiny test with a glance. I'd give that type of synchronization a very healthy A- at worst. At least, all the Tsunamis and QSI's in my fleet worked that way and kept 'in synch' for the duration until I had to reset them for some reason.