It may depend on how you use them. Since you only mention adjusting BEMF, I assume you aren't using the momentum settings, or setting speed curves, or speed matching engines. If that's the case, the engines will run pretty much the same as they did under DC, so there won't really be much difference to compare.
"...So I’m just curious about the statement “better motor control”, what am I missing? "
This statement is in reference to the range in efficacy between brands and models of decoders in the hobby. Initially, when I got into it back in 2005, ESU easily dwarfed the other available decoders with respect to fine motor control, and this applied even to the eagerly awaited Tsunami back in 2006.*
I would say that ESU has largely continued to dominate the market for those who wanted silky-smooth drives, but that changed with the introduction of the WOW several years back. The two brands went toe-to-toe and the difference is essentially negligible...it reduces to fandom.
The statement, to continue, pertained to getting locomotives to start at very low driver wheel revs at speed step 'one', and to continue that fine acceleration with each additional speed step. The idea was to overcome the tiny defects in the gear interfaces that might cause very short pauses or jerking.
*Turns out that original Tsunami was a darned sight more capable of fine-tuning the host drive mechanisms than was original thought. I read a document produced by a gentleman who explained that there are several parameters that could be fine-tuned at higher CV numbers in the 200+ range. I followed his recipe and was able to get a jerky BLI Class J that was sold decoderless in the "Stealth" series back in 2006 to run amazingly smoothly right from first driver revolution.
There's a whole group of modelers, or maybe I should say operators? that feel the need to tweek everything, to get things to run the way they think they should, so they use the programing availiable to accomplish this. Which is fine, if that's what your into, and that group is what the decoder manufacturers cater to, with "new and improved/anvanced motor control".
I use enough of the capabilities of my DCC system to start and run trains. And that's as far as I go.
Mike.
My You Tube
Mel,
Some thoughts on your observations: Selector is right in that many people were comparing the motor control on the Tsunami with Lok sound. The first generation TSUs had a propensity for what was known as the "jack rabbit" start. While this could be programmed out of the decoder with some tweaking, it was annoying. As a result "better motor control" was an advertising catch phrase. The new TSU2s have fixed this issue.
I would suggest that the type of locos that you are running (big steam and smooth diesels) are making it harder for you to see the differences in motor control as most of those locos will run great with out any tweaking due to the either to the size of the loco and/or the quality of the parts you have use to remotor. When you get down to smaller wheel based steam and diesel critters etc. is where the motor control issues begin to be more obvious.
There is also the "creep factor". Many operators prize slow speed operation. Some anomalies won't show up in the meduim speed range but are very apparent in slow speed operation.
I would say in general that you are blessed if everything runs so well that it hard to tell differences in decoders.
Guy
see stuff at: the Willoughby Line Site
A big difference may be in the speed steps used. I always use 128, which is the Digitrax default. NCE defaults to 28. No idea what MRC does because their 'simplified' documentation leaves out things like this - sorry but this has always been my experience with MRC, decoders and their other stuff. There's a huge difference betwene HAVING the technical details available and REQUIRING you to read said technical details to use the system. A common complaing on Digitrax is that the manuals are too complex. Why, because they provide nearly EVERY bit of information on using and configuring the system? But the first couple of pages are the smae as everyone else's manuals - hook theses wires to your track, put a loco on the track, press these buttons, and you are running a train. No one says you HAVE to read the nitty gritty details that come later, but Digitrax and NCE provide that information in their manuals. MRC tends to not provide it AT ALL.
Anyway - in 128 step mode the difficiencies of the motor control in many decoders becomes fairly obvious. Even Digitrax - i will not use any Digitrax decoders because of one major fault - computers, including the microcontrollers in decoders, use binary. The calculus used for BEMF control equitions (differentials and derivatives) results in numbers with many decimal places. Not all decimal numbers can be accurately expressed in binary, so there is rounding error. Digitrax decoders seem to lump all that rounding error into two places within the speed range - so between two particular speed steps there is always a 'jump' in speed compared to the nice even progression of all the previous speed steps. No matter how carefully you tune the BEMF and other things like momentum, you can never truly get rid of this - it's always there, and I can handily demonstrate it
For others - the difference is also readily apparent when running at a slow speed. The better decoders will happily chug along non stop at step 1, no stalling. Decoders without BEMF, or with lesser BEMF implentations, will often stall when there is increased friction - steam loco rods and valve gear, or just entering a curve in the track, unless you set the minimum speed a bit higher. Yet these better decoders that cna do this don't operate like some kind of cruise control - the loco will slow down if more cars are added, or it goes up a grade. They CAN be set to act like cruise control - i saw an ESU or maybe it was Zimo demonstration where they had a large scale loco on a simple loop, the loop was tilted as far as it could go without the loco falling off, and the speed remained constant on the uphill side and the downhill side.
TCS has automatic tuning for BEMF. You don;t have to do anything except runt he loco. ESU has CV54 which enables the automatic tunning and then drives the loco down the track to gather motor data and set up the BEMF parameters. Others rely on you to play around witht he elements of the BEMF equations using CVs and more or less trial and error unless you have a full blown computer simulation of th physics of the loco and its drive train where you can allow the computer to determine the required constats for you to plug into the CVs - now you see why the TCS and ESU automatic modes are so useful.
I'm kind of surprised that when you swap the TCS tender between locos with different motors you don;t notice some slightly erractic operation for the first few feet after connecting it to a new loco - especially when the motors have widely different characteristics. It takes a little bit of running for the TCS BEMF to calibrate. I've seen this with several TCS installs where the first bit of running on the main, the loco is a little jerky and rough when running through the speed range. Bring it to a stop and from then on it is smooth as silk.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I'm glad to hear that all of your decoders are working satisfactorily. I think that you have proven that in many cases that the difference in operating characteristics is a non issue.
For me, I'm into critters so good slow speed operation is a big issue. For that reason I'm using Loksound Selects simply because they work for me.
When I buy new decoders they will be Loksound Selects too even for the bigger engines, not so much for the slow speed operation, but more for the fact that all my decoders will operate and program the same way. I have a couple of FP7s with QSIs in them and they sound and operate just fine. The problem is that I can never remember which level of shut down they are in or how to start them so getting them running usually requires getting out the manual. Part of the problem is that I don't get to run them very often because I don't have my own layout so, given my already forgetful nature, I can't remember how to run them when I want to. Programming the things is also painfully slow.
By standardizing all of my decoders, when I do get to run my trains at the club, I won't have to be scouring the manuals trying to figure out how to get them to run.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
I have 5 or 6 1st generation EMD and Alco engines using MDC sound decoders. Just recently installed an MDC sound decoder in an Atlas RS-1, using an MDC decoder with first generation Alco sounds. Worked out quite well; since you already like the EMD version why not try the Alco decoder in your Alcos?
p.s. you could always put a non-sound decoder in your geared steam engine until you find a sound decoder you like for it.
RR_Mel I’ve never used Momentum, never turned it on the DC power packs that had that feature. As for speed matching I’ve never had a need to do that either. All of my decoders have been plug and play, no matching necessary with one exception. A recent remotor, I used a 8700 RPM Philips 9904 series motor and dropped the motor speed with gears. It’s close enough for steam because I never consist with my steam.
I believe it was a 1704, the older version of the 112704 decoder. MRC also makes a decoder with multiple prime mover sounds - two Alco sounds (539 and 244) and four different EMD sounds.