First Look at Upgraded MRC Sound Decoders

by Larry Maier

• BUY HERE

MRC# 1626 HO Diesel Sound Decoder to be released 04/04.

I ran through the sounds on the MRC #1626 Diesel sound unit. I placed the unit inside a diesel shell to get a better feel for how it would sound in actual use. Without the shell, there is a little too much high frequency boost, but with the shell in place, the high frequencies are somewhat filtered, and the result is reasonably good sound with good high frequency content (i.e it sounds crisp and clear). While the overall sound is improved, I did observe some problems.

Bells 0, 1, and 2 are all good with clear sound and appropriate attack. Horns 0, 1, and 3 all have very good sound, but the sound splice to make the short sound long is apparent. The splice between sound sections for these horns needs to be made more seamless. Horn 2 sounds poorly recorded. There is a lot of air noise, but the horn chime sound is weak. Unlike the other horns, the sound splice in horn 2 appears clean.

The exhaust sounds are well recorded and sound convincing. There is a good mix of diesel rumble and higher frequency sounds of rotating and moving hardware. The acceleration sounds between notches seem to be too short in duration and often the speed at the end of the acceleration does not match the speed of the notch after the acceleration. The worst problem, however, is transition between notches as the prime mover slows down. The transition sounds between notches as the engine decelerates are the sounds of the prime move accelerating. The effect is to hear the diesel accelerate in speed only to end up at a slower RPM. This is disconcerting at least. It stands out particularly because it is contrary to normal experience.

Other sounds included are brake release, gear, dynamic brake, sanding, coupling, air pump, two ramp-up sounds, and two crashes. Some sounds are available when idle and some are available when moving.

The 1626 is furnished with a ¾”Speaker and enclosure. For the test I used a 1.2” speaker.

Here are more speaker options.

MRC #1627 HO Steam Sound Decoder

I ran the MRC Steam Sound Decoder through its sound paces. I found the unit to be an improvement over the initial release diesel unit. The steam chuff is synchronized to the speed step, and assuming the start voltage is set correctly, there should be a reasonable correlation between engine speed and chuff rate. The chuff rate can be adjusted to match the speed reasonably well.

The bell sound is a recognizable generic steam era bell sound. I found the whistle 0 to have slightly too much steam noise and not enough whistle resonance. Covering the speaker actually made the whistle sound better, and it may be reasonably close to correct once installed in a tender with the attendant high frequency losses. Whistle 1 comes fairly close to a good generic steam whistle. Whistle 2 seems to lack ambience, but is a good selection for a small switcher. The short whistle on whistle 2 seems to be too short.

Other sounds provided are sand release, coupling, brake squeal, coal feed, firebox door, cylinder cock, water injection, and air pump noises. These all are short noises that are realistic, although the brake squeal seems to be a bit too short. Some are available when standing, while others are available while the engine is in motion. For former Lionel fans, there is a conductor shouting “All aboard”.

The MRC Steam Sound Decoder is an acceptable general-purpose steam sound decoder. It is an inexpensive method to start adding sound to your steam engines.

The #1627 is furnished with a 1” Speaker and enclosure.

Here are more speaker options.

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