At first glance it's easy to assume the Kato Sound Box is merely a way of plugging a sound system into your DC controller and listening to the noises change as you turn the controller dial up and down. But in reality, it's far more sophisticated than that. Here we're going to look at the Sound Box in conjunction with one specific sound card (22-204-1) with the modern specification C11 steam locomotive released in 2021.
Background
The Kato Sound Box makes most sense if you understand the context of railway modelling in Japan compared with, say, the situation in the UK. Japanese N-scale models are much less expensive than their British equivalents, which allows Japanese modellers the luxury of being collectors as well as modellers. If you want to have EF66s in all the different liveries and refurbishments they enjoyed across their long lives, go for it! For what you'd pay for a British model of a Class 90 electric locomotive, you could get 3-4 of the modern spec Tomix EF66s.
Why does that matter? Well, a British modeller might not baulk spending another £100 adding DCC sound to a model that already cost £175, but would a Japanese railway modeller be as sanguine about doing the same thing to a fleet of EF66s that cost around ¥9000 (around £40) a piece? That's assuming that Japanese model locomotives were easily upgraded to DCC sound, which on the whole they're not. If you have a fleet of locos rather than just one, moving the sound to an external sound box and running whichever loco you want makes a lot more sense.
Contrary to the impression that the Kato Sound Box is a half-baked alternative to on-board DCC sound, the reality is that it offers a very market-focused solution that makes a lot of sense in Japan. On top of that, the Sound Box avoids the 'tinny' sound effects so typical of N scale models simply by using a much larger loudspeaker. Add external speakers (or for that matter, headphones) via the line-out socket, and you can add deep bass sounds simply impossible when using on-board DCC sound effects.
Kato Sound Box (22-102)
- Sound box
- Jumper cable
- Detailed 14-page instruction booklet in English and Japanese
It's easiest to use the Sound Box with a standard Kato controller. It clips onto the 12V DC snap-lock accessory ports on the side of the controller and gets all the electricity it needs to work that way. If you don't have a Kato controller, it's best to use the Kato 22-081 (12V Accessory Power Supply) rather than the 12V DC supply from your Gaugemaster or whatever controller.
Sound Card for C11 steam locomotive (22-204-1)
- C11 sound card with removable protector for the exposed electrical contacts
- English and Japanese instructions on the backing card
- Removable (bilingual) card that sits on the Sound Box control panel
The packaging is quite clever. Besides being able to slide open so you can re-used the packaging to keep the card clean when out of use, the backing card folds open to reveal a more detailed set of instructions than the summary on the back of the card.
How does the Sound Box even work?
On one level, the Sound Box reads the voltage from the controller and adapts the sounds produced accordingly. Voltage goes up, the chuff-chuff sounds become quicker, the voltage drops to zero, the Sound Box transitions to sounds of an engine coming to a standstill. Unlike DCC-sound equipped locos operating on a DC layout, the sounds don't just vanish! At standstill you'll hear whining generators, idling engines, or whatever's appropriate to the train in question.
So far, so simple. The clever bit is that the Sound Box is also monitoring what's happening on the tracks, not just the DC controller. It measures something called Back EMF. Basically, when a motor turns, it acts like a generator, creating its own current. This conducts through the wheels of the loco onto the track. This is the Back EMF, or electromotive force, and opposes the voltage from the controller.
(Incidentally, Back EMF is related to how real world trains do regenerative braking, where the momentum of the train turns its motors into generators, sending current to the overhead wires, while magnetic resistance inside the motors slows the train down.)
Back EMF matters because the Sound Box doesn't sent a continual voltage to the track like a traditional controller would do. It sends 12V pulses of DC current at a steady frequency to the track, but varies the length of those pulses depending on the voltage it reads from the controller. The controller, therefore, isn't controlling the train directly in the same way as when it's used normally. It's simply the way the user interacts what the Sound Box does, the Sound Box working as what modellers call a Pulse Width Modulation (PWM) controller.
When you turn the handle on your Kato controller, the Sound Box detects the change in voltage and makes the pulses shorter or longer. Shorter pulses mean the motor spins more slowly, longer pulses make the motor spin faster. Remember that back EMF you get when motors spin? In between those pulses it sends out, the Sound Box detects changes in the voltage of the track to determine the magnitude of the back EMF from the motor. If the Back EMF is high, the motors must be spinning nice and fast, but if the back EMF goes down, the motor must be working harder because it's spinning more slowly. That, in a nutshell, is how the Sound Box knows when to adjust the sound effects when the train suddenly starts going up an incline or has to negotiate a tight curve. It's really incredibly clever, approaching, if not quite matching, the abilities of high-end DCC sound cards.
A nice side benefit from the use of PWM is that Kato LED lighting kits (and train headlights) usually stay illuminated even if the train is stationary. The Sound Box is sending out very narrow pulses that aren't sufficient to overcome the motors inertial (so the train doesn't move) but the pulses are sufficiently wide enough that the LEDs light up. Presumably, they're flickering thousands of times per second, but to the human eye that's undetectable, so we see them as 'on'. Sometimes you need to tweak the Start dial to get this function to work exactly right — turn it up or down until you find the sweet spot where the locomotive doesn't move but the lights stay on.
Using the C11 card
Perhaps the thing that's most important to say about the Sound Card is that it was specifically designed with the modern-spec C11 in mind. For example, as the crosshead slides across the sidebar, you'll notice the two 'chuff' sounds happen when the crosshead reaches each end of the sidebar, just as would happen on the real loco. There's no need to change the Sync dial — which you might need to do if tuning the sound card for use on an older spec Kato C11 or one made by another company such as Tomix.
The card details six main features, one for each button:
- Whistle
- Drain
- Brake
- Injector
- Drifting
- Coal shovelling
Some of these have additional features that come into play depending on what the locomotive is doing. The Whistle (#1) is pressure sensitive: a short tap gets a short whistle, hold the button down for a long whistle. The Brake (#3) plays a 'release' sound when stationary, versus an 'application' sound when the train is moving. The Drifting button (#5) plays the sound of the water tanks being filled when stationary, but when the train is moving, cuts out the chuffing sound but leaves all the clanks and whirs you'd hear as a steam train coasts down a hill or towards a stop. Should you dial the controller up, telling the loco to speed up, the drifting stops and chuffing starts up again — an intuitive and elegant feature. The Whistle (#1) has two whistles to choose from, but only one plays at a time. If you hold down buttons #1 and #2 at the same time, the Eject button flashes green and red. Press #1 to toggle through the sounds, and when you're happy with your choice, press #2 to lock it in. The Eject button will stop flashing.
The Eject button is also the emergency stop button. Pressing this stops everything, including the train: very useful if you're about to see the train crash into the end of a siding or something! A red 'emergency' light now flashes over the Sync dial. You won't be able to drive the train again until the controller throttle is dialled back to zero, at which point that light goes from red to green, but the Sound Box will now be silent. You need to press the Eject button once more before the sound effects start up again.
The C11 card is one of the Controller Synchronised types, denoted by having a blue symbol resembling a Kato controller. These cards are designed for simplicity, and leave the user to determine how quickly the train accelerates and decelerates. The basic idea is that the user proceeds through a series of steps to 'tell the story' as the train leaves the station, something like this:
- #6 to shovel coal into the fire
- #1 held down for a long whistle telling people to step away from the train
- #3 to release the brake
- #2 to drain the cylinders
- #4 then #6 as the driver injects steam into the valves then the fireman shovels more coal onto the fire
- #1 briefly pressed for a short whistle as the train passes some waving children...
All the while, the user is dialling up the controller's throttle, the chuff-chuffs becoming more frequent as the locomotive picks up speed. Should the locomotive hit a gradient or tight curve, the Sound Box picks up the drop in Back EMF, changes the sounds to indicate the engine is working harder and slowing down. Hitting #5 as the train coasts adds some variety, but if you increase the throttle the chuff-chuffs return as the engine gets back to work.
Conclusion
How does the Sound Box compare with DCC-sound equipped locomotives? The positives are the relatively cheap Sound Cards (￥2,500 for the C11 card, about £12 or so) and the consistent functioning on DC layouts (DCC-sound locos, even when described as DC-compatible, seem to be inconsistent in how well they work on DC layouts, especially if the track isn't spotlessly clean). On top of that, and unlike the situation with DCC-sound locos on DC layouts, the user has full control of the sound effects, not a random selection that plays depending on how the DCC chip was programmed.
The Sound Box itself is relatively expensive in the UK, over £300, though I bought mine secondhand for about £180, which isn't far off what these devices cost in Japan (￥35,200). Given the seller included an American steam train sound card to boot, I'm pretty pleased with the value at that price point.
But I can see DCC-sound enthusiasts pointing out the shortcomings of the Kato Sound Box, and there are some obvious ones. You only have one sound set playing at a time, and the sounds are coming from the Sound Box, not the engine. The range of sound effects doesn't match the dozens included on many DCC-sound locomotives these days, though many of the sounds can be a bit esoteric if not completely unnecessary — my BLI E8A sound-equipped locomotive has some farmyard and factory sounds, for example!
On the other hand, the depth of sound you get from the Sound Box is massively better. Bass sounds are good as it comes, but plug in an external sound system (with a subwoofer) or decent headphones and it's phenomenal. There's really no comparison with the tinny little speakers built into N scale trains.
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