Happy New Year Tim!

I am interested in this also, I'll be following this thread.

I've watched a few videos on youtube that have had the Fat Boy swapped in.  I also did a search on this forum and read several interesting posts about it.  I have a lot of the same questions you do, so this will be a great reference thread to keep. 

AlexM posted this some time ago about his Challenger conversion.  I would like to do this to mine someday.

https://ogrforum.ogaugerr.com/t...engerwith-videos3513

I'll second that, get in touch with Alex, Tim, hes done a few. He did that challenger, Lionels CC Niagara, and he may have even done that hudson... you know the one

I'm sure he'd be more than happy to let you know the "ins and outs".

Have always been curious about the 'fat boy' name. Is that just Lionel's marketing terminology or is it an actual brand or model? I would assume it is meant to conjure up images of Harley's 'fat boy' power and presence...

It's just what we call it. 

Just like home audio or car audio, speakers make a huge difference in sound quality.

If you visually compare a standard speaker to a Fat Boy, there's a huge difference. If you can see the difference in a speaker, I'm quite sure you'll hear a difference too.

There's also a Baby Fat Boy, incase you need something smaller, but still excellent sound quality.

Just make sure you match the ohm rating of the speaker when making the swap.

It basically comes down to how much room you have. Can you fit 1 FatBoy, or maybe 2. Do you need a baby Fat Boy instead? How bout an enclosure? There are various sizes of enclosures as well.

I've done a few speaker swaps recently using Fat Boys, and enclosures. Sound quality definitely improved. Of course your volume really won't change because that's based on the wattage that your amplifier is pushing.

This is a swap I made on my Sunset GS4. Fat Boy with enclosure that was modified just a touch to fit inside the tender shell. 

So are Fat Boys a specific speaker or just a Nickname for any speaker with a big magnet. Where you guys getting them?  Cost?

Bob

I would like more info on these as well. Maybe the experts will be along soon, I will be following along also.

Here is another link, a little more detailed.

https://ogrforum.ogaugerr.com/t...lc-challenger-boiler

I hope Alex or one of the real experts weighs in on this topic but you can learn a lot from the JLC Challenger thread already posted.

FWIW I'll say what I have found about Fatboy conversions.

I have put these speakers, which I got from Lionel, in two recent 3rd Rail engines and an Aura brand speaker in a 3rd Rail Jawn Henry. In each case I had been disappointed in the sound quality of the engine. In the Jawn Henry the problem was with the forward speaker that produces the turbine sounds.

One engine is a GS4 and I did almost the same modification as Laidoffsick describes above after seeing his earlier posting on another thread. The difference in my case was that I used an aerosol spray can top for the speaker enclosure rather than the Lionel part that goes with this particular speaker, which would have required a lot of grinding down to fit in the GS4's tender. The high improvement in sound quality was exactly as Laidoffsick describes. I am sure that the difference was as much down to putting the speaker in an enclosure as it was to replacing the stock speaker, which did not have one, with a Fatboy.

Before that, I put a Fatboy speaker in a recent issue 3rd rail E7 diesel, which had exactly the same stock speaker as the GS4.There was no room in this model for a speaker enclosure over the original or the new speaker. Maybe more important, unlike my recent Lionel diesels a new speaker could not be mounted in the fuel tank, where Lionel use two baby Fatboys in a large clear plastic enclosure, because of the location of the 3rd Rail horizontal drive system. There was a sound improvement but it was relatively slight.

In the Jawn Henry I tested a whole load of different speakers, including a Fatboy. I found no real improvement over the original until I tried an Aura full range speaker rated at the same Ohms as the stock speaker but also rated at a whopping 15 watts rather than the stock speaker's 2. Aura is a brand that I found reference to in yet another thread about alternative speakers. This produced a noticeable improvement but again nothing dramatic. I have no idea whether the wattage rating made a difference or whether the relatively quality of the new speaker did. Frankly, I did not expect this speaker to work in this engine but it does. I am mystified by how the sound board drives a speaker of that wattage rating.

So the results were mixed and most definite where the new speaker was enclosed.

I can't tell you whether "Fatboy" is a brand name or speaker type description and whether they are made by a particular manufacturer, although I have tried to find out. Lionel carry no small number of these speakers and enclosures/gaskets/mounts to go with them. I think that just swapping a Fatboy for a stock speaker won't make for an impressive change in sound quality; the mounting/enclosure of the speaker matters more.

Would you happen to have a link to the Aura speaker? 

The wattage rating of a speaker refers to how much power it can take before damage occurs. Not how much power it takes to give a certain sound level.

I suspect Fatboy is just a term to reflect the size compared to the small flat speakers they replaced.

These speakers have a large magnet which is good but its a ferrite magnet which does not have the highest magnetic strength. A rare earth magnet could be much smaller and still have the same force but ceramic/ferrite magnets are cheaper to make.

Fatboys and others of similar construction can produce more volume and lower frequencies because the suspension which includes the surround and spider allow the cone greater excursion. To give the same sound level a speaker has to move twice the distance for half the frequency. If it moves 1/16" at 400hz it will have to move 1/8" at 200hz and 1/4" at 100 hz. I am not aware of any 2" drivers than can move that much which one reason you will never hear those frequencies. Still their excursion is much greater than the cheap flat speakers.

Pete

Hi 

Hope this will clear things up the name fat boy is not a brand or is it the magnet on the back. 

Is is the in closer that is put on the back that brings out the base sounds and makes a smaller speaker sound bigger and louder than it really is. 

You can do this by putting a paint lid on the back of a speaker. 

It should be sealed. Most use silicone to put around edge of cap to seal it.

this has been done for years with HO to bring out the sound on those small speakers.

this is what a fat boy speaker is.

Bose has done this for years with there speakers witch are top of the line In speakers.

hope this helps I asked this question a few years ago and it is the answer I got From a man that was an expert in speakers. 

Fat Boy is a registered trademark of Lionel used to describe their speaker so in a sense a Fat Boy speaker is whatever Lionel says it is.  

According to Western Depot they are 8 ohms 2 Watts and $10

I have not used this particular speaker but here is an 8ohm 5 watt speaker with a decent sized magnet.  You might be able to squeeze that in a dummy engine.

Mini 8 Ohm/5W, paper cone speaker 
with shielded ferrite magnet. Response: 25Hz< >20KHz
L: 3-1/2" H: 1-15/16" WT: .42

Jameco also offers a small speaker with a big magnet.

2 Inch 8 Ohm 3-5W 100-5000Hz Paper 85db

That's interesting about the Lionel trademark because if you Google "Fat Boy speakers" you will come up with a product for motorcycle audio systems.

However after doing some research of my own I am persuaded that the actual defining characteristic of these speakers is the closer on the back referred to above, which must help deal with the problem of acoustic resonance.

The rectangular speaker pictured above is identical to the ones I replaced in my 3rd Rail diesel and GS4. I was wrong about the wattage of those speakers; it is 5 watts not 2 but that spec seems to make no difference in this context. The one in the Jawn Henry was a very flat unit mounted in a custom frame. It looked a lot like the Tsunami speakers found in HO models and I think was the one rated at 2 watts.

All the models I have worked on have Railsounds 4 systems and a new speaker alone won't cure some of the difficulties of that system. There is still something like static in the sound effects but I found that using the same Lionel Fat Boy as Laidoffsick did improved the low frequency/bass sounds and whistle effects and the static was not so pronounced.

There is an earlier thread that actually got me started on the speaker upgrade project and this makes clear that it is not only speaker type that matters but what system is driving it and how it is mounted:

https://ogrforum.ogaugerr.com/t...-use-in-locos?page=1

Yes that is a Fat Boy from Lionel. They also have a short enclosure that's only a tad taller than the speaker itself. I wish I would of found it before I started cutting on my 3rd Rail tender....but oh well. Its done, and now I have a couple tall enclosures, and a couple short ones just for future use.

If you have a Fat Boy now, I would just put an enclosure over it. 

The one above is actually what Lionel refers to as a Baby fatboy. That standard fatboy measures 50mm or slightly over two inches.

Pete

Here's a Fat Boy, with 2 different size enclosures, a mounting ring, and a stock MTH speaker that I took out of a PS2 GS4 that got a Fat Boy and a short enclosure. Lionel has several different sizes and shapes of enclosures, or just make your own. Yes, that Fat Boy fits in the short enclosure, it just don't leave as much room to move a lot of air. A Baby Fat Boy is perfect for the short enclosure.

Would you happen to have a part number handy for the taller one? or can you tell me what engine it was off of? I think I could just use that and even if it doesn't fit it would be nice to have as a spare.

So what we're after here is a miniature size long-excursion "acoustic suspension" speaker setup. The sealed baffle capsule creates the same effect as a sealed speaker cabinet, which makes for a pressure differential between the open-air side of the cone and the enclosed side. This tends to "work" the speaker harder, but sound engineers used it to their advantage  to build speakers with stronger "presence" in the sound, but not necessarily louder output -- which pretty much describes the fatboy speaker effect. The size of the baffle enclosure relative to the speaker can be tuned for the best effect.

Interestingly, drilling a hole in the baffle capsule will create a "ported" speaker, which tends to result in more loudness from the speaker, at the cost of slightly less clarity. The size of the hole, like the size of the enclosure, can affect the efficiency of the design. Speaker engineers have been playing with these principles forever.

The short enclosure is 6911147T38 Lionel list as a Speaker Enclosure/Fat Boy Spkr $3.50

The tall enclosure is 6911152T56 Lionel list as a Speaker Enclosure/Challenger $4.00