I'm very confused on Speakers (Solved)

[ron045]

Hi All,

The RP users guide states,  "An 8 ohm speaker that is rated for less than 7 watts or a 4 ohm speaker that is
rated for less than 13 watts may be damaged by the LM-3S-G and could become a fire hazard. "

As far as great sound, am I correct to assume that 8 ohms is better than 4 ohms? 

Assuming I use 8 ohms, I interpret this to mean I need to get a speaker that is 8 ohms and rated for 7 watts or greater.  Because if it's less than 7 watts it could cause a fire.  Am I understanding that correctly?

 Any suggestions?
Thanks.
Ron


I will be using the LM-3S-G and installing it in a O Scale Engine.

[KPack]

Yes, your assumption is correct.  Follow the specs for the LM-3S-G and you will be fine.  As far as an overdriven speaker becoming a fire hazard I don't know about that.  It would likely just ruin the speaker, but I've never heard of a speaker catching fire.

On the LM-3S a 4 ohm speaker would allow the amplifier to pump 2 watts of power into it, rather than 1 watt of power into an 8 ohm speaker.  Halving the resistance allows the amp to double the power.  I don't know how that translates to the LM-3S-G because I don't know what the amplifier is capable of doing.  Tim Ring would be the one to ask about that.

-Kevin

[ron045]

Thank you.  So lower ohms is better?  More power?

[KPack]

Yes, if the amp can handle it.  More power means more heat on the amp, so you'll need to be sure it can handle pushing a 4 ohm speaker without overheating. 

A quick look through the LM-3S-G manual shows that amp can handle it:

"Audio Output Power: 13 Watts into a 4 ohm load.  7.4 Watts into an 8 ohm load."


So if you want something a little louder get a 4 ohm speaker.  But keep in mind that speaker and enclosure design have more to do with sound quality than the resistance of the speaker.

-Kevin

[ron045]

I contacted Ring Eng via email and I have to admit I'm very disappointed.  Wouldn't these folks be the experts?  If anyone had a recommendation or experience wouldn't it be them?

Their reply ...  Call our vendors who sell our product.

Why wouldn't Ring who developed this product have some good suggestions?

The very first vendor they suggested sells a speaker... But does not identify any of the specs.

Looks like this will be a trial and error thing for me.
Ron

[KPack]

What was the question you asked?  "What speaker do you recommend"?  That is a tough one to answer because a lot of it depends on the particular model that it is being installed in....how much space is available, how loud does the person want it, does the person plan to build their own baffles, etc.  If someone asked me that question my answer would be "it depends".  I don't expect Ring to know what speakers will fit in what locomotives...that's not their wheelhouse. 

If you're doing O-scale the first place I would check would be some of the O-scale forums.  There are sure to be people who have installed speakers into the same locomotives that you have and will be sure to have recommendations on what they used that worked.  The speakers they used should be able to work just fine with the LM-3S-G. 

In HO scale I've started using TB Speakers because they come as a fully enclosed module with passive radiator.  The bass has been unmatched by any other speaker I have used.  They have a large range of sizes and designs that may work for what you are looking for.  http://www.tb-speaker.com/products/t1-2121sd

-Kevin

[ron045]

I guess I was hoping for a dialog to start where they could ask the right questions and provide a recommendation.  I guess I expected too much.

 Ron

[KPack]

Out of curiosity, what locomotive are you planning on installing a speaker in?  I'm unfamiliar with O scale, but maybe we can at least get an idea of space available and go from there.

I don't expect Ring Engineering to be much help in regards to speakers.  Keep in mind that they don't do any installs.  They produce Railpro products, that's it.  ESU Loksound and Soundtraxx also do not do any installs.  All sound installations are either done by model manufacturers (where the exact speakers and baffle designs are chosen and designed by them), or by 3rd party installers such as a hobby shop.  Ring pointed you to their distributors because they are the ones installing the products, not Ring.  A good place to check with would be Remote Control Systems of New England (RCS): https://rcsofne.com/.  They do a lot of Railpro and sound installs on large gauge....O and G scale.  They could at least get you pointed in the right direction in regards to speakers.

-Kevin

[ron045]

The Engine is an older Weaver SD-40  Here are some of the measurements.

The speaker is in the fuel tank.  The width of the fuel tank (inside) is 45mm by 100mm in length.

There is a 33mm round hole (With an extra cut out for speaker wire) in the frame to accomodate the height of the speaker.  While there is an old board there now, my RP retrofit really gives me any height I need to the top of the shell.  So that is not an issue.

I'm finding it difficult to identify a speaker that will fit in that space that can control the wattage requirements 13 Watts into a 4 ohm load.  7.4 Watts into an 8 ohm load.

Ring recommended three installers. RLD Hobbies, RCSofNE and GScaleInstallations.

I have reached out to them with questions.
Ron

[G8B4Life]

I'm late to this one but...

I guess there wasn't a speaker with the model? If you had it it might have been fine to use.

Searching, I only found one photo of the interior of a Weaver SD40-2 (https://ogrforum.ogaugerr.com/topic/protosound-in-a-weaver-sd40-2?reply=64921785540213693#64921785540213693). If yours look like this you might have more room in the body to play with than putting the speaker in the fuel tank once you've gotten rid of the existing electronics (one of the long narrow TB speakers perhaps).

I'm guessing it's designed to take a speaker like this: https://ogrforum.ogaugerr.com/topic/weaver-u25b-ps1-board-questions. TB speakers has some like that, as do places like DigiKey but you really want to find what the original diameter and height of the speaker it was designed to take is and start from there.

Finding a single speaker rated for 13 or even 8w in a small size might not be easy so something else you can do is to use two speakers wired in series. eg, two 4 ohm 4 watt speakers wired in series will give you an 8 ohm load with 8 watts of power handling.

- Tim

[ron045]

Thanks for the reply Tim,

The speaker in the engine now is a 16 ohm.  It's older, so I was hoping for something with more gusto.

Thank you for the tip on series wiring.  I was not aware that was an option.

I think you are right, there could be a lot of room left over even with a RP board and battery installed.  But there are no vents or openings like some of the newer models.  Everything is molded solid plastic.  Wouldn't that have a negative effect on the sound?

Bob Buck at GScaleInstallations invited me to his shop to see what could fit or we could rig up.  I'm just waiting for delivery of my RP components. 

Has anyone ever purchased stuff from Timber River Railway and Sales?  https://www.timberriver.net/railpro-products.html
They had a great price on the RP system but the item has not shipped yet.  He mentioned having to get it directly from Ring.  I hope the microchip shortage is not an issue.

Thanks all for the thoughts and feedback.
Ron

[ron045]

A Big Shout out to Bob Buck over at G Scale Installations
I drove over to Bob's shop in York.  Bob helped me with my other battery projects and today was no different. 

So today we fitted the loco with a battery, a speaker and switch and charging accessories.   I will be upgrading an  GP-38 after this project which is why you see two of everything.


I'm also going to do review for Bob on these Coin Type Exciters that you see.  If these are attached inside the shell of the loco, the shell is supposed to become the speaker.  That sounds exciting and I can't wait to see how they work.


More to Come.
Ron