16 ohm vs 8 ohm speakers

If you are thinking of doing this, remember MTH has no more 5V boards.  You might find yourself needing one.   I found it a very good idea to replace speakers with the proper one.

 

MTH does not have any more 5 volt boards (16 ohm speaker) but they do have many 16 ohm speakers.  For the sake of saving 10-12 bucks, play it safe.

As a general rule of thumb, you can replace a lower-rated speaker with a higher rated one without any danger of damage to the electronics. However, the sound will be proportionately lower.

 

On the other hand, replacing a higher-rated speaker with a lower-rated one will run the risk of damaging the sound amplifier.

I was thinking about it for some of the new Legacy engines. Lionel reduced the overall volume, Jon Z said it was to have better sounds and less distortion, not sure if I buy that but. I asked him if I substituted a lower ohm speaker would I get louder sounds and he said I might.

 

So, that is why I posted the question.

 

Should have been specific about what manufacturer.

I did an upgrade a few years ago where I did two 8 ohm speakers in parallel off a EOB board with TAS approval.  In parallel the resistance/impedance becomes 4 ohms and the wattage doubles, if I got it right.  It did work but the EOB mother board seemed to be excessively hot.  I dropped back to one 8 ohm speaker and was happy with that.  I believe the EOB mother board,corresponding Sound power board and sound board are designed with limits.   The MTH equipment would have similar design issues.  Why one system uses 16 ohm speaker and the other 8 ohm is beyond me.   

FWIW, the EOB boards, or any other 3rd party boards that use RailSounds, depend on the output of the stock RailSounds audio board for their speaker drive.  I'd personally recommend against paralleling two 8 ohm speakers on a RS audio board...

Maximum power transfer (volume in this case) is when the output impedance of the amplifier (speaker output from board) matches the load impedance.(speaker)

   If the output impedance is 16 ohms an 8 ohm or 32 ohm speaker will have less volume.

  Some outputs are more forgiving than others and will drive a wide range of speaker impedance. 

   Either way you take a chance of damaging the board by using the wrong impedance speaker.

    Don

So to further this discussion;  can you keep the the speaker (s)  impedance the same but up the watts from 0.5 to 1.0?
What would be the effects to the board? Would the sounds improve? Thanks

If you keep the impedance the same, it's less of an issue with a higher rated speaker.  OTOH, you may not get the desired effect, because if you put a 100 watt speaker on a 2 watt amplifier, you don't get 100 watt output.

 

I wouldn't be concerned about going from 1/2W to 1W, but going big on the speaker is unlikely to yield the desired result.

Speaker replacement is described here

 

www.jcstudiosinc.com/BlogShowT...=621&categoryId=

 

Lower than the rated impedance can over drive an amplifier and damage it.

 

Dale H

The wattage the amplifier puts out is determined by the speaker impedance and volume control. The wattage rating of the speaker is what it can handle,not what is put into it by the amplifier.

 

Many stock speakers are cheap and crappy. Good replacements are often more efficient putting out more volume at the same wattage. Also they have much better frequency response duplicating low end sounds not replicated by the stock ones.

 

Dale H

 

The usual result of trying to get more power out of an amp than it's capable is the THD goes way up and the sound is lousy.  Yes, if you have a 5W amp and a 0.5W speaker, going upscale on the speaker is a good idea for better sound.

Keep the impedance the same or you'll damage your board. If you want better quality speakers and they're only available in 8-ohm, add a 5-watt 8-ohm resistor in series to have the proper impedance or better still, if you have the room, put another 8-ohm speaker in series -- a good trick for a powered/dummy pair to have sound coming from both locomotives.

So I guess to get things right. I have an older stock Lionel engine with two speakers wired in series that are rated @ 16 ohms and 0.5 watts.  What type of speaker (s) should I buy to improve the sound and who makes them?

Space permitting here is a good source of quality speaker replacements

 

www.madisoundspeakerstore.com/approx-2-fullrange/

 

Dale H

I doubt you're seeing two 16 ohm wired in series, most likely they're wired in parallel.

As John indicates it is doubtful they are wired in series.

They are likely wired in parallel giving an effective impedance of 8 ohms.

Liionel's Fatboy speaker has good sound, but it is 8 ohm and usually only one is used.

You could try using a single Fatboy; this should match your RS output if the engine is anywhere from about 1996 or later.

 

Rod

Well looks like the Legacy K4 has two mini-fat boy speaker at 16 ohms and 2 watts while the PRR U28c has a single mini-fat boy at 8 ohms and 1 watt.

 

Somehow, someway, Lionel lowered the overall volume on the newer products. In fact the fan motor noise in my 3667 K4 is actually louder than the chuff. I found that the U28c diesel, which does not have any annoying squeals like the K4, uses the same motor to drive the fan. Maybe I'll get one and replace it in the K4 to see if it makes a difference. 

 

I'm not sure if the noise in the K4 is related to the puffing circuit or the motor itself. I'd gladly give up puffing smoke for a quite fan driven smoke generator.

Trainman;

Can you not just use your Legacy controller to crank up the sound volume?

Or did I miss something?

 

Rod

Check the volume control and see if it's been turned down, I had this happen on a Legacy GP9 with low volume.

Trainman, The latest RailSounds use the TI TPA2005D1 Power Amp.  The RS Power supply can deliver the power needed for using 4 ohm speakers; but be aware the power amp could overheat with a 4 ohm speaker.  It is worth a try, but don't put full volume active (full power) in this configuration. 

 

You can look up the datasheet at TI, for more details on the chip's capabilities.  Also I can confirm we did lower the sound mix volume on later Legacy Locomotives.  This was implemented to produce a cleaner sound at higher volumes.

Jon;

Thanks for the clarification; now we can see the rationale.

 

Rod

I was thinking of putting a second speaker in a dummy unit and driving it off the sound board in the loco.  So I would need two 16 ohm speakers in parallel for a 8 ohm output?

John;

Right you are.
So if you ever ran without the dummy you would in effect have 16 ohms load and the sound level would be somewhat lowered, but it would not hurt anything.

 

Rod

Direct link to the TI spec. sheet.  1.45Watts.   You would also have to be careful that the two  16 ohm speakers did not exceed 1.45 watts.  IMO Even (2) .5 watt speakers would max this small drive amplifier with limited heat dissipation.  Which explains partly why the EOB boards tended to heat with two speakers. (Noted to touch the sides of the engine.)  I must admit lots of sound.  

 Must be well built.  I never smoked the sound board via the two speaker install.

One speaker in the fuel tank and one rear of unit, Weaver E8's EOB upgrade.

For a speaker the wattage rating is the speaker rating.  Not what it draws.  That would be based on the ohm rating and the audio amp.

 

The MTH PS-2 5V amp is rated at around 3W at 16 ohms.  The speaker primarily used is a 16 ohm 5Watt.  This prevents the amp from blowing the speaker.

 

Additionally, the sound file can control what the audio amp puts out and in many applications a speaker rated at only .25 Watts or .5 Watts was in some applications very early on in the PS-2 5V systems.   The current standard for PS-2 5V is a 5W.  The PS-2 3V I have seen 3, 4 and 5 Watt speakers.

 

I also have seen audio amps rated for different speaker impedance, but the wattage available changes also.

 

So you could change speaker impedance to see if the sound is improved to your liking, but as Jon said you need to becareful with volume control if you go down in impedance.  You do risk blowing the audio amp or power supply to the amp.  G

Hard to get a quality 16 Ohm speaker. If anyone has a source please share. Instead I would use 2, 4 ohm speakers in series.

 

These are what I use which perform well if they can be fit in.

 

www.madisoundspeakerstore.com/...-2-full-range-4-ohm/

 

Dale H

 

Yep, you missed something.

 

Everything at full volume.

Yep FULL VOLUME

I never had any issues with the sound volume on any of my older engines. My PRR M1a with the two fat boy speakers can rattle the windows on the second floor. At full volume there is no distortion at all.

 

My PRR Congressional Station Sounds diner can be heard from across the street. Again no issues with distortion. In fact the Williams GG1 that I upgraded to TMCC and  Railsounds 5.0 is just fine with the Digital Dynamics speaker.

 

What I don't understand is why companies insist on fixing things that are not broken. Makes no sense to me at all. Lionel always had the best sound in the business but no longer.

 

If I can't get rid of the noise from the smoke unit on my Legacy PRR K4 I'm going to dump it on the Buy/Sell board.

 

I doubt if I will ever buy another Legacy engine regardless of price.

I have no intention of trying anything as long as this engine is under warranty. If I did anything it would void the warranty.

Trainman9;

I understand your annoyance.

It is disappointing when things seem to get changed for the sake of change, not because it needs to be changed. We see this everyday in the worlds of TV and the latest I-whatever. The high-tech thingy you rushed out and paid good money for a year or two ago is now obsolete and only good for the recycle bin.

If I understand you correctly, you have had this experience with more than one new Legacy engine? If not perhaps your K-4 is an isolated case. Perhaps the sound amp or speaker is defective in some way?

What I don't get is why Lionel would make such a dramatic reduction in available sound level across the board.

I can understand a 20-30% reduction for the sake of cleaner sound, less TDH, etc.

One of the things most of us O gaugers have come to love is the huge sound we can get out of our engines.

Lionel would do well to not mess with something if it ain't broke.

 

Rod

 

For maximum power transfer transfer, the impedance of the

load should equal the output impedance of the source. 

I don't believe the delta volume was more than a few percent.  I simply confirmed:

 

Trinman9's comment:

I was thinking about it for some of the new Legacy engines. Lionel reduced the overall volume, Jon Z said it was to have better sounds and less distortion, not sure if I buy that but. I asked him if I substituted a lower ohm speaker would I get louder sounds and he said I might.

 

Also, I tried to give some info to assist Trainman9's comment about if a 4 ohm speaker would work.  The datasheet for the power amp spec's 4ohms, with restrictions. 

 

There are many reasons sounds are not the same from loco to loco.  One of them is the speaker enclosure, another is the speaker itself.  Distortion can vary based on many metrics besides the sound mix, which also varies from loco to loco; after all they all sound a bit different, right?

 

We did not set out to change anything, we simply are doing our best to deliver a decent user experience given the model's constraints we have to work with on a sample.  I am sorry it does not please everyone, but truly the Railsounds system seems to be highly regarded by most of our customers.

 

It's not just related to the K4 the Legacy PRR U28c has very low volume in my opinion. At least the U-boat does not have the annoying noise of the K4. The sound is so low on the K4 that the noise from the smoke unit pulsing is louder than the chuff sound of the engine.

 

I wish I had the opportunity to run the K4 before buying it. It would have been nice to try it out on my layout, not in a store or other place where the noise might not be heard.

 

I was at a friends layout, his is about 25x30 feet and when the new engines get to the other side of the layout you don't even hear anything from them at all. I'm talking about the new Legacy Blue Comet and a couple of other steamers.

We did not set out to change anything, we simply are doing our best to deliver a decent user experience given the model's constraints we have to work with on a sample.  I am sorry it does not please everyone, but truly the Railsounds system seems to be highly regarded by most of our customers.

 

Not if they own earlier production engines!

 

I agree that speaker enclosures and the speakers themselves along with the type of engine makes a difference. It is just hard to understand and justify why a big engine like the PRR U-boat has overall lower sound levels than a Legacy GP9 NYC which was produced a couple of years ago.

 

Even the recently produced 726 CC Berkshire has a louder whistle than my Legacy K4 which costs three times as much.

 

You almost make it sound like I am the only one with an issue. There is another forum member who posted about his noisy smoke unit and one that constantly failed. I think he sent the engine back numerous times.

 

Also, the instructions say to add 20 drops of smoke fluid when initially running the engines. This is not enough to wet out the new smoke wicking. If you only put 20 drops in the resister will burn up. It's more like 40 drops in order to get the proper amount of smoke.

 

Maybe that's why Lionel has had so many smoke unit failures. So many that they have discontinued whistle smoke in all but the most expensive steamers.

Trainman9;

Jon's response seems reasonable and sensible.

Maybe you should get an RMA and send the K-4 in to Lionel for a check over?

 

Rod

That's the last thing I would ever do. When I sent my Legacy PRR U28c in for a warranty repair they sent me someone else's engine. It had a broken front pilot, cracked snow plow, missing MU platform in the rear along with the retaining hinge and a broken chain on the railing in the front of the engine.

 

Fact of the matter is that the sound level is what it is and there is nothing more to check out. I'll be replacing the fan motor to see if I can stop the anoying noise that the puffing smoke makes. If that does not solve the problem I'll just dump the engine on the BUY/SELL board.

My Legacy K4, 6-11327 and my two PRR U-Boats are plenty loud, I don't see any difference that is significant between those and other locomotives.  My single issue is with the loud smoke fans in the U-Boats, something that will get addressed one of these days when I get around to taking them apart.  If the smoke unit in the K4 is making noise, I can't imagine that's a difficult fix if you're willing to remove the shell and swap the motor.  That job should be a 15-20 minute job as a rule.