Speaker Installation question

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trailrider

Well-Known Member
#1
I'm in the process of installing a Soundtraxx Tsunami2 decoder in my kitbashed Mantua 2-10-4. Normally, I would install it so the sound would go through holes drilled in the Zamac floor of the tender. But this particular kitbash has a long-haul tender that I stretched from two Manutua Mikado tenders, with a steel plate to bridge the two sections. When I set the speaker face-down on the plate, the magnet in the speaker attracts to the steel plate. I haven't tried connecting the speaker to electric output from the decoder yet. My question is: Would the attraction to the speaker's magnet, stop it from generating sound? If so, do I need to create a standoff so the speaker is above the plate? How far?

I saw an article...someplace...where the author drilled holes in the top of the plastic "coal", facing the speaker upward, and somehow disguising the holes. But I can't find the article! :( Any idea how to disguise the holes in the coal load without blocking the sound?

I picked up a "sugar cube" speaker at my LHS. I was thinking of placing this on top of the gearbox in the engine, but not sure if this small speaker would give me enough volume. If I used two speakers, how would they be wired? In series or parallel?

Appreciate any help.
 

Iron Horseman

Well-Known Member
#2
I'm in the process of installing a Soundtraxx Tsunami2 decoder in my kitbashed Mantua 2-10-4. Normally, I would install it so the sound would go through holes drilled in the Zamac floor of the tender. But this particular kitbash has a long-haul tender that I stretched from two Manutua Mikado tenders, with a steel plate to bridge the two sections. When I set the speaker face-down on the plate, the magnet in the speaker attracts to the steel plate. I haven't tried connecting the speaker to electric output from the decoder yet. My question is: Would the attraction to the speaker's magnet, stop it from generating sound?
No, a magnet is a magnet with the same power regardless of how many things it is attracting.

I saw an article...someplace...where the author drilled holes in the top of the plastic "coal", facing the speaker upward, and somehow disguising the holes. But I can't find the article! :( Any idea how to disguise the holes in the coal load without blocking the sound?
All my first installations of sound were upward firing through the coal. Usually I made the holes so small they didn't need disguising. Just had to make so many it took forever. So I went to downward firing. But real coal makes a good disguise. You could just remove the plastic coal, replace it with a screen an put real coal over the top. Coal is one of those interesting substances that "scales" very well.

I picked up a "sugar cube" speaker at my LHS. I was thinking of placing this on top of the gearbox in the engine, but not sure if this small speaker would give me enough volume. If I used two speakers, how would they be wired? In series or parallel?
This is my new favorite installation. I put one speaker in the loco itself and another in the tender to "fill in" the sound. Series or parallel depends on the speakers and on the decoder. Check if the Tsunami2 has an intended output at 4, 6, 8, 16, or 32 ohms. Then you have to match the speaker(s) to that. Remember the speakers can be a higher ohm than the driver but not lower. Also remember that speakers are ohms impedance not ohms resistance. The formula for parallel is not a simple arithmetic. It is Rt = 1/(1/R1 + 1/R2 + ... + 1/Rn). However you don't have to calculate it, there are many web pages out there where all you have to do is type in the values and it calculates it for you.
 
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trailrider

Well-Known Member
#4
IH-
Much obliged, sir! The T2 has an 8ohm output. Both speakers I have are from Tsunami and are rated that level. I'll just have to experiment with the best method.
 

Iron Horseman

Well-Known Member
#6
IH-
Much obliged, sir! The T2 has an 8ohm output. Both speakers I have are from Tsunami and are rated that level. I'll just have to experiment with the best method.
With 8 ohm expected load and 2 speakers of 8 ohms - I would say series is the answer. That gives a load of 16 ohms and will not over drive the unit.
 
#7
Two of the same speakers won't give you more volume or better sound since basically the speaker is the same.

One should be full range and the other mid-range.



Visit:

Dual Speakers


Thank you if you visit
Harold
 
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tootnkumin

Well-Known Member
Staff member
#8
Their are, as far as I am aware, in HO, only 2 manufacturers that put sound in their locos with twin speakers, BLI and MTH, as far as their diesels are concerned and use the same speaker for both. Both brands do seem to produce a "richer" sound. One of the club members who runs steam, did improve the sound from his engine by adding a smaller enclosed speaker into the smoke box, quite markedly in the high frequencies of the chuff and steam release sounds. It also deflected the direct attention away from the main speaker in the tender.

What speakers have you used in your example, Harold?
 

tootnkumin

Well-Known Member
Staff member
#11
Toot: To add to your list of locomotives, I have several Proto GP-9 that had twin speakers.

Greg
You're right, I forgot them. I've got a GP20 of theirs without sound, but the parts sheet that comes with it shows that the sound version has 2 speakers instead of the brass flywheel, behind the motor. Different chassis for each model.
 
#12
As I said earlier two identical speakers in my experience will not improve sound.

The sound output for the both speakers is the same.

Harold
 

tootnkumin

Well-Known Member
Staff member
#14
I'll ask this question here seeing it's about speakers and the affect of magnets has been mentioned. When trying out places to place a speaker, I was placing one directly above the motor and it's magnets. It would either be pulled towards the motor or pushed away depending how it was arranged, because of the interactions between polarities. How much would these polarity interactions have on the speakers ability to deliver sound, especially if it were permanently mounted so there was that definite magnetic reaction?
 

Iron Horseman

Well-Known Member
#15
I'll ask this question here seeing it's about speakers and the affect of magnets has been mentioned. When trying out places to place a speaker, I was placing one directly above the motor and it's magnets. It would either be pulled towards the motor or pushed away depending how it was arranged, because of the interactions between polarities. How much would these polarity interactions have on the speakers ability to deliver sound, especially if it were permanently mounted so there was that definite magnetic reaction?
Hmmmm, in this instance I would say it should be mounted so that it is attracting the motor and its magnets. This will enhance and preserve the magnetic field of both. However, remember in elementary science class and one sprinkled the iron filings over the sheet of paper with the magnet under it. That pattern would look different with two magnets, so how much it changes the lines of flux and hence the performance of both the motor and speaker depends on many variables. I would guess if both are seated where the magnets naturally want to be that means the lines of flux have aligned and it will be fine. Any shifting of that natural placement will be changing the magnet field of both, and ???. Any physicists in the crowd?

Mounting in the pushed away position each of the magnets is weakening the other and I would guess eventually demagnetize themselves.
 
#16
Iron Horseman: Your comment about magnets eventually demagnetizing themselves started me thinking about Kadee uncoupling magnets. If Kadee uncoupler magnets are stored on or next to each other, what's the likelihood of the uncouplers becoming demagnetized over time?

Maybe this could be a separate post in itself?

Thanks.

Greg
 

Iron Horseman

Well-Known Member
#17
Iron Horseman: Your comment about magnets eventually demagnetizing themselves started me thinking about Kadee uncoupling magnets. If Kadee uncoupler magnets are stored on or next to each other, what's the likelihood of the uncouplers becoming demagnetized over time?
Unlikely as de-installed Kadee uncouplers will usually align themselves in a stack so the magnets are working together to keep themselves strong.
 

tootnkumin

Well-Known Member
Staff member
#18
Mounting in the pushed away position each of the magnets is weakening the other and I would guess eventually demagnetize themselves.
That would be the position they would be in if I were to place the speaker as intended, hence my question. Basically they would have to be secured against the rejecting of each others same polarity force to keep them there. I suspect the speaker's magnet would end up the loser in the battle of irresistible force over immovable object. I was trying to avoid having to remove some material from the rear weight to accommodate the speaker, Athearn's being critically challenged generally in that respect. But, so be it. Thanks for confirming my thoughts.
 

tootnkumin

Well-Known Member
Staff member
#20
Turning it 180 degrees doesn't help? Or maybe flipping the motor top to bottom?
Hadn't thought about flipping the motor, I'm still using the original 5 pole open frame, could be done I guess. The speaker I intend to use is one of the iP6s Plus that I have, which is slim and long. I'm using the original lighting board (trimmed and cleaned) which clips onto the top electrical strap to mount the Tsunami decoder onto, or the speaker and then the decoder on top of that. I'll do a bit more fiddling, see what I can come up with.
 





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