Hello everyone. I know this is going to be a really dumb question. I just purchased a a TSU-1000 medium steam decoder for my brass locomotive. I have all the wiring set up for installation and the speaker as well. The problem is I can't figure out which wire for the speaker is positive and which ones negative. They are both purple and the same length. The instructions say that purple wire 10 is speaker negative, and purple wire positive is 12. This is the first time Im installing a sound decoder so any help is greatly appreciated. Also one quick question. If I mount the speaker up in the tender, should i still isolate it, or will it be fine if i mount it to the top of the tender with drilled holes?
The speaker polarity is not important for only one speaker. I use the Tsunami decoders. I have one Spectrum with the speaker facing down with holes in the tender floor. The tender shell makes a nice baffle. My other has the speaker pointed up under the coal load with a bunch of small holes drilled in the coal load. The tender shell is the baffle.
With a larger tender and better baffle might be better but others will have to comment.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Thank you! I wasn't sure with the diagram. That really helps
You'll get MUCH better sound with a proper baffle instead of relying on the tender body. A tender body has too much space to serve as a proper baffle.
cacole You'll get MUCH better sound with a proper baffle instead of relying on the tender body. A tender body has too much space to serve as a proper baffle.
This is always a topic for debate; it depends on several factors, 1.) the size of the speaker; 2.) the cone material: paper, treated cloth, or mylar; 3.) the tonal effect you are trying to achieve.
Some people would prefer the deeper tones by using the entire body if the speaker does not distort or " breakup" when using the tender as the enclosure. using a smaller enclosure (proper term; commonly mistaken for baffle) with an air tight seal will guarantee a brigher, non-distorted sound. It is the safest method for speaker installation. In some cases the sound volume will increase.
In some cases, adding such an enclosure will not yield greater results. Small tenders make a nice enclosure if you can make sure the air pressure on the speaker's front side does not mix with the speaker's back side air pressure.
In the past when using decoders requiring coupling capacitors, the sound output was lower because of the value of the capacitor; most used a value of 33 microfarads to 50 microfarads. Small cap values create more than 3dB loss at 1000 cycles and as 6dB or more at much lower frequencies (60Hz to 500Hz). The decoder+cap+speakers did not produce much volume with a large enclosure. Using an smaller enclosure within an enclosure does two things: produce brighter, tight output with pressure inside the small enclosure, while resonating sound within the larger enclosure - think placing a sealed speaker inside a drum. The advantage is more output if the larger enclosure's resonant frequency is close to the usuable bandwidth of the speaker. F units and E units, for example, give favorable sound results in this fashion.
The modern sound decoders are different in several respects. One, the output is greater:
Digitrax: 1 watt at 32 ohms impedance (SFX064D)
QSI: 2 watts at 16 ohms (Revolution)
ThrottleUp (Soundtraxx): 1 watt at 8 ohms (Tsunami); no loss to coupling cap;
Two, the frequency bandwidth (low to high) is wider.
None of the above use coupling caps; the Tsunami has a frequency equalizer to optimize speaker output.
QSI decoders have the ability to produce lower frequencies with certain sound schemes, identified by the term HI-Bass. Also speakers are available to take advantage of these schemes. With more output and more bandwidth, availability of fuller range speakers, there is more incentive to utilize the entire tender, locomotive body, boxcar, etc.
I encourage everyone to experiment with different enclosures and speaker sizes. You may be pleasantly surprised at what you'll find.
Carl in Florida - - - - - - - - - - We need an HO Amtrak SDP40F and GE U36B oh wait- We GOT THEM!
cmarchancacole You'll get MUCH better sound with a proper baffle instead of relying on the tender body. A tender body has too much space to serve as a proper baffle.This is always a topic for debate; it depends on several factors, 1.) the size of the speaker; 2.) the cone material: paper, treated cloth, or mylar; 3.) the tonal effect you are trying to achieve. ... I encourage everyone to experiment with different enclosures and speaker sizes. You may be pleasantly surprised at what you'll find.
A 1" speaker on an open (not sealed) 18" pipe has a really good harmonic for an EMD 567 prime mover. Unfortunately it won't fit inside an HO locomotive .
The other thing to remember is that "better sound" to some people means "louder sound". The human ear can hear some frequencies better when louder. Hence the "loudness filter" on most stereo units. This is also why a stereo or speaker salesman will turn up the volume when demonstrating the product. Unfortunately loudness has other issues, especially with tiny speakers. It is easy to get extra vibrations, blaring, and cone distortion.
The final thing is that your ears are different than other peoples. What sounds good to me might not sound good to you.
Texas Zepher In my experience, generally the issue with a tender body for an enclosure isn't the size, but the fact that it is not air tight and/or that the side walls can flex or worse vibrate. I am in the school that says a sealed air chamber should have a volume of a minimum of 1.5x the surface area of the speaker. Preferably 2.5x the area. It also depends if the enclosure is empty, baffled, and/or filled with poly fiber. A large flat area inside of a speaker enclosure that has no filling material can cause echo's. A 1" speaker on an open (not sealed) 18" pipe has a really good harmonic for an EMD 567 prime mover. Unfortunately it won't fit inside an HO locomotive . The other thing to remember is that "better sound" to some people means "louder sound". The human ear can hear some frequencies better when louder. Hence the "loudness filter" on most stereo units. This is also why a stereo or speaker salesman will turn up the volume when demonstrating the product. Unfortunately loudness has other issues, especially with tiny speakers. It is easy to get extra vibrations, blaring, and cone distortion. The final thing is that your ears are different than other peoples. What sounds good to me might not sound good to you.
In my experience, generally the issue with a tender body for an enclosure isn't the size, but the fact that it is not air tight and/or that the side walls can flex or worse vibrate. I am in the school that says a sealed air chamber should have a volume of a minimum of 1.5x the surface area of the speaker. Preferably 2.5x the area. It also depends if the enclosure is empty, baffled, and/or filled with poly fiber. A large flat area inside of a speaker enclosure that has no filling material can cause echo's.
Very well put; we are on the same page. The manufacturers of DIY sound decoders have a tight set of recommendations to net acceptable results in any situation. I believe in thinking outside the box (no pun intended). Keeping an open mind, while understanding speakers and acoustic theory are helpful.
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For those reading this and are new to sound / DCC, do not be afraid to ask questions. If you are curious there are contributors here and other forums that can offer assistance. Many manfacturers' speaker / enclosure recommendations net good results. There are situations where the solution to installing sound may require removing some of the weight, milling a frame, or building a custom baffle. There are several on this forum, as well as others that can offer guidance. Photo examples and descriptions can go a long way to finding a solution.