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I was just wondering if, in a consist, you can have a sound decoder and speaker in one engine and run wires from that speaker to a speaker in the second engine? Just wondering if I could save on a second sound decoder.
I'm sure you could. A couple of my atlas engines have 2 speakers in them as welll as my Blueline AC6000's. What you do is get two 4 ohm speakers and wire them in series or two 16 ohm speakers in parallel.
You really won't notice any difference though since the sound source is exactly the same. 2 different engines with slightly different sound would be a little noticeable. When consisting it'll sound fine with just the lead engine with sound.
You don't really need an extra speaker in a two or three engine consist. One sound equipped engine will rovide all the sound you need and, sometime, can tolerate. What I would consider is putting an extra speaker in a trailing unit so you increase the Doppler effect. Point the speaker backwards and you'll get a much more realistic sound of the engines passing a single point.
No wireless speakers in HO, I'm afraid. You can run wires between units using mini connectors to attach the wires and still be able to unplug them. It's very similar to the normal MU cables that real railroads use. Paint them black when you're done and they will be almost unnoticeable.
This parallel verses series speakers subject is something I would like to explore a bit more.
It seems that most decoder manufacturers want their decoders to look at 8 ohms, correct? The early Soundtraxx made a point of recommending not to hook to series dual speakers as this would be looking at 4 ohms, correct?
Are there many 4 ohm speakers offered to the HO scale? And particularly are there 4 ohm speakers in the new hi-bass series speakers? Seems this 4 ohm lot is rather limited...almost like the 100 ohm speakers required by Lok sound decoders.
All audio systems are designed to provide maximum output at a particular impedance, in this case 8 ohms. When you have 2 speakers there are 2 ways of hooking them up, series and parallel.
When hooked up in series you add the impedance. 2 speakers at 8 ohms would be 16 ohms. If wired in parallel the 2 would be the product of the 2 divided by the sum. For 8 ohm it's easy, it equals 4 ohms. the product 8 times 8 for the other speaker is 64. Divide this by the sum which is 8 plus 8 which is 16. 64 divided by 16 is 4 ohms. Seems simple until you use mismatched speakers.
In your case Soundtraxx recommends going with series and not dropping below 8 ohms. 16 ohms will give a little less volume but also won't overload the decoder. My recent installs have them in series with plenty of volume. Also note that you should wire them in series with the same polarity or the sound will cancel out. Imagine one speaker with a baffle pushing while the other one is pulling. This is what happens when you have them wired incorrectly. Hope I didn't confuse things.
I had known the R(total) = R(one) + R(two) for series hookup.
And I had known the 1/R(total) = 1/R(one) + 1/R(two) for parallel hookup.
Those are the two formula I remember.
I just thought I detected a number of dual speakers being hooked up in parallel contrary to recommended specs. Is that not true?? I haven't seen enough different installations to know this to be true or not.
QSI has this for their speakers: http://www.qsisolutions.com/news/09/best-sound-parallel-wiring-073109.html As you read, you will see the biggest obstacle for parallel speakers configuration is if the decoder can handle the output power. You can always use combinations of series/parallel. I have two J1E's with Quantum Revolutions and paralleled "High Bass" speakers that will knock your socks off; a world of improvement, but don't expect miracles from tiny speakers.
Easiest way to remember for Z formulas:
inductors: same as resistors series/parallel formulas
capacitors: same as reversed series/parallel resistors formulas
For parallel resistors: just say the reciprocal of the sum of the reciprocals. (or for even values) sum of the parallel resistors divided by the number of resistors.
From this QSI page; "The Quantum decoders were designed with special components to utilize the parallel connection, but most prior applications notes stated to use a "series connection" to minimize heating and power consumption. This was done until the parallel connection could be thoroughly tested.
After a year of field testing we are recommending that all Quantum HO/S/O/G scale decoders can support parallel speaker connections for 8 Ohm speakers.
Some other sound decoder manufacturers do not recommend the parallel connections."
Over in this document I site in the first posting, I find this quote in that latter part of the document, "The Quantum System is designed to drive 16 Ω speaker assemblies. We generally use two speakers to increase the sound output. Since 8 Ω speakers are the most common and the least expensive, two 8 Ω speakers are usually wired in series to produce 16 Ω as shown below."
It appears as though the QSI decoders can handle all three situations of 4, 8, or 16 ohms (2/parallel, 1 single, 2/series)
On the other hand I recall this paper document handed out with the Tsunami TSU-1000 decoder system; Tsunami is designed to operate with speakers whose impedance is 8 ohms or higher. Using a spaeker impedance less than 8 ohms may result in erratic operation or even component failure"
What I would consider is putting an extra speaker in a trailing unit so you increase the Doppler effect. Point the speaker backwards and you'll get a much more realistic sound of the engines passing a single point.
