The only real drawback would be the fact both engines will sound EXACTLY the same (prime mover / bell / horn / etc.). Unless you have your ears right down at track level to actually hear two separate speakers going by, you won't notice the effect standing at the layout.
Standing by the layout, two speakers in the A unit will sound the same as a speaker in the A and a speaker in the B.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
gregc but won't two speakers partially cancel one another unless you are equal distance from both?
but won't two speakers partially cancel one another unless you are equal distance from both?
Only if you wire them out of phase. With a single speaker, the + and - markings make no real difference, but when connecting multiples, it matters a lot. If one is moving in while the other moves out, they will cancel each other out and reduce the sound. But if you put them properly in phase, then you have basically just doubled the cone area (assuming two identical speakers).
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
you could blue tooth it with electronics from old cell phones and a few extra parts.
RR_Mel My layout is small and having the sound of the SP AC-9s pulling a grade on my layout really brings back the memories of my teens in El Paso. Having ridden in an AC-9 and a Cab Forward for my 14th birthday sound on my layout really does it for me, I still remember the desert flies in my mouth from the open windows of the early air conditioning. Locomotive air conditioning in 1951 was open windows at 50 MPH in the desert heat. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
Mel, even though I am not generally thrilled with the sound quality of most HO locos, if I was only operating one train at a time on a small or even medium sized layout, I would likely go for DCC and sound.
I think DCC is much more "valuable" on smaller layouts, where operations are in a tighter space, especially layouts with no signals or CTC.
And I think sound is much better when you only hear that one locomotive, not eight of them, as well as a dozen people talking to the dispatcher, and to each other, etc.
And actually, on my proposed layout, there might easily be seven or eight trains going at once, but many of those trains will require multiple locos.
So you could have trains with 4 unit diesel lashups with every unit blasting sound, no matter how low the volume, or two/three steam locos, each with sound, times at least the five or six mainline trains in motion.
Sheldon
Thanks Mel,
As I mentioned, I have been in HiFi almost as long as model trains.
Still have over 1700 vinyl record albums........
Which in the new house will keep me company in the train room with a pair of those speakers.
I'm not totally opposed to model train sound, but I have never enjoyed it on large layouts with multiple trains running like I am planning to build.
My theory is that large layouts increase that sense of viewing from a broader perspective, putting the viewer effectively farther away, making sound less important.
That combined with my sensablities about fidelity make it not a good choice for my goals.
No, not in any measurable way. Speaker designers have been successfully using multiple drivers since the beginning of audio.
If that were true, the famous Bose 901 would have sounded like crap, it used nine identical drivers aimed in three different directions.
Many of my own designs use multiple drivers for the same frequency range.
I designed and built these in the 1980's, and manfactured and sold a few sets:
Here is a clearer picture of the drivers:
They use two tweeters, two mids and the single woofer. In this case the small drivers are 4 ohm and wired in series, the woofer is 6 ohms with an impedance stablizing circuit, giving the whole system a stable 8 ohm impedance.
But the fact that each driver need only work half as hard is an advantage, not a disadvantage.
Another design of mine, a large floor standing speaker that doubles as an equipment cabinet/end table, has a tweeter and two mid range facing forward, and a second tweeter and the woofer rear facing. In that case the rear firing speakers are wired out of phase with the front speakers. But it works great.
greg - Philadelphia & Reading / Reading
gregc if a decoder is rated at 8 Ohm, placing two 16 Ohm speakers in parallel would meet spec, but won't the audio output be less for the combined speakers? will half the power from each speaker really sound as loud as the same power from a single speaker?
if a decoder is rated at 8 Ohm, placing two 16 Ohm speakers in parallel would meet spec, but won't the audio output be less for the combined speakers?
will half the power from each speaker really sound as loud as the same power from a single speaker?
Yes, it will be just as loud, or maybe louder. And the sound quality will be better. Quite possibly much better.
Speaker volume response to power increases are not linear. As power increases, excursion increases, as excursion increases, physical resistance increases, so does impedance, and distortion increases exponentially.
While speakers are rated for a given impedance, that is just an average. The actual impedance is different at every frequency and volume. The static voice coil resistance is obviously fixed, but the impedance fluctuates continiously.
Full range speakers, no matter how ridiculously small, need a somewhat rigid cone suspension to clearly reproduce high frequencies.
By contrast, bass drivers in hifi systems can be designed more like pistons with soft suspensions relative to cone mass, and high excursions with minimal distortion in the desired frequency range.
Full range speakers are never linear in output across the whole frequency spectrum, they are always loudest in the middle of the frequency range. That is why hifi systems use multiple drivers for different frequency ranges, or use electronic equalizing circuits, or both.
Maybe this is why I don't like onboard sound, I have been studying speaker design, and building hifi speakers since age 16. I know all the reasons why two 1" speakers cannot sound very good, and I have well trained ears in that regard.
Since 100% volume is generally too loud for one speaker anyhow, perhaps 50% for two speakers may be just about right...
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Time...It marches on...without ever turning around to see if anyone is even keeping in step.
2x 4 ohm in parallel results in 2 ohm impedence. Don;t think any decoders support that, and it will fry the amp. Some sound decoders like ESU are good with anything from 4 to 16 ohms, so for 4 ohm or 8 ohm speakers they should be placed in series. Many of these sound decoders are capable of 2 watt output, but the speakers are often 1 watt peak - so going with the higher impedence keeps the power down. As does making sure the volume is not of full.
Only problem with putting a second speaker in a dummy unit and wiring it in series with the main loco is that if you run the powered unit alone, the speaker won;t work, unless you make up a shorting plug to replace the dummy unit connection. So twox 16 ohm in parallel may be a better option. Unless they are going to be drawbar coupled and never taken apart.
I haven't done this, but I do have a dummy F7 B unit from Bowser that I put a sound decoder and th ebiggest speaker I could fit (which is pretty big - there's a LOT of room in there with the dummy chassis, which is still metal for weight, but not fully enclosed like the powered A chassis). Sounds great - the big speaker really helps with full range sound reproduction.
woodoneYou could use two 4 ohm speakers in parallel, you will still have an 16 ohm load
I don't think so, the impedance goes down in parallel.
Henry
COB Potomac & Northern
Shenandoah Valley
You could use two 4 ohm speakers in parallel, you will still have an 16 ohm load. Two speakers of 8 ohm's , go series.
It is possible With 6000 posts you must have seen Mel's mini connectors made out of 40 pin headers to use as a plug.
Series or parallel? I believe Larry Puckett, in his recent Youtube video on speakers, said that he always uses series
If I had 2 say f units and one was a dummy and a sound decoder in the powered engine would it be possible to piggyback a speaker in the dummy? I realize it would require speaker wires between the 2 engines but would I make the speakers in parallel or series?