I will start this as a new topic.
In the past I have wired 2 typical large oval speakers to produce a 16 ohm pair. I see diagrams showing how to wire 4 8 ohm speakers in series parallel to produce an 8 ohm load.
My question: would this 4 speaker set be successfully driven by a typical sound decoder amplifier?....a Tsuanmi or the like? Would it be better/easier or harder on the decoder than two speakers drawing 16 ohms?
Thanks.
Two 8 ohm speakers in series will be a 16 ohm load. The key issue is that the speakers are matched, and 'in phase'.
A 4 speaker array in series/parallel will be an 8 ohm load. Again phasing is critical, and is the wattage output of the decoder capable of driving the speakers? That said, I have put 8 ohm speakers on a Digitrax sound decoder and have had no big issue with overloading the decoder(even though they supply a 32 ohm speaker). Of course I usually drive my decoder speakers at half volume.
Maybe some audio experts can chime in with more info...
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Thanks, and if I recall, the phasing is achieved by connecting the proper + and - terminals correctly?
And if a decoder is rated a providing 1 watt, and the speaker rated at 1 or 2 watts peak power....what happens if 4 speakers are connected in series parallel ? What wattage is drawn? If anyone has an idea, I would be grateful.
[Edit....ahh found that good web page with calculators and diagrams. http://www.sbs4dcc.com/tutorialstipstricks/wiringmultispeakers.html ]
The following is general information. If you work the AC formulas, you can get down to the nitty-gritty, but for simple understanding we won't get in to that now.
Current is the main consideration here. The lower the resistance, the more current that is needed. The higher resistance, the less current that is needed. Then there is the voltage part. The higher the resistance, the more voltage needed. Both the voltage and current are needed for good sound amplitude. Now there is one more piece of information you need to understand. The more current you draw, the more heat that is generated in the decoder. Most circuits are specified for a single speaker load. Sometimes we can get by with two speakers. The safe way to connect them is in series because the resistance is higher, 16 ohms, thus less current draw from the decoder. You can also connect them in parallel which would be 4 ohms, but the resistance is lower and you will draw more current, and produce more heat, which is not good for the decoder. Now, if you connect four speakers to the decoder, even if the resistance is 8 ohms, the power needed to drive them will go up. P=IE whereas P is Power, I is current, and E is voltage. Once you exceed two speakers, both current and voltage increase and the decoder will get hotter than normal. And the sound volume will not be as much. What this all means is there a balancing act going on.
The only real way to find out how four speakers will affect the decoder and the sound output is to know the decoder sound output specs, know the speaker power specs, and then get the formulas together and run the numbers. Or you can just call the decoder manufacturer and ask what they recommend. A rough way of knowing is to work the numbers using the power figures. If the decoder says the sound output is one watt, and each of your speakers power requirements are .5 watt each, then you can use two speakers safely. (Just add each speakers wattage requirement to get the total wattage required to drive them.) Once you exceed the power requirements of the decoders sound amplifier, you are walking a tightrope.
Hope this helps.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
Thanks, Gandydancer. I know this is a little out of the ordinary and speculation right now,
But, by speaker power rating, does that mean the number given as peak power rating.....such as 2 watts for a typical large oval speaker?
So, what get for 4 speakers with a 1 amp power source is .25 delivered to the speakers, and this would be at maximum power. So that means a large oval would be getting a fraction of what it needs to sound good, or a fraction of what it can safely handle?
I have many to play with and will just hook them up....just don't want to fry the decoders. I will start with 2.
The only case wher you could damage your decoder, is if the total ohm calculation for your speaker array is less than the rating for the decoder itself. You can go higher if you want, but it will cause the volume to be somewhat diminished.
If your decoder is configured for 8 ohms, shoot for that target in your experimenting. I done a few multiple speaker arrangements - some sounded pretty good, while others didn't sound much better than a single speaker. In all honesty, I'm found that a single high quality speaker in a properly sized envlosure made from wood veneer goes a lot further than stuffing in MORE speakers.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
http://www.mrdccu.com/curriculum/speakers.htm
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.
gandydancer19 ...Once you exceed two speakers, both current and voltage increase and the decoder will get hotter than normal...
...Once you exceed two speakers, both current and voltage increase and the decoder will get hotter than normal...
gandydancer19A rough way of knowing is to work the numbers using the power figures. If the decoder says the sound output is one watt, and each of your speakers power requirements are .5 watt each, then you can use two speakers safely. (Just add each speakers wattage requirement to get the total wattage required to drive them.) Once you exceed the power requirements of the decoders sound amplifier, you are walking a tightrope...
You are perfectly safe using speakers with a higher power rating than your decoder(and in fact is what you want), what you cannot do is use speakers with a lower power rating than your decoder. The speakers power rating is how much it can handle, not how much it requires. The decoders power rating is how much it can provide. If the decoder's power rating is less than the speaker's power rating, that means the decoder can not provide more power than the speaker can handle. If the speaker's power rating is less than the decoder's power rating then the decoder can provide more power than the speaker can handle, and you can blow the speaker.
Actually, in an audio amplifier circuit, the speaker acts very much like the resistor for an LED. The amplifier requires a given load / resistance to work properly. Like an LED, you can use a higher resistance, but the output will be diminished.
And we all know what happens to LEDs if the resistor value is too low ....
Cisco,
Why go to all that trouble when it would be so much simpler and cheaper to purchase the correct speaker that you need?