# Multiple speakers from a single sound card?



## Michael Glavin (Jan 2, 2009)

Anybody out there drive multiple speakers within consisted engines from a single sound source or card? I am acutely aware of the need to not overdrive said sound systems driver. I simply was curious as to the soundability of same. Reason being I have a several engines that must be consisted with battery power from a single radio controlled ESC. I have a Sierra card or two that matches the engine types. 

If it’s not plausible due to the available power output of said sound card, what about a aux amplifier? 

Michael


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## Rod Fearnley (Jan 2, 2008)

Michael I only have the cheap old MRC Diesel sound card. But I run two speakers from it in my USA Trains Cow and Calf. Not brilliant sound, but visitors love it.
Rod


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## flats (Jun 30, 2008)

Michael, I have Phoenix sound cards in my engines and they will drive two speakers 
with good sound. Don't know about the other sound cards. 

Ken owner of K&K the road to nowhere


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## K27_463 (Jan 2, 2008)

It is complicated somewhat. Sierra boards are not comfortable with loads under 8 ohms.They are also only 1 watt. So, if you use 2- 4 ohm drivers in series you are ok, 2 -8 ohm in series will reduce output too much, 2- 8 ohm in parallel will cause issues for the power amp due to low impedance . So, the answer is a qualified maybe, as long as you select components correctly and install correctly- for Sierra Soundtraxx. Phoenix is generally not a problem as they can handle lower impedance without difficulty. Depending on speakers selected it is possible to arrive at unusual loadings however. Remember, a lower impedance is a LARGER load. 

jonathan/EMW


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## Kovacjr (Jan 2, 2008)

If you wire them in series you keep the impedence the same. if you wire in parallel you cut the impedence in half. If it calls for 8 ohms only wire in series. meaning tie the speaker together with one wire from + to - on the other then use the remaining + and - wires to the board. That will keep it at 8 ohms.


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## Bill Swindell (Jan 2, 2008)

I am planning on putting a Soundtraxx DSX in each of my F-3's. They both will be driven by one AirWire receiver.


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## toddalin (Jan 4, 2008)

I do this with my Sierra systems. I put a very efficient 4 ohm speaker in the engine and have 3 ohms worth of resistance in series (7 ohms total). There is a jack on the back of the engines and when you plug in a trailing car with a speaker(s), the 3 ohms are disconnected and the rear speakers (two 8 ohm speakers wired to 4 ohms) replace it (8 ohms total).


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## RimfireJim (Mar 25, 2009)

Posted By Kovacjr on 30 Sep 2010 08:01 AM 
If you wire them in series you keep the impedence the same. if you wire in parallel you cut the impedence in half. If it calls for 8 ohms only wire in series. meaning tie the speaker together with one wire from + to - on the other then use the remaining + and - wires to the board. That will keep it at 8 ohms. 
That is incorrect. The equivalent impedance of speakers wired in series is the sum of the individual speaker impedances. It works just like resistor networks. You can Google "speaker series impedance" and find plenty of the same answer. The only way to end up with the same impedance is to do a series-parallel arrangement, as shown here: http://www.bcae1.com/spkrmlti.htm


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## Madstang (Jan 4, 2008)

All my diesels are consisted with each having 2 speakers and no problemmo! 

My BigBoy has 2 speakers also and the same thing.


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## Stan Cedarleaf (Jan 2, 2008)

Just an additional note with some input from Jarrette at Soundtraxx concerning using 2 speakers with the Sierra boards. 

He doesn't recommend it. In fact, he was very firm in saying don't do it.


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## Madstang (Jan 4, 2008)

I forgot to say I have only ever used Phoenix...I always thought there was ONLY Phoenix! So my information is only with Phoenix applications...sorry for the mix up.


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## Michael Glavin (Jan 2, 2009)

Lot's of good information gentlemen, thanks. 

What about the sound is it worth the trouble, anemic or is a sound card in each loco worth the expense? 

On another note, I jus opened up an Aristocraft U25 I purchased a while back, again battery powered from consisted source. Lots if custom electronics inside, in fact it’s quite a rats nest. Behind the access door there are 8 mini toggles (lights, ditch lights, step lights, head lights front and rear, beacon, SOUND and a momentary push button for horn) inside there is voltage regulator and what appears to be an analog sound card with lighting effects herein. It’s big and clumsy but works with pooor sound quality IMO, any ideas on the origin of this dinosaur? PS also has 9v battery and at least one trip/trigger circuit used to sound the horn. 

Michael


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## toddalin (Jan 4, 2008)

Posted By Stan Cedarleaf on 30 Sep 2010 09:10 PM 
Just an additional note with some input from Jarrette at Soundtraxx concerning using 2 speakers with the Sierra boards. 

He doesn't recommend it. In fact, he was very firm in saying don't do it. 


Actually you can use as many speakers as you like. But he recognizes that many/most people will wire them in parallel and Sierras do not like to see less than about 6 ohms or they start "motor boating" and can burn out their amps.


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## Greg Elmassian (Jan 3, 2008)

And there is the answer! It's not just how many speakers, in fact it's not the number at all as Todd says. You need to know the impedance of your speaker system (and you can't tell it exactly with an ohmmeter, it's not the same as resistance). 

Since so few people grasp how impedance changes with series and parallel connections, it's common that manufacturers are afraid to recommend anything except a single speaker of the correct impedance. Luckily, the impedance of a system of speakers follows the same rules as the calculation of the resistance of a circuit, i.e. how parallel and series connections affect the system resistance/impedance. 

Regards, Greg


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## Madstang (Jan 4, 2008)

I use 4 ohm speakers whern I can find them. Using them in a 2 lash up GPs'. Phoenix says they are OK to use...less impedence the more sound. 

If you look at amps they usually give rms power for BOTH 4ohm and 8ohm. 4 ohm being almost double the output. 

Example: 200 watts rms at 8ohms........380-400watts @4ohms. I used to have a set of 4 ohm Advent speakers powered with a Sun Fire Cemina grand with the aformentioned wattage..when I cranked it up the house lights would brighten and dim...with the 8 ohm I would, at the same volume level clip the amp! 

Are 4ohm speakers in an engine louder? with some applications yes.....some I can tell very little difference. But there again it depends on the enclosure.

MHO


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## Greg Elmassian (Jan 3, 2008)

Yep, as long as the amp does not overload or overheat lower impedance gives more power. 

But, Bubba, check the harmonic distortion specs on any amp on 4 ohm vs 8 ohm, typically you will find the extra "power" comes at a price, extra harmonic distortion! 

Running an amp near it's limit will do this. 

So, you might get more volume, but sometimes it's at the expense of quality. That said, some people can hear the distortion very easily and some don't. 

With the advent of sound cards using class D amplifiers, you should be seeing much higher power amps with no heat problems, I think Zimo or someone already does this. 

Regards, Greg


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## Madstang (Jan 4, 2008)

Well when I had that audio set up I would dim the lights with the DVD Top Gun, the jets did not care about harmonic distorsion, or you really could not hear much above the ROAR of the jet engines taking off in the beginning of the movie. 

Playing audio, turned up too much the music looses the luster..so-to-speak. 

Now I am into class A sound that Meridian brings and I have never heard music as I hear it through the DSP speakers, now it is not loudness but quality. 

As for the Phoenix even turned up with 4 ohm speakers the only thing you would realize is the imperfections of the encloseure that surrounded the speaker, and fixing that then no problem..that I have ever noticed. But again how long can you stand to hear the choo choo full blast befiore it gets to you anyway..unless you are showing off...and yes sometimes that is just what we do.


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## Greg Elmassian (Jan 3, 2008)

Yep, give me lower distortion even if the volume is down a bit. I also agree the first bugaboos seem to be rattles and buzzes in the enclosure. Water hatches rattling, the 4 pieces of grill on my RDC, various parts rattling inside. 

I have a Krell full class A, I hear (pun intended) what you are saying Bubba... First time I fired up that amp, the lights dimmed and stayed dim. Ran my AC power from a quad box through the floor right to the panel. 

Greg


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## toddalin (Jan 4, 2008)

I'm of simple taste, listen to classic rock, and want to hear what the engineer who mixed the master heard. If it was mixed in the '70's, in all probability it was mixed on a variant of the speaker on the right. If it was mixed in the '80's or '90's, chances are it was mixed on the speaker on the left.


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## Greg Elmassian (Jan 3, 2008)

Spent every dime I had in college for a stereo system... JBL L-100 speakers was all I could afford. Made my own power amps. First pre-amp for my Gerrard (sp?) turntable was tapped into cassette tape deck preamp circuit for the tape head itself. The speaker on the right looks familiar, but cannot place that radiator "lens"... 

Greg


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## toddalin (Jan 4, 2008)

Posted By Greg Elmassian on 02 Oct 2010 12:25 PM 
Spent every dime I had in college for a stereo system... JBL L-100 speakers was all I could afford. Made my own power amps. First pre-amp for my Gerrard (sp?) turntable was tapped into cassette tape deck preamp circuit for the tape head itself. The speaker on the right looks familiar, but cannot place that radiator "lens"... 

Greg The one on the right is an L200 modified to an L300, but I've added ~3/4 cu ft to the interior volume and used audiophyle components in the crossovers (large gauge air core inductors, Solen caps with Theta by-pass caps, etc.) The L200/300 are home versions of 4320/4330/4333 studio versions that are intended for soffit mounting. They all used an exponential horn for the mids and the lens acts just like an optic lens to change the dispersion pattern to widen it in the horizontal plane.

The tweeter is the slot tweeter which was a later version of the ring radiator that trades volume for dispersion. Again, just like in optics and wave theory, the thinner the slot opening, the greater the dispersion.

The one on the right uses all AlNiCo components and the one on the left uses essentially the same components except that the magnets are ceramic and the mid driver uses a titanium rather than aluminum diaphram. The titanium extends the frequency range of the mids and there is no separate tweeter on those.


Recognize that the current versions of these, the K2 S9900 now sell for $44,650/pr.


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## fiona (Sep 21, 2011)

have you even heard about a kind of Vibration Speakers? 
i was attracted by a diamond shape mini speaker from a online wholesale site: SpeMall.com, so anyone here tried these innovative speakers? or any experience on that site?


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## Dan Pierce (Jan 2, 2008)

The newer Zimo sound decoder is rated at 10 watts audio via 4 ohm impedance. So, 2 8 ohm speakers in parallel will allow 5 watts each and 4 ohms. 

But is this rms or peak audio watts by all these manufacturers????


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## Greg Elmassian (Jan 3, 2008)

Almost always peak... looks better on paper!


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## Madstang (Jan 4, 2008)

Posted By Greg Elmassian on 01 Oct 2010 05:11 PM 
Yep, as long as the amp does not overload or overheat lower impedance gives more power. 

But, Bubba, check the harmonic distortion specs on any amp on 4 ohm vs 8 ohm, typically you will find the extra "power" comes at a price, extra harmonic distortion! 

Running an amp near it's limit will do this. 






Yes it does! If you turn the sound up too much..you get distortion. Besides you cant listen to it for long that loud anyway.

Bubba


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## Madstang (Jan 4, 2008)

Posted By Greg Elmassian on 01 Oct 2010 09:54 PM 
Yep, give me lower distortion even if the volume is down a bit. I also agree the first bugaboos seem to be rattles and buzzes in the enclosure. Water hatches rattling, the 4 pieces of grill on my RDC, various parts rattling inside. 

I have a Krell full class A, I hear (pun intended) what you are saying Bubba... First time I fired up that amp, the lights dimmed and stayed dim. Ran my AC power from a quad box through the floor right to the panel. 

Greg In my threatre room I have $500 worth of wiring in the walls and 10 circuts to handle all the amps inside the 6 speakers..thank GOD my #2 son is an electrcian, so we agreed to swap my Maggies for the work....win win.









Bubba


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## izzy0855 (Sep 30, 2008)

I've been driving three PUI 5W 8ohm speakers for almost three years now with Phoenix's P8 Sound Card in my NW2 Cow & Calf drivin by my C-10TL Trailing Battery-Car, and haven't had any problems. 

Rick Isard 
Cordless Renovations, LLC 
RCS America


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## Greg Elmassian (Jan 3, 2008)

Well Bubba, you appear to be one of the few people that hears distortion as unwanted sound... many people just hear it as louder... yeah, I hate distortion also. 

Yeah, my old stereo system (too big after marriage) has 0 gauge wire ... ( pronounced "awgt" gauge ) 

That last 10% of sound quality is what costs! 

Rick: did you do a series/parallel arrangement? (two in parallel, and that in series?) 

Greg


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