Hi all,
I’m assembling a slope-back tender kit for one of my models, and the way the tender body is laid out means I’ll only have space to use 1/2" speakers (with baffles), rather than anything larger. With this in mind, I’ve decided to use two speakers under the front of the tender.
I’ve done a few sound installs before, but not one with two speakers. Do I need to hook the speakers up in paralell or series, and how does the polarity of the speaker come into it?
Hi Danny:
First question is: what speaker configuration is your decoder able to accept? Most decoders will accept an 8 ohm speaker. However, if you want to use two 8 ohm speakers together, you will not end up with 8 ohms impedance. If you wire them in parallel you will have 4 ohms impedance, and if you wire them in series you will have 16 ohms impedance. The question is what decoder are you using. If you can tell us that we can give you much more accurate information about how to wire your speakers.
Sorry if I am complicating things, that is not my intent. Two speakers are better than one.
Regards,
Dave
Whoops. Thought I forgot something :-/. The decoder is a Soundtraxx TSU-1000.
Danny:
Do some reading here:
http://www.sbs4dcc.com/tutorialstipstricks/wiringmultispeakers.html
This web site is a superb source for DCC sound information.
Regards, Dave
Dave,
Thanks for that, but I’ve still got one question. I can either wire the speakers so they’ve got an impedance of 4 or 16 ohms, but the decoder’s wired to use speakers of 8 ohms impedance. So do I wire less than or more than 8 ohms to avoid blowing out the decoder’s amp?
Tbdanny,
That decoder has an audio amp rated at 1 watt at 8 ohm’s, so You would be better off wiring it in series with the two 8 ohm speakers for 16 ohm’s, reason being at 4 ohm’s, the volume may sound louder, but it will also make the amp work harder and warmer, which is what You don’t want. Ideal situation is to match the amp. output. But it is also better to go to a higher impedence, than a lower, so as not to overheat the amp.
There are Decoder’s out there that have 2 watt 4ohm impedence output, but I don’t believe You want to go there.
Take Care! [:D]
Frank
TBdanny,
I enjoyed looking at your layout blog. Some very sophisticated and interesting modelling!
All the suggestions I have seen recommend in series.
Bruce, the below fellow use to own Litchfield Station and now does DCC articles in a couple Yahoo DCC Groups and the MRH forum. Bruse posted a nice DCC Myths article in that forum.
Scroll down a little.
http://mrdccu.com/curriculum/soundtraxx/tsunami.html
Rich
ESU (Loksound) has a full line of 4 ohm speakers. My recommendation would be to use two of their speakers in series for the correct 8 ohm load.
Mark.
That’s what I would do…they are the one’s that have the 2 watt 4ohm audio output.
Take Care! [:D]
Frank
Unfortunately, I’ve already bought the dual Soundtraxx 1/2" speakers - did so before posting this thread. With shipping costs, etc. and the fact that I’ve already bought the wrong speaker (1", without measuring it) once, I’m not really in a position to spend more money on speakers at the moment.
More to the point, if I went for the Loksound speakers, I’d have the soundtraxx ones just sitting around. This is the last loco I’ll be building.
No small speaker sources in Australia, so you wouldn’t have to pay crazy shipping costs from the US? Model railroad speakers aren’t anything special. 2x 8ohm in series is the safe way, you can always put more speaker impedence across the amp than specified and there is no risk of overloading the amp. Downside will be reduced volume. May not be an issue since most sound decoders can go way too loud anyway.
–Randy
ESU has quite a few dealers in Australia - might want to contact one.
Mark.
Here is one and there are others further down the page:
http://www.hotfrog.com.au/business/nsw/blacktown/model-railroad-craftsman
The above, has great reviews.
Take Care! [:D]
Frank
Thanks. Looks like I’ll be listing the Soundtraxx ones on Ebay, then.
Thank-you to everyone who’s provided advice.