Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Could I use 4 ohm in place of 8ohm speaker here?

4298 views
7 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Sunday, April 13, 2014 3:12 PM

Thanks, Randy.

It has obviously been a while since I added sound to a loco.....three years, I guess..and still using up my stock of large ovals.  These sugar cube speakers look intriguing.  I get the idea of sound chamber extensions.

Anyone have a quick opinion as to the best of these cubes vs. some of the bass reflex or expanded range speakers offered by Zimo and others.  Which wins in a comparison?

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Sunday, April 13, 2014 1:49 PM

 TONS of speakers that are 8 ohms and less than 16mm in the longest dimension:

http://store.sbs4dcc.com/sugarcubespeakers.aspx

 

No connection to this vendor, haven't even bought anything from them, yet. Just what came up searching for a variety of 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.

  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Sunday, April 13, 2014 12:50 PM

Thanks, all.

Reason I asked was that I was just getting around to looking at the better quality speakers, and the Zimo I mentioned is one of those bass reflex types at about $18.00 ea.  I have other 8 ohms in the drawer that would fit, but wanted to put a superior speaker in as a test since these decoders are noted for poor sound and I have a couple more to play with in the future.

So, if anyone knows of another of the top end 8ohm speakers no bigger than .63" or 16mm wide, oval or round I would be interested.

  • Member since
    April 2009
  • From: Sweden
  • 1,468 posts
Posted by Graffen on Saturday, April 12, 2014 11:19 PM
But two 4 ohm speakers in series is equal to 8 ohms. Or 4 speakers of 4 ohm coupled in series/parallell.....

Swedish Custom painter and model maker. My Website:

My Railroad

My Youtube:

Graff´s channel

  • Member since
    October 2004
  • From: Colorful Colorado
  • 8,639 posts
Posted by Texas Zepher on Saturday, April 12, 2014 11:03 PM

Cisco Kid
Would I be able to swap in a higher quality Zimo 4 ohm speaker for the 8ohm default one?

No, not unless the SDN144 specifies it can use a 4 ohm speaker.

I wish to use just one speaker in my new VO-1000.  Would I be able to do it with additional electronics added....

Since you don't want to use a second speaker, you could get another 4 ohm inductor to put in series with it.  Something like this. http://www.mouser.com/ProductDetail/Sumida/5406-391-34-00/?qs=sGAEpiMZZMukHu%252bjC5l7YRKILtFu0hlh0nMowAHeUNc%3d.  Note that I am not recommending this unit, just using it as an example.

What I can't tell  you, without knowing a whole lot more about the speaker and doing come calculations,  is how to match the resonance frequency of the inductor with the speaker to prevent it from acting like a low-bypass filter. 

Since you say your not good with electronics this probably won't help.  All the on-line sites I can find that are related are for building crossovers.  This one has a "first order" section which is actually the most simple  Butterworth crossover.  The inductor would be L1.
http://www.apicsllc.com/apics/Misc/filter2.html

As the others have said, the best thing is to find an 8 ohm speaker that meets your size needs.  There are bunches and bunches of them out there.

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Saturday, April 12, 2014 10:48 PM

Absolutely not. It's already pushing it to use an 8 ohm with those decoders, you will need to turn off BEMF to prevent slowdowns when blowing the horn, although that's not really an amplifier load problem, it's a "the cpu can;t do all those things at the same time" kind of load.

Is this an N scale ot HO scale VO1000? If it's HO, a Loksound Select Micro and a rather large speaker actually can fit, Bowser has done this with the factory sound versions. I bought a power chassis and swapped my existing shell from an older non-sound one. Sounds infinitely better than the old 8 bit Digitrax sound decoders.

You should be able to find small 8 ohm speakers - like the CT sugar cube speakers, to fit in an N scale version.

                --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    April 2004
  • From: Ontario Canada
  • 3,571 posts
Posted by Mark R. on Saturday, April 12, 2014 9:42 PM

The ohm rating has nothing to do with the physical size .... unless that just happens to be the only options offered.

Simply put, you should not use a four ohm speaker on a decoder designed for an eight ohm load. You could go higher (16 ohm), but not lower (4 ohm) - you will damage the audio output amp.

You could wire two four ohm speakers in series to maintain your eight ohm load, but if space is a consideration, that's probably not an option. There are MANY sizes of eight ohm speakers available out there from numerous sources.

Mark.

¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ

  • Member since
    April 2003
  • 305,205 posts
Could I use 4 ohm in place of 8ohm speaker here?
Posted by Anonymous on Saturday, April 12, 2014 8:31 PM

I have a few of the inexpensive (not great but useful) digitrax SDN144 decoders.  Would I be able to swap in a higher quality Zimo 4 ohm speaker for the 8ohm default one?  I wish to use just one speaker in my new VO-1000.  Would I be able to do it with additional electronics added.....  I'm not a electronics smartie, but well able to solder up whatever I am told.

Unfortunately the 8ohm Zimo is too big.

Thanks for any tips.

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!