# Train with a subwoofer!



## Rene (Dec 27, 2007)

Hello,

I want to put a diesel sound unit in my train, but the speakers in the trains tend to be tiny! usually only 2" or 3" and only about 1 or 2 watts. So heres the idea, build a box car out of 3/8" MDF with one or two 4" hi performance speakers run by a 20-30Watt car audio amp and on board battery. This should significantly boost the low end and give the sound a bit more ...oompf! 


Has anyone tried this or something similar?

Ren.


----------



## Greg Elmassian (Jan 3, 2008)

I have one steam loco with a 4" speaker in it, set up as a subwoofer (putting tweeter in smokebox)... it has a metal shell. I'm getting a larger amp, the Zimo has a 13 watt amp, class D. 

Yes, it sounds great. 4" speaker from Jonathan at Electric Steam Modelworks. 

So, a subwoofer car might be cool, the problem is you will really need to put a tweeter up where the sound should come from. Even at 20 feet you can tell where the sound comes from. 


Greg


----------



## jake3404 (Dec 3, 2010)

Hmmmm, I have a 3" speaker in my K-27 and I think it gives out plenty of sound. 

Keep in mind if the sound from your locomotive is "blaring" then you loose the sense of distance on your railroad. The railroad is in a scale, so should the sound. If you dont hear the sound fade away as it gets further away then I think the whole purpose of sound is lost.


----------



## ralphbrades (Jan 3, 2008)

It should be possible with twin 4 inch speakers to use the Linn "Isobarik" speaker system. This runs two speakers in tandem separated by a sealed length of tube. Thus the mass of both speakers and the mass of the air between them allows it to remain stable at far lower frequencies than it would normally. Both speakers are in parallel and "fire" in the same direction and it would be quite easy to do. Alternatively you could build a totally air tight enclosure and fill it with Carbon Dioxide -which is how my REL subwoofer works.

regards

ralph


----------



## noelw (Jan 2, 2008)

Posted By Rene on 24 Jul 2011 03:32 AM 
Hello,

I want to put a diesel sound unit in my train, but the speakers in the trains tend to be tiny! usually only 2" or 3" and only about 1 or 2 watts. So heres the idea, build a box car out of 3/8" MDF with one or two 4" hi performance speakers run by a 20-30Watt car audio amp and on board battery. This should significantly boost the low end and give the sound a bit more ...oompf! 


Has anyone tried this or something similar?

Ren. 


Have to laf.... 
We did one a few yr's. ago with a Aristo Gon. Put a Guitar batt. Amp on it "20 watts" Turned up the Vol. full blast. Wired the sound off of our C-16 to it and almost lost the whole train..... Wife came flying out of the house when she was trying to watch a TV soap channel. This kind of upsets them.. laf.
Now back to 2-1/2 inch spk. in the tender. lol Noel


----------



## Rene (Dec 27, 2007)

Thanks for the replies guys, 

@Greg, cool, good idea about putting the tweeter where you expect to hear the sound coming from. 

@Ralph, Isobaric is a good idea given limited box size (ie a boxcar). I'm curious about the CO2 filled sub box, sounds fascinating, I've never heard of that before, is it something to do with sound waves traveling slower in heavier gas? Does it work???


----------



## Greg Elmassian (Jan 3, 2008)

Yep, I used argon for higher performance over CO2 and more inert. 

Greg


----------



## Torby (Jan 2, 2008)

Posted By Rene on 27 Jul 2011 08:32 AM 
Thanks for the replies guys, 

@Ralph, Isobaric is a good idea given limited box size (ie a boxcar). I'm curious about the CO2 filled sub box, sounds fascinating, I've never heard of that before, is it something to do with sound waves traveling slower in heavier gas? Does it work??? 
Here's a warning. Ralph is deaf, so when he's listening to a speaker, he's listening to a SPEAKER[/b].


----------



## ralphbrades (Jan 3, 2008)

Yes Thomas! This IS a reason why the speakers on my living room are a metre square!!! The reason REL fill their subwoofers with Carbon Dioxide is to do with the speed of the sound through it. The "small" REL that I have is only about 60cm cube -but the speaker thinks that it is 24 Cubic metres. When I was first dating "Her Pinkness" she asked "What is that heap of junk?" (People have been murdered for less...) At the end of the first side of my lp she said 'It sounds better than the system they have at the Ministry of Sound". 

The other reason that REL use Carbon Dioxide has to do with the problems of using an "Noble" gas such as Argon. Since Argon is monatomic -to seal it in an enclosure is far harder than the large triatomic molecule of Carbon Dioxide plus the speed of sound through Argon is higher than that of normal air because of its monatomic nature. I would assume that Sulphur Hexaflouride would be a better gas than Carbon Dioxide -but there would *other* issues!!! Normally Argon is used in the UK for welding (MIG and TIG) and for filling double glazing units with. 

I hope this has helped. 

regards 

ralph


----------



## SteveC (Jan 2, 2008)

Speaking of SF6 you might find this entertaining.


----------



## Rod Fearnley (Jan 2, 2008)

Phew! you guys, I feel under edumacated. There I was thinking I should go out and get a degree in Electronics, just to keep up with Greg, George and the other "Pinkies". Then along comes Ralph with "Noble" gases and words that I can barely pronounce. So, do I drop the Electronics and go for Chemistry now? LOL 

(This is all tongue in cheek guys, no offence intended. I could just see the funny side of this thread for guys like me)


----------



## toddalin (Jan 4, 2008)

Sulfur hexafluoride has 23,900 times the greenhouse gas potential of carbon dioxide and stays in the atmosphere 3,200 years. It's some bad stuff in that respect.


----------



## Greg Elmassian (Jan 3, 2008)

I hear they put it inside relays...


----------



## toddalin (Jan 4, 2008)

Posted By Greg Elmassian on 28 Jul 2011 11:57 AM 
I hear they put it inside relays...









That may well be. They use it in electrical items such as transformers and power lines.


----------



## Rene (Dec 27, 2007)

So how to you get CO2 into your speaker box? i was thinking getting some dry ice and throwing it in with the box on its back with the speaker hole on the top so as the dry ice displaces the air in the box.


----------



## zubi (May 14, 2009)

Ren, all you need to do is to fill your speaker box with a damping material, such as mineral wool, usually the more the better, just make sure it makes no contact with the speaker membrane. Best, Zubi


----------



## gnichols (Jan 9, 2008)

Manny Moons ago, in a galaxie far away, there was a fellow who sold plans for a Bose style speaker enclosure that fit in a box car. A friend built one, and it sounds great. Perhaps there are some archived threads on these? Sorry I don't have any other info, but as I recall the plans were advertised in GR. Later, Gary


----------



## jebouck (Jan 2, 2008)

I put a pair of "automotive speakers" in a set of LGB F-7s.
Got them at the automotive section at Wally World.
There is a tweeter mounted in front of the 4" regular speaker.
Sounded great!


----------

