Speaker Box Size?

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Fergmiester

M.E.S.S. Maker
I just recieved two Soundtraxx DSX 150 Sound Decoders (with no manual:confused: ) and after looking at the Soundtraxx Website I'm a bit confused. My original understanding on speaker boxes was to make them as air tight and as small as possible but according to Soundtraxx as long as you seal up the front around the speaker (not over the face) and seal it in you've got a boxed speaker. I figured this cavity would be too big. The speakers I'm using are the oval type 1.38" x .63" x .28", which according to Soundtraxx would mean the minimum size box would be 1.38"L x .63"W x 1.38"D or would it?

If anyone has any insight I'd appreciate it.

Fergie
 
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grumpybob

Lake Shore Lines
Fergie,

where did you get the Soundtraxx stuff from? Soundtraxx makes a box to fit their round speakers. Without question that speak needs to be sealed into the box. There can't be any air leaks, otherwise the sound quality will dimish. If you bought it from a LHS, i would go back and ask for the manuals, if not, go back to the Soundtraxx web site and download the manuals appropriate for either diesel or steam.

I know when I bought my first soundtraxx decoder i got at least 4 or 5 manuals to go with it. You definitely need something to help understand all the CV's.

Bob A.
 

HaggisKennedy

Coal Shoveler
Tony's has some speaker boxes that work for most of the common speakers out there. They should do the trick.

Sizewise, it depends on where you're installing them. Some say that a tender box is OK, other say you should put the speaker in it's own box. I think that if you are using a huge speaker inside a tender, sealing up the tender would do. In a diesel, use a regular enclosure; some folks use a film canister or perhaps the bottle that prescription meds comes in. Whatever fits the back of the speaker. I seal the enclosure using silicone rubber glue; I learned this back in the late '70s when I was building my own stereo speakers from Speakerlab.

Bruce Petrarca, of Litchfield Station, sometimes puts the enclosure on the opposite side, so the magnet side faces out. You see this in some of the 'tuner' cars out there with the big stereos. He says that setup works well also.

Kennedy
 

Railphotog

Railroad Photographer
I just recently installed Soundtraxx decoders and speakers in my On30 Bachmann Shay and Climax - my first introduction to DCC.

The 1" diameter supplied speaker fits onto the bottom of the small tenders, below the orginal circuit boards, and over pre-drilled holes in the chassis.

The new decoder plugs into the original circuit board, and is the same size. This fills the tender on the Climax and almost all of it on the Shay. Both tenders have removable metal bunkers and resin wood loads in them, and there is no way to really seal their tops.

Has anyone done anything in these installations to seal the speakers? One of the whistle sounds in the Shay results in a resping sound as if the speaker cannot handle the lower tones.
 
Fergie
I have upgraded seven of my loco's (2 steam and 5 diesel) to sound using various Soundtraxx variations. I just completed a LL GP-7 after removing a small bit of chassis I put in a 1.5 x 3/4 in speaker. I did'nt have enough room for a store bought enclosure so I simply put tape over the back of the speaker holes. I tried it both with the speaker holes open and with the taped up holes (with the loco completly assembled) and the sound was significantly better (and satisfactory) with the holes simply taped up. I am sure if I had the room for an enclosure it would be better but I run my loco's at low volume and was very happy with the results. Sometimes the easy way works. I just got my new Athearn RTR NYC RS3 today, I promply took it apart and was delighted to see there is plenty of room for two decent sized speakers and a PnP LC sound decoder. Hope this helps.
Terry
 

Fergmiester

M.E.S.S. Maker
Well I did some more digging and found out the original speaker box I had in the LL Berkshire was too small



So after talking to one or two people and reading some more I decided to do this.



This improved the quality considerably. the bigger the box, in this case the whole tender, the better the sound quality, as long as one side of the speaker is sealed.

Kennedy, Bob & Bob Thanks for the additional info.

Fergie
 
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Fergie
Wow you do some fine work. How did you get the hole in the styrene so perfect? Very professional looking. Much better than my tape job.
Terry
 

Fergmiester

M.E.S.S. Maker
scubaterry said:
Fergie
Wow you do some fine work. How did you get the hole in the styrene so perfect? Very professional looking. Much better than my tape job.
Terry
Pencil, straight edge, sharp razor, 1/2 round file, drill press and my tongue held in a 47degree angle adjacent to the right ascending side of a waning moon in the fourth quarter!

Wait till you see my retro-fit in my FEF-4:D

Fergie
 

HaggisKennedy

Coal Shoveler
Fergmiester said:
Well I did some more digging and found out the original speaker box I had in the LL Berkshire was too small
There is a formula that is used to calculate what should be the optimum size for an enclosure. I don't recall what it is exactly, but it has to do with cone size, and I *think* it's 1 to 1. As in, for a speaker that's one inch in diameter, your enclosure size should be one cubic inch.

Now, that doesn't mean that it has to be exactly that size. There is a fudge factor either way. But, if you stay within the ballpark, you should get good sound.

Kennedy
 

1shado1

New Member
Fergmiester said:
Wait till you see my retro-fit in my FEF-4:D

Fergie
Or even your FEF-3 (FEF-4??? No such critter):D

Damn, you do nice work!:eek:

Jeff
 
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Fergmiester

M.E.S.S. Maker
HaggisKennedy said:
There is a formula that is used to calculate what should be the optimum size for an enclosure. I don't recall what it is exactly, but it has to do with cone size, and I *think* it's 1 to 1. As in, for a speaker that's one inch in diameter, your enclosure size should be one cubic inch.

Now, that doesn't mean that it has to be exactly that size. There is a fudge factor either way. But, if you stay within the ballpark, you should get good sound.

Kennedy

As the Surgeon once said the operation was a success but the patient died:eek:

Well I installed the speaker and decoder this morning and the sound bite is missing one thing... A little blue pill!:mad: It's loud, but the DSX is Hokey!!! Very disapointed in the quality of the chuff and whistle. I can blow my nose and do better!!!

I'll post pics of the install tomorrow after I mend my wounds.

Fergie
 

RexHea

RAIL BENDER
Fergie, I think you did right in using the entire tender for the speaker box and from the looks, you could have doubled the size of your speaker. Most of the formulas for baffles are really giving you a minimum size more than an exact size. There are so many things to consider when you try to figure the volume of space, such as how much of the actual tender space is free-air or has a decoder, light board, and etc.. I know BLI uses the entire tender for theirs and I did mine with excellent results. As I said in an earlier post, the key is sealing off the back of the speaker from the front and allow plenty of air space. My2cents
 

Fergmiester

M.E.S.S. Maker
This is the speaker box installation in the tendetr of the UP 4-8-4 tender



Speaker box is the tender chamber. Speaker is pointed down through the tender floor.

Fergie
 

RexHea

RAIL BENDER
That's good when it can be done. I believe you get a better production of sound when the speaker is aimed down...reflecting in all directions kind of like a sound board. With the speaker pointed up, the sound goes up and if you are on low volume and away from the engine, the sound is not as apparent. I guess it depends on your perspective of where the sound should be coming from. i.e, If you have a low layout then pointed up would be beter.
 

Fergmiester

M.E.S.S. Maker
Unfortunately due to the size of the Speaker and the big brick of zinc in the way this was the best fit. Well I'll try a straight install in my Hudson and if the sound doesn't sound right I won't be installing the DSX in anything but the cheap ones, maybe. My Soundtraxx 100LC sounds much better.
 




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