Sealing Speakers

[CPPedler]

Has anyone got ideas about the best way to seal speakers in body shells for DCC sound sometimes its a bit tricky getting the speakers to sit level with some irregular shapes inside shells . CPPedler.

[SPFan]

When I was building speaker systems I used Mortite string calk. It will seal but not really adhere to surfaces so you can remove the speaker if necessary. You could probably use plastic modeling clay as well but its not as sticky and is less pliable than Mortite.

Pete

[Virginian]

Silicone caulk, not the adhesive caulk, just the plain caulk. About $5 for enough to do about 500 small speakers.

[mcouvillion]

CPPEdler,

I've built a couple of enclosures out of sheet styrene, and you are right, it IS difficult to get everything to line up right. I finally did get the enclosure tight enough to baffle the sound. The enclosure is cemented into the inside top of the engine shell and the speaker is mounted on the chassis. They mate properly when the shell and chassis are together.

Just a quick couple of notes: 1) Use a properly designed baffle (enclosure) for your speaker if at all possible. 2) The back of the speaker will usually release the same amount of sound as the front, so you don't always have to face the front of the speaker out from the enclosure (and have to drill holes in it to get the wires out. Just point the speaker into the enclosure to protect the cone and have easy access to the wires.

Mark C.

[NZRMac]

The latest MR mag has some hints on speakers.

Ken

[gvdobler]

The idea of enclosing speakers, is to prevent any sound coming out the back. You want sound from the front only of any speaker. The shape of the enclosure can be modified to fit the allowed space.

The article in MR is very good. I have seen people spend a lot of money on home stereo speakers to go with a cheap amplifier and be disappointed, where a powerful amplifier will make cheap speakers sound great.

Jon - -Las Vegas

[mcouvillion]

The purpose of the baffle is to isolate the sound waves generated from one side of the speaker diaphragm from those generated on the other side of the speaker diaphragm, especially those in the lower frequencies. That's why baffles are used to enhance the deep, throaty sounds. With a single speaker, you will never know the difference of whether it is "facing" into the baffle or out of the baffle. It is easier to assemble and wire, and protects the speaker cone better, if it faces into the baffle. For two or more speakers, the problem of phase comes into play, where the speaker cones must move in the same direction at the same time to enhance the sound, again, for the lower frequencies. For most applications, there is no reason to have to face the cone to the outside of the baffle.

Cheap amplifiers ruin speakers when they overdrive the speaker and the signal "clips", causing distortion that ruins the speaker. A good amplifier can make a cheap speaker sound great if the power to the speaker does not exceed the rating of the speaker and the signal never "clips". It's not how loud it is, it's how clean it is.

Mark C.

[Don Gibson]

BETTER sound in Hood diesels can be obtained by fitting a speaker to fire through a fan. Any moldled decorative fan may can be replaced by a 'see thru' type, allowing the sound to escape upwards, and the body to form a baffle.

Engines with multiple fan holes will enhance their sound by sealing off the unused holes, so the body can separate the speaker's back from the front wave until it reaches the bottom of the shell. This helps the lower tones.

F7's (particularly Highliner) can benefit by replacing their Dynamic Brake fan with a larger larger one that a speaker can fire through. some roads replaced theirs for better cooling. Again the body becomes a baffle.

[CPPedler]

Thanks guys, this is another interesting subect, I'll check out the article in M.R. CPPedler.