Speaker enclosure

[gmpullman]

I'm using the term speaker baffle in respect to a plane which will stop the sound waves from the front of the diaphragm canceling out those from the rear.

In most cases the speaker baffle is the front face of a traditional speaker enclosure. Ideally it would be on the same plane as the diaphragm.

Unfortunately we don't have a lot of room to play around with in a locomotive shell that shares a decoder, drive hardware and electronics. In the example of the SD7, above, I certainly couldn't use any type of total enclosure. The drive shaft runs right along the bottom edge of the speaker. However, by placing that ring of styrene around the outer edge enough of the forward and rearward driven sound waves get separated so that the sound produced is noticeably louder and has more presence.

Being able to experiment with various designs of "baffles" or enclosures helps to get the best sound out of the smallest spaces. The smaller "sugar cube" speakers work best with air-tight enclosures. 

Good Luck, Ed

 

 

[BigDaddy]

Should the baffle be on the front side or the back side.  I watched a Bruce Petrarca video, and he only confused me.

[gmpullman]

BigDaddy

Does it need more of an enclosure?

An enclosure would be helpful, however I have found that sometimes a simple "baffle" will work wonders. I've made styrene enclosures that work fine. You should seal the four mounting holes if you are not using them.

This one was made to nest into the coal bunker of a brass tender:

Q3_decoder0 by Edmund, on Flickr

This SD-7 has two speakers. Note the baffle on the 28mm round speaker. It is amazing what a difference that small arc of white plastic makes. There is an ESU cube speaker toward the short hood. 

BLI_BLE_RS15dcc by Edmund, on Flickr

BigDaddy

The front has a plastic gasket, is that meant to seal the speaker or seal the speaker assembly to a flat piece of styrene?

IF you were using the four mounting holes the gasket would work. I generally "seal" the speaker using a tacky cement along the lines of Aileen's. Something air-tight but not as permanent as, say Goo.

I like to test speakers before finally assembling them into the loco. I use an MP3 player and play some "full dynamic range" music through the speakers to see what kind of performance I can expect. Sometimes a speaker is a complete dud — so testing before assembly is a good idea.

SPKR_test by Edmund, on Flickr

This also allows me to check the wiring. Sometimes series is best, other times parallel. Yes, the resistance of the speaker matters but I have found that experimenting with series/parallel arrangements matters when the speakers aren't "matched". As long as the decoder can handle the load.

I've become convinced of the excellent sound output of the "cube" speakers. No two are the same, though. Again, auditioning several enclosures and speaker sizes will help you determine what sounds best to your ear.

BigDaddy

Mounting it upwards or downwards should not matter?

Nope, the sound seems to get out either way. It's all about moving the air.

[RR_Mel]

I’ve been using that speaker for several years and I custom build the enclosures for each locomotive.

 

 

The above has a pair of 4Ω speakers in series installed in a Rivarossi Cab Forward oil tender.

 

 

This is a single 8Ω speaker in a Model Power E7.

 

The picture is an 8Ω speaker mounted in a Cary E7 shell.

 

 

I use .04” sheet styrene to make the enclosures.

 

These speakers put out the best DCC sound of any I’ve tried.

 

It is very important to cover the speaker opening because of the Neodymium magnet, it will pickup tiny metal particles and ding the speaker cone.

 

 

 

I went with a coarse first then a fine grain piece of cloth.

 

 

 

 

Mel

 

 

 

My Model Railroad   

http://melvineperry.blogspot.com/

 

Bakersfield, California

 

I'm beginning to realize that aging is not for wimps.

 

[mbinsewi]

Now that sounds intetesting, or at least, I bet it will.  I want to try something of the same, but maybe a wood enclosure.

I see they sell a seperate enclosure.

I'm going to have etched metal intake grills, and fans on mine, so my thought was to mount them facing up.  But it probably wouldn't make any difference.

Mike.

[BigDaddy]

I want to put this Soundtrax speaker, in a Stewart B unit.

1. Does it need more of an enclosure?
2. The front has a plastic gasket, is that meant to seal the speaker or seal the speaker assembly to a flat piece of styrene?
3. Mounting it upwards or downwards should not matter?