Speaker Enclosures

[Don Gibson]

All enclosures - even partial - have resonamce. This includes one's living room - as you will hear when some trucks roll by.

LAWS OF PHYSICS:
The larger the encloser, the deeper the resonant frequency..
The smaller the enclosure, the higher it becomes.

'BAFFLES' separate back and front waves of a speaker preventing cancellation due to fact that when a speaker 'pushes', it' also 'pulls' on the backside. This push/pull cancells each other beyond the diameter of the speaker.The longer the physical separation, the lower this cancellation point - making the speaker sonically larger.
AIR COLUMNS produce resonance. The longer the air column, the lower the pitch.

TEST APPLICATIONS:
A Margarine lid is about 4.5" in diameter. A Toilet paper insert is about 4.5" long BOTH separate the back wave from the front wave 4.5". There the similarity ends.

Cut a single or a couple of smaller holes at the center of the circular lid,
Take a speaker (1" is good) hooked up to a sound source - such as one side of your stereo. 1). In your hand. 2). against the holes in the lid. 3). into one end of the toilet paper insert. try to seal the speaker end.

LISTENING TEST:
1. is No Baffle
2. With Baffle separation
3. Baffle, plus Air Column Resonance.

Like in Lovemaking, it takes two to Tango, and size does help[.

[Anonymous]

The best response from any enclosure is is f rom one that has only one opening. The rest of t eh enclosure is sealed (as air tight as possible). This prevents the air pressure from opposing the movement of the speaker cone.

A good and relatively inexpensive speaker that sounds good for a layout is a 5x7 inch oval with a wizzer (not electrically driven tweeter) cone.

For DCC sound decoders, I have had very good luck by placing two 1" round speakers facing each other in a sealed placstic tube (a 35 mm film canister with the bottom cut off). Cross- connect the terminals. This makes the cones move in phase wit heach other ie both move left or both move right at the same time. The result is better base response than from one alone.

I hope this helps. --- Steve

[jfrank138]

Don't cover the front with any old cloth. Speaker grille cloth (available at Radio Shack and elsewhere) is an open weave of non-acoustically-absorbent fiber, designed to pass all frequencies. Normal cloth will tend to absorb higher frequencies, resulting in muffled sound.

[bcammack]

Radio Shack sells a book with all the plans for ported and infinite baffle enclosures that includes all of the necessary formulas necessary to compute the proper enclosure properties based on the resonant frequencies of the the drivers.

[Don Gibson]

ONE CAN build a speaker enclosure - but every speaker has a resonant frequency - as does every speaker enclosure, and commercial loudspeakers try to arrange a marriage of the two - which is tricky.

It is unlikely YOU can exceed their results - for the same price. THAT being said, Radio Shack sells raw speakers and may have some plans for building enclosures for some of them.

[tomwatkins]

For onboard sound speakers, Loy's Toys sells sheet lead which works wonderfully well if weight is not a problem. I've also used .080 thick styrene sheet to make speaker boxes where weight was an issue.
Have Fun,
Tom Watkins

[orsonroy]

If you're talking about onboard sound speakers, use cut-down film canisters.

[bcammack]

Radio Shack has a book all about building speaker cabinets.

[cwclark]

Just build a four sided box out of light weight lumber, add some black cloth across the front, frame it, cut a space out of the fascia board , and mount it.. The speakers can sit inside the box to be heard throughout the layout through the cloth...Chuck[:D]

[Anonymous]

Any ideas on wher to find plans so that Speakers enclosures can be home built?