Resonance -- let's get this hammered out!

[erv]

you can't have an accurate chart cause the wavelength (and therefore the lamda/4) relies on the resonnant freq of the speaker, which is not only related to its diameter. But we could at least make a chart for specific speakers that we know about.
Erv'

[xwingband]

lol, Jonitus... I guess I should word it better. What you are talking about is good. I think a good ear can just find it with experimentation, but that would help to have a chart.

What I was referring too would be someone overthinking it and trying to design certain pitches, say the average of the hum sound, and making there saber to resonate with it... that's overboard. :P

[Jonitus]

lol, Jonitus... I guess I should word it better. What you are talking about is good. I think a good ear can just find it with experimentation, but that would help to have a chart.

What I was referring too would be someone overthinking it and trying to design certain pitches, say the average of the hum sound, and making there saber to resonate with it... that's overboard. :P

...totally

I thought that going only so far as charting what size chamber is needed for certain speakers for certain boards. It might be handy to determine if you want a Hasbro speaker or a Radio Shack speaker or one of Novastar's nifty speakers or whatnot for whatever type of board you happen to run.

If I can get use of the equipment, since I work as a safety professional by day, I can borrow a sound level meter and start taking measurement of some of this stuff.

If someone wants to get carried away and tune their chamber for a particular frequency shift, they are welcome to it. Not gonna be me.

[supertrogdor]

I'll throw in my 2bits here. Having competed (and brought home trophies every time) in some amature stereo competitions in my formidable youth, and specializing in box building, i can tell you that speakers have what are called thiele small parameters.(for more details you can look here they have a good general explanation) They are basically measurements on how the speaker moves and are used to calculate what kind of box you should build for each speaker based on those parameters. I have a few programs that calculate that for me, but there is one problem i see. Speakers this small will still be affected by those numbers, but getting them for a speaker small enough to fit into a saber would be another story, and are not likely available to john q public.
On a more workable note, the sound will protrude just as much from the front of a speaker as from the back, so it doesnt really matter which way you mount the kind of speakers we would use here.(even though most of you will not believe that try the test i reccomend here in a second mounting the speaker both ways and prove me wrong if you can) Having what everyone here referrs to as a resonance chamber is mostly a way of putting a sealed chamber of air behind the speaker for it to work against. The increased air pressure makes the speaker move more concicely in its intended path of travel along the magnetic pole. This is most likely going to need to be small in porportion to the speaker, i would guess less than an inch an a half in most cases, but you will likely find that making sure it is sealed airtight will make the biggest difference. I would get a length of pvc pipe that will both fit your speaker and the inside of your saber and find a plug for the opposite end. Mount your speaker and adjust your plugs propinquity to the speaker, then taking your apples to apples test, stop when you think it sounds best, but make sure to adjust around the sweet spot both in and out to verify your test. Adding a dampening material to the inside may also help you out here. Try a variety of things: cotton ball(s), crushed styrofoam peanuts, lining your chamber with cloth... that sort of thing as it can help produce a more balanced sound. I could go on, but that should be enough for most of you to be getting on with. Let me know if i can answer any further questions.
Cheers

[erv]

this is very useful info, I like it ! Surprisingly, the last saber I'm building is for the first time really loud, and I know it's partly due to the speaker itself, since the resonnant chamber is quite the same as on the previous one I did, so I'll try to make accurate measurements and simulation to know how to reproduce that for future sabers !
I'm going to study that wikipedia article, thanks for posting this !
Erv'

[Jonitus]

In the two MHS sabers I bult for my GF and I, I used a length of 1.25" white plastic sink tube for the resonance chamber. I had about half an inch behind the speaker and about an inch and a half in front of. The back part was stuffed with cotton from cotton balls and the whole thing was sealed with silicone. In effect, I made a sealed enclosure similar to what supertrogdor was talking about. It worked and the sabers were loud.

This may not work for everyone, since space is often a resource in short supply in our hilts.

Yes, to truly get a louder speaker, you have to have something behind the speaker to push against. Most of us will just free-air the speaker and let the hilt act as the rear resonance, but give something else a try.

[Novastar]

This = good thread to bump.

So... *SLAM*. *Thunk*. *Bonk*.

[Donnovan Sunrider]

Thanks for the bump Nova.
I'll keep this in mind when I get mine put together. I'd think a sealed capsule with the speaker at one end wouldn't be too hard to do. I just gotta seal off where the wires come out.

[Goodman]

I personally hate necroposting, but I think this thread *really* deserves being brought back to the front. Sound is half the fun of a lightsaber, IMHO, so certainly there is more information to be learned and contributed on this topic of maximizing the volume for our saber application.

Have any of the original posters completed any tests? If not, for what it's worth I'll be conducting a comparison between an MR speaker, a TCSS, and a 3W speaker. I'll be basing the comparisons on the directions given throughout this thread back in 2007, using different types of chamber materials, backing materials, sealing methods, and front/rear spacing.

I'll be the first to admit I don't have much experience with box building, etc, so if anyone has any more tips to contribute, or types of sound setups they'd like to see me add in my tests, please chime in. I'll probably start the tests in two weeks.

[mmafighter]

Here is what I did... I bought a relatively low end Ipod speaker system, and gutted an R2 unit fishtank, and put the system inside the R2 unit. Not realizing, that the sound was going to be really hollow, I had to redo the whole entire thing. I strated out with eggcrate on the walls of the R2, but since this is a saber discussion, we cant do that, lol.... I ALSO put stirofoam directly on the speakers themselves, and foam eggcrate BEHIND the speakers. Hope this helps, becuae what I essentially did was get rid of the hollow sound, and added more distortion throughout the R2 unit... good luck Nova!