A Study on Hilt Sound Resonance

[erv]

the tweeter just has 2 pins, it's a speaker.

A 4.7uf ceramic capacitor is soldered on the positive leg of the bigger speaker then connected to the tweeter. This is needed to only pass higher frequencies to the smaller speaker. Making it only produce higher frequencies. I used a surface mount 0805 size part .

from what I read, capacitor is between the 2 positive the speakers. Both have a common ground (obviously).
A 4.7 uF ceramic looks like the pic above indeed.
0805 is the footprint dimension in mil (L x l). You can use anything, including a classic capacitor with leads. SMDs are space savers though. Avoid an electrolytic capacitor on that kind of setup.

[Matt Thorn]

the tweeter just has 2 pins, it's a speaker.

Yes, I assumed that was the case.

from what I read, capacitor is between the 2 positive the speakers. Both have a common ground (obviously).

So the two speakers are wired in parallel, and the capacitor straddles the positive leads of the two speakers...?

A 4.7 uF ceramic looks like the pic above indeed.
0805 is the footprint dimension in mil (L x l). You can use anything, including a classic capacitor with leads. SMDs are space savers though. Avoid an electrolytic capacitor on that kind of setup.

Thanks!

[Sunrider]

Thanks Matt. I haven't verified how useful these ideas are with a CF but we are working on it.

Ok as Erv said SMT or SMD (surface mount parts) are small enough that you can actually use then in a hilt. The passive crossover idea is only limiting lower or higher frequencies to a single speaker.

A ceramic cap will pass only higher frequencies to the smaller speaker.

An inductor will pass only lower frequencies to a speaker.

This in turn improves the performance of the speakers.

Here is a good site that will elaborate and let you play around with numbers. Depending on speaker specs you can tailor a setup to your needs.

http://www.bcae1.com/passxovr.htm

[Matt Thorn]

Thanks Matt. I haven't verified how useful these ideas are with a CF but we are working on it.

Ok as Erv said SMT or SMD (surface mount parts) are small enough that you can actually use then in a hilt. The passive crossover idea is only limiting lower or higher frequencies to a single speaker.

A ceramic cap will pass only higher frequencies to the smaller speaker.

An inductor will pass only lower frequencies to a speaker.

This in turn improves the performance of the speakers.

Here is a good site that will elaborate and let you play around with numbers. Depending on speaker specs you can tailor a setup to your needs.

http://www.bcae1.com/passxovr.htm

Thank you, Sir! The text of the link is mostly Greek to me, but at least I can understand those wiring diagrams!

P.S.: I think it's wild that Pi is used in those formulae. Primitive me, I just use it to calculate circumferences!

[Novastar]

I guess one of the only things I can add here (hopefully to the understanding?) is that... well... basically, since sound is dynamic, think of it like...

If you were juggling 2 balls--it's not too tough...
Think of that like maybe 2 "specific & close" wavelengths of sound. For example, the "tinnier" treble like wavelengths. So... 1st set is super-tinny (~15,000 to ~20,000Hz or whatever)... and maybe the next is more like mid/top range (~9Khz or 10Khz, whatever).

If you were juggling 12 balls--NOW we're starting to see some complication! You'd drop them often... things would get mixed up... the quality of your "juggling" would start to get muddled...

...this is one way to look at it regarding ONE speaker... having to do "ALL" of the frequency output.

So... even though Sunrider's recent suggestions are a bit more complex... and in many ways, tougher to fit into a saber (possibly)... they certainly SHOULD produce better sound output, since the speakers will be sort of "splitting the work", for lack of a better term. Like one guy is juggling 4-6 balls, and the other guy--the same.

This isn't to say that ALL sound fonts are ALWAYS producing most ALL of the wavelengths at any given time... but even so... most speakers have a "sweet spot" within the range of wavelengths that they even support. If possible, it's best to have that speaker output only those frequencies (if you can help it).

I mean... a speaker may be listed as being "Response: ~300Hz to ~20,000Hz"... but that doesn't mean (in fact it almost NEVER means) that the sound quality, volume and general timbre will be "awesome" for ~ALL~ of those said wavelengths...

In fact... some speakers just plain sound awful... even if the response curve is IDENTICAL to another speaker's. It's ridiculous to have to figure all of this out, but... sorry... those are the ABCs of sound for sabers, baby doll... :P

[equinox13]

and that's why i spent several years getting my car stereo as good as it is - 10 total speakers carefully selected for perfect output in certain bands and 4 amplifiers driving them.

too bad you can't put a sound system like that in a saber...

[Novastar]

PRECISELY, Equinox! I mean, sure... maybe someday in the future, people will figure out how soundwaves could be "cheated" in smallform?!

But the fact of the matter with sound is... they are waveLENGTHS, and it's really really tough for a tiny tiny speaker to output "strong and long" wavelengths.

Then you get to the fact that they are battery powered... and... although you CAN draw lots of juice for a speaker if you so choose... tiny amps have issues with that... ... AND (at the present time, and probably for long in the future)... those amps/current/volts/whatever are better utilized by going into none other than your main LED for the blade...

I, for one, think sabers CAN PRESENTLY be made to be "loud enough"... and actually... thanks to Sunrider, I'll be testing out some of his precision work soon enough!! Which will probably just show "how far" you can go--even without giant CNC machines and/or precise calibration gear to figure in "in phase" perfection...

...if any of that makes sense...

[equinox13]

exactly! though i know that if i want my lightsaber hum to be optimized for 67Hz, i'll need my car's interior as a resonator chamber... impractical yes, however we do have miniature speakers that can output fractional waves that can travel fairly well in that range and aluminum housings to quite well for producing a tinny sound to things that can simulate hum fairly decently.

ribbon speakers... need to look into those again...

[setelf3of5]

The original saber hum was modeled after 60hz power line buzz. So idle hum should be around there. It is hard to get good sound in this range but can be done.

When I mention sealing I mean not letting air pass by the main speaker. By no means should any chamber be sealed. They must be well vented.

Nova has mentioned that he reduces the sample level below 80hz. Maybe he could explain more. I'm guessing a two speaker setup could candle this frequency range better than the single speaker.

I don't think we will ever get meaty rumble which is below 50hz. But the idle hum is right on the edge of what we can improve.

This is the difference between a speakers with & without resonance chambers.



Then I took off the tubes woah . difference?
data



I is important to note that while the specs on these speakers drop off at 400hz we can still see a huge change at 250hz of 15db.

The frequencies below 250hz would also improve by sealing the speaker against the end of the tubes and making the tubes longer.

A waste of time is it? If never you try, never know will you.

Since these images are no longer available does anyone have new diagrams of this? would love to see a cut away hilt of this.

[Forgetful Jedi Knight]

This thread is 4 years old, which is probably why the images are missing after all this time.