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Author Topic: what happens between a teslacoil the battery the incadescent bulb and the ground  (Read 41436 times)

gotoluc

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Hey Mags,

I also think along the same lines with acoustics as sound engineering (recording) was a hobby of mine in the past.

Lets say we have 10 identical acoustic guitars that are identically tuned and place them in a circle. Pluck one string of one guitar and all the other 9 guitars will vibrate the same.
Do the other 9 guitars dampen the first one so they can all vibrate?... I don't think so! as long as they are all identically tuned which is not an easy feat with wood grain variation of each acoustic chamber. Maybe it could be done with a plastic molded Guitar like the Ovation?

Anyways, I'm still trying to perfect the circuits losses. Hope to have something better to show soon.

BTW, I don't think I would agree that one could fully hear a low frequency of a speaker producing 20Hz let alone 15Hz inside a car. There's just not enough distance from the speakers to the listener for this to happen. Have a look at the chart of frequency wavelength distance needed in a room.

"Quote" and chart from: https://www.acousticfields.com/wavelengths-in-our-rooms/
"If we use 20 Hz. as our frequency, we take the speed of sound 1130 ft./sec. and divide it by 20. Our answer is 56.5 ft. This means that a 20 Hz. wave has a wavelength of 56.5′. How does this 20 Hz. or 56.5′ wave fit into our home theater, listening, or professional recording studio?"

Kind regards

Luc

TinselKoala

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You don't actually need a real 20 Hz signal in order to _hear_ a 20 Hz tone.

https://en.wikipedia.org/wiki/Missing_fundamental

Magluvin

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BTW, I don't think I would agree that one could fully hear a low frequency of a speaker producing 20Hz let alone 15Hz inside a car. There's just not enough distance from the speakers to the listener for this to happen. Have a look at the chart of frequency wavelength distance needed in a room.

"Quote" and chart from: https://www.acousticfields.com/wavelengths-in-our-rooms/
"If we use 20 Hz. as our frequency, we take the speed of sound 1130 ft./sec. and divide it by 20. Our answer is 56.5 ft. This means that a 20 Hz. wave has a wavelength of 56.5′. How does this 20 Hz. or 56.5′ wave fit into our home theater, listening, or professional recording studio?"

Kind regards

Luc

Actually there were some systems in older corvettes that you could hear down to 10hz. Of which is highly unnecessary. There is definitely a lot of tracks with content in the 20hz range that most never get to experience unless they are in a movie theater or have a home/ car system that is designed to do so.

In a room, larger than a car or suv, the best placement for a sub is in the corner, and the worst is on the middle of the room. From the corner the wave can only propagate outward from that corner. As you move the sub around the room the waves off of different walls can create nodes in the room where you can get the full effect here, but close to nothing there, and freq will affect where the nodes and nulls are.  Similarly in the car say even an suv, it is best to have the sub all the way in the back, where if it were in the middle of the vehicle, some of the wave travels forward and back thus reducing what you hear up front due to that loss of the wave toward the back. Been doin this for a long time.



Mostly I was exclaiming that is that most ported subs are tuned around 30 to even 49hz. The cutoff below the tuning freq is steep 24db per octave and tuned to 30 the port is way out of phase with the speaker mostly canceling out around 20 and below. Thats why they make adjustable subsonic filters as to  not waste power moving the speaker for nothing. But I like those lows so I like to tune low so there is a gain in that area.  And, below 80 hz, the db level gains gradually up to 12b at 20hz in a car compared to the graphs a box design prog would show.

https://www.youtube.com/watch?v=9cwOyqHi7kU

Mags

gotoluc

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I agree that a car or home system can be designed to produce 20Hz or lower but if you don't have the distance from the speakers then you're not truly hearing it, you're feeling it along with the air displacement caused by your secondary enclosure (car) as demonstrated in this video: https://www.youtube.com/watch?v=u4LNeh3htyQ

Ever noticed that you hear a better deep subsonic sounds (not feel) when you're further away from one of these mussel sound cars.

Regards

Luc

woopy

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Hi everyone

are we on track with the sound propagation ?

Is any similarity or analogy with what happen around the Tinselcoil and if yes please explanation.

Laurent

gotoluc

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Hi everyone

are we on track with the sound propagation ?

Is any similarity or analogy with what happen around the Tinselcoil and if yes please explanation.

Laurent


We're only hopping that sound resonance can be similar to electrical resonance.
I'm still making different coil sizes (geometry) to try and find the ideal power transfer from transmitter to receiver without input power increase.


Regards


Luc

Magluvin

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Yes in a way, when in the car you are in the box. But different factors determine what you hear in the car and what you hear outside.

A guy came to the shop in an older extended cap 2 door truck and his bass was wrecking hovoc in the shop from outside. He came in and we were asking what he had in there. 2 12s and a long 2kw amp. The box was full width of the cab and on the floor with the subs facing up behind the front seats. He said yeah its loud. Only on the outside. I got in and sure enough the inside was nothing compared to outside.  So I told him to flip the box upside down and use 3in spacers on the ends to raise it up about 3in from the floor. He said ok.

Came back the next day and the truck didnt shake the shop as it did the day before, but inside it was crazy loud. So just that adjustment to the system and it changed the way the sound propagated like 180deg

If you look into transmission line speaker boxes, and understand them, then this should be a good example. Just turning the box upside down gave us some transmission line effect. If he had gone all the way and made a large transmission line enclosure, the bass would have been even stupider, in a good way. ;D

I get what you are saying with the wavelength, but I dont see that in all cases. Like I made this ported sub box to test the pioneer sub. 3cuft and tuned to 25hz with a 15in long 4in dia port.  Nowhere in that enclosure from the back of the sub to the output of the port is there a length of even 1/4 wavelength at 25hz. Then use a 10in sub with a 3in port and that distance is shorter, but still can be resonant at 25hz.   

As I said earlier, the in car response increases gradually from 80hz down to 20hz up to 12db gain. That corvette that 10hz could be heard acted like a horn from rear to the front. It was a Car Audio magazine that printed the article. I believe it was 2 8in subs. Long time ago. It was their speaker n sub test car for many years.

If it is loud enough, we can hear below 20hz.. Like if you have heard the deepest of thunder, try to replicate that on most home systems. For me it is hardly a replication, unless the system is set up to be able to do it.

Mags


Magluvin

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Hi everyone

are we on track with the sound propagation ?

Is any similarity or analogy with what happen around the Tinselcoil and if yes please explanation.

Laurent

Hey Woopy

I think there are differences as in how air temp affects sound and such.

Here is an interesting fact...

If a speaker is playing frequencies that the wavelength(or I think its half wavelength, was a while ago and will look it up again) is shorter than the speakers diameter, it will have a beaming effect on axis of the driver. like a pair of 6.5in speakers with separate tweeters and passive crossovers, will be usually crossed over around 3khz and some 8in need to be crossed over between 1.5khz and 2khz to avoid the beaming effect.   So a sound laser can be had of sorts. You can try this with a speaker and play a higher freq than the diam allowance and get your head right in front of the driver then move off axis and compare to lower freq. If we had an ultrasonic transducer large enough in dia, or even better mounted to a very stiff flat panel, like carbon fiber, we could demonstrate some fascinating beaming effects.

So it may be possible to not lose a lot of the sound pressure from the driver box to the receiver box if positioned optimally.

Mags


gotoluc

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Hey Mags, that's the best picture I've seen to date on an T-Line enclosure design that solves part of the low frequency wavelength issues.
Looks like these would give an extra 12 feet of room space but not practical in a car ???

The below pic would be more space saving for a car.

Interesting stuff

Luc

Magluvin

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Yeah. I just had shown that as a CRAZY example. 

I havnt built one yet. Have known of them for a long time. Ill have to give it a go one day.

The 3cuft sub box I built is a test box. Next test box is the same size and dimensions but it is a dual chamber reflex where the 3 cu is divided into 2cu and 1cu with 3 of the same size and length ports, one out of each chamber and 1 between each chamber. You tune it by calc the whole box 3cu and 2 ports, then divide the chambers and make all 3 ports the same length. So if I tune it to 25hz, it will also ring at 50hz, giving me a 6 db advantage at 50hz. Thats a lot of db. Takes 4 times the power to gain 6db. So hopefully it sounds good as it is a no brainer for going loud at low cost vs other systems. We are going to compete in daytona last weekend in march 2018 Spring Break Nationals.

Mags

gotoluc

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Hi everyone,

I've made some improvements to the TinselKoil circuit which has reduced the input power by close to half from the original demo.
Wound 3 new secondary TC of lower resistance (used 24 AWG instead of 33 AWG) which has helped in the most part (on transmitter) to lower the input power.
The other 2 identical (red) TC you'll see in the video were made to test the effect of adding multiple output loads on identically made and tuned TC to see if the bulb intensity reduces which it did by half.
So I decided to wind coils that I use to experiment with Resonance so 8 years ago. Once I found the correct balance between inductance and air capacitance I'm able to add a second load with no effect to the first load and the input current.
I think I can keep adding loads if the coil geometry, inductance, capacitance and load are identical. However, the problem now is I only have 2 identical variable air capacitors. It won't even work with a different make of air capacitor (which I have and tested) even if I tune it to the identical capacitance value.
I've also had no success in substituting the air capacitor with a regular capacitor of identical PF value.
So to further test the results of adding more loads to see how far it can go I'll have to try and make my own variable air capacitors.

Had to remove the Ferrite bead on the DC input power line as it got really hot, probably because of the new resonant frequency being 1.14MHz compared to the previous 750kHz.
If I hold (with my fingers) a 7w 120vac night light bulb and connect to the battery terminal the bulb fully lights but input current increases (no free lunch there)

Here's the update video: https://youtu.be/5HD6bvzexBc

Regards

Luc

gotoluc

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Hi everyone,

I accidentally deleted the above test 2 video and can no longer edit my post, so here is the replacement link: https://youtu.be/kndYHIHSAE8

woopy

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Hi Luc

so a lot of work winding those long coil.

How do you wind them , because i wound mine by hand and it took so much boring time?

And anyway fantastic results, i have just dismanteled a vintage radio and got out the variable air capacitor which is 2 time 30 up to 500 PF, and will try to tune a coil receiver for my little Tesla coil.

Very intersting stuff there

Keep up the good work

Laurent

gotoluc

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Hi Laurent

All the coils are hand wound for now. Once I know what I want and need to make many I'll build a mechanical winder.

Don't take too many old radios apart just for this, since once I've find a substitute for the variable air capacitor I'll post a video demo.

Maybe in a few days I'll make a video demo of how I test and tune these pickup coils.

Regards

Luc

gotoluc

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Hi everyone,


Still moving forward with the same ideal of trying to add as many tuned receiver circuits as I can.


Here's an update video demo: https://youtu.be/oAGGE8NHii0


Regards


Luc