what happens between a teslacoil the battery the incadescent bulb and the ground

[gotoluc]

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]

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.

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]

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]

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]

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