Resonance Circuits and Resonance Systems

[Magluvin]

Efficiency in speakers are very relative. We talk about 1 meter from the source. Half meter measurement distance of a 112dB@1m sensitivity speaker does not mean that the measured 118dB is more than 100% efficiency.


Horn loaded speakers easily exceed 112dB/1W@1m because the horn does not have a 4pi distribution of sound.
Also, a large area of the membrane emits a more narrow pressure wave, so a measurement at 1 meter might not mean a difference at 0.5 meter measurement by as much as 6dB.


Vidar.

I know that the 112db 100% eff is at 1 meter and that is just relative to that distance, but it is a standard measurement procedure and if at 1 meter it is 112db @1w then that tells us that the efficiency of the speakers input vs real output is 100%. Same energy in is same energy out. Like I said earlier, coreless motors are some of the most eff motors and these are coreless, meaning that the armature for each has only the windings and light weight but strong mounting support of the windings. Like the pancake cooling fan motor TK has shown recently, the flat disk armature is basically its windings encased in a thin disk of plastic, possibly Bakelite type or something close to it. Very efficient and able to accelerate or change speeds very quickly.

But, a very eff way can be made to be less eff by design. From what I read increased flux density will increase a speakers eff. So the pancake motor has a ceramic ring magnet that has opposing poles in say 6 pie sections. So what ever eff that motor is, it can be improved upon by substituting neos for each pole. Or buy pie section neos to remake the ring, NSNSNS.  So could the 112db @1w speaker eff be increased by installing stronger magnets?  I dont care about sound quality and more damping by doing so and so on, Im just interested in power in and power out even if it is just 1 freq. A ported box with a Q of 7 produces the flattest response for sound quality purposes down to the bottom tuned freq. Here again I dont care if it only plays 60hz and is useless for audio. Im just looking at in and out powers. Pioneer has 3 suggested box types for the pro 12. Sealed enclosure, vented tuned port and what they call turbo. It is a 4th order bandpass where the sub is mounted in a small sealed enclosure inside a larger enclosure that is port tuned to 60hz. The response is just a huge spike peak at 60hz and the rest is useless for sound reproduction. Why do they show this turbo box? Because at the DB Drag Races at car audio shows, the upper limit for db drag is 60hz. That is all that box is good for is DB drag to see who is louder. And having that 105db advantage for a $100 sub, it can beat a $600 massive 15in 88db@1w sub playing 5kw with only 800w on the pro 12.  Funny thing is nobody seems to try it cuz most of them dont understand what Im telling you all here. The pro 2 is a shrimpy looking thing compared to the 15in that is longer than it is wide in dia and 60lb.

Mags

[lancaIV]

        "We talk about 1 meter from the source."
It is common in physics and technics to conditionize the measurement.
For comparison of results by strictly same tests methods.

Clearly 1,5 or 0,5 meter distance gives other results,
different humidity,test chamber/room volume et cet. also !

https://www.google.com/patents/US5130608
https://www.google.com/patents/US5942858
In a specific application of the above-outlined principle of load control, the invention provides that the load is an electronic horn or siren.
Electronic sirens are known. An electronic transducer (loudspeaker) is driven by means of a modulation stage via an amplifier final stage. The mode of operation of this known electronic siren is basically analog. When commonly required loudnesses are to be achieved (e.g. 115 dB at a distance of 32 m), considerable power must be fed to the transducer. It is necessary to adapt the chracteristic output impedance of the final stage of the amplifier to the impedance of the load. This causes considerable losses.
The electronic siren according to the invention comprises a needle pulse generator which, via an electronic switch of the final stage, connects the electroacoustic transducer to a voltage source, in particular a battery

The load L in the instant case specifically is an ohmic load, in particular an electric incandescent bulb. The embodiments described herein are also suitable for inductive and capacitive loads or complex loads (loads of a combination of ohmic, inductive and capacitive elements). However, the invention is used in particular with ohmic, inductive and capacitive loads with low efficiency, such as incandescent bulbs, electro-acoustic and piezoelectric transformers and the like.
As an example of the application in an electroacoustic transducer as load, an electronic siren will be described further below, which constitutes a good example of the excellent energy exploitation


Practical tests show that an electronic siren 100 according to the invention can produce the acoustic power of a conventional electronic siren with only about one third of the electric power. It can thus be built with electronic parts of lower price.

[Magluvin]

Here is the computer model of the pro 12 at 1w below in the recommended Turbo enclosure by Pioneer. The peak is at 118.75db @1w.  100% efficiency is 112db@1w.  There ya go. Boom!! Overunity! How can we say it is not? Ive provided most all the sources here that show it is correct.

The key was me finding that conversion calculator today. Magluving it.

Mags

[Magluvin]

With just a bit of fiddling I changed the sealed internal enclosure to .3cu and the larger ported enclosure to 4cu. just changed box sizes.

123.37db@1w    That equates to 1370.88% eff of input vs output.     Can anyone tell me if Im wrong here? If so please provide sources and references for your arguments.

Mags

[Low-Q]

The efficiency cannot be greater than the mechanical force x exursion of the actual speaker cone.
If you put two 112dB speakers in the same sealed enclosure, and power up one of them at resonance frequency, do you expect the same electrical energy output of the other speaker?


Even if you short circuit the second speaker, the powered speaker will still play. This proves that the speaker cannot have 100% efficiency.
You have 100% efficiency when the system (with one short circuit driver) is perfectly scilence no matter how many Watt you put in.


Vidar