Efficiency in speakers, or high sound pressure level SPL per watt inputted. What detail in the manufacturing process of a speaker achieves higher figures ?

 

http://www.sengpielaudio.com/calculator-efficiency.htm

Studio monitors have a small energy efficiency around 1 %, but that gives a very high uncolored sound quality.

If you are looking for big party loudspeakers with high efficiency you have really to think of impedance matching (power matching) andmegaphones. They have always an efficiency of more than 10 %, but with the well known distortions and giving a strange colored sound. That comes really through and has "pressure" and you can hear the "power".

If you need even more efficiency you have to think of a siren on emergency vehicles.
But the frequency bandwidth is very limited.

 

All of them. Primarily the magnetic flux in the gap where the coil moves. Then, weight of the cone and coil, stiffness of the two surrounds, width of the magnetic gap, centering of the voice coil in the magnetic gap, the density of magic smoke in the insulating enamel, the resistance of the coil wire, and probably a few I didn't think of.

 

Thank you. Then, not many chances I will find 1 inch diametre chinese speakers with impressive voice range loudness...
Those speakers in laptops "rated 2 Watts" are chinese Watts, right ?

----> https://www.amazon.com/Ohm-Internal...=2025&creative=165953&creativeASIN=B01MXIWIX6
---> https://www.aliexpress.com/item/New...lgo_pvid=24447234-7e7f-4cf4-a1cf-4feeaf43fb36

Edited : I wish a 1 inch speaker with a 1 inch voice coil and the 'spider' being inside the coil anchored to the magnet instead of the rim. Just the 'dust cover' behaving as the 'cone'
Any chance such animal exists ?

 

The second part of the loudness equation is the efficiency of connecting the speaker cone to the air. The instant I mentioned that your mind jumped to the various shapes of speaker cabinets. That's what cabinet shape is all about...connecting the cone to the atmosphere.

 

Edited : I wish a 1 inch speaker with a 1 inch voice coil and the 'spider' being inside the coil anchored to the magnet instead of the rim. Just the 'dust cover' behaving as the 'cone'
Any chance such animal exists ?

Look around here: When I was building speaker and Home Theater systems most of my parts came from them.
https://www.parts-express.com/resources-speaker-replacement#!

 

On the subject of speakers and acoustical physics, the most efficient device in the audible spectrum would be the so called "Hard Diaphragm" sound transmitter used in electronic foghorns for marine signaling.

These transmitters use a tuned steel diaphragm with a very high "Q" and a very narrow resonant frequency. The sound is very limited to a pure tone at the resonant frequency of the diaphragm and consequently they are useable not speakers. The diaphragm is coupled to the air through a acoustically matched hyperbolic horn and the efficiency is extremely high. Some of these transmitters have an efficiency of 75% and produce an omnidirectional signal of 55 phons at 3000 feet.

Sound transmitters used for foghorns must be approved by the Coast Guard (in accordance with Code Of Federal Regulations 33CFR67.10) and tested for sound pressure level (SPL) and frequency in an anechoic chamber. It's interesting to note that the atmosphere has a definite bandwidth for sound transmission for a given distance and there is a family of curves showing the frequency, SPL, and audible range.