Resonance Circuits and Resonance Systems

[ramset]

Mags
Be safe these next few days , Irma packs a big punch !!

[Low-Q]

Resonance systems are interesting. I have built countless of speakers in my life, and feel that I have something to offer, LOL


A bassreflex tuning, will harness the rear side of the driver cone. This resonance is counterforcing the speakerdriver, so the excursion of the cone will drop when it hits the resonance frequency of the port. However, the "engine" that drives the speakerdriver should be powerful enough to achieve gain. This gain is in fact not a gain, but the soundpressure that does not come out from inside a sealed enclosure, will come out via the port.


The efficiency of a speakerdriver is very very low. At 96dB/1W/1m, the efficiency is approx 1%. That means the energy in the moving air 1 meter away from the speaker driver, is 1% of the input energy to the driver. Then you can calculate the maximum efficiency in dB/1W/m at 100% efficiency.


Also remember that the air provides a very inefficient mechanical energy transfer. This is the main reason to the low efficiency.


Vidar

[lancaIV]

https://worldwide.espacenet.com/publicationDetails/description?CC=US&NR=6178316B1&KC=B1&FT=D&ND=3&date=20010123&DB=EPODOC&locale=en_EP#

https://worldwide.espacenet.com/publicationDetails/description?CC=TW&NR=200727310A&KC=A&FT=D&ND=3&date=20070716&DB=EPODOC&locale=en_EP#

0024]    Resonance is widely misunderstood. There are several slightly differing views across all the different scientific disciplines as to what resonance represents and means to a circuit. In radio theory, resonance is accepted as special frequency and phase relationships which create a self reinforcing "boosting" effect on the signal which closes the gap of peak to RMS (Root Mean Square) power of the signal. In one aspect of audio theory, resonance is a special relationship between frequency and the characteristics of matter in an object which creates a "bootstrapping" amplification effect which causes a catastrophic destructive effect on the material. In energy theory, resonance is accepted as the alignment of the phases between the voltage and amperage of a circuit which creates an idealized energy state. This state is determined by the calculation of the power factor of the running circuit. 

( a freedom fighter ?! : http://people.com/archive/contempt-of-court-or-academic-freedom-the-question-sends-a-stubborn-georgia-professor-to-jail-vol-14-no-13/ )

https://www.youtube.com/watch?v=b9fzHBJU1Oo
https://en.wikipedia.org/wiki/Emma_Goldman
,,If I can't dance, I don't want to be part of your revolution

https://www.google.com/patents/US4004210
Accordingly, as the elemental circuit size is reduced to the order of the electron mean free path the production of kilowatts of power output per square centimeter of surface area of layer is obtained.

[Magluvin]

Resonance systems are interesting. I have built countless of speakers in my life, and feel that I have something to offer, LOL


A bassreflex tuning, will harness the rear side of the driver cone. This resonance is counterforcing the speakerdriver, so the excursion of the cone will drop when it hits the resonance frequency of the port. However, the "engine" that drives the speakerdriver should be powerful enough to achieve gain. This gain is in fact not a gain, but the soundpressure that does not come out from inside a sealed enclosure, will come out via the port.


The efficiency of a speakerdriver is very very low. At 96dB/1W/1m, the efficiency is approx 1%. That means the energy in the moving air 1 meter away from the speaker driver, is 1% of the input energy to the driver. Then you can calculate the maximum efficiency in dB/1W/m at 100% efficiency.


Also remember that the air provides a very inefficient mechanical energy transfer. This is the main reason to the low efficiency.


Vidar

Hey Vidar

Do you have a formula that expresses the mere 1% of 96db @1w?  More as in how did you arrive at that number? That is what im really interested in. Thanks

Mags

[Low-Q]

I know an engineer who worked in the Norwegian speaker factory SEAS, one of the world leading manufacturer in high quality speaker parts. See www.seas.no for more information.
The efficiency in % is an expression that depends on temperature, pressure, humidity - the mass of the air at a given standarized form.


I have no formula, but the efficiency was once expressed in both SPL and %. I am quite sure you can google the mechanical transfer function between a moving diaphragm/membrane, and the surrounding air. Shorter the distance to the speaker will increase the mechanical efficiency.


The mechanical efficiency of the speaker driver itself is much higher, but still quite low. It depends on loss in suspension, resistance in the voicecoil, flux density through the coil, moving mass.


Vidar

Hey Vidar

Do you have a formula that expresses the mere 1% of 96db @1w?  More as in how did you arrive at that number? That is what im really interested in. Thanks

Mags