This loudspeaker how much dB increase

[Sanon]

Dear Members,

I came across a loudspeaker with 4 drivers the pic is below

An externally hosted image should be here but it was not working when we last tested it.

I want to ask if many sources are combined this way wont it create ,

1. interference
2. turbulance , cancellation etc .

and finally will it sum to 6dB with 4 drivers?

Thanks

 

[Sanon]

Is this a non standard procedure and unknown to members?

 

[phase_accurate]

Theoretically the SPL should quadruple - meaning an 12 dB increase. In practive it will most probably be a little less.

Regards

Charles

 

[Sanon]

Theoretically the SPL should quadruple - meaning an 12 dB increase. In practive it will most probably be a little less.

Regards

Charles

Hi Charles , I think you man 6dB . Is the loss sever or ignorable when speakers are placed tis way.

Thanks

 

[Defo]

Theoretically the SPL should quadruple - meaning an 12 dB increase. In practive it will most probably be a little less.

Regards

Charles

More like 5,25 db increase in spl as far as my knowledge goes.

One additional driver gives 3 db
Two gives 4,5 db
Three gives 5,25 db

And so on...

 

[phase_accurate]

Two correlated sound sources (i.e. they reproduce exactly the same signal) give a doubling of the sound pressure which is a quadrupling of sound power i.e. 6 dB increase. This is of course a theoretical ideal and it will be lower in practice.

If you use two uncorrelated sound sources with the same acoustic power then the sound power is doubled, giving an increase of 3 dB.

Regards

Charles

 

[AndrewT]

to help avoid confusion, I'd suggest you separate the power changes from the efficiency changes when you couple speakers.

The efficiency changes come with very restrictive conditions. You can get +3dB with each doubling of the numbers of drivers, but only over a very restricted frequency range.

If you feed the same power into one speaker as you feed into a multiplicity of speakers then one does not get any extra power input.

If spreading the same input power between a multitude of speakers helps avoid power compression then that is the gain one can get from adding drivers.

 

[Sanon]

Two correlated sound sources (i.e. they reproduce exactly the same signal) give a doubling of the sound pressure which is a quadrupling of sound power i.e. 6 dB increase. This is of course a theoretical ideal and it will be lower in practice.
If you use two uncorrelated sound sources with the same acoustic power then the sound power is doubled, giving an increase of 3 dB.
Regards Charles

So it is 12dB (theoritically) for 4 drivers as you have said earlier. Thanks for the information .

to help avoid confusion, I'd suggest you separate the power changes from the efficiency changes when you couple speakers.

The efficiency changes come with very restrictive conditions. You can get +3dB with each doubling of the numbers of drivers, but only over a very restricted frequency range.

How can we judge this frequency range(where doubling occurs) is this found emperically.

I have a further worry as it can be seen the drivers are placed side by side (above attached speaker picture) therefore the direction of wavefront will be facing each other , can this cause a heating or distortion , as I can visualize that the two wavefronts are a kind of colliding with each other in opposite direction.

Thanks for the inputs