I need 130 dB sound pressure

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Thread Starter


Joined Jun 26, 2018
Hi friends,
I made the circuit stated above. It works perfect but the sound pressure is not high as much as I wish. I use a 16 ohm horn speaker and strongly probable this is the reason for relative low sound pressure. The other factor maybe the car battery supply voltage ( 13.5 v ). My questions are stated below.
1- Does it work if I step up the battery voltage up to 18 v or 20 v by a DC to DC converter ? Do I catch approximately 120 or 130 dB ?
2- TC 1411 safe side working voltage is up to 16 v. Can I use suitable resistance serial to power (+) leg in order to keep it in this safe margin ? If yes what should be the value of this resistance if I power it with 18 v or 20 v ?
3- May a step up audio transformer be connected directly to the speaker output ? If yes what should be the winding turns and wire thicknesses ?
4- If I make the circuit stated below, does ancient TDA 2050 catch the 120 or 130 dB if they are connected as bridge and powered +/- 18 volt symmetrical ?

I have to use 16 ohm horn driver.

Thanks in advance for your comments and suggestions.

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Joined Jun 4, 2014
You need to start with the speaker specification. How much power or voltage does it need to reach your required sound pressure.
Who are you trying to deafen?

Audioguru again

Joined Oct 21, 2019
The original circuit produces a squarewave output of about 26.4V p-p which is 9.33V RMS. Then into a 16 ohm speaker the power is only 5.4W at the fundamental frequency and an additional 38.2W for all the harmonics of the squarewave.

The TDA2050 circuit produces 36W into 16 ohms with low level harmonics if the input is a sinewave. The bridged amplifier cannot drive more than two 16 ohm speakers.

You did not say the sensitivity of the speaker at 1W/1m or the distance you need the very high sound level.

Thread Starter


Joined Jun 26, 2018
Thanks for your comments. The sound source schematic is stated below.

This circuit can drive a loudspeaker by LM386 itself but the sound level is like a toy. So I made the circuit with Power Mosfet. I am not an engineer. This is my hobby so I don' t know some technical parameters. For example; the condenser 220 uF serial to the speaker output should be kept as the same value ? I wonder if the output level and the input impedance are matches each other ? I guess the output of the circuit is sinewave but I am not sure.
I read that the siren sound pressure is about 120 - 130 dB ( I don't know the distance ) but when I compare mine to a police car, it gives the half of it with recent combination.

So I have asked if bridged TDA 2050 can give more than Mosfets to 16 ohm 100 watt horn speaker ( similar like below ) or not ?

Or is it possible to modify the recent mosfet circuit like step up the supply voltage, adding extra transistors or directly connect a step up audio transformer. Does it works if I change the 10.000 uF condensers connected as serial to the output of the amplifier with higher or lower valued one ?

Thank you.


Joined Jan 29, 2010
hi @ilker06
What is the purpose/application of this 130 dB sound pressure project.?


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