AMPLIFIER POWER

FREE CALCULATOR

The Amplifier Power Calculator (APC) makes it easy to calculate the sound pressure that can be achieved in a room for a given speaker and amplifier.

Do you need more power, a more sensitive speaker, or are you just curious to know what your system can do? APC does it all.

    • This calculator is provided entirely free of charge, with no credit card required.

    Click below to access the calculator or scroll down this page for instructions.

    The calculator provides a PDF file upon completion.

    Access Calculator

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    Instructions for Data Entry

    In order to create the report, the Amplifier Power Calculator needs some information about the project. Cinema Tools does not store or record any data that is entered into this form.

    Project Name:
    Enter the project name so that the report can be easily identified.


    Prepared By:
    Enter the name of the person creating the report


    Calculation Units:
    Select the measurement units that will be used in the other form fields

    Speaker Efficiency:
    Enter the rated speaker efficiency in db/W/m

    Efficiency Measured at:
    Select which speaker efficiency measurement method was used to measure the rated speaker efficiency.

    Speaker Impedance:
    Enter the rated speaker impedance

    RMS Amplifier Power at 8 Ohms:
    Enter the RMS power rating of the amplifier when driven into an 8 ohm impedance

    In Wall Speaker:
    Select if the speaker model is an in wall model where the rated efficiency is clearly noted as having been measured in free air.

    Distance:
    Enter the distance between the speaker and the listener.

    Nominal SPL Level:
    This is the nominal level of the audio format being analysed. In most cases this is 85dB. Nominal SPL values for different audio formats can be found in the knowledge base.

    System Headroom:
    This is the difference in SPL between the nominal and peak level that the system should achieve. This would normally be 20dB but in some cases may be as high as 30dB. System Headroom values for different audio formats can be found in the knowledge base.

    Target Peak SPL:
    This field is supplied for information only and can not be edited. This is the absolute maximum SPL that the system must achieve and is sum of the Nominal SPL and System Headroom.

    The SPL Decrease as Distance Increases page of the report is used to show how the SPL achieved by the selected combination of speaker and amplifier decreases as the distance from the speaker increases.

    The red line on the chart shows how the Maximum Peak SPL that the system can deliver will decrease as the distance increases.

    The blue line on the chart shows how the Maximum RMS SPL that the system can deliver will decrease as the distance increases.

    The RMS SPL is the level that the system should be able to maintain constantly and this should be kept above the specified nominal SPL to avoid a seriously compromised performance.

    The Peak SPL is the short term maximum level that the system should be able to deliver. Ideally this will be greater than or equal to the specified peak SPL to avoid any constraints in the dynamics of the system.

    The right hand data bar details:

    • Speaker sensitivity in dB at power measurement reference
    • Speaker impedance in ohms
    • RMS amplifier power in watts
    • In wall gain added yes or no
    • Distance to listener
    • Target peak SPL in dB
    • RMS SPL at seating distance in dB
    • RMS SPL at 1m in dB
    • RMS amplifier power required to hit peak SPL target in watts
    • Peak SPL at seating distance in dB
    • Peak SPL at 1m in dB
    • Peak amplifier power required to hit peak SPL target in watts