Peak SPL Calculator

Instructions

Enter your speaker sensitivity and amplifier power to see what your system will achieve just before clipping.

The rated power of the Benchmark AHB2 into 8 Ohms is:

• 100 Watts per channel in stereo mode
• 380 Watts per channel in mono mode

Interpreting the Results

This tool calculates the peak sound pressure level (SPL) that your system can deliver to your listening position. For recorded music, you will need to be able to achieve a peak level that is 12 to 18 dB higher than your desired listening level (as measured with an SPL meter). Some uncompressed recordings may require 18 to 20 dB above the average SPL.

Dolby-approved professional mix rooms must be capable of delivering 105 dB SPL peaks in order to achieve an 85 dB SPL calibrated listening level. These professional environments are designed to have 20 dB of headroom above the desired listening level. In a home environment, a 100 dB peak output may be sufficient. This will provide headroom for 15 dB peaks above the 85 dB (average SPL) corresponding to the Dolby listening level for movies.

Change the speaker sensitivity, amplifier power, listening distance, number of speakers and room configuration to gain an understanding of how these things work together.

Listening Room vs. Anechoic Measurements

The dB gain from room reflections is an approximation, but it should be within a few dB of your actual results. Room size and reflectivity will change the actual results.

Notice that listening to stereo speakers in a typical room at a distance of two meters, gives the same peak SPL results as listening to a single speaker in an anechoic room at a distance of 1 meter. This is a good rule of thumb, and it is based on measurements I have done in my own listening rooms. Remember, your room may be slightly different, but only by a few dB.

Amplifier Power

Notice that every doubling of the amplifier power only increases the SPL by 3 dB.

Speaker Sensitivity

Notice that low-sensitivity speakers need a lot more power than high-sensitivity speakers.

Low-sensitivity 85 dB speakers will require 10 times as much power as high-sensitivity 95 dB speakers to achieve the same output level.

Very high-sensitivity 105 dB speakers driven by 1 watt will deliver the same acoustic output as 85 dB speakers being driven by 100 watts.

Efficiency to Sensitivity Conversion Tool

If you have a speaker efficiency specification (1 W, 1 M), and your speakers are not 8-Ohms, you will need to convert efficiency to sensitivity using the following tool, before running the Peak SPL Calculator: