Simple audio system tuning




How To Use HouseCurve

  1. Connect iPhone/iPad to the audio system using AirPlay, Bluetooth or line out (headphone connector). See FAQ for more information.
  2. Set initial volume to a low setting using the Volume Up / Down buttons on the side of the iPhone/iPad.
  3. Tap Measure to start measurement process. HouseCurve will play a test signal through the audio system and measure the frequency response. This process will take a few seconds.
  4. Adjust volume as needed to obtain successful measurements. Ideally, measurements should be taken at a normal listening level. Excessive volume levels may degrade accuracy and may increase risk of damage to hearing and/or equipment.
  5. Measurements are displayed in green, the reference curve is displayed in yellow with a +/- 3 dB band. When tuning the audio system, the goal is to get the average measurement within the reference band.
  6. Tap plot to show cursor, move with finger, tap again to hide. The cursor shows adjustment needed to match reference curve at selected frequency.
  7. Collect additional measurements by tapping Measure again.
  8. To clear the measurements, tap Reset.

Display Modes

HouseCurve can display measurements to suit a given task. To change the display modes, go to Setup.

Average mode (default) is used to capture how an audio system sounds in a listening area. Use this mode when tuning the audio system to match a reference curve.

History mode is used to see the effect of an adjustment from a single microphone location. Use this mode for initial system setups, such as adjusting subwoofer phase or speaker position.


Try to reduce background noise as this will improve accuracy.

Measurements may be affected by iPhone/iPad cases when using the built in microphone.

Take many measurements. Try to cover all the places a listener might be in the listening area. Try to hold the microphone where a listener’s ears would be located. The average measurement will cancel out small variances allowing a best-fit tune for the whole listening area.

Tune the audio system in small steps, collecting the same measurements after each change. When most of the average measurement is within the reference band, the audio system is sufficiently tuned. Further tuning may not be perceptible.

Advanced Setup

When using HouseCurve with compensation turned on, the built in iPhone/iPad microphone is accurate enough to get within a few dB of the reference curve. HouseCurve supports calibrated external microphones for users seeking higher accuracy. Go to Setup to select or load external microphone calibrations.

HouseCurve provides some common reference curves or “house curves”. The selection of curve is subject to individual taste. Custom curves may also be imported by going to Setup. When in doubt go with the default curve. See FAQ for more information.

For custom reference curves and microphone calibration, HouseCurve supports the following (de facto) standard: A space or tab delimited text file with a frequency (Hz) followed by a gain (dB) on each line. A third phase value may be included but is ignored. Lines starting with non-numeric characters are ignored. Frequencies must be listed in increasing order. HouseCurve will interpolate a curve from 20-20000 Hz using the values provided. The file extension may be txt or frd.

Example Reference Curve