https://github.com/molke-productions/qloud

Tool to measure loudspeaker frequency and step responses and distortions
https://github.com/molke-productions/qloud

loudspeaker measurement

Last synced: 3 months ago
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Tool to measure loudspeaker frequency and step responses and distortions

• Host: GitHub
• URL: https://github.com/molke-productions/qloud
• Owner: molke-productions
• License: gpl-2.0
• Created: 2018-05-26T14:51:37.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2022-08-07T16:41:27.000Z (almost 2 years ago)
• Last Synced: 2024-01-07T01:08:14.017Z (6 months ago)
• Topics: loudspeaker, measurement
• Language: C++
• Size: 132 KB
• Stars: 27
• Watchers: 4
• Forks: 7
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: COPYING

Lists

• awesome-linuxaudio - QLoud - tool to measure loudspeaker frequency and step responses and distortions (Software / Audio utilities - Meters & Analysis)

README

        
# About

QLoud is a tool to measure a loudspeaker frequency response and distortions.

This was just an attempt of porting it to QT5. It now uses Qt Charts instead of Qwt for plotting.

The original app page is here:

http://gaydenko.com/qloud/

Writing this app was inspired by excellent applications written

by Fons Adriaensen:

http://users.skynet.be/solaris/linuxaudio/

Theoretical background belongs to Angelo Farina:

http://pcfarina.eng.unipr.it/

In particular, this method was used:

http://pcfarina.eng.unipr.it/Public/Papers/134-AES00.PDF

# Target use

* loudspeaker DIY (crossover tuning).

# Measurement chain

* the app, generating excitation signal

* sound card line out

* power amplifier

* loudspeaker under test

* measurement microphone (with microphone preamp)

* sound card line in

* the app, capturing loudspeaker response

# Result

After audio system response capturing is done, an IR (impulse response)

is calculated. Currently, these IR-aware analysis outcomes are available:

* plotting of SPL (sound pressure level) as a function of frequency (dB/Hz)

* plotting of IR power as a function of time (dB/s)

* plotting of step response as a function of time (amp/s)

* plotting of harmonics as a function of frequency (dB/Hz):

	* 2nd – green

	* 3rd – red

	* 4th – light green

	* 5th – light red

The IR power plot is useful to see room reflections behavior.

The step response plot is useful for speakers time alignment in multiway loudspeakers.

# A few hints

* move mouse above “?” sign at plot window and wait

* to change a measurement description double-click it

* to delete a measurement, use the context menu on the measurements table

* to see what the app does, just connect the app’s JACK ports directly and try

* to see what your sound card does, use loopback for line in/out

* take into account your measurement mic slope at high frequencies when

  observing harmonics plot