Android apps by jjbunn

AudioTool

Sun, 24 Oct 2010 18:05:07 +0000

AudioTool - SPL (deciBel) Meter featuring RT60, Spectrum Analyzer, Spectrogram, Chart Recorder, Signal Generator, Polarity Checker. Two methods of Mic calibration are offered.

Recommended by "Sound and Vision" magazine.

Features 1/1, 1/3 & 1/6 octave RTA modes, Leq, RT60 (wideband, Octave), Spectrogram, Peak frequency, Fast, Medium & Slow filters, Flat & A/C Weighting, Averaging, SPL Chart Recorder, Noise Criteria, White/Pink Noise, Sine, Square, Triangle, Sweep, Ramp and Impulse signals & loudspeaker polarity checker. RTA Store & Load, Hann windows, "Keep Screen On", pinch to zoom, scroll to center.

Exclusive ISO 1/3 Octave Calibration - correct for your phone's microphone response. Octave calibration discs are moved up or down to obtain a flat response, and match the overall SPL to that of an external meter. Save/Restore of Cal files (Dayton Audio iMM-6 also supported).

Use: home theater, audio engineer, car audio, etc

AudioTool FFTs sets of samples recorded at the microphone. Aliasing reduced by Hann windowing. SPL calculated in realtime. Spectra may be saved as files on the SD card, then loaded and displayed with the live spectrum. The "Store" button stores the current live spectrum - "Load" shows a list of stored spectra to select.

To hide the buttons, tap the screen. To restore them, tap again. To zoom the scale, pinch the screen. To move the scale, drag it up or down (left or right).

The deciBel meter uses IIR filters and exponential averaging to calculate Flat, A and C weighted response at speeds of Fast, Medium and Slow speeds.

A pair of cursors can be shown on the RTA and Chart Recorder displays: each can be moved to any position, and will display the SPL & time/frequency values there. Initially, both cursors are positioned mid-screen - simply drag them to a new position with the fingertip. The cursors can be turned on and off in the Menu.

The loudspeaker polarity checker can be used to check whether a loudspeaker is wired in phase: connect the AudioTool output to the speaker under test, select "Polarity" from the signal generator screen, then return to the RTA screen. If the speaker is out of phase (polarity reversed) AudioTool will show "Pol ---", otherwise "Pol +++" if the speaker is in phase.

The Noise Criteria (available from the Menu) function shows a set of NC contours overlaid on the 1/1 Octave RTA display and the calculated real time current NC value is also shown.

The Chart Recorder shows a moving trace of the SPL measurements over the last few minutes.

RT60 measurements can be made by starting the RT60 component using the "RT60" button, and then using a loud clap (or similar) to trigger the measurement. RT60 can also be used with Pink Noise from the AudioTool generator. RT60 times measure how much reverberation or echo there is in a room or auditorium.

The Signal Generator generates White and Pink Noise, Sine, Square, Triangle and Ramp waves, Sine Wave Sweeps and Impulses. The generator uses multiple cycled buffers that are refreshed randomly so ensuring truly random White/Pink noise. The Pink Noise algorithm uses Kemmet's method to adjust White into Pink. Frequency is set via the arrow buttons or directly via the keyboard.

The frequency accuracy of the generated periodic signals is typically around 1%. Sine wave fidelity is good throughout most of the audio range. Other signals' leading and trailing edges show ringing and decreasing frequency response artifacts in the upper ranges, depending on the Android used.

Please consult the online manual for complete descriptions of the AudioTool features:
https://sites.google.com/site/bofinit/audiotool

Please join the friendly AudioTool Discussion Group to request features, find Calibration files, or report problems. Feedback is always welcome:
http://groups.google.com/group/audiotool-discussion-group

Disclaimer: AudioTool's performance depends on your Android hardware, and is not guaranteed to meet any audio measurement or safety standards.

Recent changes:
v5.9.4 Support for large tablets like Nexus 10, Nook HD+, etc. restored
v5.9.3 Pinch to zoom on RTA and Chart Recorder dB axis.
Scroll to shift scale on RTA and Chart Recorder dB axis
Pinch/Scroll on RTA frequency axis

v5.9 Introduce new 1/3 octave calibration offset feature.

Please report any bugs/problems/desired features on the AudioTool forum (not via app ratings) otherwise there is no way of contacting you to get enough information to fix or implement them - thanks!

SoundForm Signal Generator

Sat, 15 May 2010 03:10:52 +0000

Soundform generates White and Pink Noise, Sine, Square, Triangle, Ramp waves and Impulses. Uses multiple cycled buffers, refreshed randomly, so ensuring truly random White/Pink noise. See website for more details.

Questions or problems? Please Email me!

If you need a combined Signal Generator and Spectrum Analyzer with dB measurement and RT60, check out my "AudioTool" app.

Recent changes:
v2.4.5: Support for small screens

Musician's Spectrum Analyser

Sat, 31 Mar 2012 12:14:40 +0000

MSA (Musician's Spectrum Analyser) is a new app for singers and musicians.

Most musical notes are not a single pure sound, but rather a complex mixture of notes called a sound <b>spectrum</b>. The Musician's Spectrum Analyser analyses this spectrum to show
the individual notes that real sounds contain.

MSA displays an ordinary 88-note piano keyboard. It analyses frequencies upto just over 8 kHz, the vertical white line on the far right of the screen shows this frequency.

The yellow trace displays the wave that the MSA is currently analysing. Pressing either the blue or the green Store keys stores this waveform. You can store two spectra. To clear a wave, press Store again when the input is quiet ('storing quietness').

MSA includes a full Help file.

Recent changes:
v1.7: Initial release.

Metaloid Field Detector

Wed, 26 May 2010 23:10:56 +0000

Uses the built in magnetometer to show the magnetic field near the Android. Three metering speeds: Fast, Medium, Slow plus Zero offsets, two scales.

Use as a metal detector: pass the Android over a ferrous metal object and observe the needle behaviour.

Accuracy determined by phone hardware.

FAQ:

Q: What do the speeds mean?
A: Fast, medium, slow refer to how quickly the meter needle moves in response to a change in the magnetic field.

Q: What is "zeroed"?
A: Zeroed and unzeroed are for looking at the difference between the value when the button was pressed and now ... For example, if you are in unzeroed mode, and the meter reads 50, then you press the button the meter will now read zero, effectively subtracting 50 from the reading.

Q: What are "coarse" and "fine"?
A: Coarse and fine refer to the meter scale ... One reads from zero to 50 microTesla, the other to 500 microTesla.

v2.1 Cosmetics & ad supported

Sensors

Mon, 07 Jun 2010 18:10:24 +0000

V2.2: Add zoom in/out buttons and Mag Field on/off button for Monica

Simple application showing the output from the 3-axis accelerometer and magnetometer. Scales variable between 0.01 and 20g for acceleration.

Recent changes:
V2.3: support for small screens

SPL and Spectrum Analyser

Mon, 10 May 2010 03:09:59 +0000

SPLMeter shows SPL (deciBels) of the Android's mic signals, and their frequency spectrum. The meter has three speeds: Fast, Medium and Slow. Shows peak envelope and frequency of maximum intensity, and clipping. ISO 1/3 Octave bars and Spectrogram.

(If you need a more fully featured RTA, with 1/1, 1/3 and 1/6 octave display, RT60, Noise Criteria, A&C Weighting etc. combined with a signal generator, please take a look at my "AudioTool" app in Android Market.)

Recent changes:
v2.9.3 Default sample rate now 44.1kHz
Min SDK now 4
Supports large screens

Ghostroid Paranormal Detector

Wed, 19 May 2010 05:10:46 +0000

Android version of Pocket Ghost paranormal detector. Subsonic (infrasound), supersonic and audible IIR filters calculate the ParaNormal Quotient(PNQ) at your location.

The magnetic field is also displayed.

An essential tool for the aspiring or professional ghost hunter!

Theory of Operation (Only for nerds) ...

It has been reported that paranormal activity is evidenced by sounds inaudible, or barely audible, to the human ear. Animals, whose hearing is more acute at higher frequencies than ours, are able to detect supersonic sounds, generally above 12-15 kiloHertz or so. For example, dogs are reported to behave oddly during supernatural events. Sounds of very low frequency, less than a hundred Hertz or so, are normally felt rather than heard by humans. The built-in microphone circuitry in most handheld devices is designed to detect frequencies in the audio range, but there is some residual response from the circuitry at the very low (subsonic) and very high (supersonic) frequencies.

Ghostroid uses fast software-based Infinite Impulse Response (IIR) filters to measure the level of sub- and super-sonic sound pressure waves arriving at the microphone. It also measures the audible sound level. The three ranges are shown on the Ghostroid display via three meters, which move dynamically and are updated several times a second. The Para Normal Quotient (PNQ) is calculated from a formula that sums the sound levels in the sub- and super- sonic ranges, and subtracts the audible range value. This yields a number which increases as the sub- and super- frequencies (which are difficult or impossible for us to hear) increase, as compared to the audible frequencies.

The PNQ value is shown by a set of concentric bands at the centre of the display. High PNQ values may be caused by a variety of events: Low frequency rumbling (e.g. from heavy trucks or machinery), High frequency noises (e.g. dog whistles, or keys jangling) as well as Supernatural phenomena (please don't drop your Android when you run away in fright!)

Ghostroid is a port to Android of the well-established "Pocket Ghost" application for Windows Mobile. Although I personally remain sceptical about the existence of paranormal activity, and the effectiveness of this application to detect it, I have received several reports over the years of Pocket Ghost being successfully used by paranormal investigators. Here are a couple of quotes:

1) "I have used the pocket ghost program on my I-mate Jasjam and in all cases the Sub-sonic and Super-sonic reading peaked at 85 to 90 and did not drop down until the visions (or what ever they were) had gone."

2) "I have seen your program successfully used by a professional parapsychologist during an investigation in London."

3) "I am a member of several paranormal groups and investigate the most paranormally active sites within the U.K. On one such investigation a parapsychologist was using your 'Pocket Ghost' to great effect."

Recent changes:
v1.12 Support for tablets
Improvements to Sightings list
Protection against missing location information
Sonar beat frequencies changed

AudioCaps

Fri, 03 Sep 2010 05:29:33 +0000

Prints a list of the supported recording and playback formats on your Android device.

v1.9 targets minsdk 9 and xlargescreens
v1.8 minor changes
v1.7 output includes Android Build.MODEL string
v1.6 allows to send results as an email
v1.5 n/a
v1.4 confirms play/record capability by send/receive of samples to the audio hardware

Questions: email jjbunn@gmail.com

Recent changes:
v1.8 minor changes

Nixoid Nixie Clock

Fri, 25 Nov 2011 00:54:53 +0000

A clock that shows the time using Nixie tube images. A set of retro toggle switches select US or Euro time/date formats, Keep Screen On, tenths of a second, and full screen mode.

The time shown by Nixoid is made more accurate by correction to the millisecond time received from an NTP (Network Time Protocol) server, if internet is available (this is why the app needs Internet permission).

Recent changes:
v1.2.1 Should fix some reported "jitter" on seconds readout

v1.2 NTP time correction (shown in message on startup) makes Nixoid time more accurate.

Randomness

Mon, 18 Oct 2010 05:36:07 +0000

Randomness flips a coin, rolls a pair of dice, or selects a random Web page for you from the millions available. It's all very random. Suggestions for further randomness e.g. lottery numbers, are welcomed.

V1.5 Initial random version number