The Sound of Bells

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Programs available from this website

Four programs are available from this website. The most commonly used, Wavanal, is a program for anylsing the tuning of bells, using pre-recorded sounds or from a PC microphone. If you are new to bell analysis, this is the program you need. Rounds is a program for turning recordings of real bells rung singly into change ringing. I use this a lot in tuning experiments. Tuner is a spectrum analyser specifically designed to help with the tuning of bells. Finally, Pitcher is a simple utility for checking the pitch of bell sounds.

A new version 5.9 of Wavanal is now available which fixes further bugs reading certain MP3 files, and returns the octave numbering to what it was prior to June 2019.

The Wavanal Program

The purpose of the bell waveform analysis program (Wavanal.exe) is the analysis of bell sounds using a personal computer. It provides facilities for graphical display of recorded bell sounds, identification of partial frequencies, and synthesis of bell sounds from a list of partials. It allows complete determination of the harmonic character of a bell using the facilities available on any multi-media home PC. It also allows exploration of the way that changing the tuning of a bell changes its resulting sound.

The program has been tested on Windows 95, 98, 2000, XP, NT 4.0, and Windows 7 and 10. CPU, RAM and hard-drive requirements are modest, though each sound file will occupy 250kbyte - 1mbyte of disc if uncompressed. A sound card is needed for capture and playing of sounds, but not for the analysis. No installation of the Wavanal program is required. Simply download to any convenient directory and run it from there.

The only additional equipment required is a tape recorder or video camera (to capture the sound of the bell or bells) and a cable capable of connecting recorder or camera to the sound card. If you have a laptop, you can record direct via a microphone.

The program documentation suggests how to take recordings of bells for analysis or analyse direct from a microphone, explains how the program works, documents how to use it and how the various screens work, and finally provides some technical detail on the transform techniques used and some restrictions on the results.

Download Wavanal - the latest version (5.9) fixes more bugs reading MP3 files and returns the octave numbering to what it was before.

Download detailed documentation in Microsoft Word format.

The documentation goes into detail on how Wavanal works and how to carry out complex analysis of the sound of a bell. If you wish to quickly analyse a bell sound, and Wavanal is loaded onto your PC or laptop, the action to take depends on whether you are working with prevously-made recordings, or wish to analyse in real time.

If analysing in real time, carry out the following steps:

If you want to record bells, see the next page for detailed suggestions and procedures. If you are working with pre-recorded sounds:

I have an Excel spreadsheet which I use to calculate partial intervals in cents for a peal of bells, and to compare their tuning with several different temperaments. This spreadsheet is available here.

Sound file formats

Wavanal can read any uncompressed waveform files with a .wav or .mp3 extension that match the following parameters:

All are converted to 16 bit mono, which is the format used within Wavanal. Conversion from 8 to 16 bit and stereo to mono is done by Wavanal, not using standard Windows drivers, because:

Wavanal can also read a wide range of compressed .wav and .mp3 formats provided your PC has the right drivers installed. Check 'Settings | Control Panel | Multimedia | Devices | Audio Compression Codecs' for a list of supported formats. The benefit of compression is that it considerably reduces the file size without significant loss of quality. The main formats you will encounter are:

Format Typical compression Wavanal results Driver
Raw PCM none Very good None required
A-law and -law 2 to 1 Good Installed as standard
MS ADPCM 4 to 1 Good Installed as standard
GSM 8 to 1 Good Installed as standard
MP3 12.5 to 1 Good enough May need special driver
Speech codecs - poor Installed as standard

MP3 files work fine unless either the recording is distorted, or there is a loud background wash of harmonics. In both cases, the MP3 file will sound 'whizzy' (though Wavanal will still find the partials OK). You may need to install an MP3 codec (search the web for 'fraunhofer mp3 codec') if one is not installed. Wavanal supports both MP3-encoded .wav files and files with the .mp3 extension. Waveform files written by Wavanal are 16 bit, mono, raw PCM format.

The Tuner program

The Tuner program is a special-purpose program designed to help with the tuning of bells. It is a PC-based spectrum analyser with special features to help with bell tuning. It shares common technology with Wavanal, and should run on any Wintel platform with Windows 95 or later. The program relies on the presence of a sound-card or sound interface with microphone for its operation. Download Tuner from here; it does not need installation and will run from any directory. Download the user documentation in Microsoft Word 7 format.

I am very grateful to Ben Kipling of Hayward Mills and Andrew Higson of Taylor's Bellfoundry for their ideas which have been built into the software, and for their willingness to test early versions.

The latest version of the program can share partials files with Wavanal, a facility added at the suggestion of Brian White.

The Rounds Program

The Rounds program is used to create 'recordings' of change ringing from the sounds of individual bells. I use it extensively to experiment with bell tuning, creating and modifying individual bells using Wavanal, and then using Rounds to hear the effect of the altered tuning in changes. The program is simple to use and has no separate documentation. The following points should be noted:

It is not possible to change the methods used from the three provided, but the resulting recording can be saved to disc (in 16-bit .wav format) for future use. The latest version allows up to 16 bells, and for the ringing speed to be changed.

Download Rounds from here.

The Pitcher Program

Complex sounds with many partials or overtones, such as bells, are usually ascribed a note or pitch by the listener. A good working definition of the pitch of a complex sound is 'the frequency of the pure tone which sounds neither higher nor lower than the complex sound'. Some complex sounds have no discernible pitch, or multiple pitches, but most bells have a single pitch which is tuned alongside the pitches of the other bells to make them sound correct together. A bell's pitch is traditionally taken as half the frequency of its nominal, but this assumption is not always true. The Pitcher program was written for two reasons: to allow quick estimation of the pitch of bells (for instance to confirm correct identification of the nominal) and to facilitate investigation into the pitch of bells without true-harmonic tuning. More detail on the issues involved is available in the sections of this website covering the timbre and pitch of bells and the tuning of nominals.

Pitcher is a very simple program. Download Pitcher here and run it from any convenient directory. It relies on the PC sound card producing stereo sound. It plays a pure tone through one speaker, and any chosen recording through the other. The frequency of the pure tone can be changed by the user. When the pure tone matches the perceived pitch of the recording, the frequency of the pure tone is the pitch required. For true-harmonic bells this pitch frequency should be half the nominal frequency. For bells with flat, loud primes, the pitch is lower than this, especially when heard in changes. Try it for yourself and see what results you get. Email me if you are interested but need further explanation.

The Pitcher program consists of a single screen. When first run, a generated tone of 440Hz should be heard. The frequency and volume sliders change the sound, as you will hear when you try them. The 'read waveform' loads a sound file. As with Wavanal, almost any .wav or .mp3 format is supported. The generated tone will stop while the file is being loaded, and starts again afterwards. Start / Stop Play controls the output of the loaded sound file. When play is stopped, the program returns to the start of the sound, there is no facility to play part of a sound.


Last updated December 18, 2019. Site created by Bill Hibbert, Great Bookham, Surrey