As indicated on the home page, this project is based around the use of a portable audio recorder...
Two of the big problems that can occur when using these devices as interview mics in their 'raw' state are handling noise and wind noise.
This project sets out to overcome those problems by housing the recorder within a foam padded microphone tube - to reduce handling noise - and then adding an external windshield to the whole structure to combat wind noise. The assembled unit looks, feels and sounds like a conventional 'vox pop' interview microphone
The sections described below show the exact details of how to create such a unit - and all at a cost of less than £50 (c.$65)..
Firstly - the 'ingredients'...
The Audio Recorder:
There are 3 important characteristics required for a device suitable for use with this project --
• Small size
• Good quality dialogue recording
• Low price
One suitable choice is the Sony ICD PX333 (the ICD PX312 has also been tested).
Other Sony models using the same housing should work fine as well.
Click on the image on the right for typical sales details - - ->
Despite their modest price, these devices are capable of excellent quality audio. Although described as mono recorders - and fitted with a mono internal microphone - they are in fact stereo units, and when used at their highest quality settings are capable of excellent quality recordings.
The files are recorded in the MP3 format - at up to a high quality 192Kbps rate - and these files are easily converted into .wav format for editing within any audio editor - including free ones like Audacity.
The device is connected to any computer via a USB link, for simple high speed transfer of your recorded audio files.
The Microphone Housing Tube:
To eliminate handling noise, and to create a more aethestically pleasing and functional interview microphone, the recorder is mounted within a tubed housing, to allow it to perform more exactly like a 'regular' recording microphone.
The type of tubing used for this project is a length of seamless 40mm (1.5") black PVC waste pipe. An example of a (typical) 180mm cut section from such a pipe - and used for the project - is shown on the right. You can of course cut the pipe to any length to suit your specific requirements...
Just click on the image on the right for more details of the actual type of pipe used (UK source) - >
For this project, the use of a windshield helps serve several purposes--
•It significantly reduces external wind noise, and also helps reduce unwanted 'plosive' sounds that can result from close mic usage.
• It cosmetically seals the top of the microphone housing tube..
In this project, we are using standard 45mm windshields, which are available quite cheaply from a wide selection of vendors.
Just click on the image on the right for a typical costing - >
The opposite end of the housing tube needs to be sealed, to provide a seating for the internal padding which supports the enclosed recorder. Several options have been tried in the prototype designs-- the image on the right shows 3 suggestions - you may well have your own ideas..
• On the left, an old 45rpm vinyl record centre piece (the sort used when the discs were played in juke boxes). To ensure a tight fit inside the tube, black insulating tape was wrapped round the (unseen) edge of the insert.
• The middle example shows an end stop made from the screw cap of a Listerine mouthwash bottle.. Some additional black insulating tape helps to both create a tight fit inside the tube, and improve the external look cosmetically..
• The version on the right uses a 35mm black film canister. This will have a smaller diameter than the tube itelf, so will need to have extra padding added to allow a good tight fit inside the tube. Single sided foam tape works well. The end result can give the appearance of a 'plug-in transmitter' - as fitted to a genuine radio mic - which might help to create a good impression!
Just click on the image on the right for typical canister costings - >
In addition to the items described above, you will need some black insulating tape to help secure the end caps, and some foam block 'offcuts' to pad the recorder when fitted inside the tube. This will help eliminate any handling noises..
Just click on the 'Assembly' button below for more on the final assembly..