Wednesday, September 26, 2007

What's The Difference Between Different Digital Audio Recorders?

Recording Digital Audio - Considering Your Options and Choosing Products

Remember when dictaphones and answerphones had mini cassettes, and you recorded radio onto your tape deck?
Thanks to advances in technology, it is now easier to record audio, in higher quality, more portably, in shareable file formats, with cheaper devices,
for longer periods of recording time.









Benefits of Recording Digitally



  • Digital recording devices typically have few or no moving parts, eliminating machine hiss and other noise.

  • Easy choice of compression, so you can store huge amounts of audio on small, portable recording media.


  • Digital recording devices, due to the lack of moving parts, are typically smaller and more durable than tape recorders, and have lower power consumption.

  • Digitally recorded audio in standard formats is easy to edit, share, store, manage, search, and overwrite - especially when working with computers.

  • Digital recordings can be stored on a wide range of digital media, giving you better options for backup and long term data fidelity.






Considering Quality


When you are considering different electronics to record sound digitally, you need to start by deciding what audio quality you require:



  • Mono, compressed audio: good for storing voicemail, voice memos, or informal recordings.

  • Stereo, less compressed audio: good for shared audio such as podcasts and records of speeches.

  • High quality lossless audio: suitable for music recordings or recording "clean" tracks for mixing later.



If you want to record audio to go along with video, e.g. the soundtrack for a movie you’re shooting, it’s advisable to use specialist equipment to make sure your audio channels are synched with the video stream.



Audio Quality


Apart from the recording device, and recording medium  / storage format, there are two main factors affecting the quality of your recorded audio:


1) The quality of the sound signal recorded in the first place. Obviously a recording in a padded room in a studio is going to sound much better from the very beginning, than something you shot on a windy day by a busy road.



2) The quality of the microphone and its connection to the audio device. You can buy a cheap karaoke microphone for under $20, but professional studio mics go into the thousand dollar range, so when it comes to getting higher quality sound pickup, you get what you pay for. Professional sound recording is a highly technical profession, so beware of asking sound engineers open ended questions.


A microphone is of course just an audio input device, from the point of view of the recording device. Digital recorders that can record from an external microphone will also accept line-in audio recording from any audio device. You could record radio, record from an electric musical instrument, or input sound data from a computer or even a telephone.









How Long Is A Piece Of Audio?



  •  Digital audio can be stored in any number of different formats. Most formats involve some kind of data compression.

  • Most formats have different "minutes per kilobyte" if you change the sampling rate, compression ratio, and number of channels (e.g. stereo or not)

  • With 1GB of storage space you can comfortably record over 4 hours of audio at very acceptable quality. The same amount of storage could hold only half
    an hour of the best studio quality audio, or over 10 hours of phone-quality audio.







Considering Devices


Let’s take a look at some of the latest Made in China gadgets that will help you with your digital recording needs, and assess what applications they would be useful for.















Device Recording Method Application
Flash-Based Personal Multimedia Player



Portable Multimedia MP4 Player
[Click Here]




Recording is via a small built-in microphone. Recording is in mono, and stored in either WAV or VOX format in variable compression on the player’s flash memory storage.


Suitable for informal voice recording. Microphone will only pick up close speaking or loud noises.

















Device Recording Method Application
Bluetooth To Wired Audio Adapter


Stereo Bridge For Bluetooth Devices

[Click Here]



This new gadget is a receiver for Bluetooth audio signals, which relays the signal to a standard (RCA or audio jack) wired audio signal.
This means you can use better speakers for audio signals from, say, a bluetooth mobile phone.



 



The reason for including this here is that if you need a solution for recording wirelessly, or for recording mobile phone conversations,
you can pair this with a compatible Bluetooth microphone, earpiece, or mobile phone, and use your normal digital recording equipment (as above, or a computer) to record in fairly good quality.


















Device Recording Method Application
Spy Cameras with Audio



Wireless Mini Spy Camera with Audio
[Click Here]


A discussion of audio recording would not be complete without dipping into the realms of surveillance.
Whilst this is not exactly an invisible bug, it is a discreet mini security camera, transmitting color video and audio wirelessly to a remote receiver.



If you want a way to record the video and audio of day to day events, from a fixed vantage point (indoors),
then this is a cheap and unobtrusive way of doing it. However this is just an AV pickup device and you will need a
DVR Digital Video Recorder for actually monitoring, recording, and storing the video and audio!












More Great Product Ideas


One other solution for recording audio is, paradoxically, to record video.
Many Digital Camcorders
have excellent quality built-in, directional microphones and you will find that for portability, battery life, ease of use, and sound quality, they are hard to beat.
In addition, most digital camcorders incorporate a voice-record-only function too.




Click Here


 


For a little audio novelty, check out this Parabolic Spy Audio Listening Device:



Click Here


 




Conclusion


Before purchasing kit for recording audio, "Begin with the end in mind". Ask yourself these key questions:



  1. What quality do I need the audio in?

  2. How many hours of audio am I going to record in one session?


  3. What is my budget?

  4. Do I need my recording kit to be portable? (Do I need the equipment to be discreet?)

  5. In what situations will I be recording? (What special aspects, e.g. for the mic, power, weatherproofing - will be required?)

  6. What kind of microphone will I be using?

  7. Where/how am I going to be storing and editing the audio? (What is the easiest way to transfer my audio to my storage or editing equipment? What starting format is going to make it easiest to store and edit the audio? )

  8. What solutions have I tried in the past, that were not good enough, and how will my new hardware overcome these problems?






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