When shopping around for binaural beats downloads you must consider quality as the deciding factor.
Quality in the first instance is determined by engineering; the studio where the recording was created and the expertise of the sound engineers involved.
Secondly it is determined by mastering, which is audible and can be determined by listening to a sample.
Why Binaural Beats Are Sold as .MP3 Files & Not .Wav Files
The majority of binaural beats recordings are available for download as mp3s. The reason for this is that the recordings are usually fairly long; approximately 15-30 minutes depending on the type.
This means that the original .wav format the recordings are mastered in is very large in size, and would take considerable time to download to your computer. These large files would then be a nightmare to transfer from device to device, and also would lack compatibility with mp3 players, smartphones, etc.
For these reasons the .wav file is compressed to an mp3 file. This reduces the file size considerably, and on one of our recordings of 30 minutes, this would reduce the file size to approximately 4oMB.
On a fast broadband connection this will take about 2 minutes to download. Mp3, however, does have a small tendency to lose quality. And so, all .wav files converted to mp3 should be converted at the higher rate of 320kbps kilobytes per second, which is much higher than CD quality.
Maintaining Quality & Frequency Response
To ensure maximum quality, all BBM recordings are delivered to you at a rate of 320 kbps. Binaural beats recordings must be mastered at high quality and compressed to mp3 at high quality in order to avoid loss of frequency response. If quality is lost, the frequency response process will be diluted and the benefits to the listen reduced.
When you buy a binaural beats recording, or any other brainwave entrainment type recording, first ask the vendor about the quality of the download(s). Many vendors master at lower rates because they want the download to be faster for the customer, or they just understand how compression affects quality.
Compromising on quality to gain 30 seconds on the download process could considerably affect the potency of the recording.
To hear what a quality binaural beats recording should sound like, download a free sample here.