Audio recorders: From spoken memos to studio recordings

By Peter Zschunke Nov 6, 2011, 2:06 GMT

Berlin - The smartphone can do everything - but not always as well as a specialized device could. This goes for photography as well as audio recording.

'The quality of a smartphone recording is simply not that good,' said Ichiro Ike Takagi, Sony's manager responsible for audio products.

An app such as Voice Recorder for Android or the integrated iPhone App Voice Memos are satisfactory for a brief recorded memo or recording a speech. But if you are looking for studio quality, then a digital recorder is clearly better.

And the current models have next to nothing in common with old-time recording devices. Even the era of the mini-disk is over. Current audio recorders feature integrated flash memory. Some even have a slot for an SD memory card for even more storage.

High-level devices record in PCM (Pulse Code Modulation) in which the analog signal is sampled regularly at uniform intervals and each sample is digitalized. The smaller the sampling rate is and the more exact the saved values (bit depth) are, the better the sound quality and the lower the risk of disturbance. A sampling rate of 44.1 kilohertz (kHz) means that the audio source is quantized 44,100 times per second.

Recorders like Sony's PCM-D50 (starting at 540 euros or 740 dollars online) or the sleeker Olympus LS-3 (150 euros) offer a sampling rate up to 96 kHz at 24 bit - matching studio quality. The technical data surpasses that of a CD recording, which is generally recorded at 44.1 kHz and 16 bit.

'We have never determined that 24 bit really makes a difference. Usually, 16 bit is entirely enough,' said Volker Zota of German computer magazine c't. He adds that no disturbances are to be expected with that sampling rate as long as it's recorded at least at 44.1 kHz.

Simpler recorders such as the Olympic VN-5500 (20 euros) or the Philips Voice Tracer LFH 0615 (45 euros) save audio files in compressed formats such as mp3. That is enough for most needs according to Zota, such as publishing an audio file on the internet.

More important than the sampling rate and bit depth is the microphone quality. Depending on price there is a large variety, ranging from a simple mono microphone to a combination of two or three angle directional microphones. 'The characteristics of the microphones make the difference,' said Zota. 'The dedicated recorders certainly have an advantage over the smartphones.'

Besides, the recorders are easier to use, beginning with the fact that they have real buttons to push. With the LS-3, the red 'Rec' button activates a pre-record buffer at the start of the recording. The recording is now started though it is not yet saved. That doesn't occur until the pressing of a second button. 'The first tones of a song will never be lost,' promise the manufacturers. The Sony PCM-D50 has a similar function called cache recording.

If a customer is not satisfied with the provided program for editing the sound files, they can use free software such as Audacity. For some Philips devices a slimmed down version of the voice recognition system Dragon Naturally Speaking is included.

Sony sees the chance to continue to develop the digital recording devices. 'We have a lot of ideas to make this category more attractive,' said Takagi. It is often the really small things that make the user's life easier.

One should make sure when buying an audio recorder that you can swap the batteries, suggests Zota. 'That way you can continue to record if the internal battery is empty and you don't have the charger with you,' said Zota.