Perhaps not quite on topic, but I wanted advice on recording samples in the field with a portable recorder. I\'m talking about something that would fit in a knapsack or even a jacket pocket.
The specs on the minidisc recorders and the walkman-style DAT recorders say 1-bit DAC. Can that be true? And wouldn\'t that mean lousy sound quality? With a 20-bit DAC on a computer soundcard, wouldn\'t it be better to get the best possible portable cassette tape recorder (even though they don\'t have any digital output), and then re-record the analog result digitally into your computer?
Please advise and thanks in advance.
It´s a little complicated. 1-bit means of course not 1-bit reolution instead of 16 or 20 bit, but the technique is differend to normal AD-conversion: Instead of taking 44100 samples of the signal with full wordlength (representing the absolute value of the waveform) the 1-bit conversion scans for the change of the amplitude compared to the sample before. Increasing is marked with 1, decreasing with 0. To get high resolution, much more then only 44100 samples are needed per second, typically 1.5 million values per scond or so. This bitstream becomes interpolated optimized 16 or 20 bit words to be stored to DAT or MD. The advantage is the cheaper technology and a uncritical filtering. The bitsream technology is also used in sonys super audio CD, but without leaving the bitstream for normal conversion.
For recording, I highly recommend a 20 bit system because of the fact you need headroom to avoid digital clipping. Alternative is a good 16 bit DAT with good prelimiter. MD´s are problematic because of the Datareduction, which causes spectral gaps.
Very good comments, Holger - you always have excellent contributions to this forum.
A couple of ideas for Arch: Tascam and Sony make very nice portable DAT recorders. The Tascam is a bit bulkier, but offers phantom power for condenser mics. Alesis offers their Masterlink ML-9600 hard disk recorder which does 2 channels of 24 bit/96 Khz in a compact package; however, it does not included mic preamps.
My own setup is not quite so portable, but is intended for field recordings:
- Compaq Presario 3550 (a very compact PC
with 15\" TFT display, 3 PCI slots, CD-R,
500Mhz Celery. I replaced the 8.4G HD
with the very fast 22 Gig IBM 22GXP).
- Aardvark Direct Pro 24/96 (4 premium
mic preamps w/ phantom, 6 outs, DSP
- Mics: two AKG 414 B/ULS, two GT AM51
Everything fits into two Plattcase hard shell cases. My application is to do surround-sound recordings and ambient samples for Giga.