Digital recording, mixing Need professional help.

To continue with Phil's discussion... a DAT is a 16 bit word just the same as CD redbook. However, DAT has the ability to record sample frequencies of 32 kHZ, 44.1 kHZ (CD standard), and 48 kHZ ( original consumer DAT standard). A DAT can make a direct digital duplication of a CD. However, a DAT recorded with a different sampling frequency from 44.1 doesn't work with CD. A DAT at 48 kHZ has a higher maximum frequency response of 24 kHZ as compared with CD's maximum of 22.05 kHz.

If a DAT is recorded at 48 kHZ and it is to be pressed onto a CD-R, it will require a sample rate convertor. Quality external sample rate convertors are expensive and typically diminish sound quality. Sample rate conversion can also be accomplished using a computer editor but there are still sound quality issues. Most people recording on DAT use them at 44.1 kHZ sampling frequency.

The process which Phil mentioned where a 24 bit word is crammed into a 16 bit word is called dithering. It is basically a fancy way of rounding down. Sometimes instead of dithering, the word is simply truncated from the higher bit rate to 16 bits but this is a practice that should be avoided. As far as dithering higher bit rates to a 16 bit CD standard, there are numerous mechanisms available such as Apogee's UV22, Pacific Microsonics HDCD, Meridian, etc...

There are also newer multi-track and high-bit technologies available to record with. These are things such as units by Tascam or Nagra. These typically record multi-track 16 bit /44.1 kHZ signals but some can record at 24 bit with a 96 kHz sampling frequency (such as the Nagra). These can be dithered down to a 16 bit CD.

Now for the history of digital recording for vinyl, there are two predominant recorders out there. The first was a proprietary mechanism used by the Decca record company. The other was the Soundstream and was the most common. Neither of these formats is a supported standard today. They were used as the master source and the lacquer to cut the LP was made from the digital source converted to analog rather than an analog tape master. A high quality analog recorder of the day (such as an Ampex ATR) is superior to either the Decca or Soundstream and goes head to head with the finest digital recorders made today.

Excellent and accurate responses!

Thanks to both of you for staying on topic and giving an unbiased and through answer.

I realy enjoyed reading these responces and I figured another sub-question in my own thread:

Why DATs arn't used in consumer media meaning why for instance there are no car DAT players or portable ones. Why there is no brand records sold on DATs such as on CDs or portable audio cassettes?

Once upon a time, our friends at the RIAA threatened to sue anyone who introduced a medium which could faithfully copy a CD... so, when DAT was being introduced it was greatly delayed because of fear of retaliation from the music industry. It was introduced with what is known as SCMS (Serial Copy Management System) as a compromise with the RIAA where only a single digital copy would be allowed on a consumer DAT. Professional machines were not restricted by the agreement with the RIAA. The first company to introduce a consumer DAT was Nakamichi with the 1000 but its cost was sky high (around $10K) and avoided problems with the RIAA. Eventually, the delay of DAT had killed its application as a consumer medium and became supported only in recording studios. CD-R followed close enough that it became the digital medium of choice for copying and we all know what has happened to the RIAA fears of piracy in the meantime.

For recording sessions, when doing a live 2 channel recording the CD-R is a very poor medium to use (dropouts, errors writing the CD-R, etc...). Therefore, DAT is very popular for this and has kept its foothold in studios and location recording. It is much cheaper to use than analog, much more robust than CD-R, and very convenient.

And to add to the above...I think it also became a victim of the constant format wars that plague the audio industry. At the time the DAT was being introduced (by Sony?? I'm not sure), Phillips was pushing their own digital cassette format. Besides that, Sony seemed to be pushing their own mini-disc format for many of the same consumer uses as the DAT. Who knows...it may have successfully replaced the cassette if all of the companies (record labels included) embraced it, but the recordable CD was inevitable and it's certainly more convenient for home users.

Thanks to Slartibartfast for the DAT bit rate info. I knew that Tascam (or Alesis?) came out with a 24/96 DAT a few years ago, but I wasn't sure what format the older DATs used.

And to Marakanetz...in the end it seems like the DAT has become one of the official replacements for the reel to reel recorder (though many people still prefer the analog feel and tape compression of a reel to reel recorder). Pros and enthusiasts use them to record live music...musicians used them for mix downs, and most studios, mastering houses, and CD duplicators accept them as a standard format. Many people have been slowly replacing them with CD burners and hard-drives for mix-downs, but they're still very useful for live recording.