Can you give me some guidelines on how to make a good DAT / CDR?

General:

1: Don't record too loud. There is a popular myth that says you are only getting the most from a DAT tape if "all the lights are on" - ie. the signal is clipping or peaking at 0 dB. Allow at least 1 or 2 dBs headroom when recording - any higher and you risk digital distortion, which can cause major problems at mastering. Some manufacturers use less than perfect metering on their machines, so we recommend you avoid allowing your recording to peak at zero, just in case there are over-levels which the meters aren't showing.

Engineers & producers - even if your customers are demanding a really "hot" reference copy, please make a clean copy for us to master from and then lift the level for the test copies.

2: Always use dither. Dither is a special kind of (very quiet) noise, added to digital files when they are processed, to reduce truncation errors. Believe it or not, a 16-bit digital file recorded or processed with dither can reproduce sounds an extra 6 dB quieter than one without. Undithered recordings can start to sound brittle, edgy, grainy and harsh. We feel many complaints about early digital recordings result partly from poor implementation of dither. If in doubt, whenever you have any processing to do, use dither.

3: Avoid unnecessary processing. Every time a change is made to a sound digitally, it is done with a certain accuracy. Even 32-bit calculations incur a small number of errors, and these may affect the sound, especially if many changes are made. So, for example, if you adjust the volume of your material, and then change your mind, don't process it again to reverse the change - go back to the original. Think carefully about whether you need to make a change at all - it's even a good idea to avoid copying except where absolutely necessary.

In addition, some software doesn't include proper dithering functions, and so degrades the sound - see point 2 above.

4: Avoid analogue copying. If your sources are digital, and you make flat copies digitally, you can maintain their quality indefinitely. But every time you make an analogue copy, a small amount of quality will be lost. Also watch out for computer soundcards. Even those with digital inputs may apply sample-rate conversion to your music (for example the Soundblaster Live series) which has the potential to degrade the sound, especially if it's done several times - see point 3.

5: Be organised, but don't worry about the order. Unless you're having a copy master, we can put your tracks in the right order at the session, but it's a good idea to make sure you know which mix you want and which tape it's on, for example, to save time in the session.

6: Avoid "over-cooking". Decent audio equipment is much more easily available than it was, and there is a temptation to try out all the options. In particular, there are many tools offering "mastering" functions, like compression and normalising. We recommend you leave this until the mastering session. It is possible to achieve excellent results with these tools, but why bother when you're paying us to do it ? By all means bring us an example to listen to, but wherever possible we prefer to work from "clean" sources.

7: Always keep a safety copy, and bring it to the session. When digital sources fail, they often can't be repaired, so always keep a second (digital, flat) copy of everything, and bring it along to the mastering session, just in case.

8: Leave "topping and tailing" to the mastering session. We will be loading your tracks to a digital editor, so we can perfect any fades and/or crossfades for you then. Sometimes mastering can bring up subtle details of the mix which weren't audible before, and it's a shame to have them chopped off too abrubtly. You can always experiment before-hand and bring in a copy for us to refer to.

DAT:

1: Don't make the gaps too short. Some DAT machines are very untidy dropping in or out of record, with the result that mutes or glitches can appear. To avoid accidentally clipping the starts and ends of your tracks, we recommend not using the first two minutes of DAT tapes at all, and waiting for at least 4 seconds after you've started recording on the DAT machine before starting to play the audio in. If you're having full mastering done, we can fine-tune the gaps for the best possible effect anyway.

2: Avoid long tapes. Longer tapes are thinner and more prone to stretching and other damage. It's best to use the shortest tape you can get away with.

3: Have your machine serviced regularly. Just like analogue tape machines, DAT recorders can get dirty and worn, and alignments can drift. It's well worth keeping your machine in good condition.

CD-R:

These tips apply mainly to people using computer or hard-disc based systems to create CD-Rs. For standalone CD-R burners, the points already mentioned above are the most important, but some of these may also apply:

1: Always use dither , if you haven't already. If you are working in 16-bit, and have followed our general advice, your files will already be dithered. But if you use 20, 24 or 32-bit files, then either before you make your CD-R, or as it is written, you should apply 16-bit dither. See general point 2 above. Some applications, for example Adaptec JAM and earlier versions of Cubase do not include dither. In Wavelab it is switched off by default.

If you are compiling your CD-R from other CD-Rs & CDs, with no level changes or processing, there is no need to use dither.

2: Allow a PQ offset. When you decide where to put the track markers on your CD-R, leave at least a third of a second before the music comes in. Some older players don't play track starts accurately, and might chop the beginning off. If we're mastering the audio for you, leave even more time, to avoid any risk of clipping ! Also a clean sample of any background noise makes de-hiss operations more efficient, if they're needed.

3: 2x is usually best. CD-writers are getting faster and faster, but we still get the best results for audio from most machines at two-times speed.

4: Try to find out whether your CD-R burner "likes" your brand of CD-R. Different burners react differently to different makes of CD-R. See if you can get a recommendation from your manufacturer. In general, well-known brand-names perform better than cheaper, unbranded varieties. The internet can be a valuable source of information on this subject.

5: Always listen to your CD-R. Just because a computer says a disc has been made correctly, doesn't guarantee it will sound perfect. Many sources arrive with us for mastering full of clicks and dropouts which our customers didn't know were there. It's always worth taking the time to listen carefully to your master all the way through before mastering.