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There are a bunch of portable digital recorders available these days, such as the Tascam DR-07 and siblings. Those devices often offer a choice of recording WAV data with 44.1 kHz or 48 kHz, both with 16 or 24 bits.

What are recommended parameter combinations for creating some demo CD? It appears that the standard sampling for audio CDs is 41.1 kHz. Then what is the point of recording at 48 kHz? What are the effects of selecting 16 or 24 bits with respect to the final objective of creating some audio CD?

Does recording at 48 kHz and 24 bit provide 'professional' sound quality when played back from a computer, which then needs to get converted to 41.1 kHz and 16 bit for some audio CD? What's the point of creating 48 kHz/24 bit data, when people hearing the results need to run those data from a computer. Most people use CDs anyway? I sure would appreciate any input here.

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What are recommended parameter combinations for creating some demo CD?

All CD Audio *must* be made from 16/44.1KHz because that is what CD Audio standard is. They can't handle anything else.

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Then what is the point of recording at 48 kHz?

If you check all the other available sample rates, you will find that they are evenly divisible (48, 96, 192...)

That means no hairy math when converting from one to another. 44.1 is another story, we get into all sorts of decimals upon conversion, which is not a great "bit-for-bit" situation. Meaning it will therefore add a certain amount of undesirable artifact if converted from or to the higher bitrates. Doesn't mean anything much if you record at 44.1 in the first place.

There are also some Creative soundcards that use "native" 48KHz clocking. They try to do bitrate conversion "on the fly" but that usually is a recipe for syncing troubles sooner or later when multitracking. For those cards, we usually set the host recording program to 48 for that reason. The difference between 44.1 and 48 is so close as to be considered inaudible.

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What are the effects of selecting 16 or 24 bits with respect to the final objective of creating some audio CD?

The higher bit depth choice has more headroom. Easier to clip at 16. Less resolution across the amplitude scale also, which translates to less control over the overall dynamic range.

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Does recording at 48 kHz and 24 bit provide 'professional' sound quality when played back from a computer, which then needs to get converted to 41.1 kHz and 16 bit for some audio CD?

The conversion can get you into audio trouble here. Instead of mucking about with that, I think it much better to simply set up to record at 24/44.1 if your soundcard can handle the task. Last thing to do after mixdown is to convert to 16/44.1, which is not a lot of math at all. Then Master the result for 16 bit.

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What's the point of creating 48 kHz/24 bit data, when people hearing the results need to run those data from a computer. Most people use CDs anyway? I sure would appreciate any input here.

If they are telling you that they can hear the diff between 44.1 and 48 KHz sampling rate, they are fooling themselves.

Now, it is easy to hear the difference between 96KHz and either of the lower too, but that isn't really needed to create your CD either, because, as you know, you will only have to apply lots of math to bring the thing down to 44.1 at the end anyway.

So try 24/44.1 and if you have a Creative card and experience sync problems, try bumping it up to 24/48 and bite the bullet by getting your hands on an Audio Editor that does a good, no, great job of bitrate conversion dithering.

--Mac

Martin,
Each bit of 'bit depth', i.e., 16 bit or 24 bit, gives you 6dB of 'headroom', or Dynamic Range. This is the amount of space between what the system can record at the bottom end of the spectrum, i.e., silence, and the loudest it can go. A bit depth of 16 bit will give you 96dB of dynamic range, which is a lot. However, 24 bit will give you a range of 144dB. Imagine a silent rustle of the conductor breathing before the concert to the loudest crescendo of the orchestra, and that's your dynamic range. If it's more than 96dB, you need to go to 24 bit.

Now, 144dB is very loud, it's actually past the painful threshold. On the other hand, 0dB is almost impossible to achieve, except in a vacuum, which isn't very conducive to recording.

For most home studio setups, 44.1kHz and 16 bit is adequate. If you have top of the line gear, use a sampling rate of 88.2 and 24 bits. Then, at some point, you'll need to convert it to 16 bit 44.1kHz for CD burning purposes.

Gary

Citing a dB figure without a reference don't mean diddly, Gary.

--Mac

Thanks for all the input, fellas. So it's all about tweaking, mixing and mastering. The final CD got to be 16/44.1. The 6db per bit seems to be a reasonable rule of thumb.