Help with understanding bitrates

[hansgauffin]

I have three questions about bitrates.

I use a maya 44 soundcard that has a 20 bit D/A converter and a 18 bit A/D converter. As far as I know there´s only 16 and 24(+) bit to work with, what should I choose when I have a 18 bit soundcard.

When I track I always track to 1/4 tape and then transfer to digital. I´ve heard that 16-44100 is enough when capturing analog signals, or should I worry about the bitrate?

I´ve heard that master engineers often want the files to be in 24 bit, Is it possible to resample 16 bits files to 24 bit (really easy in Goldwave) before sending it to mastering.

Thank you for your answeres, and have a great day
/Hans

 

[mattr]

Just being picky, this is bit depth (or word length)... the number of bits per sample.
Bit rate is a different thing - the number of bits per second.

If you've only got 18-bit A/D then you may as well record at 16-bit. Some will say that you should squeeze out those last two bits by recording at 24-bit, but you probably wouldn't notice the difference and it would result in unnecessarily larger files and more load o your computer. If you had 24-bit converters though then there would be no question about recording at 24-bit.

On the other hand, considering you are bouncing from tape, you have to look at the noise floor of the signal coming from your tape equipment and work out if it is really worth recording at a higher bit depth.

And there is no benefit of converting a 16-bit file to 24-bit. You can't magic back the bits that were never there in the first place! They just stay blank and result in larger files.
However, mixing down to 24-bit can be beneficial even when working with 16-bit files... tracks that are quiet in the mix, very quiet reverbs, etc, would make use of the increased dynamic range (whether you can hear the difference or not in a 2-track mixdown though is another debate! ... probably very dependent on the type of material, listening room and gear, etc... delicate, quiet passages in classical music are probably where the benefits of working in 24-bit would be most easily noticed)

 

[gecko zzed]

I´ve heard that 16-44100 is enough when capturing analog signals

Yes . . . 16/44.1 is fine, and you are not likely to experience problems with this. Do so in confidence.

There are ongoing debates about the merits of higher specifications, but for most applications, those debates are largely academic.

 

[mshilarious]

Given that you are doing a tape transfer (a repeatable source), there is no reason you can't record with peaks at the appropriate maximum level (say -3dBFS). So 16 bit should be adequate given that it will exceed the dynamic range of the tape.

However, I can't think of a reason not to record at 24 bit if you're sending it out for mastering. Doesn't really cost nothing. If you are mastering yourself, I would probably record at 16.

You don't need to "resample" to go from 16 bit to 24 bit; really there is nothing to do as the dynamic range is gone and can't be restored. You can simply save the file as a 24 bit file, but it will still have 16 bit resolution (the least significant bits will be stuffed with zeros). However, if you have applied any DSP that extends dynamic range you should save the output of that process as a 24 bit file.