Can I record at sample rate 48k and still write to a CD?
You will have to export your session to 44.1KHz before that, recording (tracking) is one thing, but burning a standard audio CD is another thing, all audio CD's have a standard format called "Red Book", and they all are 44.1KHz @ 16 bit. If you can record from the start at 44.1 it would be "theorically" better, that way it won't have to go through sampling rate conversion which can add some weird artifacting, if not then try for 88.2 since it's simply double the value of 44.1 and reconversion will be smoother, although it will take a bit more preocessing power. More important it would be better to track @ 24 bit and not 16 bit, you will have more headroom to play with especially during the mix and mastering process.
Here's a nice debate I started off with similar question:
Your subscriptions & donations are critical help that make it possible for full-time development of Ardour to continue. Your support is critical and much appreciated.
May goal US$6200 (US$74.4k/yr)
Total till now: US$661.57
Subscribers 1411 US$4222.00/month
Support Ardour, get free upgrades: pay $1, $4, $10 or $50/month: