Record to CD real time

16 replies [Last post]
jmamboman
User offline. Last seen 23 hours 24 min ago. Offline
Joined: 2015-12-14
Posts:

It's it possible to burn a CDR real time on my laptop while recording in Ardour? I usually hook up a CD recorder and record on that from an output on my side interface, but I would think theoretically it's possible to do within Linux using the laptops built in CDR DRIVE, although, I don't know how. any ideas?

paul
paul's picture
User offline. Last seen 3 hours 59 min ago. Offline
Joined: 2006-03-16
Posts:

I don't believe this is possible, certainly not on Linux.

jmamboman
User offline. Last seen 23 hours 24 min ago. Offline
Joined: 2015-12-14
Posts:

Thanks. Line out it is!

seablade
User offline. Last seen 1 day 2 hours ago. Offline
Joined: 2007-01-22
Posts:

Out of curiosity... why?

Seablade

Seb
Seb's picture
User offline. Last seen 4 days 20 hours ago. Offline
Joined: 2006-04-07
Posts:

It's the 70s all over again!
https://en.wikipedia.org/wiki/Direct-to-disc_recording

jmamboman
User offline. Last seen 23 hours 24 min ago. Offline
Joined: 2015-12-14
Posts:

Seablade, I record large wind ensemble concerts where most of the time the delivery method is one archival CD. I use a laptop and a portable setup to travel to the site, setup my gear, record the concert, and hand the conductor a CD after the concert is over. Would be nice to either not have to lug the CD recorder around or wait on the export process after the performance. I've been working on an electronic delivery method, but that requires the conductor waiting even longer for the files to export then upload. Doing festivals would be impossible without a CD recorder because each bands back to back with little downtime in-between; that would not allow time to export then write to disk to finish before next group starts performing.

alexmitchellmus
User offline. Last seen 4 days 11 hours ago. Offline
Joined: 2017-11-05
Posts:

@jmamboman would it not be just as easy to dump the audio files, (.wav, flac etc) onto a USB stick?

Many AudioCD players now come with USB media slots. This would also reduce any issues with click's or pop's in the Audio CD. (I remember burning AudioCD's at 8x to reduce the probability of this). 2-4x AudioCD's are still coveted. Remember even if there was a software that could achieve what you want, the 'physical' drive doing the burning may not be able to burn at such low speeds necessary for high-quality Audio CD generation.

In Audio CD land, both the burner and the CD medium need to agree on the speed of burning:
https://www.soundonsound.com/sound-advice/q-why-does-cd-burning-speed-make-difference

alexmitchellmus
User offline. Last seen 4 days 11 hours ago. Offline
Joined: 2017-11-05
Posts:

EDIT: 1-4x Audio CD's

jmamboman
User offline. Last seen 23 hours 24 min ago. Offline
Joined: 2015-12-14
Posts:

I'm thinking the best solution for electronic delivery is SD card on from a field recorder. I'm thinking the process is setup Ardour and let it run all day. For the electronic delivery: record each group on a zoom recorder. Between groups power of zoom, swap SD cards, record the next group, while group is playing use another device (my phone) to upload files to cloud. I could have sharing setup ahead of time for each director. That way electronic delivery would be almost as instantaneous as CD delivery.

jmamboman
User offline. Last seen 23 hours 24 min ago. Offline
Joined: 2015-12-14
Posts:

My biggest concern is that I may not be about to monitor recordings as well as I want while uploading.

alexmitchellmus
User offline. Last seen 4 days 11 hours ago. Offline
Joined: 2017-11-05
Posts:

@jmambomon I don't quite understand, are you using Ardour for mixing only? So the zoom is taking a feed from Ardour? It's possible to render out the tracks very quickly offline from Ardour.

jmamboman
User offline. Last seen 23 hours 24 min ago. Offline
Joined: 2015-12-14
Posts:

I usually run 4 mics into individual tracks on Ardour. I run the tracks into a "Dry" & "Wet" bus. On the wet bus I use IR reverb. I then run the buses into CALF EQ plugins, then to limiter, then back to Ardour master. Sometimes I use noise repellent on the master, depending on the venue. I would want to run the master out from Ardour into the field recorder, but I have also run all 4 tracks individually onto the zoom. Basically, the zoom is my backup, in case something goes wrong with the computer. What is the fastest way to render tracks from Ardour? I've only used the export dialog.

jmamboman
User offline. Last seen 23 hours 24 min ago. Offline
Joined: 2015-12-14
Posts:

What usually happens is a CD is gived directly to customer after concert and files on my computer that get polished (if requested) at a later date. Some directors just want to hear concert on the way home in their car; other performances are need to be polished for entry into contest.

alexmitchellmus
User offline. Last seen 4 days 11 hours ago. Offline
Joined: 2017-11-05
Posts:

If you are using the export dialogue, then you are probably already using offline render. There are two options, 'freewheel' and 'RT' (although I don't think freewheel has a name next to it).

RT allows for rendering projects that have external feeds, such as Jack sessions, hardware effects, hardware synths etc.

Lexridge
User offline. Last seen 3 days 7 hours ago. Offline
Joined: 2007-09-13
Posts:

I am pretty sure I read not long ago that vinyl LPs were actually outselling CDs for the first time in like 25 years. WOW! Of course digital downloads are still king, but what a statistic!

ccaudle
User offline. Last seen 11 hours 20 min ago. Offline
Joined: 2009-12-08
Posts:

@Lexidge: Actually for 2017 digital downloads have fallen below sales of physical media. Top revenue category is now streaming, followed by physical media, followed by digital downloads. Physical sales accounted for 30% of revenue, and vinyl sales accounted for 3.7% of revenue, so a little over 12% of physical media sold was vinyl. Perhaps you were confusing growth numbers with total sales numbers, vinyl sales are growing again, but from such a small starting base, and CD had such a large starting base, that even years of growth won't cause the sales numbers to cross over any time soon.

Which is completely off topic. To the original question, the typical way to record CD-R for quite a while has been disc-at-once mode where the disc table of contents and the track contents are determined ahead of time, and the disc is recorded as one single operation. For real time recording I think you would have to use track-at-once recording, where the audio data gets recorded, then after that is finished the recording software calculates the exact length of the track(s) and writes the table of contents.

One difficulty with using track-at-once mode will be that the default and recommended format for use for editing in Ardour is single-precision floating point in WAV format, but for recording a CD you must use 16-bit fixed point data format, so you would either have to configure Ardour to record in 16-bit WAV instead of floating point, or you would have to setup a program to take streaming floating point data, convert to 16-bit fixed point (preferably with triangular PDF dither), and then use wodim or cdrecord to record a track at 1x speed, then "fixate" the disc (create and finalize the table of contents) after recording the track. You would need to start Ardour recording, then after it had recorded a few minutes you would start the chain of convert piped into wodim at 1x so that the cd recording would be progressing at real time, just offset by some number of seconds from the current recording point in the file.

It seems that the entire process should be possible in principle, but it seems really fragile to me, I don't think I would trust it. A CD only holds a little over an hour, recording a disc at 8x speed takes under 10 minutes. Can you really not wait an additional 10 minutes after an act finishes to hand off the CD?

sciurius
sciurius's picture
User offline. Last seen 3 weeks 2 days ago. Offline
Joined: 2018-03-12
Posts:

As far as I can imagine, I think a conductor (artist, ...) would very much like to get a good impression of the concert, maybe looking for points to improve, etc.. They wouldn't need a great quality sound. So record using the best mics and gear, and make a demo recording using a simple but decent CD recorder.