The Twelve Days of an A Cappella Christmas Album

December 27, 2015

For those of you who know me well, you know that I should not be singingI should stick to my guns, which are percussion and recording. Even though the extent of my vocal ability rarely leaves the confines of my shower, I ended up auditioning for an a cappella group at school, and to my surprise, I ended up making the cut!

Five of the a cappella groups on campus decided to join forces and make the first-ever Santa Clara University A Cappella Christmas Album, and I was to produce that album.

Preparation

To prepare, I listened to a lot of a cappellaso much that YouTube still suggests a cappella videos on a regular basis. I researched best practices in recording multiple voices, and found out that isolating voices is very important so that autotune can work its magic on a clean signal. I discussed my plan of action with the recording teacher at school, and he told me that he has a friend that produces a cappella albums. Cool! Everything was on track. I went home and Googled the name of his friend, Bill Hare. It turns out he produces some of the best-known a cappella artists, from Pentatonix to Street Corner Symphony.

Further discussion with the recording teacher led to a field trip of about eighteen people (a mix of recording students and a cappella members) to the studio of Bill Hare. While there, the group learned about Bill's experience with a cappella groups, including recording practices, mixing/mastering techniques, and live performance techniques.

One interesting practice Bill does is to record vocalists using a MIDI backing track. When recording multiple vocalists, I had previously had them sing at once and use that recording as a backing track as I record individual voices. However, with that practice, vocalists can be a few cents off from the true pitch, which will lead to them being off from the true pitch of the song when they record later. With MIDI, however, the sounds are exactly in tune. It never crossed my mind before, but in hindsight, it makes a lot of sense.

On the first day of recording, my true love gave to me...

...the largest a cappella group on campus17 members! I booked the school studio for four hours, and got there an hour early to set up three microphones in an isolation booth. The back of the microphones faced each other, since the null point of a cardioid microphone is in the back. There was a little bit of bleed into each microphone, but it was an acceptable amount.

I recorded the remaining groups over the next five days. On the sixth day of recording, I recorded the last group. It was time to start editing and mixing!

Editing/Mixing

I had already started to mix the groups I recorded first. My process was as follows:

  1. bounce out each individual trackthis creates a new audio file based on the best composite take, thus keeping the original audio intact
  2. edit individual tracksI started by lining up each note for rhythm, then applied autotune where necessary. This also included standard mixing techniques, such as EQ and compression
  3. bus each voice part to their respective sectionsthis resulted in 4 to 8 busses (soprano 1, soprano 2, alto 1, alto 2, etc.). This makes it easier to get a good section blend and then mix SATB voices
  4. create reverb for the ensembleeach section bus had an auxiliary send to a reverb track. I wasn't sure if I should add reverb at the end of the mixing stage or at the beginning of the mastering phase. I experimented with both and had better results with keeping it at the end of the mixing phase.

My final mix levels were somewhere in the -6 dB to -3 dB range. I knew that I would end up putting some mastering compression to make the overall mix more lively.

Mastering

For mastering, I wanted it to sound pretty produced and not like a live a cappella performance. My reasoning for this is because in live performance, it's much more theatrical and the audio is only one component of the overall performance. For studio a cappella recordings, I found that there's a fair amount of compression. Many of the reference tracks I used in this project had RMS levels in the -10 dB to -5 dB range. That's pretty high, which means that there's a good deal of mastering compression on the tracks.

I ended up using the Waves L3 Ultramaximizer on a mastering session with a -9 dB threshold and a -0.1 dB output ceiling. This added a lot of compression, which makes the tracks sound more intimate and lively. It applies compression to the top-end of the audio signal, thus allowing the track to be played louder without clipping. I felt a little funny doing this, because I felt like I was contributing to the Loudness Wars. (I'm working on a blog post about the Loudness Wars, stay tuned!)

I spent the majority of my Thanksgiving break working on this album. I had to have everything done by the day after Thanksgiving, as that's when the leaders planned to burn the CDs. There were a few late nights working on this album, but it was all worth it since I enjoy working on projects like this. On the twelfth day of the album (the day after Thanksgiving), everything was done! I uploaded the mastered tracks to Google Drive, and my work here was done.

Reflection

Overall, it was a great project to work on. It was great recording, editing, and mixing several of my friends and seeing it become something I could be proud of. If I was to do it all over again, I would do a few things differently:

  • start this earlier12 days is not enough to record, edit, mix, and master 9 songs
  • have the groups make the MIDI backing tracks for their own arrangements
  • work with someone else in the editing/mixing processyou start to hear (more) voices in your head when mixing a cappella for hours on end. I spend a little more than 60 hours on this project, the majority of which was spend in editing and mixing.

The leaders of the a cappella groups started distributing the CDs the Monday after Thanksgiving. 150 CDs were ordered, and they sold out within 8 days! I was stoked that so many people were interested in this album. After all, CDs do make great stocking stuffers!

This CD was a great stepping stone for me, because I'm also working on producing my band's first album, which is set to release early 2016.

Thank you do Bill Hare, Jeff Hanson, and Dean-Austin Mayor for your help on the album, and to all the a cappella groups on campus for contributing to the album!

Thanks for reading!