An Uncommon Culprit Behind Unusable Recordings: Not All Wave Files Are The Same

Recently, an engineer was referred to me because of my experience with using Reaper as a live multitrack DAW. The original ask was relatively vague. However, like anyone who has ever worked in customer service, 90% of the time you can expect to answer one of a few familiar questions. This time ended up being different and led to me uncovering something that has flown under my radar for my entire audio career.

The conversation started by this engineer presenting the specs of his recording rig. It consisted of a pretty standard recording deployment: Mac mini, DVS Pro, Reaper, and an external SSD. The channel count was also not large; around 60ish channels at 96k. Every channel was mono aside from the FOH mix record. The stereo track of the FOH mix made it easy to drag and drop into Dropbox for convenient team reference night to night. This engineer moved to Reaper because of the increasingly popular app “MarkerMatic” to be able to drop pre-named markers from the console over OSC. Being a Logic user, they never had a reason to switch until the benefit of the markers allowed for much easier navigating. They reluctantly swapped to Reaper on their previous tour and had no issues. Their current tour has been a different story.

This is where the problem arose: for some reason, the FOH mix file was unable to be opened by any other audio player: Logic, Pro Tools, VLC, or even QuickTime. The engineer discovered that the file had an odd file type of “Wave64” so as a result, they swapped the file format to force a standard “WAV” (also known as RIFF/WAV). The next night resulted in a different issue. When they uploaded the FOH mix to Dropbox, it played back, but only for about 27 minutes of the 2+ hour show.

Unfortunately, these recording woes were perpetuating their disdain toward Reaper. While it was understandable to want to switch back to Logic, I was grateful that they allowed me to troubleshoot the problem. This issue seemed too specific to be an error in the software.

Without going through my whole troubleshooting process, I would like to present my discoveries because this blew my mind:

I had no idea that there were different types of wave files… “.wav” does not always mean “.wav”

First, a quick history lesson: back in the early 90s when the first wave file was invented by Microsoft in collaboration with IBM as a way to store digital PCM audio, they created a format that would allow this audio to be stored using 32-bit integers. A 32-bit integer can hold a large amount of data; about 4 GB. In the 90s, 4 GB was far more than they thought would ever be needed because at that time, hard drives were smaller than 500 MB.

As file sizes grew, two versions of the wave file were introduced: Wave64 (designed by Sony) and RF64 (designed by the European Broadcasting Union). These two file types expand on the wave file type by using a 64-bit field, which allows for an exponentially larger max file size of 16 exabytes. How big is 16 exabytes? It is just over 1 million terabytes. Yes, you heard that right. For now, this is effectively an uncapped recording file size.

Now, the downside is compatibility. The Wave64 file type is far less adopted than the RF64. However, in macOS finder, both file types present themselves as “.wav”.

This is where the problem lies. The Reaper Project Settings defaults to a wave file type of “Auto WAV/Wave64,” meaning that it will record in the standard RIFF/WAV format until it reaches that 4 GB limit. It will then automatically change it to Wave64. However, if you intend to open this file in anything besides a Wave64 compatible program, it will not work.

This is where the second issue comes into play. The engineer set Reaper Project Settings to “Force WAV” because it was easy to see that the Wave64 file type was not working. However, since the recording exceeded 4 GB, the file was unreadable and became truncated. (One aspect I do not understand is that Reaper can still read this forced WAV file type, and it can still be exported to a different file format, so no recordings were actually lost.) This is why the playback of the FOH mix file was only about 27 minutes. The file header and the field chunk information did not align.

So how do we fix this?

Technically, nothing is actually broken. If you do not have stereo recordings at 96k over 2 hours and 15 minutes, chances are that you can leave everything at default settings and Reaper will always just give you normal wave files. However, if you want to be safe, you can go to File > Project Settings > Media > Change “Large Files” to “Auto WAV/RF64” > Click Save as default project settings. This will cause Reaper to create RF64 wave files, which are more universally compatible. Additionally, because this is a project setting, even if you update the default project settings, you will have to update your templates as well.

Lastly, I would like to give you a quick tip on how to check the type of wave file, since they all present as “.wav” in Finder. Open up Terminal, type “file” then drag and drop your wave file which automatically pastes the file address path, then press enter. This will then give you the file information with the exact wave file type so you can see what you are working with if you are unsure.

Discovering all of this blew my mind. Much like the previous post about pan law, how did I not know that there were multiple types of wave files? If you have ever had an experience like this with a file format issue, please let me know. I am curious about your audio file management systems and experiences.