non STREAM master = streaming master
For years, I have been delivering dedicated masters for streaming services. Back when I started with this, it was an option which I could do if specifically requested. This all started when iTunes came up with the so called ‘Mastered for iTunes’ program. MFiT (now called Apple Digital Masters) is based on hi-res wav files in 24bit in at least 44.1khz sample rate and checked with the MFiT tools. These tools where basically doing checks to see if there where any Inter Sample Peaks (more on ISP’s later) after conversion to their AAC+ encoding. To do that, you had to ‘run the master’ through their codec tool and check if anything goes ‘above 0dB’, which is basically what an ISP is. In practice this means that you want your max peak value to be lower, like in -1dB. Only certified Apple MFiT mastering-engineers could (can) deliver those MFiT/ADM masters. Back then I was among the first mastering-engineers in the Netherlands to be MFiT/ADM certified by Apple. (NOTE: I am a windows user, so I had to buy a Mac mini to become certified, Marketing for iTunes anyone?) Basically, that MFiT master was a streaming (STREAM) master; it was a bit more dynamic (most of the times) and had a max peak of -1dB (or more).
Coffee and Inter Sample Peaks
The biggest difference in masters for streaming and ‘regular’ masters is the max peak value. In practice this means that the max (true) peak is -1dB, so 1dB below full scale. I’d like to explain things in a simple, understandable way so that even if you do not have a lot of technical knowledge, you will still understand.
Let’s compare music in the digital domain with a plastic cup of coffee. It’s not that hard to fill a plastic coffee cup up until the edge, that coffee cup edge is our digital 0db. But when you try to put in more, you will spill that precious coffee, your coffee cup will have stains and your table gets dirty. Now when that plastic cup filled up right up to the edge without spilling is still on the table, all seems fine. But as soon as you try to pick it up, you will spill and loose precious coffee and burn your hands. That is because you squeeze the cup, shake it, you get the idea. So that’s why it’s good practice, to not fill your coffee cup until the edge, but leave some room to avoid spilling. Here we go, we have a streaming master! We leave some (1dB or more) room below full scale/0dB so that you will not spill the coffee or hmmm.. audio (Inter Sample Peaks) over the edge.
‘But you loose headroom when not going full scale!’ Hmm.. yeah.. let me explain.. The human brain has a hearing range of 120dB at 1 to 2khz, which is only in an ideal environment (anechoic chamber) and only when there is no hearing damage and such. In practice, you will only perceive something like 80dB because of background noise and everything else. At 24bit, we have 144dB of headroom, so that 1dB less is still way more then you could ideally perceive. Even at 16bit (96dB headroom) it would be OK, but it’s 2022, so let’s all go 24bit which is what distributors support nowadays anyway.
I don’t hear those ISP’s, so who cares?
Agreed, you will most likely not hear those ISP’s if your music has transients like drums, because they will be so short that the human brain will not register them. But that also depends on the encoding used and even more important, the DAC used in the playback device. In your studio the DAC, even the cheap ones, will be better than the ones we find in let’s say a phone or Bluetooth speaker. We don’t really have any control over that and it could be that all of a sudden that ISP/clipping sounds really bad on one of those devices. I’m not even talking about single vocals or an acoustic guitar without short transients but rather long ‘sinewave’ waveforms. That will not sound like fun don’t you think? I think it’s simply a good idea to take care of those peaks just to make sure and it will not make your music less loud if that’s what you are worrying about. I have more blogs on my website on how that works, so I suggest you read those as well.
Masters in 2022
I decided that from now on (17 January 2022) the default masters that I deliver are masters optimized for streaming, so with a max peak of at least -1dB. The previous streaming masters had the word STREAM after the master date, from now on that will be removed. So that means all masters are streaming masters and you don’t really have to worry about what masters to use for what. They work great for streaming, they will sound brilliant on the radio, they will sound awesome for download-portals and soundcloud will thank you later for this.
If you really want a ‘louder’ master, so with a really big chance of ISP’s/clipping, you have to let me know instead and I will gladly make that MAX master for you. But you always have to keep in mind that in the end it will not be louder, it could/will just potentially sound more distorted. It’s up to you.
EDIT 20 January: all masters will be delivered in 24bit from now on, 16bit files are optional.
With kind regards,