I was so proud of myself when I finished recording and editing my first podcast episode – until I realized I had not a clue what the proper podcast audio bitrate was.
So, I started Googling all kinds of queries to get the answer.
There wasn’t a lot of information available for my question:
What bitrate should I use for a podcast?
The short answer to that question is that it depends on whether the podcast audio is mono or stereo. For mono, the typical recommendation is 64 kbps, 44.1 kHz, constant bit rate and for stereo, it’s usually 128 kbps, 44.1 kHz, constant bit rate.
Let’s take a deeper look at this and why these numbers.
What is Bit Rate?
Bit Rates are a little complicated.
To understand bit rate, you have to understand a few components in the creation of digital sound.
Digital representation of sound
Bit rate really didn’t come into discussion or existence until the end of the analogue era and the beginning of the digital one.
Previously audio was stored on vinyl or cassette tapes.
However, with in the digital age, a way to represent sound digitally was created.
It works like this:
A piece of audio is split into lots of little pieces.
Really little pieces.
Each of those little pieces (technically called a sample) is only one – 23 millionth of a second.
It takes 23 million of those pieces to create one second of sound.
Audio sample rate is simply the rate at which samples are taken of the digital media.
Different storage types usually have varying standard sample rates.
For CDs, the standard rate is 44,100 samples per second.
Impressive isn’t it?
So thinking about this, what do you thing happens to your storage as your sample rate is increased?
It fills up faster, right?
The higher the sample rate, the more storage space that will be needed.
To balance this difference between audio quality and storage size, 44.1 kHz was chosen for CDs.
Ok, now to how all of this relates to bit rates.
So, the samples we discussed earlier are each represented by a number.
Bit Rate is made by multiplying sample rate by the number of bits in the digital number (16 – the number of bits in the sample).
If the audio is stereo, we multiply by 2 for stereo.
For a stereo CD, that would be:
44,100 x 2 x 16 = 1,411,200 bits per second (bps) = 1,411 kbps
Bit Rate and Storage
Based on what we’ve already discussed about samples and bit sizes, you can probably deduce that the higher the bit rate is, the more storage is needed to store it.
So, while a higher bit rate definitely means better audio quality, it also means that the file size will be larger.
When determining what bit rate you want to use, you need to consider the tradeoff and a few other things.
The quality vs size issue means that you’ll have to consider a few other things before you make your chose.
Let’s talk about them.
Depending on your audience, download speeds may not even be a factor with a major impact.
However, even in the US in rural areas, data signals can be spotty and commuting listeners may have a bad experience trying to stream large files.
I know because I’ve been there.
Nothing more irritating than a podcast that plays 10 seconds, buffers 30, and then plays 10 more seconds.
On the other hand, if you know that your listeners are not likely to have this issue or the majority of them aren’t, then you may not even consider it.
Similar to the download speeds, the podcast length may be another consideration worth making.
Here’s what I mean.
If you record 15 minute podcasts audio files, you could double your bit rate and be equal to someone who does 30 minutes podcast shows.
On the contrary, if your show is particularly long, you may want to consider a lower bit rate to provide a better user experience.
Remember, your listeners’ experience is everything.
Typical Podcast Audio Bitrates
Ok. Now that you understand the concept of bit rates and considerations you should take into account before settling on one, what podcast audio bitrates are standard?
And that is a hard question to answer.
Numbers are actually all over the place.
An estimate of typical ones is as follows.
- 32 kbps – Poor audio quality. Usually used only when download time and file size reduction are needed.
- 48 kbps – A reasonable lower end rate for longer speech-only podcasts
- 64 kbps – A common bitrate for speech podcasts
- 128 kbps – Common standard for musical and high quality podcasts
- 320 kbps – Very high quality – almost indistinguishable from a CD
And according the the BBC, a reasonable rate for mono is 64 kbps and for stereo is 128 kbps.
So we see that there is no one size fits all approach to podcast audio bitrate standards.
In fact, podcasters everywhere use different sizes.
However, whatever choice of bit rate you decide to use, be sure to take your listeners’ experience into consideration.