What Bit Rate for Podcasts?

I really, honestly do not know the answer to this question. What is the best bit rate to encode a podcast at? Also does that answer depend upon the fact that you are a listener or a podcaster or hosting service?

I do the post production work for the Global Geek Podcast. Before moving to TPN I always encoded the podcast at 44khz and 96kbps. That works out at about 35 – 40MB per show (depending on length between 40 minutes to an hour). We have what I think is great audio quality, but am I spoiling ourselves and our listeners and potentially excluding others?

We have never had a complaint about the file size of the show. No-one has ever said it was too big. People have commented on the quality and said it is great and we have worked hard to get it that way. But I now question if that is over kill. So I tried to figure out what bit rate is the most common. I did a very small survey of the podcasts I have on the computer. I only have nine on it at the moment – most of them are on the MP3 Player (where they should be).

Anyway I got the following breakdown:

Total of 9 Podcasts:

  • 2 encoded at 96kbps
  • 4 encoded at 64kbps
  • 3 encoded at 48kbps

A conclusive survey that does not make. But maybe I am aiming too high. What quality do listeners expect of a podcast? Do they want a small file and lower quality so that they get the content without the bandwidth. Or do they want great quality and a larger file size? With the size of MP3 players now the storage is not an issue I don’t think. But I know in Australia the cost of bandwidth might be. The cost of faster connections is expensive and so many users are on a maximum of 256/64 or 512/128. So does a larger file size deter them from listening to our show? Could we have a bigger audience if we made it smaller and if that is the case what size is acceptable?

With the uptake of broadband technology there is a step towards encoding at a larger bit rate but what should it be? Perhaps 64kbps is a good place. I listen to quite a few podcasts that are recorded at 64kbps and they sound good. A one hour podcast encoded at 64kbps is about 28MB (voice only). Is this a big difference to 96kbps? Well it is between 10 and 15 MB. Will that mean the difference between more listeners and a balance between keeping your existing ones because of what they expect? Will you loose listeners by lowering the bit rate dramatically and will it matter because of the number you pick up. To me it does anyway, I care that we keep the listeners we have.

The other big consideration here is the hosting cost. I know that I had to go to the plan one up from the basic plan in order to have the podcast encoded at such a high bit rate. So that privilege cost me $10US/month instead of $5US/month. That was a cost that I thought was worth it. Also what if your podcast is being hosted by a network, what file size is reasonable for them to host? Is it acceptable that you have a higher bit rate than the other shows that are hosted there and is it necessary? Personally, I would like to find a happy medium between file size, bit rate and quality. I want the best quality at a reasonable file size. I don’t want my hosting provider to get pissed off that the show is too large. In addition to that fact; the network wants as many people to listen to as many shows as possible. If it is possible that people are “turned off” by a large file size, then that is not for the benefit of the network and I would not do it. In that instance the file size should be smaller at the sacrifice of quality for the benefit of the network and I need to accept that.

As a listener I do not care what size a file is. I have a fast Internet connection and it really does not bother me. I like high quality podcasts but I listen to some that are not of a high quality as far as bit rate because the content is good. So is good quality a cover for shit content? If it is; it is not sustainable long term. So as a listener of podcasts I don’t search for podcasts based on audio quality or file size, and maybe I have just answered my question in part.

Having made these points I will say that some basic editing will improve quality out of sight. I have turned off podcasts because they have not bothered to do this basic editing. They were unlistenable and total shit and they should have thought the same! I wonder if some podcasters even listen to it after they have recorded it. So what do I mean by “basic editing?”

Basic editing in my opinion is:

  • Setting levels before you start, especially if you are recording Skype using a software application. This means setting your levels with enough “headroom” to get loud during a podcast so that you don’t “clip” the recording. And not so soft that you have to amplify it dramatically to get something to work with.
  • Don’t edit the podcast as an MP3, MP3 is a “lossy” format and gets worse and worse in quality every time you re-encode it or open it and save it.
  • Run a compressor on the audio to “smooth” the audio. That is take out the high’s and bring up the lows.
  • Run the compressor a few more times.
  • Normalise” the audio, basically set the zero level. Makes the podcast the same volume and means that the listener isn’t constantly turning their volume up and down.
  • You may need to “amplify” the whole audio after using the compressor and normalising the audio. You don’t want the listener running out of volume because it is too soft!
  • Any added or imported audio needs the above steps.

Believe it or not the above takes the least amount of time in my editing but makes the biggest difference. I do go a step further and edit the actual audio and take out the umms and errs and we always stuff things up and say well we will edit that out. The time is also in the transitions and the mixing of the imported audio, making it all work together (the best that I can). So maybe you can see why as a podcaster I want it to sound as good as I can, I put a lot of effort into both the pre and post production. But is that at the neglect of other issues? Is this basic and advanced editing enough to make it a “quality” podcast?

Please leave a comment and tell me what you think. Tell me if you are a listener or a podcaster. Podcasters, tell me what you encode your podcast at and why. Listeners please answer my questions for me. As I said at the start of this post I really do not know what the right answer is, that’s why I have posed lots of questions. It would be great to get some answers, although I am not sure there is one.

Global Geek Podcast Number 8 is Out Now!

Hey everybody, just letting you know that the latest podcast is out. Sebastian and I had an absolutely great time preparing for it and doing it. In addition to that we have worked on the audio and we think that it is much improved.

This week we did some things that made a big improvement to the audio, for a start Sebastian bought a mixer and a great microphone (check out the set-up here). I really need to put some photos up as well. The other thing is that I tweeked my audio to try to eliminate some of the background noise that I can not avoid. My computer sounds like a 747 taking off! But here in the tropics you need that as it gets pretty hot. So to do that I turned down the gain and had the microphone very close to my mouth. What do you know it worked. Don't know why I didn't do it before. But I think one of the reasons was that I was not that good with the levels and could not get it right. So I am glad that my skill has improved and I managed to get it so that it sounds good.

Sebastian's additions to his set up has made setting the levels for the show much easier. The reason being that using a mixer on line-in means that you over-ride Skype trying to adjust your audio setting as well as the fact that you can push the sound higher than you would be able to otherwise. The result is that we had a podcast in the raw format where the levels were pretty close. That ment that I did not have to "compress" it much or amplify it nearly as much. The other thing that we did before the show this week was we forwarded Skype on our routers, without going into it; that means better audio and no use of super nodes – rather a forced direct connection. It was an absolute pleasure to edit.

Sebastian was a bit disappointed with the result, he thought it would be better than it was. But as I said to him, look at how we are recording it; we are using Skype, then Hot Recorder to record it. Then after editing it I am encoding it as an mp3, inherently a lossy format and looses some quality in the encoding. Factoring all that in I think that comparatively we have a very good sound, especially if you get out there and have a listen to some podcasts out there that I don't think spend any time or effort on their audio.

Just a note for our regular listeners to Global Geek Podcast that there will not be a show released over next week end as Sebastian is going to South Hampton for inspiration. But we will hopefully be getting a show out mid week next week as the following week end I am working and it is a big effort to get anything out. So It will work out anyway.

Don't forget to check out the podcast if you have not already and don't forget that you can listen to it straight off this page just find the "PODCAST" button on the right and it stream off the site for you.

Podcast Titles: Get Catchy!

I just finished listening to From The Directors Chair number 17. Sebastian Interviewed Dave Jackson of The School of Podcasting. I really enjoyed the show and the interview was great.

Dave had some great hints and tips for new Podcasters and I am going to try to implement at least one of them, not that there were not others but I actually do the other ones he mentioned. The main thing that he mentioned was to choose the titles of your podcasts carefully. That is the title that will appear in iTunes, or in peoples RSS readers. The reason is that you need to grab peoples’ attention to in order for them want to take the time to listen to your podcast. Or for that matter the titles to your blog entries as well.

The other thing that was mentioned that I may as well mention here is the error of editing a podcast in mp3 format. As you may or may not know mp3 is a lossy format. Or in other words every time you open and save it it “looses” some of the quality. By the time you get round to publishing your podcast it has been edited and re-saved about twenty times and the quality is significantly reduced. This is especially evident if you publish in low bit rates. This is one error I did not make. I record and edit the whole vocal audio as a .wav file and add the songs last as they are downloaded as mp3’s and I can not change that as they come from the Pod Safe Music. So the addition of them last means minimal quality loss.

So it was a top show and there was heaps more than I have mentioned here so go and download it and listen for yourself.