The best audio is the one you don’t have to improve. Some simple steps you can perform in advance to maximize quality:

• Use quality equipment. Here are some articles about the equipment great-sounding podcasters use. You don’t have to spend a lot of money, but definitely stay away from the built-in laptop microphone
• Eliminate ambient noise as much as possible (close windows, draw the blinds, stop other electronic equipment in the room, etc)
• Record each person on a separate channel – if possible on a computer local to them (avoid recording trough Skype, GoToMeeting or other VoIP solutions)
• Try keeping the recording volume for each microphone at the optimal level – not too low, but also avoiding clipping

After you have the audio recording there is still a lot you can do, but it is preferable to start out with the best source material. For the example below I’ll be using the raw recordings from a recent SE Radio podcast:

The situation with this recording is as follows:

• There are separate audio tracks for the interviewer and interviewee (good)
• There is background noise on the tracks (easily correctable)
• Both persons were picked up by both microphones (correctable)
• The interviewer has some clipping (partially correctable – luckily it’s not the interviewee who has clipping)

The steps to improve the quality of this recording are as follows:

First, install the Noise Gate plugin for Audacity, since it requires program restart (under Windows you have to copy the downloaded noisegate.ny to C:Program Files (x86)Audacity 1.3 Beta (Unicode)Plug-Ins or to a similar location, under Linux you have to place it in /usr/share/audacity). After copying the file you have to close and restart Audacity. To verify that the plugin was properly installed check in the Effect menu – you should see an entry title “Noise gate”.

Now that we have Audacity all set up and the plugin installed, first split the stereo track into mono tracks, since they don’t actually represent left-right channels but rather two speakers which will be mixed together at the end. For this click on the arrow after the filename in the track and select “Split Stereo to Mono”. Sidenote: some people will prefer to mix different speakers in podcasts with different panning (that is to the left or to the right). I would advise against this: it is distracting if you are doing something else while listening to the podcast (like walking / jogging / riding a bike / etc). It can also backfire if for some reason the listening device is missing one of the channels (the “damaged headphone” scenario).

The first thing will be to remove the constant background noise (like AC hum for example). To do this zoom in (Ctrl + 1) and look for low volume zones. Select those zones and go to Effects –> Noise Removal –> Get Noise Profile. Now select a zone where the noise is mixed with speech and test out the settings (Effect –> Noise Removal –> Ok). After the test you can use Undo (Ctrl + Z) to roll back the changes. You should watch for the noise being removed but also the natural sound of the voice being preserved (too aggressive of a noise removal can lead to a “robot voice” effect). If you are satisfied, you can go ahead and apply it to the entire track. Also, since the noise source might change during the recording, you should at least do a quick scroll to check for other low-volume zones which can be a sign of noise. If you find noise from other sources, you can use the same steps to remove it.

Now that you have removed the noise, the next step would be to remove the voices from the channels they don’t belong to. This is where we’ll be using the Noise Gate plugin: since there is a considerable level difference between the wanted audio and the unwanted audio on each channel, we can just declare everything below a certain volume “noise” and use the plugin to silence it. A couple of tips:

• This needs to be done separately for each channel, since the cutoff volume will be different
• You can use the “Analyse Noise Level” function of the plugin to gauge the approximate level of the cutoff volume – this will only give you an estimate and you will have to play around with the settings a little bit to find the optimal volume
• Use a “Level reduction” of –100 dB to completely filter out the sound and an “Attack/Decay” of 1000 milliseconds to avoid false positives
• As with all the steps, you can experiment on a smaller portion of the audio file (since it is much quicker) to fine tune the settings by repeatedly applying the effect with different parameters and undoing (Ctrl+Z) the result after evaluation. When the parameters seem right, just select the entire track and press Ctrl+R (Repeat last effect)

After we’ve finished with both tracks, we have a better situation:

Now we will fix the clipping as much as possible (a perfect fix isn’t possible since clipping means that information got lost and all the plugins can do is to “guess” what the information might have looked like). First we reduce the aplification of the second track (the one which contains the clipping) by 10 dB as the Clip Fix plugin suggests (Effect –> Aplify –> –10 dB) after which we use the Clip Fix plugin. Unfortunately this plugin runs very slowly if we would to apply it to the entire track at once. Fortunately we have a reasonable workaround: select portions of the track and apply the plugin to them individually. After the first application you can use the “Repeat last effect” shortcut (Ctrl+R) to speed up the operation. Sidenote: it is a good habit to use the “Find Zero Crossing” function whenever you do a selection (the shortcut is Z – so whenever you select a portion, just press Z afterwards). This eliminates some weird artifacts when cutting / pasting / silencing part of the audio and it might even help when applying different effects. The fixed audio looks like this:

Now, that all the cleanup steps have been performed, there is one last step which is as important as the cleanup: maximizing the audible volume without introducing clipping. This is very important because all devices can reduce volume but few of them can increase it (some exceptions being: the Linux audio stack and VLC). The easiest way to do this is by using the Levelator (note: while the Levelator is free – as in beer – and does not restrict what you can do with the output, it is not free as in freedom if this is a consideration for you).

To do this, export the audio to WAV (make sure that all tracks are unmuted during export) and run the Levelator on it. The end result will look like the following:

Of course the Levelator isn’t magic pixie dust either, so here are a couple of things to check after it has been run:

• Did it amplify some residual noise which wasn’t available in the initial audio? (if so, you should remove it using the Noise Removal plugin)
• Did it miss segments? (it is rare, but it happens – those segments need to be amplified manually)
• It results in “weird” sounding audio if the recording has been preprocessed by a dynamic compressor – for example GoToMeeting has an option to improve sound quality which uses dynamic compression and thus makes the recording unsuitable for the use with Levelator

That’s it for this rather long article. Don’t be discouraged by the length of the article: after going over the steps a couple of times, it shouldn’t take longer than 15 minutes to process a 2 hour interview (excluding the cutting / pasting / moving parts around) and you will gain listeners because of the higher production value.

A final note on the output formats: while during processing you should always use lossless formats, the final output format I recommend is: MP3 at 64 kbps CBR, Joint Stereo, 22050 MHz sampling rate. I found that this is the best balance between quality, file size and compatibility with the most playback devices out there.

The bad news? They stopped it in 2008. The good news? A documentary titled “Don’t listen alone!” – a great title if I may say so – about it just came out! So watch it below (sorry for splitting it up into 10 minute segments, but YouTube limits you to this):

Or go over to Jono’s site and watch it from blip.tv (my problem with blip.tv is that their delivery method seems to be much less bandwidth friendly – I’ve got constant “buffering” even on connections where YouTube HQ clips play fine) or download it from archive.org. You can also read up on how the documentary was created (on Linux!) here.

Finally, if you still miss their voices (as I do), head over to ShotOfJaq or to FLOSS weekly and you will be pleasantly surprised!

PS. Offtopic rant: I’m all for open formats and such, but when – after days of searching! – I can’t find a tool which supports the OGV container (or the Theora codec for that matter) properly, I’m tempted to give up on them! On the AVI/XVID/h264 side there is Avidemux for example… Finally I had to re-encode the whole video into AVI/XVID just be able to chomp it into 10 minute segments.

PS: If you are interested in software development / design, this is definitely a podcast you should give a listen.

Picture taken from Manuel_Marin’s photostream with permission.

• Vote for your favorite podcast on the Podcast Awards website. Votes are open until November the 30th and you can vote once per day (after you vote, you can an email with a link, which you must click on to validate your vote – this is to reduce the number of “fake” votes). If you are unsure for which podcast to vote, here are some suggestions: in the “Best Video Podcast” category I would recommend Buzz out loud – it is a very good (informative and fun) daily tech-news podcast. In the “Business” category I would recommend Career Tools– it (together with its sister podcast Manager Tools) is a great resource. In the Technology category I would recommend FLOSS Weekly – it is a superb podcast for all people interested in free / libre / open-source software. And it would be a great gift for them for the 100th episode which is quickly approaching. And besides – TWIT already won a couple of times :-). So go ahead my minions readers, fly like the wind and vote!
• And here is a second poll related to Perl IDE’s: What other technologies, languages, templating systems are you using besides Perl?

After you have done your deed :-D, you can relax with two fun flash games: Little Wheel, a fun old-school point-and-click adventure game with very nice artwork (including an interesting soundtrack). Or play nine-balls. Let the lightning be with you!

Little Wheel

Billiard Blitz 3 – Nine Ball

One characteristic of the interview style of the author which I find slightly irritating is the heavy editing. Particularly he regularly introduces long-ish comments relating his opinion about the given issue. I would prefer that he rather do it live, so that the guest has a chance to react to it. But this is just a personal opinion.

My recommendation would be: the podcast is professionally produced, so give it a listen, especially if you are interested in the MS/.NET universe. Even if you are not, you might find an occasional episode which scratches your itch and you can just disregards the episodes which don’t interest you.

Picture taken from nikkicookiebaker’s photostream with permission.

Their episodes are high quality, and even if some (read: me :-)) might complain that there are to many  audio/video effects, it is just a matter of taste. There are only ~8 episodes out there, so you can go back and watch them all :-). Some interesting episodes I really liked are the interview with Jon "Maddog" Hall and Revenge Of Cinelerra.

You can find a complete list of episodes in different formats here. This also includes streaming Vimeo, so you can watch it in your browser, without having to download it.

Disclaimer: the review is a personal opinion and I do not have any relationship (business or otherwise) with the authors of the show (other than the occasional comments on their blog).

A minor negative aspect is the complexity of sending feedback: to leave a comment on their blog, you must first register, but I never got the confirmation mail. They also have an email address (and a voicemail number) which is mentioned at the end of each blogpost (just search for “email” in their show notes).

Also, currently it seems that their blog has been modified by an unauthorized third party, which inserted links in the feed to a site (which again, is an innocent, modified site) which redirects to a pharmaceutical site. I notified both parties and hopefully this will be fixed shortly.

Below you can listen to a (very funny) promo Leo Laporte did for them (if you can’t see the embedded player, download the mp3 here):

In conclusion – if you are interested in weather, give it a listen.

Picture taken from Katya Trischuk’s photostream with permission.

Here are the albums for your enjoyment (if you are reading this from an online reader and not seeing it, you might need to come to my blog, because some RSS readers block third party Javascript / Flash for security reasons):

• The IT Security Pubcast – a South African podcast with security professionals who have real, hands-on experience with the physical aspects of security. Being a more electronic-only guy, this is a very interesting source for me. Also, the sound quality is very good. If you are interested in security, be sure to listen to it, it’s well worth your time.
• The Reality Check podcast. From the host of the Silver Bullet podcast. It is described as:
  

  The Reality Check Podcast with Gary McGraw will focus on software security practitioners and practical software security. We’ll interview people involved in running large-scale software security initiatives.

My colleagues are about the same age as me and have or are working towards a university degree in the field of informatics / computer science. They are a group I feel part of.

Still, awareness about new media is pretty low even in this group. Almost all of them have heard about blogs, however (as far as I know) I’m the only one who actually blogs. A few use an RSS reader to follow some blogs, but most of them still manually check news sites. Almost nobody (including my boss, who is a very smart and very technical fellow – for example he runs Slackware not Ubuntu :-P) has heard about podcasts.

My conclusion is: our new media microcosm is much smaller than we thought. On the bright side: there is more room to grow than we thought possible, including a large body of technically savvy people who know what MP3 is and what devices they can use to listen to it.