4

I very rarely provide audio for podcasts.

I have worked on widgets, games, bonus scenes and BTS clips...but, not long amounts of continuos streaming dialog. When I make clips into files for email and iphone approval, I like .m4v with H.264 video, and AAC-LC audio at 160 Kbps, 48kHz, stereo. I boost a little low end and 2-4K and normalize to -6dB digital. (BTW Let me now if you do something differently for this situation too.)

There must be streaming secrets for Podcasts specifically. What are your preferred compression, level, and EQ practices for podcasts to retain quality while optimizing them for streaming online playback? Some just sound atrocious, while others are quite nice.

4

As someone who has produced thousands of hours of podcasts and listened to just as many, I find that there is a lot of ways to skin the cat. First and foremost is the recording needs to be good. The biggest issue with podcast is that 98% of them are recorded using internal microphones on computers or headsets used for gaming and skype, etc.

Now on to your question. Some people like the highly compressed sound of NPR and other American radio stations, this requires a fair bit of outboard hardware. Leo Laport of TWIT fame has a good write up somewhere of his hardware. Personally I find it crushes the life out of the audio. Australian radio is more liberal in allowing dynamic range and yet having a smooth compression across the board. This is really something you want to experiment with to find what you like. My personal preference is to use a soft-knee 3:1 compression around -20db and add a hard limiter at -3 db for spikes, generally very loud laughter. I match my levels around -6 db when recording giving head room but keeping it fairly consistant.

Please note I am generally live mixing this with up to 6 people on mic at once including myself. Check out the results (but NSFW warning here for swearing and stupidity at times) at http://www.coolshite.net

So in summary.

  1. Best recording possible
  2. Play with you compression till you find the right dynamic for you and your audience.
  3. Remember it isn't a hard rock record, so it doesn't need to be a wall of sound.
  4. Listen to shows that do it well and see how they are doing it (including broadcast radio).

Hope the helps.

  • Thanks so much. Wondering....what file format do you normally upload? – Karol Urban Jul 4 '11 at 23:42
  • I always upload mp3 128k as it works for all players, including online flash. Never use variable bitrate and anything over 128 is a waste unless you are pushing something out that really needs the fidelity (most people won't notice). Also remember that storage and bandwidth costs of people downloading the shows. – Bruce Jul 5 '11 at 0:01
  • I also archive all my shows as lossless audio for historical sake, but that is just me. – Bruce Jul 5 '11 at 0:02
3

I work on a podcast (only 7-odd episodes in, though I have a background in online/radio for an int'l broadcaster) which marries non/fiction with predominantly electronic musical composition and what with my lack of expertise passes for sound design. It's called Paper Radio [paperradio.net]. The sound is an important part of the storytelling, so my mixing priorities are fairly balanced between voice and 'sound'.

I use a combination of Waves Renaissance Vox and Compressor on voice and instrument submix busses respectively. I also sub-group certain source groups (at the moment I've separated SFX, raw interviews, studio voiceover, synth tracks, rhythm tracks, guitar and cassette tapes) and compress or limit them depending on the material. And I use L1 or L2 on the master channel.

But there aren't any particular ratios or thresholds I apply regularly. I change my settings every time according to what's there. The biggest challenge for podcasts, to my ears, is headphones or speakers.

It's fine if you're mixing voice program only, or voice with backing music — you can afford to lose the music a little. But if you want a clear and even balance of voice and music/sound, at roughly equal volume, I've found that's something difficult to achieve for listeners on both headphones (especially crappy iPod earbuds) and speakers.

Speakers tend to lose the music while headphones can make it so loud that it gets in the way of the voice.

I agree with @Bruce in that excess compression really can destroy the dynamics and texture of a piece; it can also make it extremely annoying to listen to. Unfortunately I have found that if I don't compress/limit material enough, people complain that our podcasts aren't properly audible on the peak hour train.

It's a bit of a conundrum and not one I can readily answer, although most of you would probably suggest the right level of dynamic compression will balance things out. My heart really favours a less compressed sound, but it doesn't seem to be easy to maintain peoples' attention with a big dynamic range, especially with similar podcasts being more of that overcompressed broadcast style.

Anyway, sorry for this rambling answer (I haven't slept much lately). In terms of file compression, I publish either 160kbps or 192kbps 44.1k/16-bit/stereo mp3s. As someone above pointed out, Flash can only stream certain sample rates (I think it's 11/22/44 - no 32/48k). The file sizes are a bit bigger but it's rich content that I think justifies the detail. If I were using voice only I'd definitely consider 128kbps and possibly even mono.

The only other thing I'd suggest is to consider who/what/where your audience are and what suits them. There isn't any real reason aside from slight added convenience why you wouldn't publish a great voice recording in 192kbps mp3 for a Scandinavian middle-class audience, but if you were podcasting primarily to an audience in the South Pacific, file size would be super important and you'd want to consider even mono 56kbps for some material, even with music. I believe in user-centred approaches for all situations where information must be communicated. A lot of work I've produced (both sound and otherwise) has been for a Pacific Islands audience, and the bandwidth and tech they can access has been instructive to say the least.

Again, apologies for my rant. I hope it helps in some way.

  • Paper Radio is AWESOME! – Kurt Human Jul 8 '11 at 10:51
1

I don't know any secrets, but I can share what I do for a comedy show.

The file I give to upload is an MP3 at 320kbits, 48kHz, stereo. It doesn't lag during playback on Podomatic, and a show thats just over an hour takes just over a minute to download from itunes.

As for processing. I don't do to much EQ, maybe a roll off around 100k with a gradual slope. When I used wireless handhelds to record I would get alot of mic handleing noise, so editing and EQ was necessary. I've since switched to using SM58's and now record off the theatre's mixing board. That has minimized handling noise immensely. Also the board supplies any EQing I need for each individual.

Unfortunatly the theatre has no compressors, so I do add compression on each individual in post and the settings vary of course. But on average, I'm compressing around -30db with a ratio just over 2:1.

Lastly I use Ozone4's loudness maximizer. I've tweeked it to where my final mix when played back in itunes is around the same level of most of my music when it plays back. The goal being the podcast isnt way quiter then other things I listen too. However I've noticed it's slightly louder then some of the other podcasts I have, so I'll probably start backing off a bit.

0

my processing chain for The Home Recording Show is typically (as of last 5 episodes or so): RX Denoiser, ReaGate, Waves CLA-3A

the 3 dialog tracks go into a bus with Wavearts Final plug with a ceiling of 6dB.

The master has T-RackS3 Clipper

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