Christopher Lydon's Portable Web Studio for Blogradio Productions

Chris interviews Joe Trippi, Howard Dean's campaign manager

A Work in Progress - Research as of December 4, 2003      Tech support     Field Systems

Chris now has nearly 40 interviews online, and recently launched the BOPnews.com website that includes his latest interviews (they get cross posted to his Harvard blog).

We have stepped up from the Nady DJ-2M headsets with boom mics to a BeyerDynamic DT 290. Its boom mic is directional and noise cancelling, which reduces echo from the guest microphone. We will get a second DT 290 for the guest to wear in field-recording setups.

An XLR-to-mini adapter lets us plug the DT 290 headsets into a Minidisc mic input. A 2-mono to ministereo adapter lets two headset boom mics record on the dual tracks. These must be dynamic mics. Plug-in power mics cannot get the low voltage for their electret condenser mics through the 2-mono to ministereo adapter.

The Sony Minidisc has proved susceptible to AM radio interference. We decided to get the expensive HHB MDP-500 Portadisc recorder (despite lack of LP mode) for the campaign trips to Iowa and New Hampshire. This unit can use balanced XLR microphones. Jay Allison recommended the BeyerDynamic M-58 as the best omnidirectional handheld, so we will get one for field use.

On the digital audio workstation (DAW) front Chris has been very happy with SoundForge editing for his interviews, but we now need to edit in a music bed to create full-length shows and we will be learning ProTools.
We have an MBox with ProTools LE, and will probably acquire a Digi 002 Rack "Studio-in-a-box" (plus the DigiPack carrying case that holds the Digi 002 Rack and a laptop computer). The Digi 002 Rack uses high-speed Firewire for multitrack inputs to the laptop instead of USB (like the MBox and our Tascam US-122).

The Tascam US-122 audio/digital interface has worked like a charm. We use it in two configurations. In the studio, the Behringer mixer feeds the US-122 line inputs (1/4" phone plugs). The US-122 line output (stereo RCA to ministereo plug) goes to a Minidisc recorder for a backup, and the USB connection sends digital audio to the laptop.


For telephone interview recording, the Plantronics MX-10 telephone amplifier connects to the Minidisc recorder mic input. Recorder output (ministereo to two phone plugs) goes into the US-122 line inputs.

We are developing a universal media controller that allows a hyperlink to open whatever media player is already installed in the browser. It searches first for QuickTime, then Windows Media, then the Real Player (which continues to open nasty popup ads when the player is closed).

Our media controller eliminates all these ads, and produces a uniform interface for all media players. We are building a small snippet of Javascript code that will allow Lydon fan sites to have a BOP player listing - and linking - the latest interviews on their pages.

See more on these developments at BlogAudio.org.

October 6, 2003

We learned a lot at BloggerCon. An important step is to make a single audio hyperlink that lets users choose their Media Player. Then we can open a special window that avoids the advertising and popup messages that happen when the browser plays the mp3 file by itself.

Here's a test link - Slugger O'Toole Choose a media player

We bought a new Sony MiniDisc recorder, the MZ-N10, because it advertised headphones out and line out jacks. It turns out these are two functions for the same jack! On our older MZ-R30, the headphones jack is available for post-MiniDisc monitoring (while the line out feeds the computer input). The headphones volume level does not affect the recording line output. With the MZ-N10, we can feed line out to the computer, but no monitoring of the audio!

(We bought the new MD recorder to get LP recording modes, which Chris uses a lot.)

Output level from the JK Broadcast Host was low and had serious cross-talk from our host mic in the caller line. We have fallen back to the Plantronics MX-10 for telephone interviews.

We gave up on monitoring after recording with the MobilePre. We have not yet explored other more expensive USB audio interfaces like the Tascam US-122 ($269/ordered for $200 from Sweetwater) and Sonic Devices USBPre (about $600). See the discussion with M-Audio engineers at Tech support

We succeeded in placing free VoIP Internet calls using speakfreely.org software.

The mixer sends line level signals to the MiniDisc, which sends line level signals to the MobilePre. Headsets plug into the MiniPre for post-laptop (DAW) monitoring. The headphones jack is available on the MiniDisc for post-MiniDisc monitoring. The MiniDisc playback volume level does not affect the recording. The latest info is that a more modern laptop might not crash with the MobilePre drivers.


Design Objectives:

The Components:

Things we learned the hard way.

Problem: Multimedia headset microphones require plug-in power. Most sound cards provide it. MiniDisc recorders provide it. Mixers do not.

Solution: Andrea Technology APS-100 inline power supply (2 AA batteries).

Problem: Laptops have (monophonic) mic in only. We need stereo.

Solution: Griffin Technology iMic USB adapter provides line in and line out.

Problem: Tascam Pocketstudio 5 has one line-level and one mic-level input.

Solution: Always use a mixer and feed stereo line-level outputs to Tascam.

Problem: Mini 1/8" phone connectors are unreliable (noisy at times) for the microphones.

Solution: When we arrive at the final design, we should rewire them with XLR connectors.

Problem: Sound will not play through the laptop during recording. We want to monitor the sound post the last recording stage. Sound plays through while recording on the 2GHz desktop/tower (our PC audio/video editor).

Solution: The tower has an Osprey 200 sound card. We need a better USB audio interface, and ordered the Creative Blaster and M-Audio MobilePre units today (7/17).

Problem: Setting manual recording in MiniDisc is not easy. (Automatic gain turns up the background noise in periods of silence.)

Solution: Print out relevant steps from online Sony manuals. Add them to the case.






Problem: Settings for Plantronics are hard, and different for skyBuilders Merlin phone and the Berkman phone?

Solution: Best setting for compatibility switch is 2 for Merlin. Press down left-hand switch to record (right-hand switch stays up).


Problem: No sound going into MiniDisc from Plantronics MX10, though we hear it clearly in the headphones.

Solution: The MinDIN cable connector on MX10 was a little loose. Pushed it in hard and sound was restored.

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