Could ip DTL become ISDN’s replacement?

by | General

In: Quality’s  ip DTL could very well rival ISDN service for recording voiceover in the future. At least I am quite hopeful after testing out this nearly free codec, produced by UK company In:Quality.  The Company’s  ip DTL won the 2013 Technical Innovation Award by the Radio Academy.

I first learned of this only three weeks ago in UK voice artist Rachel Naylor’s blog.
As a result, Ip DTL has been the buzz for the past few weeks in a number of VoiceOver groups across the web.

I purchased the annual subscription (Around $125) for ip DTL – VO  . The VO account connects at the higher bitrate of 128kbit/s and is therefore aimed at voiceover, production houses and audio professionals who require real-time high-quality speech communication.

All that’s needed is a Windows laptop, MacBook Pro , a usb interface to your microphone, and the Google Chrome browser.  In the studio, for recording, you’ll need a mixer with USB interface.

Fellow voice over actor, skilled audio engineer, and author of Sound for VO,  Dan Friedman who is no stranger to ISDN, has been collaborating with me in researching and Testing ip DTL  for the viability  of use for voiceover recording sessions from a web browser.

After some trial and error and switching from recording through his MacBook sound-card, (the initial recording exhibited some hiss and downsampling) .

ip DTL Test 1

But we  found the cleanest vo signal  came about when Dan recorded this audio of me while switching to a four channel Yamaha USB mixer connected to his Apollo interface and then into his DAW.


ip DTL Test 2

We were both impressed at the improved vo quality using the second recording configuration.

Check out this video tutorial put together by Kevin at In:Quality on how to get started with ip DTL.

It should be noted that I also received a newsletter from Digifon’s  Dave Immer about ISDN restoration in the Northeastern US , (after it was discontinued in May 2013) and will be available again via Verizon on a Centrex overlay.

And the same day a notice arrived from Source Elements , creators of web codec, Source Connect has recently come out with enhanced audio and video services- all available online for recording and voiceover professionals.

  • Source-Connect Pro X (Extended/Surround)
  • Source-Talkback AAX with Auto mode and 2Q remote controller
  • Source-Nexus audio application driver with AAX support

Bottom line thinking: if movies can downstream over the web while maintaining all video data and sound quality intact, I believe that if both sides ( voice over actor and producer) have a wide bandwidth that an ip codec can handle the equivalent data and voice attributes of ISDN and other online services for a fraction of the cost. It’s going to happen, soon.


    • Hi Nicola,
      Yes, a good idea. Later that week during an ISDN session, there were a number of line chirps and drop outs. The engineer also knew about ip DTL and we finished the session without further glitches. So it’s been used in a real working situation and ip DTL performed very well.
      Happy New Year!

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