ProComm Blog

Source-Connect For Voice Over

In 2005 Source Elements released a new product for sending and receiving audio via the Internet called Source-Connect. Since then, Source-Connect has led the way in this emerging technology in the voice over industry. Voice talent and engineers often inquire about ProComm’s experience with Source-Connect, so I thought it would be helpful to share some of the most frequently asked questions and answers from those conversations.

Since our preferred DAW (Nuendo) uses VST plugins, our early testing in 2009 was with Source-Connect VST plugin version 3.1. We found it to be somewhat unreliable and less supported than the RTAS version that Source Elements created for ProTools users. To be fair, some of the problems were due to the Internet itself, with broadband connections less prevalent than they are now. Still, the consistency of experience was less than the reliable ISDN connections we were accustomed to.

With the release of the Source-Connect 3.6 standalone application in 2011, Source Elements brought improvements that made the technology more attractive to the voice over professional – studio and talent alike. With the latest version, (currently version 3.7) users get the simplicity and stability of the standalone application and improved integration with DAWs through the new “Source-Connect Link” plug-in. The Link plug-in operates as a virtual patch cable between the DAW and the Source-Connect standalone application. The standalone application, in conjunction with the Source-Connect Link plug-in has made great strides in quality and consistency, however there are still a few issues that need to be considered.

Delay and Dropouts

ISDN connections have always had an inherent latency derived from the encoding/decoding method. Most talent and studios have learned to work around this delay in audio getting from point A to point B. But with Source-Connect, this delay is noticeably greater, even at the lowest buffer setting. This can make dialog voice overs between two talent, as well as general conversation, somewhat awkward.

Additionally, users still occasionally experience “drop-outs” in the audio signal caused by missing data packets. Some connections are better than others, but the potential for a rough session still remains. Source-Connect has addressed this issue with it’s Auto Restore and Auto Replace features (which we will discuss later) but without compatibility on both ends it is not a perfect solution.

How fast does your broadband connection need to be for successful Source-Connect sessions?

A high-bandwith connection is probably the most important requirement for successful Source-Connect sessions. Source Elements states that 300kbps for upload AND download is the minimum recommended connection speed. This download speed is easily achieved by nearly every broadband provider. However, be mindful that an ISP’s upload speed is usually much slower than its download speed. Consistent bandwidth is something else that should be considered. Some broadband technologies such as with cable Internet, can suffer a great deal from shared Internet traffic. During peak usage times you may be only getting a portion of your potential bandwidth.

Also, Source Connect recommends a solid ethernet connection as opposed to Wi-Fi.

Which brings us to…

Traveling with Source Connect

It’s easy to assume Source Connect can enable one to simply pack up a laptop and studio gear and record from any location on the road with a high-speed connection. While this is possible, there are a number of preparations you would need to make with your hotel or motel in advance of your stay.   Many hotels only offer WIFI connections and those are usually problematic for Source Connect.  Further, Source Connect operates best if the port it uses is properly “mapped” through a router – something you’d most likely have difficultly with at a hotel.   The Source-Elements website has Network Configuration documentation.  So while traveling and recording with Source Connect is doable, it is not as simple as “plug & play.”

What’s the difference between the Pro and Standard versions?

There are a good number of differences between the Pro and Standard versions of Source-Connect.  Three important differences are price, possible bit rate, and the Auto Restore/Replace capabilities.

There is a fairly large price difference between the two versions. At the time of this writing, the Pro version is approximately $850 more than the Standard version.

With the Pro version, the highest possible mono bit rate is 160kbps. The highest possible bit rate with the Standard version is 96kbps. As a comparison, the highest bit rate used on standard ISDN codecs is 128kbps. At first glance it seems that the Standard version cannot deliver the same quality as an ISDN codec since its maximum bit rate is 32kbps less. Source Elements, as well as other experts in the field, argue that the compression algorithm that Source-Connect uses (AAC) is a more efficient algorithm than what typical ISDN codecs use (MPEG Layer 2, MPEG Layer 3, G.722, etc.). Therefore, Source-Connect’s lower bit rates can equal the quality of higher bit rates via ISDN due to better compression algorithms.  The Source Elements website states, “It is generally considered that 96kbps AAC is equivalent to the 128kbps MPEG2 ISDN standard. Thus, Source-Connect Standard can transmit at ‘ISDN’ quality at the High quality setting, and Source-Connect Pro can transmit at ‘Higher than ISDN’ quality at 128kbps and higher” (Source Elements, para. 2).

Another important difference between the two versions is the Auto Restore/Replace capability.

The Pro version has the ability to fix any corrupt audio caused by “drop-outs” with the Auto Restore feature. The Pro version can even replace the AAC encoded audio with a full fidelity AIFF file after the session (but only when connected to another Pro version). These are important features for studios that are recording via Source-Connect. The Standard version cannot restore or replace corrupt audio. The Standard version can simply provide Restore (and not Replace) data to a Pro version. The Restore/Replace capabilities are of less importance to a voice talent since they are typically sending audio and not recording it.

What gear is needed for a voice talent to use Source-Connect?

The gear on the front end is the same as an ISDN studio (microphone, pre-amp, mixing console). But instead of plugging the output of your pre-amp or mixer into a codec, you connect to your computer interface, or Analog-to-Digital converter. (An Analog to Digital converter usually connects to your computer via USB or Firewire and translates audio into data that the computer and Source-Connect software can process.)  The Avid M-Box is a popular example of an audio interface. There are many other manufacturers as well, including Tascam, RME, Apogee, and Presonus.

A DAW such as Pro Tools or Nuendo can be used with Source-Connect as well, but it is not mandatory now that the stand alone version works well. However, it is still necessary to use a DAW with some of the older versions of Source-Connect.

For the sake of simplicity ProComm encourages voice talent to use the standalone application. A voice talent can hook up with the remote recording studio without having to worry about Pro Tools or another DAW. One less potential problem!

An iLok USB dongle is required to hold the licensing data and of course the Source-Connect software is required.

Should I sell my ISDN codec and go with Source-Connect only?

Source Connect could very well be the way of the future, but at the moment ISDN is still preferred. Early adopters of Source-Connect technology have been attracted to the cost savings, however at ProComm Voices we rely on the consistency of ISDN connections to uphold the service our clients expect. Currently, we see Source-Connect as an important studio asset in three ways:

  • Greater compatibility with remote voice-talent and studios
  • A back-up for your ISDN rig
  • Preparation for the future

Greater compatibility is an obvious asset and can equate to a potential increase in business for  some voice talent. We do have clients who regularly request to connect via Source-Connect and we are happy to accommodate those requests.

Having Source-Connect as a backup can potentially be an account saver for a voice talent or studio. When ISDN service is interrupted, repair time can vary from hours to days.  Most of the time when service interruption occurs a client will understand and reschedule. However, sometimes there are time constraints and a new talent must be cast or a new studio must be used to meet a client’s deadline. It is VERY important to have a back-up plan in this situation.

At this time ProComm still requires voice talent that we work with to have access to an ISDN studio. It is possible that in the near future we will include Source-Connect as suitable substitute for ISDN, but we’re not there yet. From our perspective, the consistency of client experience and reliability we have come to expect with ISDN connections outweighs the potential cost savings that might come with Source-Connect. We are glad to see the improvements that Source Elements has made in their product and we’ll be keeping tabs!