by Bob Kirschner
In my previous post Remote Audio Voice Recording Part 2 I took a look at the top two platforms for remote voiceover connections in the audio post industry: ISDN and Source Connect. In today’s post I will do a similar comparison on what I’m referring to as my ‘Group 2’ platforms: Source Element’s Source Connect Now, ipDTL and Session Link Pro.
As a reminder, these are the remote technologies I’m writing about, and how I am grouping them for comparison purposes:
Group 1 - Highest Audio Quality
• ISDN
• Source Connect
Group 2 - Very Good Quality (Google OPUS codec)
• Source Connect Now
• ipDTL
• Session Link Pro
Group 3 - Acceptable Quality (standard audio over IP)
• Skype
• Uberconference
The three ‘Group 2’ platforms have many things in common, but the most important point is that these are all based on the open-source codec developed by Google, the Google Opus codec. Opus supports a wide range of bit rates and sample rates, making it very flexible to implement. And the audio quality of its compression is very good. So, as far as audio quality is concerned, these three platforms can be considered practically identical (assuming the connection settings are the same).
What makes these technologies different? The major differences are price and features. I’ll start with an overview for each platform:
Source Connect Now is a free platform with much fewer features than the others. It connects two parties, and lets the user do in-app recording. A registered Source Connect user can invite anyone else to connect. Easy and straightforward.
ipDTL is subscription-based, and the basic subscription cost is $80 annually for an individual. Costs increase depending on the features you need, and there are many amazing features available! ipDTL supports multiple parties (up to 5 simultaneous connections), telephone number dialing, ISDN compatibility, video connections, and in-app audio mixing and recording. An all-in subscription is in the neighborhood of $500-$600 annually. Their custom browser provides and excellent user interface. And they have an excellent FaceBook group for support from ipDTL and users. One down side to note - registered users can only invite other registered (paid) users unless your subscription plan includes guest invitations, which is an additional cost.
Session Link Pro is also subscription-based. This platform is widely used in Europe but is not used much in the U.S. Cost annually is 200 Euros (about $228 USD). They have a Recording package which connects up to three parties and includes features like in-app recording and MIDI support (a benefit for remote musical collaborations). They also have a separate Conferencing package which connects up to four parties but at a lower bit rate. Video is supported in both packages. The user interface is excellent.
Now let’s take a look at some specifics to see how these platforms compare:
App/Browser Support
The Google Opus codec is supported by a few different browsers. But to use these remote connection platforms Google Chrome is required for full support. ipDTL has developed their own custom browser (free for Mac and Windows) which is recommended for their platform. Generally, desktop and laptops are fully supported, but tablets and mobile devices are not.
Audio Quality: Bit Rate & Sample Rate
All platforms support 48K Sample Rate. So It’s the Bit Rate that determines the overall quality of the connection. All platforms support multiple bit rates, and you should use the maximum available bit rate unless you don’t have the fastest internet speed, in which case you can connect with a lower bit rate. So what are the maximum bit rates?
Source Connect Now - 256 kbps per channel in mono and stereo
ipDTL - 260 kbps in mono, 320 kbps in stereo (which means 160 kbps per channel in stereo)
Session Link Pro - 256 kbps in mono, 320 kbps in stereo (which means 160 kbps per channel in stereo)
How Many Parties Can Connect?
While Source Connect Now allows two parties to connect (user and one guest), Session Link Pro in Dual Mono provide connections for the user and two guests. But ipDTL stands out here - with their Gold subscription the registered user can connect with four guests. This allows for a scenario where a studio or producer/engineer can host a podcast or interview recording, and send invitations out to four guests to join. Additionally (and incredibly), the producer/engineer will have access to the isolated audio from each connected guest. The isolated tracks can be combined later for mixing and post production. Session Link Pro also offers this same access to isolated audio for their guests.
Guest Invitations
Connecting with ‘guests’ (non-registered people) who you’d like to record is a common thing to do. Both Source Connect Now and Session Link Pro allow connections to guests. But as I mentioned above, ipDTL doesn’t allow guest invitations unless you pay more for this service, called ‘Send A Link’. You can connect with any other paid ipDTL user no problem, but if you want to connect with a guest you’ll need to double your subscription cost: If you have the $80 subscription (Bronze) it will cost you $80 additional to ‘Send A Link’.
So in summary, I will say without a doubt that ipDTL is the most feature-rich and flexible platform of this group. From a studio or producer point of view, allowing you to record a host and four guests with isolated audio is really incredible. ipDTL covers pretty much any need you may have, including adding a dial-out telephone feature, and ISDN compatibility. Their support is excellent as well. For someone with a career in audio post, ipDTL’s service is well worth the cost. For someone just starting out in remote session work, Source Connect Now is a very good platform that is free and easy to use. Session Link Pro, while not having much presence in the U.S., seems to have some features more tailored to musicians and group conferencing. But the cost is perhaps a bit higher than a similar level of service at ipDTL.
That’s a wrap for my ‘Group 2’ comparison. In my next post I’ll discuss voiceover recording using consumer conference connection platforms like Skype. Stay tuned!
