Technical details re: VST Connect - performer's talkback mic, bit rates

If you need talkback mic for a performer recording an instrument direct, do they need to connect a mic to their audio interface, or can VST Connect Performer access a mic built into the laptop or in an attached external web cam?

In my tests today with a friend running VST Connect Performer on a MacBook Pro, setting the macOS Sound preference to use the audio interface for I/O apparently meant that the laptop’s built-in mic was no longer usable for his talkback. Is there a work-around I’m not aware of?

He played electric bass and didn’t have a separate mic and mic stand handy, so we had to talk via cell phone. It would be great if VST Connect Performer could access the built-in mic (or video camera mic) behind the scenes and not have to depend on the user-facing OS options. That’s certainly possible, as Rogue Amoeba’s application “Loopback” has shown.


The following questions are regarding the spec on the VST Connect product page which says the highest upstream bit rate for SE is 320 kbps and lossless for Pro.

  1. Am I correct that this means that in SE, the performer receives a cue mix at 320 kbps maximum? And in Pro, the Performer can get a lossless cue mix?

  2. When I listen to that mix via the Control Room in Cubase, am I hearing it before compression? (It sounds that way…)

  3. Does this mean that with VST Connect SE, the resolution of the stream coming in from the performer is 320 kbps maximum? So I’m recording a compressed stream at the Project’s sample rate/bit depth (in my case, 96/24)?

  4. How much greater demand on the connection speed does lossless compression make?


a) I don’t know that about MacOS, but afaik choice of input devices is just as with other DAWs like Cubase.

b) 1.: yes, 2. no, that wouldn’t make any sense, 3: yes, 4. depends on both signal and rate/bit depth. If you play a whole stereo mix at maximum level, that will require more bandwidth (probably around 1.5 to 2 MBit/sec) than a single mono vocal channel with 6-12 dB headroom. Nowadays internet connections should well be able to provide that easily. Note we talk about upstream (not download), and also speed (as you mentioned it) is usually of no concern, while network quality (packet loss) is big time.

But lossless is only available with the PRO version, which also features recording the signal at full bandwidth on the Performer end and transfer later with automatic insertion into the Cubase project.

Thanks, musi!

I’m not clear on your answer to #2, so let me ask it another way: Am I hearing the Performer cue mix pre or post compression?


Suppose I want to record six mono channels with PRO. My standard practice when setting input levels is to have peaks at -12 dBFS.

In order for the performer to send me lossless streams for monitoring, what upstream speed should they have?

My upstream speed is around 6 MBit/sec. If I understand you correctly, that should be more than enough for sending a stereo mix (not maxed out!) and my talkback mic. Right?

As for packet loss, I just learned I can check it with the Network Utility app included in macOS. Can I get the address or URL of the server used for VST Connect so I can test for packet loss via my ISP? Or is that not shared publicly?

Thanks again!

As said that wouldn’t make sense. The stereo stream is beeing compressed on the Performer end and sent to studio (and vice versa). So no, you don’t hear the uncompressed signal because if it could be transmitted uncompressed, it wouldn’t have to be compressed in the first place :slight_smile:
The reason why you doubt that is because for instance a vocal performance at 320 kBit can hardly be distinguished from the uncompressed version.

The audio stream from Performer to Studio is always stereo. For that stereo stream, signals are mixed within the recording section above the Performer monitor faders.
After recording you apply the “Get HD files” function which will transfer all recorded takes and create separate tracks (in your case, six) in Cubase where those takes are put. Thus, the max upstream rate for audio would be losslessly encoded stereo, see other mail.

Correct. stream from Studio to Performer is also always stereo, essentially the Cubase Control Room cue mix which also includes TB.

Usually the connection is peer-to-peer. When you connect, a connection server is involved but after connection, that isn’t active anymore except for disconnect. Thus, the “URL” is usually the IP address of your partner. In some cases relay servers are involved when router and firewall problems prevent a direct connection, but those practically never fail to receive and send packets.

With the new version comes a diagnose view which shows packet losses and audio glitches. Meanwhile connection quality has improved significantly, most of the times there are no losses except when using shaky wireless (WiFi, LTE etc) connections.

Hope that helps.

Thanks very much for all this! Very clear, very helpful.

Is there an ETA for the new version?

Meanwhile, it sounds safe to assume that if they have a wired connection, it’s probably fine. I’d only need to test for packet loss if they had a wireless connection, or if we have problems.

I’ll try the demo of Pro next.