When playing back software, the signal chain looks like the diagram above.

Control Points

The playback system can be controlled via three control points. The touchscreen and mouse/keyboard are self-explanatory. The Android tablet has BubbleUPNP and mConnect installed on it – both of these cast audio to JRiver’s DLNA input, and both have Tidal and Qobuz integration. Both of them are also able to browse my audio library stored on the local HDD.

A major annoyance that I have is that ALL streaming services with the exception of Spotify are unable to cast audio from the tablet to their own app running in Windows. This prevents you from using the tablet as a remote control for browsing and playing back music. Tidal and Qobuz can be cast using software like BubbleUPNP and mConnect, but these apps do not support any other streaming service.

The streaming service that I would really like to use is Idagio, given their focus on classical music. However, there is no way to control Idagio via any other method except keyboard and mouse. It is possible to use screen share (i.e. mirror your Windows PC on your Android tablet), but in practice it is extremely laggy and it is very easy to push the wrong button given how fat your finger is compared to a mouse.

Playback Software

I use JRiver as my playback software and convolver.

These are the advantages of JRiver over Roon, and why it works best for me:

  • It is inexpensive – a Windows license costs USD$70 and you can use it for up to 10 activations. Roon costs USD$830
  • Both JRiver and Roon have built-in convolution engines. Other players require purchase of a third party convolver.
  • Both JRiver and Roon have remote control software.
  • JRiver is able to host VST’s. Roon does not. Some other players (e.g. Foobar) can host VST’s via plugins.
  • JRiver has an ISO226 volume control. Roon does not.
  • The DSP engine in JRiver is really powerful and configurable.
  • JRiver can have multiple configurations called Zones, and you can quickly switch between them. For example, you could set up a “Zone” for music listening with long FIR filters, and a second “Zone” for movies and videos with IIR filters – the advantage being lower latency and less lip sync issues.

The main disadvantage of JRiver as a convolver is that it lacks an ABX comparator. Up till Media Center 30, switching convolution filters required a restart of JRiver making it difficult to compare different filters. This is why I bought Acourate Convolver. You can load up to 27 different configurations in Acourate Convolver and immediately switch between them with very slight latency.

Convolver

A convolver takes the correction filters generated by Acourate and mixes it with the 2 channel audio input from the source. It then outputs 8 channels of digital signal to the Merging ASIO driver, which sends the signal to the NADAC.

This is a simple description of how a convolver works: I have 8 correction filters representing 8 channels on my system – left and right subwoofer, woofer, horn, and tweeter. The convolver takes the left channel and mixes it with all 8 filters.

In addition to convolving filters with music, these programs might have a number of other features. For example, they might be able to delay individual channels relative to each other, or adjust volume of each channel independently. They may have a number of filter banks with different configurations loaded into each, allowing you to switch between banks to compare what different filters sound like. For Windows, an important feature is how the convolver receives input from your player – some do it via ASIO (which means your player software needs to support ASIO output), and some do it via WDM. If it lacks this feature, then you will need third party software such as VB-Cable to route signal from your player to your convolver.

Some convolvers, like AcourateConvolver, have additional built-in DSP options. AcourateFLOW increases crosstalk between left and right channels, simulating vinyl playback which has higher crosstalk than digital. It also has a virtual center channel (“Trinaural mode”) which increases the stability of the center image. Other convolvers, like HQPlayer (though strictly not only a convolver) is capable of convolving in DSD without having to convert the signal to PCM, although it does this with a heavy CPU load.

This is a comparison of various convolution engines on the market: