When using the Liquid Channel the incoming analogue signal is converted to the digital domain at one of 6 sample rates. When we sampled the impulse responses of the original gear it was done at 44.1kHz and at 96KHz. For a system running at a different sample rate to these, the emulations need to be created from impulse responses sampled at the same rate. Instead of sampling the gear again at all other sample rates (which is time-consuming) we simply sample rate converted the responses already taken. The 44.1 responses were converted to 48KHz for using the Liquid Channel at 48KHz. The 96KHz responses were also converted to 88.2, 176.4 and 192kHz when running sessions at those sample rates. Note the sample rate of the digital audio signal is not converted in the Liquid Channel at any point.
When running at 44.1 - 96kHz, each sample is processed by a different dynamic response but at the two higher sample rates there is one impulse response value used to process every two consecutive samples. At 192KHz two consecutive samples could have different values and after the DSP stage they will still have different values but the same mathematical calculation will have been used to process them both.
We did not sample the original units at 192kHz to give true 192KHz processing since it presents no sonic advantage, requires increased processing power and is also more time-consuming.
So if the original gear was sampled at 96kHz and then the responses sample rate converted up to 192KHz, is there any advantage in running at 192kHz?
The two situations to consider are going analogue into the Liquid Channel and out digital, and going digital both in and out. With the first situation, there will be an improvement in signal quality when you switch from 96 to 192KHz because owing to the nature of conversion, the digital signal will be more true to the original analogue waveform. Also, a shallower anti-aliasing filter can be used to even out the ripple in HF response which arises from using a sharper anti-aliasing filter.
With the second situation, there is no sonic advantage since the Liquid Channel only processes the signal at 96KHz so will apply exactly the same processing to a signal at 96 or at 192KHz.