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I have a MacBook Pro with Thunderbolt 3 ports, to which I want to connect an Allen & Heath digital mixing desk via USB to be able to capture multi-channel audio. This desk uses isochronous mode USB 2 to send audio in real time, but there are known incompatibility issues that cause audible artefacts in the data when connecting this desk to a USB 3 port (on an Intel xHCI controller), even though USB 3 is supposed to be fully backwards-compatible with USB 2.

So I was wondering whether there exists a docking station or adaptor of some kind that would connect to the laptop via Thunderbolt 3, and offer a true USB 2 EHCI controller with one or more type A USB 2 ports (possibly in addition to the usual suite of HDMI/TB3/DisplayPort/USB3 ports).

A USB-C to USB-A adaptor/dock doesn't work, as this uses the laptop's built-in USB controller, which is xHCI. And every TB3 dock I can find offers only USB 3, not USB 2.

I found this item on Amazon which claims to offer one USB 3 and one USB 2 port, but while the latter port is USB 2 in terms of the hardware (4 pins), it is still attached to a USB 3 xHCI controller inside the box and suffered the same audible artefacts as the built in xHCI controller in the laptop. I need something that will appear to Mac OS system information as a "USB 2.0 Bus" rather than as a USB 2 device on a USB 3.0 or 3.1 bus. I suppose there's the option of a TB3 PCIe external enclosure into which I could plug a PCIe EHCI controller card, but given most such enclosures are designed for things like external GPU cards that would be massive overkill.

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