There’s also the question of where to place your filter or should that be filters? After all, given the physically extended nature of even a compact audio network, if one filter is good, won’t multiple filters be better?
With that in mind (and with a pair of both Aardvarks and CADs on hand) I experimented with placement and ‘stacking’ the filters, starting at the router and working forwards. I won’t bore you with the progression, but the results were both clearly ordered and consistent – at least in the two networks I had to hand…
Rule one – place your first filter as close to the network endpoint as you can (the Wadax Ref Server in one case, the C1.2 Ethernet-HD input in the other).
Rule two – always place the filter at the cable termination.
Rule three – multiple filters multiply the benefits, but it is not a linear progression. If you have a switch located as close to your network endpoint as possible (and you should) then adding a second filter at the switch input will bring a handy further improvement, delivering more of the same benefits that the first filter did: not quite as much, but still a financially viable proposition.
Rule four – every rule has its exceptions: circumstances and situations will vary, so it is worth experimenting. My final configuration in the Wadax-based set up was to use the CAD Ethernet Controls adjacent to the Ref Server and its SOtM switch, but to add an Aardvark at the input to the optical bridge that galvanically isolates the audio network from its router.
Put in its most basic terms, the conclusion here is simple: network configuration matters; network hygiene matters just as much. One filter should be considered essential, that filter being the best you can afford. After that, adding a second filter offers perhaps the optimum price performance balance. However, there is another, inescapable observation that it would be obtuse to ignore. Whilst the attraction of after-market/after the fact filters is obvious, why not eliminate yet another junction and streamline the infrastructure still further – by building the filter into the destination end of the ethernet cable? This is far from a novel concept. Indeed, CAD’s USB filter is derived directly from the hardware built into their USB cable. How long before we see the same approach applied to network cables? They’re probably already out there…
English Electric EE1
www.chord.co.uk
Aardvark
www.aardvark.co.ar
CAD Ethernet Control
www.computeraudiodesign.com
