what are the major considerations for an av receiver to be future-proof?
The way I see it, future proofing a receiver is quite limited and can be a gamble. I am almost certain entry level receivers can't be future proofed. But there may be exceptions. One easy sign is the ability of the receiver to process firmware upgrades via a computer-typical terminal like an RS-232 at the back. Some may just require a CD upload. Upgrades on chip performance or firmware patches to solve certain quirks are quite common. Or putting in more soundfield DSP functions. Such upgrades can often be done only within a short time, maybe a year or two at the most. But not always on audio decoding capabilities. Some perhaps. Like upgrading from regular DTS to DTS-Neo. After that, I doubt if new audio decoding formats can be supported with those upgrades. It may be easy to upgrade an old DTS-enabled receiver to accept DTS 24/96 or DTS-Neo. But I doubt if the same receiver can accept firmware upgrades to the latest HD-DTS. The data volumes in the new formats are just too immense for older chips to handle. So it seems to me future proofing can be done, but not beyond 2-3 years from manufacture date. That doesn't mean though you can no longer use the receiver after that. Ofcourse you can, but you may not benefit from the newer formats. Even 15 year old prologic receivers can still work fine these days. But even those upgradeable flagship prologic receivers could no longer be upgraded to DD and DTS encoding abilities.
Since the time DD and DTS first became commercially available thru DVDs, sometime late in 97, if i recall right, we're really looking at only 9 years. Around half-way thru, the more compute intensive SACD and DVD-A came along. Receivers took some time before they can handle the SACD bass management functions. And I doubt if there were firmware upgrades the allowed older receivers to handle SACD. These days, only mid-priced to flaghship models have bass management functions to handle SACD via firewire, I-link or D-link connections with similarly equipped players. No receiver firmware upgrade allowed any old DD/DTS receiver to handle SACD processing. You just have to get a new receiver if you want that function.
We are now on the threshold of HD-DVD and Blu-Ray with newer audio formats like HD-DTS and Dolby TrueHD. Within the year, I am sure new receivers with these audio formats will appear. They will certainly make even a flagship Yamaha Z9 or the flagship Denon A1XV obsolete.
So it seems getting a new receiver at this time may not be the right time if future-proofing is a priority.
