These would be used for two channel vinyl playback with a Denon PMA-1700NE.
I have plans to get some basic room treatment done in the coming year or so and the savings on these would get me there a bit quicker. Planning to get the GIK 242/244 (or DIY equivalent) two on front wall, two on rear wall, four (2x2) on side walls as a starting point, corner traps where I can get them.
I ordered a pair of these because why not? If they turn out to be a dud I can return them or sell them to get my money back. Can't really pass up the opportunity to at least try them at this price.
I highly doubt the HDI-1600's are going to be duds & yes such a great price this weekend.
Putting the panels will help with any over excessive reflections in the mids, so in a smaller room that is probably a good plan. Dealing with bass is specific to certain frequencies. I don't want to trap bass below 200hrz 'globally' & trap the wrong frequency's along with the peaks. 5.25" material cannot trap the huge waves below 100 hrz which is where you will get some big peaks. 3 Biggest peaks will be likley around 45-50hrz & 65-70hrz and around 80hrz(this does not factor in SBIR, just room modes).
If you are going for it fidelity wise, I highly suggest skipping any big bass traps and doing the corrections below about 200hrz in Parametric EQ(PEQ). Unless you are going to be performing live there, fixing the bass issues in the electronic domain is so much more powerful and easy to do correctly.
You don't need endless advice from one person but I'd skip the overpriced Denon and do the $299 WiiM amp with built in streaming(are you really only doing vinyl?) and 4 bands of PEQ*(or it can do 10 bands of graphic eq) You'll need and external Phono Preamp but there are many good ones for low $. I guarantee you I could get superb sound with more ease from that vs buying the Denon and expensive corner traps. (*they also are trying to double the PEQ bands from 4 to 8 in a future software update)
Ther are also other options besides the WiiM that cost more or are not as user friendly.
FWIIW the power output of the $299 WiiM and the Denon is identical. I can pretty much guarantee you the Denon doesn't measureable or audibly beat the WiiM. (It does look richer and nicer though.) But I mean you are saving some serious cash and saving on the bass traps. You would have to navigate setting up the PEQ and doing measurements to get it correctly which I realize is hard on some folks but you should also be measuring as you add bass traps and the like. Not just randomly sticking them in there and praying that they affect the correct regions/frequencies.
Anyway this take of mine posted here and in Post #497 is not all directed just at your situation but anyone reading who is deciding things. Just my 2cents. I'm sure some others will have a totally different legitimate take.
P.S. if you don't know this site and are cool with refurb
www.accessories4less.com