Room Treaments - Where To Begin...

on the issue of spikes vs springs…or ?….. probably best to get a reputable product ( there are many  ) from a vendor that allows returns and listen, tweak and decide for yourself.

I would start w your Spendor dealer. I know a really good one with a great ear, exacting standards and impeccable ethics…not prone to hyperbole but an innovator in his own right…let me know if you need his firm name.

Audiotools is a good start, you can run the RT60 test w a handclap but a popped ballon is better.  Audiotools runs on iphone or ipad. I would not trust the iphone microphone below 120 hz. Audio Control ( Lynnwood, WA make a decent affordable calibrated microphone that can be trusted ). Of course you can get there….eventually..just by listening….you can also wander in the desert randomly looking for water…

Jim Smith’s book - Get Better Sound may also be of use. 

Acoustics is part science, part art and some luck….but my mentors put together great rooms you can hear…in the reference recordings they help create….

Best to you

Jim

Textbook RT60 for a mastering control room, mostly accomplished with natural treatments, a bit of hidden in art absorbers, etc.. 

But first a question (s ) to the OP about your tastes, what is your resident orchestra and where are your preferred seats in the hall ? Have you heard your Spendor in a better room or system ? what does it do that yours does not ? Congrats on the Spendor BTW, most excellent.