Without measurements there is no acoustic treatment well done...
Without measurements there is no mechanical room tuning controls...
Why?
Because the BALANCE between reflective/absorbing /diffusive surfaces is the KEY... but it is not enough, even the location is important...
And in the mechanical control side of acoustic, how someone could tune many, many , resonators without adjusting size volume, neck/mouth cross ratio? and critical locations?
Measurements are mandatory in acoustic...
How to make them ?
You can apply EQ.
But no EQ. will be able to do the COMPLETE job right...
I chose at no cost to make it by ears like someone tune a piano, in fun times months long experiments...
It worked more than great... Cost me nothing but it take a dedicated room for me...And much time...Much....But you can do minimal experiments in a living room and take care of the esthetical aspect, which i did not do... My basic materials were cheap and anyway i am creative but not crafty at all... 😁😊
Now there is acoustic but there is basic psycho-acoustic measures also...
I also used measures of distance here, locations of diffusers and resonators with a foldable treated wood screen behind my position.... Psycho-acoustic help us to correlate in timing the front/back/lateral reflections with the first frontwave coming from speaker A and from speaker B for ear A and ear B...
All this is impossible without measures experiments...
This is the bad news...
The good news is it is way more easy to do it with your ears in ongoing listening experiments...Nothing is more fun than learning...
A small room is a complex set of geometry, size, topological factors, and specific acoustic properties content materials distributed in the room ...I dont own a program able to compute all this for my human ears and in place of them... Acoustician have learned to use their ears and measures...In small room acoustic reverberation time will not be used like in a great hall...We must tame them for postive effect... All which i talk about you can search on the internet and study basic...
Why?
Because learning acoustic by ears will help you to learn HOW to listen and WHAT to listen to...
The concept of "listener envelopment and sound saurce width ratio, for example, will no more be a "chinese" concept or the deceptive illusion it is for some ignorant, if you read only about it without experimenting with it...
Acoustic is easy and complex, easy if you go slowly, complex because it will take a long time with experiments...
But trust me the results and the fun exceed any non necessary short satisfaction related to an upgrade....If your gear choice is good to begin with for sure...
There is another aspects of measurements that is more difficult to understand for ordinary customers: electronic measurements...
Here there is arguing without end...
For sure the designer measurements are essentials for pairing components, but there is no way that electrical measurements all by themselves can predict good sound...It can predict only a POSSIBLE good sound, because the designer know his art of trade-off... Some...
A good component must be paired with other components and not only that his full potential cannot be experienced in a bad room either or other non synergetical components...
Then measuring components to VERIFY design sheets is good...Like Amir do...
Promoting the idea that this is enough to know if a component will sound good is ignorance...This is what some few of his zealots do...
Then listening without measurements is ludicrous, and taking ONLY one species of measurements, electrical one, without taking the other acoustic and psycho-acoustic measurements is ludicrous too...
I know what i know by experiments... And reading acoustic basic, and applying it...