When choosing new Speakers, what matters most to you?

detailed specs are a great guide but they only go so far for me. i MUST be IN THE ROOM with the speakers, playing MY music ONLY, what i am familiar with. if it sounds musical but doesn’t image well, FAIL. if it images like 3D holography but sounds bad, FAIL. gotta be the whole package, with imaging AND great sound [with a notably luxurious never-flagging EASE] that never fatigues, never is edgy even with harsh-sounding material IOW it doesn’t make edgy-sounding stuff more edgy. the system must make low-level signals clearly audible with no straining to hear. my present system using Thiel cs.5 speakers does this, and before that my maggies did it. the energy 22 pros had it about like my thiels. the snell class A [revised] had it. a speaker i couldn’t afford or even have room for, the magnapan tympani IIIs, they had it in spades. so to answer the OP’s query, it can’t just be one thing. obviously, if the speaker is a 2-ohm power drainer and amp wrecker, it is disqualified no matter how otherwise splendidly it performs as i can’t afford a krell monster amp or its ilk. so there are practical considerations as well.

“Auditioning” some speakers as I write this. (Sort of…)

Ive had a speaker design in mind for a while, ordered the parts, built the enclosure and spent several days tweaking  the crossover and damping. They are at a point now where I need to listen to them for a while to see what is missing and what is bothering me.

No measurements as of yet. There was obviously some math that needed to be done prior to any of this happening based on specs of the driver and the components. Since CV19 happened I’ve built at least 3 dozen pairs of speakers. I’ve been working towards the pair I am currently listening to. 

Not sure I really care how they measure, but I will be doing detailed measurements as I may take them to market. (Which is what the last year and a half has been about - building, listening and trying things)

So, the question is timely for me as I met with my business partner earlier today and discussed what I thought the problem with the the sound presentation was. He didn’t hear anything out of place, and I explained what I thought was off and how I planned to address it.  Then we discussed measurements and what to do if they measured terribly. Am I all of a sudden not going to like them? Does it invalidate what I’ve worked towards, designing and building a speaker that I, and everyone who has listened to them,  really enjoy?

Emotional resonance, tonal presence, contrast, clarity, balance, physicality and impact are what I listen for. Do they present an engaging image of the recording? Not a live performance, but rather the recording.

Much study has gone into these, but in the end it’s about how they sound. I have never bought speakers based on measurements beyond the basics of sensitivity, impedance and size. 

When you buy them what are you going to do with them.  Listen to them.  I therefore suggest you listen to them. Specifications are very unlikely to tell you what they sound like, even if they are an honest and accurate presentation, which many specifications are not.

1. DESIGN. I don't mean that they 'look kool' but rather that they look like they were shaped by an honest sonic objective and that everything...every element defers to that objective. I'm a big fan of Tannoy Legacy and Klipsch Heritage. Timeless design in the broadest sense of the word. Lastly, I need to look at it and it needs to looks interesting.

2. EFFICIENCY + IMPEDANCE. Both together need to be easy. I want more than 91db efficiency and no less than a 4ohm dip. 

3. BIG DRIVERS. I now less prefer small speakers with high excursion and prefer large surfaces producing effortless, velvety bass even at very low volumes.

4. FULL RANGE RESPONSE. I like the simplicity of not having subwoofers. So the LF response needs to reach below 40hz.

5. ADJUSTMENTS FOR HF. I have an 8k notch (loss) in my left ear. My Tannoys allow me to juice the left tweeter a tad to make up for it. This is an amazing feature for someone like me.

I don’t care how it measures if I don’t like the way it sounds. And if I like the way it sounds then why do I care how it measures. It’s not like I have the option to EQ my ears and I doubt they have a flat curve.

The most important spec is price. Why torture or tease yourself with options grossly out of reach? Likewise, you can’t just ignore amplification because if the speakers require different amps then that needs to be in the budget. Reviews and subjective evaluations are much more likely to pique my interest than any measurement can. But they’re also less likely to deter me if I’m already interested. Confirmation bias is human nature. We look for data to support the conclusion that we want.

Bottom line is I’m going to check price and amp compatibility (as relates to price) before anything else, and then look for reviews because I don’t have any experience correlating specs to whether or not a snare hit, cello, or vocal is going to sound right.