Speaker companies with a focus on parts quality and measurements

Researching my next upgrade and am looking for good price/performance ratio with high quality drivers and public measurements. Currently using a pair of Chane A1rx-c bookshelf with a Rythmik F15 sub, and I'm actually quite happy with this setup. Right now I'm primarily looking at Ascend Acoustic's sierra-2 or something from Philharmonic, but I'd like to know if there are similar companies that I'm not yet aware of.

Nearly every reputable speaker company claims the criteria you suggest in your search. Have you seen many companies with claimed low price/performance, low quality drivers and no measurements? You may get recommendations from Cerwin Vega to Raidho.

You would do better to discuss your preferences in terms of the type of speaker, i.e. technology employed, and listening preferences along with firm budget.

Revel, B&W, Magneplanar, Vandersteen all do this - but you won't see them put their trade secrets out publically.

The above all have been in biz a long time and have a lengthy period of development towards a certain subset of goals for a perfect speaker.  No speaker does everything perfectly so you need to listen and decide what criteria are most important to you.

I believe the closest approach to perfection would be to build a large warehouse in the desert near a BPA high voltage line and put 4 maggie 20.1's in it ....
Zu Audio are in your price range. I own the Omen Bookshelf and can attest to their sound reproduction. They also have a trial period so you can see if you like them.
Otherwise, a pair of Vandersteen bookshelves would be another option.
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We are pretty big big into this too 🎶

good listening

shahinian acoustics could be a thought, USA made although a bigger seller in Europe... 

Both PBN and Shahinian are pretty accurate, based on what I've heard and talked with personally. I would also recommend Defiance Audio and, of course, Devore.

Personal bias, but Reference 3A are beautifully matched in terms of price to performance. As are Acoustic Zen Adagios.
You should watch R Vandersteen U-Tube video on pistonic motion.....real science about how driver cones behave ... or not.
He has been working on time and phase accuracy for decades, which some have just discovered...

Researching my next upgrade and am looking for good price/performance ratio with high quality drivers and public measurements.

You may want to have a look at Golden Ear .
+1 for Vandersteen speakers.
The Shahanian's are nice speakers, and I am glad they still have a following, but they rely on reflected sound, much like Bose. A nice sound presentation, but not very accurate, in my opinion.
Once you go 'phase aligned', you won't go back...
Appreciate all the suggestions guys. I should have specified a budget though, as some of these are just too expensive right now. Probably looking to spend $1000 to 1500 on a pair of bookshelves, possibly up to $2k. Some of this stuff, especially the zen adagio junior, looks great but I'd have to find a great used price.

I've owned pair of magnepan 1.7 before, but they didn't really work due to my small room size. The planar sound is something I really enjoy in both speakers and headphones, which is why I'm drawn to speakers that employ those type of drivers.

The Revel M106 for $1600 would be an option, as would the Zu Omen or PSA MT-110. I've got a lot of review reading to do.

I just want a highly resolving speaker. MUST it have Accuton drivers? Why do dealers look confused when I say the word "resolution"?
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I second Revel. Best value w best quality. Kevin V is a great designer with superb resources. 

Thiel must be added to the list.  For the "CS" series and older, parts and crossovers are still available from the KY facility.  Happy Listening!
Unfortunately for your budget you are not going to able to find any speaker with speciality in house engineered transducers except a great pair of headphones. Sorry to disappoint you but your budget is firmly in mass market speakers with outsourced parts - perhaps if you look vintage used then you may find something.

That said mass produced speakers with parts from Seas/Peerless and others increasingly all from China can be quite good - so don't feel bad. 
Watkins Generation 4 bookshelf size speaker; right in your price range and the best $ for value you can get.....quality materials, not mass produced, decades of engineering experience behind them. www.watkinsstereo.com 
It would be most helpful if you could tell us what speaker characteristics are most important to you and/or what you'd like to improve upon along with your other equipment and room size.

If you like the Maggie sound, then the Vandersteen line should be to your liking. You can definitely score a pair of used VSM's or Bookshelf speakers for your price range, though I would pair them with a decent (Vandy, HSU, REL, JL) sub for optimum reproduction. 
The Zu are a bit more 'direct', so they may not be your 'cuppa'. The nice thing is you can try them for a month and send them back if you don't like them.
Can you tell us what you are using for amp/pre/source? It would help in narrowing down what will work for you.
PMC DB1+ here on the 'gon. Two mains and a single for a center. $999
+1 @keithtexas I have currently the PMC DB1i and they are the speakers I enjoy most from everything I owned previously (MA GX50, Neat Motive 3, SA 705, Epos, Quad 11L)
OP have you heard the Ascend Acoustic Sierra 2? if so what do you think of them?
To answer your original question about "public measurements", besides the two companies you already know about, the only other I know of that does that is Salk.

Toole and Olive’s philosophy at Harman is that people prefer flat FR, so between their designs and DBT process, Revels usually measure very flat. As do PSB. Many studio monitors (i.e. Mackie HR) measure very flat. Technics’ new bookshelves measure fairly flat up to 7kHz and their off-axis graph is very good (Stereophile - Class A 2016). Only handle 50 watts though.

Stereophile and SoundStageNetwork show the FR graphs of many of the speakers recommended above as being all over the place. On- and off-axis smoothness is one of the key features I look for in cone speakers. But then again, some people prefer a colored sound. However, my philosophy is that if you start from flat you can more easily tweak the EQ to suit your needs.
Not true that at this price he can't get custom drivers and high quality parts - check out Vandersteen VLR
they go pretty low for a small bookshelf

I suggest you have a look at Tekton speakers. They are renowned for using quality parts and have had some excellent reviews.
To answer some question:

I haven't heard any of these speakers, nor do I have any way of auditioning any of them. I'm in the midwest and would have to drive 3 hours to Chicago to find the nearest high end audio shop, and they still wouldn't have most of the speakers I wanted to listen to.

Currently running off a Yamaha RX-A1060 receiver, but I'm probably going to swap that out for an Emotiva XPA Gen3 and either an Emotiva XSP-1 or Parasound Halo 5 pre. I'd use my RME ADI-2 Pro as my DAC. Everything I look for in audio, whether recording or playback, is reference ruler flat response, detail, and clarity. Not looking for 'musical' speakers. Low end extension isnt a concern since ill be using a crossover with my F15HP sub.

Based on all of your suggestions and reading lots of reviews, I feel like I've narrowed my search a bit.

Ascend Sierra 2 - $1300
Revel M106 - $1350
PMC DB1 Gold - $~1300
Vandersteen VLR - $1275

Some that I've decided against
Philharmonitor - I feel that they are so similar to the sierra 2, but based on reviews I would probably go with the sierra for a planar tweeter speaker.
Monitor 100 - Too expensive
Amphion One18 - Too expensive

Again, really appreciate all the suggestions here. I've found a lot of companies that I'd never even heard of.
In case anyone is interested, I ended up getting a used pair of scansonic mb-1. Might also order the Sierra-2 and compare them.

Sounds good OP.

Give us a review when you've had some time to enjoy them.