Opinions on Pure Audio Project Quintet 15 Horn 1 Please

Hmm, I just had good experience listening to Spatial X3, that in comparison to my much modded Klipschorns. Not saying Spatials in this setup superior to what I have, but certainly didn't hear non fleshed out mids. Prima Luna Dialogue Four I modded powering Spatials. I also used Alon OB speakers for years,  I've always enjoyed OB speakers, but then I enjoy horns as well. Pure Audio Project certainly on my radar prior to Klipschorns, I haven't heard so can't help here.

I’m not trying to say the X3 isn’t a good speaker, it certainly is. I was an early adopter and kept mine for a year. Like all good speakers they have shortcomings and you have to decide if the trade off is worth it. I can see them being an end game speaker for some.

I am a fan of open baffle speakers in general and quite liked the Spatials I heard at CAF in 2019. I also heard Pure Audio Project, not sure which model, in the VPI room that year and didn't care for them. All that said you should at least audition them shows are not the greatest place to evaluate speakers and we all hear differently.

Lots of variables, and no, I've not heard Spatials long term.

My issue with a number of different models of Alon OB was incoherence between OB mids and tweeters and acoustic suspension woofers. I would have had to biamp with tubes on top, ss on woofers to get balance I desired. Don't know if open baffle woofers along with mids and tweeters have this issue?

I've owned the Spatial M3 TS and while they were light on bass, they really turned me on to dual concentric designs which led me to Tannoy.

I did cross shop the M3 with the Pure Audio Project trio, and the major issue I saw with the PAP was that I'd never be able to sell them if they didn't work out. The DIY build approach means you can't easily package them back up and ship them to a willing buyer, and the Quintet being an even larger speaker is going to have fewer potential buyers due to low WAF (despite their very good looks IMO). If they work for you, great!  But, what if they don't?

Open baffle speakers have their upsides, but bass is not one of them if you have a room with large volume. The room needs to be small enough to pressurize, but deep enough you can place the speakers far enough from the front wall (1-2 meters).