I’m always happy when the HRM-6’s or the 5’s come up, because I feel like a lot of people shot right over them in their dogged quest to buy the M50X’s.
Unfortunately for Pioneer, I’d absolutely pick the K371’s over their HRM models, even though I loved them a couple of years ago.
The 371’s simply have better audio performance for the price. The HRM models are still smoother listens than the popular Audio-Technica studio pairs, but don’t have quite the same sonic accuracy as AKG’s new pairs.
Now, it’s possible you might not personally want the flat, accurate sound that the Harman curve used in developing the AKG’s provides. But without knowing your personal tastes intimately, I couldn’t say. The HRM-6 will has a little more warmth to the bass range, but isn’t quite as true to the source.
The bigger issue with choosing Pioneer’s HRM5/6 models right now is that I’m reasonably certain they’re about to hit end-of-life status. Retail availability is scant compared to when I reviewed them, with Amazon showing only third party availability with sometimes-inflated prices, and other retailers showing weird discounts. These are usually signs that a product is on the way out.
I don’t doubt that Pioneer will still honor warranties should you find a new one, but they’re clearly not excited about these headphones any more. They’re no longer listed on Pioneer’s main page for headphones:
And they’ve been demoted to the bottom of the list on Pioneer’s DJ spin-off brand site, which was their flagship consumer headphone branding at one time:
https://www.pioneerdj.com/en-us/product/headphones/
With the AKG’s being the new hot thing in the audio community, I’d imagine they’ll be easier to find at a good price, and easier to get extended support for.
Hope that helps you out! Thanks so much for reading.