How far can room treatments solve boomy bass?

You can't fix acoustic problems with EQ. You're using the wrong tool. Fix the acoustics, and THEN see where you stand.

My understanding is that the PARC is an analog variation of room EQ. Audysey, ARC et al work in the digital domain. I'm not sure whether PARC includes an RTA function (room analyzer), but if it doesn't you'll probably use a stand-alone RTA for set-up.

As to Ja2's contention that you can't fix acoustic problems with EQ, I'd respectfully disagree. Respectfully, but emphatically. Modern parametric EQ is an amazing thing and - to my ear - makes a bigger improvement in overall sound than just about any other change you'd make in a system. To test this claim, find any AVR with Audyssey and do a "before/after".

As always, however, YMMV.

Marty

Martykl, It is not only issue of loudness but also extended decay time. I also feel that additional pieces of electronics in the signal path don't improve clarity.

I agree with Ja2austintx assessment: fix the room, then decide.

For those problems that are caused by uneven modal distrubtion . . . why not fix them where they live, which is in the acoustics? Trying to EQ out the lumpiness is just fighting the symptom, not the cause.

To be clear:

1) Per Kijanki, EQ is not a "magic bullet" that fixes all problems. It is - IMO - a magic bullet that fixes one BIG problem.

Per Ja2) FR issues below 150hz or so have been IME virtually impossible to correct with traditional room treatments - including tuned Hemholtz devices.. Even if you fir out the walls to achieve ideal (or near ideal) relationships, you still have serious FR issues in most rooms with most speakers.

For instance, you will end up with destructive interference - unless your speakers are mounted on the wall or soffited into the walls. Quarter wave effects generally result in gross FR deformation (>10db at some point in every room that I've measured) below 150hz. Parametric EQ can bring that to virtually dead flat (depending on the system you're using). I find the delta instantly and dramatically audible. A simple visit to any HT retailer will allow you to A/B Audyssey. Form your own judgement, but I would be shocked if anyone missed the impact of the parametric EQ.

This certainly doesn't mean that everyone will like the sound of such a system. But, for the OP's question regarding a room too small for his loudspeakers, I don't know of any alternative to EQ. Even in a good sounding, fully treated room, I've yet to find a passive room treatment that is effective much below 100hz where these effects are so clearly audible.

I'd agree that traditional passive treatments are useful for many problems (particularly as Kijanki noted, issues related to the reverberant field - slap echo, etc.). That is why my listening room is heavily treated. However, I still use Audyssey. If you wanna fix the bass, there ain't nothin' like parametric EQ.

IMO.
YMMV (but I kinda doubt it.)

Marty