How important is a flat response?

While it is not necessary to have ruler-flat frequency response in a room to have enjoyable music reproduction, you DO want to avoid having pronounced peaks or dips in the response curve. Large peaks, particularly in the bass frequencies, can significantly color how the mid-range sounds. Likewise, significant valleys in the response curve makes the adjoining frequencies sound too pronounced.

As most long-time audiophiles know, the room is itself a "component" in the audio chain -- perhaps the most important. The Rives product is an intelligent, cost-effective way to address the problem of response peaks in the lower frequency range -- it does NOT, however, act like a graphic equalizer to address the problem of valleys, as its system is designed to reduce response peaks, not boost sagging frequencies.

To answer your question directly, you are NOT hearing your audio system at its best performance if your room has a lot of peaks. You may be very surprised how much better your audio system sounds if you can tame some of those room anomalies.

It is possible to love a system that is not musically accurate. Just because a person likes the sound of their system doesn't mean it's accurate, and just because a system is accurate doesn't mean you will like the sound of it!

Some people like exaggerated bass, or midrange; that's their personal preference. It all depends what a person is trying to accomplish when establishing their system. Since this is a subjective hobby, anything goes, but there are many to whom tonal accuracy is everything. To reproduce a tone accurately a system has to have an accurate frequency response.

Sdcampbell is correct with his assertion that the room will adversely (usually) affect the sound of a system. A good system in a compromised room will not be capable of good sound. Fortunately it costs less to treat a room than it does to buy new gear. You will not have to sink tons of money into fixing some of the anomolies you are experiencing.

I've had the pleasure to listen in a Rives designed dedicated room. Wow! I'm not quite sure how to explain the benefits beyond the pure, flat frequency response except, other things are allowed to happen that otherwise wouldn't. Things are....life sized. I hope that makes some sense. Headphones don't measure up to or equal the overall effect either, IMO. Those that say the room is the most important system component have a point that I can't argue with. After saying that however, I spent the last four hours in my non-professionally designed room and enjoyed it immensely.