Good Analog EQ

Besides mixing, these are probably used for analog mastering.

That's very true, but the pro audio community usually thinks nothing of putting all kinds of things in the signal path for the convenience of manipulability, and are often looking for pleasing colorations rather than maintaining ultimate transparency. IME, you can hear an additional solder joint, let alone a volume pot, active circuit, tube or transistor, coupling capacitors, resistors, etc.. Just because they have already been used in the signal path of the recording, mixing and mastering doesn't mean they wouldn't further degrade the sound. The question is whether what you gain from the device is worth the degradation to YOU. There's no question the Manley EQ is a good one. There's also no question that you could hear its presence in the signal path on a resolving system with its settings set to flat. Some may remember the EQ offered by Cello about 15 years ago, although I believe that was marketed primarily to make EQed recordings iistenable rather than to correct for the room.

Peidpiper makes a good point. There are many types of EQ and each is best suited to particular applications. Manley's Massive Passive is a parametric EQ which could be used for room correction (2channel only) with the support of external measurement/filter calculation programs like REW. OTOH, it is best suited for (and designed for) equalizing the sound source for mastering. Contrast this with modern digital EQs (yes, I know the title of the thread) which can offer a very large number of filters with complex parameters more suitable for the complexity of room acoustics. The first step is to determined what you are trying to accomplish in your particular room.

Kal

Also, best to start with an optimized setting so as to minimized required corrections.

Speaking as someone from the pro audio community, I would offer that there are a number of excellent eq's depending on your price range. I would not use a parametric eq of any kind with a stereo system. They are a diffferent animal and meant pretty much for surgical stuff. A transparent broadband eq could be fine or you could go for something with a little more color.

The trouble with pro audio stuff though is that most of it is parametric. EQ causes phase shift so you have to be careful but your ears can be the judge.

A pass filter set might do you well too depending how severe your problem is. These are passive and so they really don't degrade the system much.