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digital eq/room correction trade-offs

I am very confused about digital room correction.

For many years, it seemed the common wisdom was to have as clean a signal path as possible, with as little processing and as few conversions as possible: use a high quality DAC to get the signal to analog and then a pure pre-amp/amp to speakers.

But it now seems that many would argue that the benefits of digital eq are such that even an extra analog-digital-analog step is worth it for the benefits of digital room eq.

So, for example, I enjoy listening to CDs and SACDs using my Bel Canto PL-1A. I go analog out to my pre-amp. Is it worth it to contemplate the extra step of analog to digital for room EQ and then back to analog to the pre? I find it hard to believe that any benefits of the room EQ won't be substantially offset by the additional conversions.

Your thoughts most appreciated. Let's assume for the sake of this discussion that my room is imperfect but not horribly so (which I think is accurate).
dgaylin
samujohn's avatar
samujohn
291 posts
 
If you listen to CD, digital is a given, as is the processing of same prior to conversion to analog. Digital equalization degrades nothing and is of considerable benefit in adapting speakers to a specific environment. The straight wire with gain folks had the upper hand as long as equalization was done in analog, but this doctrine no longer makes any sense for CD. For a real improvement, get a digital preamp and skip an analog stage instead.
kirkus
502 posts
 
I think you're hearing so much about it right now mainly because there are a TON of new products out in the past few years, and this is a result of some new directions in the OEM (chip-level) DSP products. It used to be that fast DSPs in general were all Harvard-model processors with fairly limited memory, so the code written for them had to be clean and concise, and thus it wasn't easy to quickly configure them for different processing arrangements. Nowadays, there are many Von Neumann-model DSPs available, with much more memory, which makes it MUCH easier to write the code . . . and many of the IC manufacturers have developed "modular" programming environments with huge chunks of common applications pre-written.

So for end-user applications, especially in professional sound, there are likewise tons of multi-configurable products that are replacing dedicated boxes. For i.e. a typical simple church sound-reinforcement application, instead of an analog mixer, analog equalizer, analog (active) crossover, and analog peak-limiter(s), you can buy a product like a dbx "Driverack", Ashly "Protea", Rane "RPM-88", etc. that do it all in the digital domain in a single box, all configured however you want it, via a PC. And this is (in general) better, cheaper, and more flexible.

The consequent of this is that if you don't know how to properly tune a system with all the analog stuff . . . suddenly finding the digital equivalents with far more virtual "knobs" to tweek isn't going to make things any better. Some of the consumer products try to get around this by automating the process . . . but IMO very, very few of these approaches hold any promise.

In general, if you get past the whole "it's better because it's new because it's digital!" thing . . . it's all just signal processing. Digital and analog products are somewhat different tools, but the thing that makes it good or bad ALWAYS comes down to the quality of the tool, the skill of the person using it, and its suitability for the intended application.
dgaylin OP
255 posts
 
Thanks Kirkus and Samujohn. I agree that it's all signal processing and it's all how well you can use the tool. I guess my thinking is that these systems are supposed to self-configure, but my understanding is that they don't do that very well. So you end up tweaking them. And even with lots of experience running mixing boards in live sound situations, I'm not convinced that I wouldn't just be winging it with these new systems. Not to mention the problems introduced with additional jitter as the signal gets switched back and forth from digital to analog to digital to analog.

To Samujohn's point -- I get the idea of elimminating an analog stage and going with a digital pre, but that's going pretty far out on a limb before I even know what the technology can do, and given how many more options there are for nice analog pre's versus the handful of digital ones. The answer is probably a home audition of one of these systems to see how it works for me...
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