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

Showing 1 response by kirkus

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.