@devinplombier wrote:
I do agree with this approach. In addition to the benefits you cited, you can match amplification with frequency range; for instance, those old Bryston monoblocks you have laying around will do great on bass duty, leaving you free to spec SS Class A amps on mids, etc. or as your heart desires.
The possibilities of amp permutations with outboard active configuration are many, and they’re tempting for an audiophile in an effort to "flavor" or power differentiate between the different driver sections as one sees fit. An engineering approach will likely have a different set of criteria for more technically founded amp matching choices that takes into consideration many factors of both amps and drivers, while also including budget constraints, heat dissipation issues and other that are not strictly linked to optimizing sound quality per se, but rather aims at working around design limitations of a bundled, a smaller sized form factor within a given price range.
The audiophile who chooses outboard active configuration and thereby mostly a "DIY"-approach to both component choices and filter settings will have carte blanche in most areas here, and essentially is only limited to achieving a particular sonic goal that falls back on his/her own abilities into implementing everything entailed and whatever time and effort is invested with that. While being inspired by pre-manufactured, bundled active speakers with built-in plateamps, DSP and even DAC’s would seem obvious, it’s also a potentially restrictive outset we shouldn’t impose on ourselves. Going outboard active, while intimidating at first, gives one a wider palette of choices that aren’t restricted by size, price, design principles or other, and while most don’t have the R&D insights of companies dedicated to making bundled active speakers we must remember that they’re also and mostly working around restrictions that we don’t have to do. Why put the amps inside the speakers when they can be outside, and typically in much better quality? To save cable length? Well, seeing the forest for the trees should put that argument to rest. Same with DAC and DSP; we can choose whatever we want outboard actively, and have better quality.
Going back to the choice of amps with outboard active config., my experience has gone from what you suggest and may even advocate; lower powered class A solid state amp for the higher frequencies and class D variant power beasts for the lower dittos that necessitate more juice, to currently using essentially the same high quality and high powered class A/B studio amps top to bottom. Using the same amp topology and preferably brand/design over the entire frequency range, including subs, isn’t trivial, and aids overall coherency and tonality (which is very much co-founded in the sub octaves). Consensus (or dogma?) points to using less power in the upper octaves and from amps that differ topologically from what’re used for the lower octaves, but if more wattage sounds equally well or even better with the highs and lends the opportunity to use similar amps from subs to highs, then I’ll dare anyone to explore the benefits provided with this approach.
Active crossover implementation is far from trivial, though, especially if you wish to avoid the AD - DA conversions a digital crossover entails.
An additional A/D to D/A conversion step with a high quality DSP unit is the least of your worries (and with a digital input you can avoid this conversion step, but I wouldn’t look for a DSP solely with the intention of eyeing one out with a digital input - there’s much more to it than that as a qualitative measure, if it even is). What is important is how you go about filter settings and all that requires within a given acoustical framework. This is the real beast and where you can really unlock the potential of your active setup, apart from using quality outboard components through and through, and not letting yourself be restricted by a small size factor of speakers.
You could put together relatively inexpensively active speakers with onboard modular amplification and a USB-programmable DSP module or even a SBC running Linux. Thermal management is going to be tricky if electronics are integrated onboard the speakers. I’ve been kind of mulling over something like that.
Indeed, but how I wish more would venture into those deeper waters for a more all-out approach with an outboard active setup. Give it a shot - you may be amazed.
