Old thread - oh well, as poster @jaystereo said. @georgehifi -- Don’t go digital to me it only led to sterility no matter what I tried. And I lost the sound of my favorite dac for whatever rubbish dac is in the digital dsp/xovers ones.
Not my experience. Recently went all-active with my existing Xilica digital cross-over, and it’s a bliss. Indeed, once clear what can be done with a quality digital cross-over (and the Xilica is that), even very early in the tuning process, there’s the strong sensation of not wanting to go back to a passive filter - like, ever. There are caveats, however; an amp channel is needed for every driver or drivers that are coupled in parallel, and in my case a 110dB sensitivity horn/driver combo can lead to a degree of background noise depending on the amp/filter used. Moreover, unless the filtering has been preset by the manufacturer (like Sanders Sound Systems) one will have to do this him- or herself, and to do this accurately measurements will have to be made, though only as a guideline; remember to let your ears be the final judge with every step taken, because measurements need to be interpreted in light of their specific implementation, and often what is measured isn’t the direct link to its audible "equivalent," so to speak. Although, audiophiles invest their time in many a thing when it comes to their stereo set-up, and I don’t see an active approach being an insurmountable task with care and attention to detail. Doing the filtering ahead of the amplification on the signal-side, and hereby letting each amp channel see its respective driver(s) directly without the interference of passive components, can have obvious advantages. To my ears passive filters invariably infuse some degree of softness or smear, whereas with a quality active configuration transient cleanness, clarity, resolution and dynamic prowess is enhanced. Actually I also find the overall presentation with active to be easier and smoother on the ear. Done right going active is the real and preferable deal, I’d say. Or what I would do with those speakers is to go horizontal Bi-amping with the apms you have as the B&W internal xovers are of very high quality and well sorted.
Or with something like a nice Pass Labs Class-A XA30.5 (amp1) on the mids and highs and a cheap Class-D (amp2) on the bass I’ve tried bi-amping both horizontally and vertically, yet every time I’ve preferred bridged mode configuration with two identical amps, where possible (and where not I usually preferred vertical bi-amp config.). To each their own, but bridging is seriously underrated in hifi. |
@georgehifi -- That’s because all you get is more wattage, everything else takes a hit, especially current drive into lower impedance’s and stability, distortions. It almost makes what was a good amp into a PA amp. Sounds to me mostly like theoretically-based conjecture. Have you listened to bridged configurations to form an opinion this way? At a friend’s place a few weeks ago I heard the latest bridged amp installment to come across my ears. My friend already had one Crown Studio Reference II in his set-up driving his main speakers, but then bought a second one for bridged duties. Once gain matching between the mains and subs had settled as well as some minor delay and PEQ tweaks, a bunch of us came over to listen (all of us were very familiar with the sound of his set-up with only one Ref. II). Each and every one of us preferred the sound of the bridged configuration, with some describing the sound as now being "more hifi" in the sense of it being even more refined and smooth in the top end, while being more open and lively overall. I agreed with this sentiment. My friend found that in bridged mode it (subjectively) didn’t sound as loud at elevated SPL’s, though clearly feeling the loudness on his body. There wasn’t necessarily anything "PA" about the sound with the two bridged Ref. II’s, but simply a more open, effortless, refined and lively presentation (sorry to reiterate) that accommodated every music musical genre we cared to throw at it. Which, btw., mirrors my impressions from the previous bridged amp constellations I’ve heard. |
@georgehifi -- Each and every one of us preferred the sound of the bridged configuration, with some describing the sound as now being "more hifi" This statement says it all.
A really good amp should sound big, tight and wash over you with dynamics and detail that don't sound like it's coming from any of the the speakers drivers, and have a sound stage you feel you can get up and walk into.
It says what? The people in attendance of said listening session, among them musicians, knows how to use the term "hifi" in its truer sense, and nothing about the statement excludes the traits you mention, on the contrary. A smoother, more refined top end could point to better transient response (i.e.: better slew rate), and a more lively and open sound is exactly that and could involve many other parameters; like more headroom, less restricted dynamic capabilities, better sound stage, etc. The traits in particular you do mention are very much a factor of the speakers as well, I should add, so it seems me you're bending the statement to have it suit your agenda. |
@georgehifi -- In general Bridged Amps
Pros=
More watts.
Cons=
Worse damping factor
Higher output impedance (has relevance to damping factor)
Lower stability (especially into low impedance’s)
Current ability is reduced (especially into low impedance’s)
Higher distortion. Some redundant info here, all of which is mentioned ad nauseam without either getting into specifics with regard to perceived impressions, nor putting the cons-info into perspective; what’s the relevance of claimed negative aspects for them to actually matter in-use, and would actual listening to bridged configurations ever be freed/independent from a preconceived, theory-laden approach? This is my main contention with "hifi:" what’s headroom is generally looked down at as being "overkill," and further relegated to the arena of PA as something more crude and less refined. In this case I can only say my impressions of listening to bridged amp constellations, cons be damned, have been positive - indeed favorable compared to their non-bridged state. The overall impression is, by and large, that of a more effortless, (a)live, open and refined presentation - qualities I for the life of me can only associate with what is intrinsically better. If the matter was solely about comparing impressions and others disagreed with me, I’d rest my case respecting the other party’s opinion. What gets to me is the "look at the spec’d cons, man - they speak for themselves"-gist, added to the conjecture that more watts are essentially about catering to the PA-segment. The only real negative of actual importance in my case would be that residual noise in bridged mode is amplified, and that matters with an active configuration of a 110dB sensitivity horn/driver combination. A lower gain setting would be necessitated here, but as is I’m perfectly happy with a 30 watts pure class A amplifier for this frequency region. What I would consider is buying a second Crown K2 for bridged mode with my horn subs (8 ohms) and/or EV bass section, but only because it would make what’s already very good even better - at any SPL. |
@georgehifi -- Some redundant info here Not in the least, still fact with Class-D’s today.
Class-D, you mean in bridged config. or stand-alone? My experience with Class-D is far from exhaustive, but what I’ve heard is noticeably different compared to a good Class-A design or even a ditto Class-A/B iteration. My as-is unwavering preference at least what concerns the central to upper mids on up is for this range to be handled by a Class-A design, but I find it less obvious from ~1kHz and down. Certainly I wouldn’t choose Class-A here for my active set-up, for a variety of reasons. @avanti1960 -- tread lightly when bypassing the crossovers of any quality loudspeaker.
they usually do a lot more than just filtering out low or high frequencies. [...] Oh, absolutely. It’s a potentially complicated process and steep learning curve, and I wouldn’t as much recommend this approach (i.e.: converting a passively filtered pair of quality speakers into actives) as a design that’s born sans passive cross-over to being with. This mostly boils down to DIY and the pro sector, with the latter having sometimes preset filter-options to implement. Either outset could be a challenge, but once you get a handle on the different filter aspects I’d wager the freedom of choice, on-the-fly filter settings changes and differentiated approach to amp topology (that’s possibly) as it applies to each driver - added to the bliss, as I see it, of avoiding a passive cross-over altogether - it becomes addictive and a rather obvious bye-bye to passive. |
@georgehifi -- Not in the least, still fact with Class-D's today. Sorry, Not in the least, still fact with bridged today.
In general Bridged Amps Pros=
More watts.
Cons=
Worse damping factor
Higher output impedance (has relevance to damping factor)
Lower stability (especially into low impedance’s)
Current ability is reduced (especially into low impedance’s)
Higher distortion. It's always has been the same.
You left out better slew rate in the 'pro' camp of bridging. In any case those "facts" offer a convenient way to make an all-encompassing statement saying bridged amps only offer more watts while taking a hit in the remaining areas. What has, truly, "always been the same" is that it depends; given a sufficiently "sound" amplifier design (those aren't difficult to come by) and a speaker load that isn't downright problematic or too low-impedance, bridging won't invite stability issues. Indeed: what's the relevance of the stated cons as they apply to actual sonics? Roughly 3x the power though gives you more headroom, ease and likely a lowering of perceived distortion, and if a better slew rate is anything to go by transient cleanness should see an uptick as well - all of which aren't too far removed from my listening impressions of bridged amp constellations. |
@georgehifi --
Bridging has nothing except more wattage over leaving the amp as stereo, you've been told now not just by me. What's most telling is that I'm speaking to a brick wall. God day, Sir. |
@georgehifi -- And you can’t see the forest for the trees.
And I thought listening, without theory dictating me what to hear, was doing exactly that (i.e.: seeing the forest for the trees).. |
And I thought listening
Na, you already proved you can’t do that with this statement.
Every one of us preferred the sound of the bridged configuration, with some describing the sound as now being "more hifi"
The "can’t see the forest for the trees" was the technical aspect of what you know, and what happens to a stereo amp when it’s bridged, all you gain is watts EVERYTHING else takes a hit.
Bridging makes what was maybe a good amp, almost a P.A. amp.
Look, George, this merry-go-round of ours leads nowhere, so let's just agree to disagree. |
@dhl93449 Regarding the subject of active XOs, it is almost impossible to find one that is built without op amps. Bryston is the only company that comes to mind that produced HP and LP versions with discrete Class A circuitry, and I do not recall if these are still in current production. In any case they are not cheap, and if you need more than just a single XO point (two way system), the costs mount up fast. This stance is a quick way to discard active XO’s when in fact they could be beneficial to a passive solution - even with opamps and A/D to D/A conversion being introduced in the signal chain. What’s the bigger picture; do the comparison and forget for a while the drawbacks mentioned to hinder the fuller realization of an active XO, if they’d even be that relevant compared to the negatives of a passive config., and then see. My take with an XP-series Xilica XO is that it trumps excellent passive XO’s in the three set-ups I’ve heard so far - quite easily. The sound in all cases went from slightly diffuse/smeared and soft to more clear, refined, transparent and dynamic going from passive to active. |
@dhl93449 -- ... So that confirms that the active XO system has merit in principle, and the class A discrete designs in practice.
Thanks for the follow-up, and good to learn that your active XO project has come through successfully. From my chair though it still goes with absolute conviction: less will do, even in excellent fashion. A pro digital cross-over from Xilica that friends of mine and I are using in our respective set-ups is a rock steady performer that has sonically lifted passive speaker systems (in theirs and others set-ups; my own speakers have been sans passive XO’s to begin with) into more transparent, tonally authentic and dynamic sounding dittos. Simply better in every perceivable aspect, period. I believe it’s an unfortunate, even dead wrong message to put there saying that only the über-best of the best active XO’s will do compared to passive iterations, especially compared to a limited range of digital XO alternatives and not least with reference to: ... it makes no sense to me to place an EQ/XO having IC opamps between a discrete component preamp and discrete component power amps.
Whether it makes sense or not is a matter decided by the ears, not theory, but of course: if what your ears tell you is in favor of a passive configuration - in a specific, singular component context, that is - then that’s what it is to you in that particular scenario. Few have actually tested their own or to them well-known passive speakers as converted-into-active dittos, with the potential experience of actives coming predominantly from all-in-one packages that leave little insight to be exposed other than the choices made with those particular designs, rather than what merits conclusive or more fully formed statements into passive vs. actives. Active configurations hold great potential, also as a solution of separate components with all that entails into the free choice of amps, cables, DAC’s and digital XO’s at reasonable prices - somewhat cheaper even, despite the more amp channels needed, than a passive set-up. |
