Active vs passive crossover
I think most of forumers in this plaftorm know what are active/passive crossover (essentially crossover before/after the amplification) and understand the pros and cons of them. Some if not all might even agree the best sound reproduction solution is active crossover with DSP. But, my question is, why the vast majority of companies in this industry still chooses the passive route.
"Best sounding" is not how I would universally qualify passive crossovers. Complexity and the desire to avoid an extra A/D, D/A conversion step are important negatives. If I am the type to want to go out and buy a fancy DAC and amplifier I don't necessarily want to have the sound quality interfered with by another component I wont' be able to evaluate as thoroughly. |
Money and the ability to blow up their drivers, with our screw ups. The tech support lines would never shut up.. I could see the warrantee lines, behind, OOPS! and expect the manufacture to pay for their messing around. I could hear the conversation. I don't know, it just started smoking and quit working.. :-) Regards |
@erik_squires"best sounding is not how I would universally classify ACTIVE crossovers." I got this part. Maybe you had experience (A/B comparison) with it and I am not going to dispute that. But why the complexity and the desire to avoid an extra A/D, D/A conversion step are important "negatives?" Why does that become "negatives"? I thought being able to avoid A-D-A in the passive crossover greatly helps preserve the quality of signal. Maybe you know something that I don't... |
Of course, active crossover systems, because they utilize two or more amplifiers are much more complex, and require more careful engineering and component matching to pull off properly. When done right, they can be quite good. These days, one is tempted to go fully digital-- use DSP to not only accomplish driver crossover, but to also apply room correction, driver correction, etc., all in one step. I have heard such systems, but none that really bowled me over (that is not to say that the DSP was the cause of any sonic issues). The closest I heard to an apples to apples comparison occurred MANY years ago. I head the Advent Loudspeaker and the powered version of the same speaker (same drivers, same internal volume cabinet, but one with active crossover and built in amps) in a direct comparison. I could not believe that these were similar systems-- the powered version was so much more alive and engaging. |
Hi OP, Sorry for the short hand. A/D was short for Analog to Digital, and D/A was short for Digital to analog. These are 2 new steps which must be introduced into the chain for active digital crossovers. Question is, how do I evaluate the sound quality of each step and decide if I like it? Well, I have to listen to the finished product. With a few decades of experience listening to a variety of great measuring DAC’s I know that some great measuring DAC’s sound like crap. On paper, if all sounded great, and all A/D and D/A steps were perfect then the active digital crossover offers a number of advantages vs. passive but it’s not necessarily simpler. Now I must deal with multiple amplifiers per speaker. Does the speaker maker pick those? Do I? My point is definitely not pro or anti either approach. My point is that in practicality there are a number of complexities and trade offs which prevent blanket statements about the superiority of either approach.
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@fiesta75, can you install in-line fuse to the wire if you concern about it? Might need to be selective with the quality of fuse and holder. I have not tried it but some people bypass the fuse in the passive crossover and get the speakers to sing with more clarity treble and tighter bass. |
Passive crossovers can get pretty expensive, so I'm not sure how much of the decision comes down to cost with the higher end speakers. Passive crossovers give the manufacturer full control of the crossover interaction once the speakers get into the end users hands....not so much with an active crossover. |
In term of the cost and simplificity of the architecture, I respectively disagree with the passive crossover system is the lesser of the dual when it is applied in the industry. Think about it, the active crossover/DSP/EQ unit has been multi-channel ready and could house, say, 3-way (6 channels) plus subwoofer, in one-box IF the internal DAC is in Hi-Fi quality. This will eliminate the need for the multi-channel DAC module. Also, as an additional benefit, the DSP/EQ module enables one to perform room acoustic correction. You would need purchase and add that into the passive system. When it comes to amplification, the multi-channel PAs can be customized based on the customer’s need just like Emotiva does. Even you have preferences in terms of selecting different PA for each signal frequency spectrum, the power requirement of each P.A. would no longer necessarily be as needy and costly as a single PA serving the full-range frequency. For example, a good 20-30 watts PA should suffice to drive tweeters (2/5kHz - 20 kHz) to sing sweetly. A good 50 wpc and >100 wpc class A/B or D should be prenty to drive midranges (200Hz-2/5kHz) and woofers (40Hz-200Hz). The amplication modules do not need to be manufactured by the venders and, instead, purchased by the individuals to their satisfaction as long as they meet the specification. Note that, in today’s high-end Hi-Fi world, it is quite common that audiphiles purchase expensive monos or multiple stereo amp of enormous power to support their full-range speakers already. Finally, when it comes speakers, as you know, they just need to be wired directly from the PA at the multiple terminals. If you are concerned about lack of protection then adding in-line quality fuses to the wires or terminals should resolve the issue. Therefore, overall, I really do not think the active crossover system will necessarily be more costly or complex than the passive couterpart. It is just the matter of taking paradigm shifts in concept, implemention and business models to make it reality. I am confident that, if you build it, "they" will come. |
@erik_squires wrote:
My take is you’re complicating matters unnecessarily here. Quite a few factors determine the sonic outcome and differences on the active side vs. a passive system, but to me it simply comes down to one listening scenario (active) vs. the other (passive). Comparing the same pair of speakers (indeed a variety of speakers in a range of setups) going from being passively to actively configured, the outcome to my/our ears has always been in favor of the latter - by a wide margin. I’ll spare you the details in perceived sonic differences though and instead cut to the chase: who cares if the A/D to D/A conversion in the DSP unit used isn’t "perfect" when what’s served in the end is the better sounding meal? You can avoid the A/D to D/A conversion with a digital input, of course, having only the D/A conversion to worry about in the DSP, but the same applies: which scenario sounds better on the whole, speculations about the detrimental effects of conversions and other be damned? If a less optimal DSP (bad converters or whatever) still pulls off the trick, then going further with a better DSP is just a bonus, and yet for some reason active has to be "perfect" in all of its implementing steps for many to even consider it, while forgetting all along that passive configuration is hardly perfect itself - far from it, in fact.
Fortunately active config. means amps are less important and less distinguished when presented with an easier load sans passive cross-over, performing much closer to their full potential and also making more effective use of their power envelope. Which is also saying that the choice of amps is less critical with active config. than it is with passive speakers. If in doubt use the same amps from, say, 100Hz on up, and wait to be surprised how well even very cheap amps sound actively configured. If you have simple, 2-way stand-mounted speakers and two different stereo amps lying around, try it out actively. Two different amps crossing over in the 2-3kHz region may not be ideal, though. Myself I have a single point source per channel from ~600Hz on up and a different amp here vs. below 600Hz (and yet another one from ~85Hz and down) - no issue at all. Truly, it sounds great with no perceived lack of coherence. Would a similar pair of amps from 85Hz on up do better in my system? Perhaps, or maybe not - a 600Hz XO would seem somewhat less critical using different amps. If similar amps do fare better, well, then - again - it’s just an added bonus. My choice has been to optimize performance of the MF/HF horn with 30W Class-A (and 111dB sensitivity), and then power the heck out of it from 600Hz on down with a combined 2.5kW per channel with excellent pro amps (Lab.Gruppen and Crown). All of this is the freedom active config. affords you, not to mention setting up filter values by yourself on the fly.
At the end of the day statements on the sonic outcome must arise from the final listening test. In all the setups I’ve heard it compared (as a separate component solution), active has always trumped passive. Let that be a blanket statement on my part for my ears, with the proviso that implementation is paramount, but even so sub-optimally implemented active still showed its merits as that which needed to be followed. |
Maybe because they are old and established? Maybe look at Buchart or Dutch-n-Dutch or Genelecs. And then listen and compare them to passive gear. Both can sound great. |
You missed WHY I was so detailed. My point was to explain why it is impossible to make blanket statements about the superiority of passive or active speakers. While evaluating a complete system is relatively simple, explaining why there's no single element here that automatically and undeniably makes one speaker type superior required explanation. |
@erik_squires wrote:
Your first reply to this thread went:
The problem is your premise: claimed complexity and an extra A/D to D/A conversion representing "important negatives." I tried to explain at least the A/D conversion can be avoided with a digital input, so an A/D conversion step is not necessarily a prerequisite of a DSP. Concerning the "other components," well, the DSP replaces a passive filter situated pre-amplification, so just a substitute here, and extra amps are just that; go with similar ones and it’s just duplication like bi-amping, or mono blocks. I don’t see how that constitutes complexity per se. And what’re the extra components here that "interferes" - more amps? There are just more amp channels, each of which now feeds its dedicated driver segment without a passive filter in between. Any which way you want to bend this, that’s a big benefit. The passive filter in itself on the other hand is one heck of an interference, as it keeps the amp from "seeing" the driver directly and controlling it optimally. The DSP here gets out of the output way and functions on signal level instead. So how does the DSP itself interfere sonically? You mention A/D to D/A conversion as a negative, and I’m saying that as taking over the place of a passive cross-over it’s the least of your problems. Forest for the trees, as they say.
Then why not keep it at that? It seems to me your dodging this simple approach is because you’re stuck with theorizing instead of actually trying out active configuration in your own primary setup, and this is where the real element of complexity may arise: setting filter values by yourself in the digital domain. If however you can deal with DIY speakers and passive cross-over using your ears is the final "tool," you sure as hell are able to take on a DSP and make filter settings on the fly in your listening position. Active configuration is new to many if not most, but the real hurdle seems to be getting started in the first place and break down those presumptions. |
Wow, you so misread me it’s sad. I’ve never disagreed with this approach nor have I dodged it. When comparing a specific implementation this is the right approach. That’s not what the OP asked though, and you keep trying to answer the wrong question, and seem to be policing me for not answering YOUR version of the OP’s question. That’s not going to work. The OP asked a hypothetical and my nuanced answer is to explain why a an absolute answer is not possible. There is no absolute "better" for active or passive in home applications. I have a long history of using active and passive speakers. The active setups I've used, configured or built involved both digital and analog crossovers in home and professional setups, but you keep trying to school the wrong schoolmaster. Maybe you can stop policing my answers now, @phusis because at the end of the day it just seems you want to be contrarian for no particular reason. |
@erik_squires wrote:
Some leeway from original topics is acceptable, you know that, yet it's obviously more convenient to admin-police yourself instead of addressing my remarks. My approach is simply disagreeing with your take on why active has less in store for it, with your reference to complexity and the A/D to D/A conversion step. While replying to this thread and more precisely addressing the OP should be trying to answer on behalf of the companies that generally avoid going the active route, it's clearly your own views you're expressing and your (or another audiophile's) reservations going active, and that's totally OK to me. As such I'm merely addressing them. So, in all fairness I believe we're both a bit off-topic here.
Your answer is just as absolute, don't you see it? Hypothetically, why wouldn't active be better, or passive for that matter? Why this staunch adherence to "there is no better" when there could very well be a better part of the two in vital aspects of sound reproduction?
I'm not a contrarian, I simply disagree on your views expressed to far, with the arguments laid out by me already. |
You want to walk around in a circle. You argue against my statement that there's no better because there's no specific, then you argue I should use specific examples, and then you say either view is an absolute and should not be used. Have fun running in circles, @phusis
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@erik_squires wrote:
More like a self-induced vertigo on your part. At several junctures I sought to have you have elaborate on your stance when faced with my views, but all you care to do is call me in the wrong as having misunderstood you or not replying to what the OP inquires about. As your wrote:
Strictly speaking, how’s your reply above an answer to the OP’s actual question (which btw. is not "hypothetical," but refers to a factual matter) "why the vast majority of companies in this industry still chooses the passive route"? Instead you hone in on the OP’s claim (the claim that spurs on the OP’s above question to begin with) about the active DSP route generally being considered the best sounding. That’s what I chose to respond to as well, though not the OP’s claim but rather your opposing take that "There is no absolute "better" for active or passive in home applications." Alright? If your takeaway from the fact that most companies still chooses the passive route is that there’s no absolute better between passive and active (so why bother with active?), then I disagree. That choice, to my mind, mostly boils down to convenience and convention, and adhering to the market that’s still most pronounced. As it is, buying bundled, active speakers is really reducing complexity compared to a passive setup, whereas the active-as-separates solution with preset filter values in an included DSP is more akin to putting together a passive system. Such manufacturers could either be selling amps for the speakers they find the right partners (like Sanders Sound), or they could recommend amps for buyers to consider. The real complexity part (and this is where I would agree with you) is setting up an active-as-separates system by yourself, that is to say first and foremost setting up filter values on your own, and to a lesser degree choosing the amps and active XO - be that a DSP solution or other analogue electronic XO. What’s really the most complex part is finding the right filter values in conjunction with measurements, speaker placement and acoustic implementation, as you may know, whereas the rest is not much different from choosing components to your passive setup. If anything amp-speaker matching is actually easier with an active setup, it just requires more amps. To sum up, and even an admission: yes, my "blanket statement" - which is not to speak on behave of others (other than several audio-friends of mine) but merely to express my own experience in a specific context - is that a carefully implemented active-as-separates system handily beats a passive ditto, period (and I have the experience with a range of setups comprising the same speakers being converted from passive to active, to back that up). Everything can be tailored to the specific environment and driver segments with the amps that feed them, and the DSP filter settings can accommodate much more elaborately and not least more precisely a range of aspects that passive filters can only dream of. Take it or leave it, Erik; blanket statements to some are just fully formed assessments to others that don’t mind calling things for what they are, be that better or worse. Why is that so provocative to you? :) |
@erik_squires @phusis , there needs to be no additional adc/dac conversion if one chooses his front end gear wisely, i.e., keep it digital --> high quality dac+dsp+crossovers processor all in one device. A couple of minidsp devices come close, but have poor quality control...some units are defective. Two stereo amps (boxes), 1 lower power class A for mf+hf, 1 high power stereo amp for bass drivers.....one 4 channel amp or 1 additional low power stereo amp if going 3 way, i.e., number of extra boxes can be kept low (it is not an issue as compared to purist passive systems). The elephant in the room is having competent speaker measurements and the ability to understand them to accurately implement an active system. For guys lacking the technical prowess to do the latter, an active system is dead. Hence, passive systems remain popular. For multichannel guys who’ve gone through the rigor of setting up prepros and so on, this isn’t complicated, it falls in the general wheelhouse. If a guy is used to purist plug n play devices, it could get complicated until he goes through the learning curve. |
@deep_333 wrote:
The digital-input DSP isn’t necessarily better. I use a Xilica unit with an analogue input (and so an A/D to D/A conversion), and it’s a great DSP - meaning it’s sonically quite transparent. Many however seem to believe avoiding the A/D conversion step is paramount, but as a single parameter it’s really moot in the greater scheme of things.
Oh, haven’t I been there, experimenting with different power amps in my outboard active 3-way setup (incl. subs). It was my initial route as well, going with a high-end, lower wattage class A amp (Belles) for the mids/tweeter compression driver-driven horn, and 2 high power, different class D variants (Crown and LabGruppen) for the mid bass and subs respectively. It sounded very, very good, but once I got 3 virtually similar class A/B power amps from MC² Audio for the entire frequency range, things really started to fall into place. I tried all permutations with a range of power amps, and one of the real eye openers was adding the same amp as the ones used for the top section and mid bass to the subs; a vital part of the tonality imprinting rests in the subs region, but few seem to realize this and instead resort to using cheaper, typically class D variants (that are different amps compared to those used in the frequency span above) for the lower octaves, with all that implies. The thing is, you don’t find out the significance of this unless you try swapping amps and trust your ears as the final judges here. That’s one of the beauties of outboard active, and as implemented with subs as well gives you a range of amps to experiment with here, instead of whatever is used preassembled in the SVS, REL, JL Audio sub or other. The challenge of using similar amps top to (subs) bottom is finding a high quality, high power amp that does it all, but once you get your head around it quite a few options lend themselves for this purpose, and actively you only harness a bigger potential of a given amp.
Sure, it’s not the easy plug-and-play. |
I don't think having the same amps in an active multiway is a bad idea at all. It's usually avoided due to cost but there is a big advantage: sonics: all the amps present exactly the same "sound" or character to all drivers. This removes one variable in achieving an integrated system when you go active. It also assures the user that the system has little chance of compromised dynamic range. Headroom in amplifiers is never a bad idea. BTW-active does not have to be a digital. ATC makes all analog active systems and has done so for many years. ATC also uses the "same amp" design principle, but they build three amps using the same topology and parts and outputs but with 3 different output power capabilities to match up drivers sonically, without spending extra on larger power supplies, output devices etc where you don't need them. ATC actives enjoys an excellent reputation for dynamics, perhaps proving the point. Its one of the reasons they are popular in studios where dynamics are definitely excessive when tracking. In the mix stage, one applies compressors or other methods to reduce dynamics, but in the tracking (capture) phase most engineers prefer to leave the signal as untouched as possible. Brad |
