After reading the whole thread I think that one element left out of the debate to this point is it is much easier and faster to adjust the loudspeakers to a room in which they will need to operate. The same is in most pro application especially touring groups that go from room to room.
Phase alignment and output adjustments are needed room by room. We are in a DIY forum and the need to change rooms with a system is rare.
The commercial offerings are a compromise since they don't know what room the loudspeakers are going to operate in.
From a DIY perspective I could always use the active to start with to develop a passive but like any test gear it is only a start. One last note though is assuring that your coils in the passive do not get into saturation so they operate as designed (common problem in woofer area of the crossover).
Phase alignment and output adjustments are needed room by room. We are in a DIY forum and the need to change rooms with a system is rare.
The commercial offerings are a compromise since they don't know what room the loudspeakers are going to operate in.
From a DIY perspective I could always use the active to start with to develop a passive but like any test gear it is only a start. One last note though is assuring that your coils in the passive do not get into saturation so they operate as designed (common problem in woofer area of the crossover).
Perhaps the proponents of "actives are better" could provide a full set of complete measurements to support their claims as such. If all they do is say "I measure with the most 'sensitive instruments in our galaxy' - my ears" then no resolution can be realized, because either party can make the claim without satisfying it with an proof. The test must compare competitively design speakers with equal drivers and supporting enclosures, as applicable. Crossover slopes should be equal and idealized for the drivers.
I vist another forum on ocassion where one member makes the time to enter almost every speaker build thread to make short and unsupported posts. His claims are always the same, that his "modified" Energy 22 speakers with unnamed active crossover will trump any, ANY passive speaker. Quite the claim, although he's not a very technical or well educated type, nor does he seem to have experience with other speakers, certainly nothing high-end. He's talked about them in third person, like when a guy sees a speaker or amplifier in a shop window or internet image and judges the design and sound based on the appearance. That's a bit of what's taken place in this " annual passive speaker bashing thread". If an individual is going to make these claims, he had best be prepared to support his agenda with unbiased results, or else it's all wishy washy.
I vist another forum on ocassion where one member makes the time to enter almost every speaker build thread to make short and unsupported posts. His claims are always the same, that his "modified" Energy 22 speakers with unnamed active crossover will trump any, ANY passive speaker. Quite the claim, although he's not a very technical or well educated type, nor does he seem to have experience with other speakers, certainly nothing high-end. He's talked about them in third person, like when a guy sees a speaker or amplifier in a shop window or internet image and judges the design and sound based on the appearance. That's a bit of what's taken place in this " annual passive speaker bashing thread". If an individual is going to make these claims, he had best be prepared to support his agenda with unbiased results, or else it's all wishy washy.
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But off-axis problems are related to the box geometry and driver behaviour instead of the xover...
The xover does cause problems. Say you have 24 dB / oct: with delay you can get it to sum on axis but it might not sum nicely off axis at the same time.
Why not? Unless you choose a filter other than a LR and a delay block which hasn't all-pass behaviour, the only way to sum-not-nicely off-axis AFAIK is due to difraction effects... and it is box problem.
The other way is if you consider the baffle-step effect, but there isn't any cure other than choose a different box geometry.
The (vertical) time alignment is affected by the xover slopes, and off axis the alignment is off thus not as nice as on axis. Also, there is pre-ringing from xovers, more ringing on steeper xovers. Pre-ringing is cancelled on axis but off axis where they don't sum perfectly it remains.
Because different drive units have diferent directivity. For example, let's say a woofer is -6dB at 30 degrees off axis compared to on axis, at the crossover requency, while the tweeter is only -1dB at 30 degrees off axis.Now if you use a high-order crossover , and optimise it for a flat response on axis, then there will be a 5dB step in the frequency response at 30 degrees off axis.
A low order filter won't give a flat frequency response of axis either, but the change in directivity will be less abrupt.
Yes...OK, but if we talk about "vertical" effects we have a preeminent one and it is the comb-filter-effect due to floor reflections, so I guess pre-ringing (only in very steep filters but not in a 4º LR one) and vertical time aligment isn´t really that important. 😕
Yep... but we are talking about a not-so-nice driver selection and not a xover's problem... 😱
Of course it's black and white. A gzillion audiophiles will jump down your throat for saying so, but that's the way it is. It's as plain as the failed o-ring in my SRB.
Q. Have I got as much or more control over the signal to each driver in an active system vs. passive?
A. More.
We have to get away from the idea that engineering is some kind of choice, some kind of lifestyle option flexible to the desires of engineers, and imposed on the general public as some kind of whim. You've been spending too much time in low company, Scottmoose.
FWIW - and perhaps I missed entirely seeing it mentioned so far, but when the term "active" is used in respect of multi-way loudspeakers, it can also refer to systems in which simple lower order filtering is done with passive components at line level - with no further filtering after the amp (except of course for the speaker wire 😉 ) - you know, the best and worst of both worlds.
It's a fact that some folks like this approach, and while it won't have the flexibility of analog or DSP line level filtering / EQ, it can certainly work quite well, and is dirt cheap to implement.
Oh, maybe that's the problem?
And as already been suggested, selection of drivers can eliminate the need for pass band filtering in the critical mid range area, even in a 2-way system.
Audio systems do not operate in a vacuum - the application and operating venue also must be considered in the calculus of total system design. There is no single panacea or one size / methodology that fits all.
It's a fact that some folks like this approach, and while it won't have the flexibility of analog or DSP line level filtering / EQ, it can certainly work quite well, and is dirt cheap to implement.
Oh, maybe that's the problem?
And as already been suggested, selection of drivers can eliminate the need for pass band filtering in the critical mid range area, even in a 2-way system.
Audio systems do not operate in a vacuum - the application and operating venue also must be considered in the calculus of total system design. There is no single panacea or one size / methodology that fits all.
Talking about 'real' active xovering, I see they have a signal over AC standard more or less dialed in now.
I'd actually designed a tube active xover for subwoofer use that went down to 12hz when I was using Chartwell LS3/5 A's - however, I used passive line filtering for the HF, so I'm not against the concept - I even developed and used for years an active notch only state variable filter to cancel a bass room mode that plugged directly into the back of my preamp without cables where all of the signal except for that which was being notched passed through only a resistor - I just don't see active eq as a universal panacea to get rid of all passive xover components, except maybe in MP3 world. With my final 'caveman' passive xovered system that I'm working on which will respond flat in rooim to 30 hz or less wo a subwoofer, this point becomes largely moot.
That reminds me that I should get going on adding my sixteen 12" 1 3/8" Xmax SW's for my HT system - I have had the drivers and a Crown K2 without using them for longer than I want to think, but the Onkyo Receiver I have with Audyssey EQ can definitely support this SW config. However, I don't think this setup has the capability to tell me what kind of op amps some LPs are made with, unlike my 'dinosaur' all-tube all passive xovered stereo system.
I'd actually designed a tube active xover for subwoofer use that went down to 12hz when I was using Chartwell LS3/5 A's - however, I used passive line filtering for the HF, so I'm not against the concept - I even developed and used for years an active notch only state variable filter to cancel a bass room mode that plugged directly into the back of my preamp without cables where all of the signal except for that which was being notched passed through only a resistor - I just don't see active eq as a universal panacea to get rid of all passive xover components, except maybe in MP3 world. With my final 'caveman' passive xovered system that I'm working on which will respond flat in rooim to 30 hz or less wo a subwoofer, this point becomes largely moot.
That reminds me that I should get going on adding my sixteen 12" 1 3/8" Xmax SW's for my HT system - I have had the drivers and a Crown K2 without using them for longer than I want to think, but the Onkyo Receiver I have with Audyssey EQ can definitely support this SW config. However, I don't think this setup has the capability to tell me what kind of op amps some LPs are made with, unlike my 'dinosaur' all-tube all passive xovered stereo system.
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Ah, we're decending to the level of personal remarks now are we? Please confine yourself to discussing the matter in question, rather than attempting to insult me, or people I may associate with. Oh well, another one for the old ignore list...
No. We do not have to do any such thing. That is your opinion only. Most competent engineers are aware that they and the products they work on / with do not exist in isolation and operating context needs to be factored in. This is not a black and white matter, however much people may desperately wish to to be. Ergo, what is the optimal compromise varies depending on a host of practical factors. End of story.
And one the most important ones being the desired (i.e. personal) target.
But using an LR8 because it can be done easiliy in an active fashion is definitely the wrong target. I wonder how the OP took driver response into consideration (if at all).
One of the most interesting properties of active speakers is the fact that raw driver responses can be easily taken into consideration. And the other one is that transient improved response can be achieved with reasonably steep filters and reasonable effort. But both of these can't be achieved with textbook filters.
Regards
Charles
With the very best speakers maybe 10% of the way towards perfection, it is possible to have 2 very different loudspeakers that equally valid.
Speaker design is an art of compromise.
dave
Well... how about ATC? Would you say that Bill Wodman knows his stuff when it comes to speaker design? Not many people on this planet would doubt him IMHO.
"an active system will show 15 – 20dB lower intermodulation distortion."
FAQ's | ATC Loudspeakers
And yes, their passive an active counterparts use same drivers in same enclosures, and are as 'idealized' as possible (I've handled passive crossover for ATC100 and one has to be careful lifting it with his knees, not his back).
Most of the other "serious" pro speaker manufacturer's top models are also active (K&H, Adam, ME Geithain, Genelec etc.). Coincidence? Don't think so.
I am struggling to make sense of this point. I think it is referring to the amplifiers and not the speakers. It is reducing inaudible levels of intermodulation distortion in the amplifiers to even more inaudilble levels? Multi-driver speakers benefit from reduced levels on intermodulation distortion compared to single driver speakers regardless of whether they have a passive or active crossover. I would expect the speaker intermodulation distortion to be significantly larger than the amplifier intermodulation distortion at a reasonable SPL.
I was assuming a competent design under normal conditions. Discussions about advantages and disadvantages become pretty hard work if one includes the full spectrum of competent and incompetent designs under normal and abnormal conditions.
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