Respectfully, the main message has been missed.
It's not that Earl has a great speaker per se, but that his carefully designed horn tweeters are far less entwined in complex ways in room acoustics than other peoples' systems. When that is the case, you have a 20% chance of carrying the speaker enclosure from your woodshop, computer room, storeroom, or dealer and having it sound OK in your music room.
For everybody else with a 10% chance, really makes sense to have control over the sound in your music space and at your listening chair from DSP.
Great waste of time to engineer a passive crossover to three decimal places and waste of money to source components thinking they can accomplish that.
B.
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Absolutely and this is quite understandable in many cases. If the whole system is active and the amps and crossover are internal THEN one can actually reduce total system cost. But it is not doable for smaller manufacturers and DIY to have custom electronics specific to a design. I looked into this later option for myself and the tool-up costs were significant, but once you paid off those the costs, the two costs were comparable between active and passive.
I'm not poo-pooing active, I've done it many times. I'm criticizing the wide spread belief that active is inherently superior - it's not. Both have advantages and disadvantages.
Yea, that's not quite fair. When I used an internal sound card I NEVER saw any problems with HOLM. But I kept blowing up internal sound cards so I switched to USB. Then I saw a few times when the sync was lost completely, but this was easy to detect as it jumped something like 100's of samples. Just take the data again and all was well. SO WHY SWITCH to another unknown approach!
And remember when I started doing this, HOLM was just about the only software that did what I needed and they were very accommodating. Had the programmer stayed at Holm I believe it would be the premier software of today, but he left more than 10 years ago. Before Holm I wrote all the data taking software myself and I was about to write a swept sine measurement software. Then I discovered Holm - why reinvent the wheel!?
I haven't done any acoustic measurements in several years, but I used Holm for well over a decade. I'll stick with what I know works, thank you!
I think that your %s are a little extreme. The direct field of a speaker will account for some 50-60% of what you perceive so a speaker with a good direct field will be basically independent of the room. If the polar response has a flat DI then another 20-30% becomes independent of the room.
The last 20% - the bass - is entirely room and setup dependent and only DSP and multiple subs can do that job correctly.
My passive crossovers have dozens of components and they are not at all simple to design. It takes a complex piece of software to get there and a lot of time and data. Wave-guide systems require very complex crossovers to get right. Its the direct radiator systems that have the simple crossovers, but the terrible polar response.
Thanks for your thorough answer.
Beyond that, I don't think I've ever heard an active crossover that sounded better than a well engineered passive one. Does active sound more spectacular, more "Hi-Fi"? Yes it does. But more natural, more musical? No, not at all. I remember the easy seduction of the active crossover, but it wore off over the years.
Of course that's purely subjective, so take it for what it's worth.
I don't totally agree with that. I say that active can often win on sound quality with a minimal amount of work. That's been said in this thread (and others) by several people, including me. Active can often get you to good results quickly. Unless you have a lot of practice - or luck - with passives it can take a lot of time and frustration to get to the good results.
Beyond that, I don't think I've ever heard an active crossover that sounded better than a well engineered passive one. Does active sound more spectacular, more "Hi-Fi"? Yes it does. But more natural, more musical? No, not at all. I remember the easy seduction of the active crossover, but it wore off over the years.
Of course that's purely subjective, so take it for what it's worth.
As for HOLMImpulse, my experience mirrors Earl's. I still use it often.
I've checked and double checked the time alignment doing measurement after measurement on the same driver, and they always align. Same thing with line inputs. Can't swear to perfect time alignment between different drivers, but I don't understand why they wouldn't be. I also use a USB soundcard.
Amazing that it's been 10 years since development stopped on HOLM. How time flies.
I've checked and double checked the time alignment doing measurement after measurement on the same driver, and they always align. Same thing with line inputs. Can't swear to perfect time alignment between different drivers, but I don't understand why they wouldn't be. I also use a USB soundcard.
Amazing that it's been 10 years since development stopped on HOLM. How time flies.
That had been my experience too Michael, I was a bit surprised when my Sanity check showed a change. It is possible that my mic dropped slightly between the first and last measurement. I was holding the whole thing onto my tripod with masking tape. I probably should devise a proper mount.
extracting minimum phase and adding offset and comparing against the measurements I had including phase, resulted in exactly the same result, so all is ok. Just an odd aberration that I haven't seen before, which coincidentally happened within a few days of it being raised here
Tony.
extracting minimum phase and adding offset and comparing against the measurements I had including phase, resulted in exactly the same result, so all is ok. Just an odd aberration that I haven't seen before, which coincidentally happened within a few days of it being raised here
Tony.
Thanks for your thorough answer.
I don't totally agree with that. I say that active can often win on sound quality with a minimal amount of work. That's been said in this thread (and others) by several people, including me. Active can often get you to good results quickly. Unless you have a lot of practice - or luck - with passives it can take a lot of time and frustration to get to the good results.
Beyond that, I don't think I've ever heard an active crossover that sounded better than a well engineered passive one. Does active sound more spectacular, more "Hi-Fi"? Yes it does. But more natural, more musical? No, not at all. I remember the easy seduction of the active crossover, but it wore off over the years.
My jaws dropped when I saw I actually said that. It must have been taken out of context. Here is the entire paragraph. Allow me to underline the context.
So what is being claimed here is if one is equally careless, active wins. As you said, passive takes patience to craft, and it is not easy. (However, let's not discourage ourselves too much. It is not that hard either.)
Which means I agree with you completely on your first paragraph.
W.r.t. your second paragraph, a well-engineered passive is hard to defeat. Certainly not without an equal amount of engineering going into the active.
I might still not seeing the big picture from a bird's eye view, but I am getting closer: I have a pair of Mission 731 gathering dust, and there are many ways its sound can be improved upon. Let's take it apart, rip the crossover, bi-amp it, and run a brick wall filter at 2k. (The original was around 3k. This is a thought experiment, but would likely be proven true if I had actually tried.) We are going to get a leap in sound quality.
But that is because the speaker was designed for a certain budget, the passive crossover was not impressive to begin with, and the crossover point was too high relative to the C2C, not to mention the midrange cone break-up. All these can be reduced by a steeper slope.
The active is always capable of shrinking flaws more effectively than a passive. But that cannot be considered "well-engineered". A truly well-engineered crossover is totally integrated with the cabinet design, fits like a groove and just "disappears". Once this happens the system does not benefit any further from any steeper slope, and thus active will no longer be able to contribute any more than passive in such a system.
I hope this explains what you observed. A well-engineered passive simply "disappears", and is thus natural and musical. An active piled on an inferior speaker simply shrinks the problems smaller and smaller but they will never go away.
I cannot deny the hands-on experience of countless people who did exactly this: rip out the original passive crossover of some speaker, go active bi-amp, and got an enormous gain in sound quality.
I cannot deny the hands-on experience of numerous people who got the opposite result: finding no improvement at all going active, and even going back to passive for cost and convenience.
Both of these are true and undeniable. Why? Because it depends on the speaker.
I cannot deny the hands-on experience of numerous people who got the opposite result: finding no improvement at all going active, and even going back to passive for cost and convenience.
Both of these are true and undeniable. Why? Because it depends on the speaker.
If I may ask, how is getting a wave-guide system crossover right, more complex than a direct radiator?
In the end, to obtain the magnitude and phase we want for good summation and pattern control,
what can we adjust beyond xover freq, type, order, supporting filters (EQ, shelving, all-pass, etc), level, and delay ?
It seems the adjustments are the same for any system...I'm having trouble seeing how wave-guides make a difference...
I get that we want to tune for both on and off axis, and maintain smooth pattern control through transition.
But that's true for any system design, no matter what the pattern control design, isn't it? Thx.
I am very ignorant of HLCD but I would expose my ignorance anyway by saying that the horn design has an influence on the impedance curve which adds another level of complexity to the passive design not to mention the FR is changed and has to be considered from multiple (actually an infinite number of) off-axis angles.
Waveguides have very uneven frequency response when un-EQ'd, far more than a direct radiator. This means more filter components to correct. And, unlike direct radiators, a good waveguide has a falling response (-6dB/oct,) not flat, which also must be corrected. This means that in addition to the crossover filter one must correct a constant fall-off AND a non-uniform response. In my speakers the HP filter is less than 1/3 of the parts needed for the waveguide as a HF sub-system.
It is true that one wants to maintain pattern control through the crossover and to have a flat DI, but since direct radiators never have a flat DI they cannot ever achieve this goal, while waveguides can. SO while waveguide require far more complex crossovers than direct radiators they are able to achieve the ideal that a direct radiator cannot.
I think that you must understand the inherent acoustical differences between a waveguide and a direct radiator before any talk about electrical correction can be made, because these differences are paramount. These acoustical differences cannot be compensated for by electronics.
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I think that we can all agree that the sound quality differences between active and passive are dominated by the specific implementations, not the nature of the implementation, whether active or passive. Active will always be easier, but for DIY will always be more expensive, with complexities in the system setup (multiple amps, etc.) than passive (which can be driven with a single channel from say a receiver, which active cannot.)
For high volume commercial systems active is always going to be the better choice as we have seen in the marketplace. For low volume it is more problematic. But these choices are purely economic not sound quality.
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The new plateamps are also dirtcheap compared to many simple 2 channel amplifiers. And most drawings for great cabinets are easily obtained from the internet - same with decent drivers. And in a jiffy, you'd be playing great music in your home - even with the possibility to correct the worst room note in your specific listening room and in this way reach further than what most speakers will normally present. Then you can always experiment with some subs and read up on the theory behind acoustics. The point is, that with the development of cheaper DSP's and amplifiers, great results can be made.
But still - nothing will be better than the room, the cabinet and the drivers. I just been to Munich for three days. And for the price of a set of bad sounding Sabrinas - I can easily build something much better sounding for much less - they dont even look good or anything. Only speakers that I will remember from the trip, will be the active ones. The rest is mostly clining on to the past by the means of .... yeah.... I dont know. Even Vandersteen used some kind of EQ in the lower octave - not a DSP - but at least some kind of correction and adaptation to the room.Some of the passives could maybe sound good in some perfect room, but who has that?
By the way - I read most of Earl's papers and saw he's precentation about subwoofers like 10 times(to understand it better) and now use 4 subs, which I also pushed on to my friends - and this works awesome!! Thank you for your work Geddes
But havent quite cought up on the waveguides though - still playnig with great enjoyment on more classical designed front speakers
But still - nothing will be better than the room, the cabinet and the drivers. I just been to Munich for three days. And for the price of a set of bad sounding Sabrinas - I can easily build something much better sounding for much less - they dont even look good or anything. Only speakers that I will remember from the trip, will be the active ones. The rest is mostly clining on to the past by the means of .... yeah.... I dont know. Even Vandersteen used some kind of EQ in the lower octave - not a DSP - but at least some kind of correction and adaptation to the room.Some of the passives could maybe sound good in some perfect room, but who has that?
By the way - I read most of Earl's papers and saw he's precentation about subwoofers like 10 times(to understand it better) and now use 4 subs, which I also pushed on to my friends - and this works awesome!! Thank you for your work Geddes
But havent quite cought up on the waveguides though - still playnig with great enjoyment on more classical designed front speakers
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