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Why do passive speakers still exist?
- Thread starter Pearljam5000
- Start date
From what I've seen, speaker driver efficiencies follow this trend:
Subwoofers often have the lowest efficiency, in order to keep the required box size down.
Midranges and fullranges often have the next lowest efficiency, though you can certainly find examples of high efficiency midranges.
Woofers come next.
Tweeters as a group probably have the highest efficiency.
On the other hand, the spectrum for music is typically quite tilted. The means you need more power at low frequencies in general, though the increase may flatten off somewhere around 100 Hz.
What this means is that a rather typical consumer may need 500 watts for their subwoofer (use a separate amp here, it makes total sense). Then they need 200 watts for their woofer, 50 watts for their mid, and 15 watts for their tweeter (unless they want to pass test signals with flat spectrums correctly). The issue here is that once you need that 200 watts for your woofer, if the technology is perfectly capable of simultaneously providing the 50 watts for the mid and the 15 watts for the tweeter, then using separate amps just adds to the expense without any real gain.
As for the topic of the larger thread:
Regarding DSP, it's been mentioned that adding delay to align acoustic centers only works for one spot. With dispersion in mind, it's not typically a good idea to have wildly different acoustic centers. Passive crossovers can be used very effectively to combine drivers that aren't too far separated in distance, although variations from theoretical slopes will be made. There's nothing magical about text-book slopes anyway, so deviating does not degrade the sound.
Phase can be manipulated with DSP, but a speaker doesn't have to be active to do it. Additionally, typical speaker phase distortions above 1000 Hz are completely inconsequential. The same is true below 200 Hz where the room dominates. There's probably some small frequency range between 200 Hz and 1000 Hz where phase distortion could even be perceived by most people (listening to speakers in a room), and then there wouldn't be a strong preference for distortionless playback. Phase correction is just not very important to human perception of sound... it can be more important for marketing with pretty graphs, though.
Passive crossovers sometimes have to attenuate a speaker driver to match other less sensitive drivers in the speaker. This wasted energy could be conserved with an active speaker. On the other hand, if you're using more amps, they have a certain draw all the time. I don't think this is a big deal either way.
DSP can also make the frequency response flatter in magnitude. However, there's a point where this also becomes inconsequential. Is a speaker that's +/- 1 dB from the target response perceived as better than a speaker that's +/- 2 dB? How about 3 dB? There are plenty of passive designs that are within +/- 3 dB (or less) from their target.
As an amateur speaker designer with a degree in electrical engineering, and a couple decades of DSP experience... I design passive speakers. Even my multi-way line arrays with very narrow and consistent beamwidth are passive. I could have designed them to use DSP, but I figured it was in my best interest to check first whether a passive implementation was possible. It took me a few months to figure out how to do it for one particular design, and then a few more months to generalize it, but it's possible. They are efficient enough that I honestly run them off an AVR. A nice, cheap, mass produced AVR.
Subwoofers often have the lowest efficiency, in order to keep the required box size down.
Midranges and fullranges often have the next lowest efficiency, though you can certainly find examples of high efficiency midranges.
Woofers come next.
Tweeters as a group probably have the highest efficiency.
On the other hand, the spectrum for music is typically quite tilted. The means you need more power at low frequencies in general, though the increase may flatten off somewhere around 100 Hz.
What this means is that a rather typical consumer may need 500 watts for their subwoofer (use a separate amp here, it makes total sense). Then they need 200 watts for their woofer, 50 watts for their mid, and 15 watts for their tweeter (unless they want to pass test signals with flat spectrums correctly). The issue here is that once you need that 200 watts for your woofer, if the technology is perfectly capable of simultaneously providing the 50 watts for the mid and the 15 watts for the tweeter, then using separate amps just adds to the expense without any real gain.
As for the topic of the larger thread:
Regarding DSP, it's been mentioned that adding delay to align acoustic centers only works for one spot. With dispersion in mind, it's not typically a good idea to have wildly different acoustic centers. Passive crossovers can be used very effectively to combine drivers that aren't too far separated in distance, although variations from theoretical slopes will be made. There's nothing magical about text-book slopes anyway, so deviating does not degrade the sound.
Phase can be manipulated with DSP, but a speaker doesn't have to be active to do it. Additionally, typical speaker phase distortions above 1000 Hz are completely inconsequential. The same is true below 200 Hz where the room dominates. There's probably some small frequency range between 200 Hz and 1000 Hz where phase distortion could even be perceived by most people (listening to speakers in a room), and then there wouldn't be a strong preference for distortionless playback. Phase correction is just not very important to human perception of sound... it can be more important for marketing with pretty graphs, though.
Passive crossovers sometimes have to attenuate a speaker driver to match other less sensitive drivers in the speaker. This wasted energy could be conserved with an active speaker. On the other hand, if you're using more amps, they have a certain draw all the time. I don't think this is a big deal either way.
DSP can also make the frequency response flatter in magnitude. However, there's a point where this also becomes inconsequential. Is a speaker that's +/- 1 dB from the target response perceived as better than a speaker that's +/- 2 dB? How about 3 dB? There are plenty of passive designs that are within +/- 3 dB (or less) from their target.
As an amateur speaker designer with a degree in electrical engineering, and a couple decades of DSP experience... I design passive speakers. Even my multi-way line arrays with very narrow and consistent beamwidth are passive. I could have designed them to use DSP, but I figured it was in my best interest to check first whether a passive implementation was possible. It took me a few months to figure out how to do it for one particular design, and then a few more months to generalize it, but it's possible. They are efficient enough that I honestly run them off an AVR. A nice, cheap, mass produced AVR.
Thread Starter
#406
I'm quoting what he wrote
"
" Both speakers deliver the best sound for money ive ever heard. They actually (to my ears) sound very alike. Transparent with a tweeter that never becoms to harsh .
Genelec 8361A has a slighly better soundstage due to the coaxial design. The midrange on the 8361A is also just a bit better , more open , clearer.
Both speakers are really good, but you need to integrate them to the room via DSP . They become twice as good then. It´s day and night in difference ."
" But they are very similar. What I can say is that the 8361A has a larger soundstage, due big wavegiude and coaxial driver. I would say that they play with a bit more ease as well . Not surprisingly, it’s a bigger monitor with more powerful amplifiers for the low end . Crazy dynamics . Both speakers are amazing, you can’t really go wrong. If I had another room , I would have saved the DD . After almost two years , it was time to move on and try something else . The 8361a is the only speaker that can be compared with the DD8C in my opinion , at roughly the same price. Do I miss the 8C , yes . Do I regret buying the 8361A , No ."
"
" Both speakers deliver the best sound for money ive ever heard. They actually (to my ears) sound very alike. Transparent with a tweeter that never becoms to harsh .
Genelec 8361A has a slighly better soundstage due to the coaxial design. The midrange on the 8361A is also just a bit better , more open , clearer.
Both speakers are really good, but you need to integrate them to the room via DSP . They become twice as good then. It´s day and night in difference ."
" But they are very similar. What I can say is that the 8361A has a larger soundstage, due big wavegiude and coaxial driver. I would say that they play with a bit more ease as well . Not surprisingly, it’s a bigger monitor with more powerful amplifiers for the low end . Crazy dynamics . Both speakers are amazing, you can’t really go wrong. If I had another room , I would have saved the DD . After almost two years , it was time to move on and try something else . The 8361a is the only speaker that can be compared with the DD8C in my opinion , at roughly the same price. Do I miss the 8C , yes . Do I regret buying the 8361A , No ."
Hmm...
To paraphrase Mr Hitler pounding his fist in the popular parodies.... Genelec! Genelec! Genelec!
Genelec is a Finnish company.
I don't know Finnish language.
I've never heard the proper pronunciation for Genelec.
Is it pronounced with a hard or soft "G" - hard like gun, or soft soft like general?
I presume, like general, but, ???
To paraphrase Mr Hitler pounding his fist in the popular parodies.... Genelec! Genelec! Genelec!
Genelec is a Finnish company.
I don't know Finnish language.
I've never heard the proper pronunciation for Genelec.
Is it pronounced with a hard or soft "G" - hard like gun, or soft soft like general?
I presume, like general, but, ???
I used to think so too, then I researched where the goal posts are for making a cab for electric piano for one of my prosound customers.
What I found is that the 27 Hz fundamental of low-A is so weak it's inaudible. The 54 Hz first overtone is also inaudible.
piano sound spectrum - YouTube
The lowest frequency which might be barely audible is the 62 Hz first overtone of low-B.
Nothing against 27 Hz in-room as a worthy goal, but imo it's not necessary for piano. As anecdotal evidence of this, consider that low-A on a piano does not begin to make the room shudder like low-A on a synth does.
What I found is that the 27 Hz fundamental of low-A is so weak it's inaudible. The 54 Hz first overtone is also inaudible.
piano sound spectrum - YouTube
The lowest frequency which might be barely audible is the 62 Hz first overtone of low-B.
Nothing against 27 Hz in-room as a worthy goal, but imo it's not necessary for piano. As anecdotal evidence of this, consider that low-A on a piano does not begin to make the room shudder like low-A on a synth does.
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I have a pair of Morrison Audio Model 19.1's that were designed to be used with an external crossover. They are designed the way I mentioned. Fortunately, they only have two drivers per speaker, so I only need to have a four channel amp to power them.
This was the problem I faced when I searched for an amp for them. I wanted Purifi for the woofers, but I didn't necessarily need all that power for the tweeters. I searched for amps that could do 10-50 watts with the same performance as the Purifi for less money, but I never found anything. The closest thing was the Neurochrome Modulus, but that wasn't particularly cheap, so it defeated the purpose. I even thought about using a low output impedence headphone amp, but decided against it. I eventually just settled with a four channel Purifi.
If we ever got passive speakers with separate inputs for each drivers, then it would take a special amp to power them. Something with 20 watts for the tweeters, and several 50 watt modules that could power the mids or be bridged to power the woofers.
This was the problem I faced when I searched for an amp for them. I wanted Purifi for the woofers, but I didn't necessarily need all that power for the tweeters. I searched for amps that could do 10-50 watts with the same performance as the Purifi for less money, but I never found anything. The closest thing was the Neurochrome Modulus, but that wasn't particularly cheap, so it defeated the purpose. I even thought about using a low output impedence headphone amp, but decided against it. I eventually just settled with a four channel Purifi.
If we ever got passive speakers with separate inputs for each drivers, then it would take a special amp to power them. Something with 20 watts for the tweeters, and several 50 watt modules that could power the mids or be bridged to power the woofers.
I don't know if anyone already said this, but it is very easy to get into the business of manufacturing passive speakers. Wood or MDF cabinet construction is definitely low tech. Drivers are available from many sources and in low quantities. Crossover and port design is well documented and both are simple to make. Going active, especially with DSP adds at least two levels of complexity, and likely requires larger production runs, more engineering expertise and more investment.
Actually I bet by now 90% of speakers sold ARE active...but nowadays they are compact Bluetooth. As for the rest, force of habit, it's the known thing, blah blah. Also because (if we're talking hi-fi speakers) my observation is few active ones have built in streaming, and certainly not AirPlay. Sure you can add boxes etc etc etc but I think customers want SIMPLE.
Heissmann has also an English version of all his pages, in this case
https://heissmann-acoustics.de/en/dxt-mon-vs-neumann-kh-120a/
https://heissmann-acoustics.de/en/dxt-mon-vs-neumann-kh-120a/
True enough BUT if that were the case with the music I play, my pair of subs (which play 80 Hz & down) shouldn't have much to do. Because not all my music has MOOG's & other synth (Edgar Winter comes to mind. I listen to synth from Morton Subotnick to now.) But the fact is my subs have quite a bit to do with most of the music I play. Now, Jazz Trio's is not something I normally listen to although I do (and almost everything else, aside from opera). I was using that particular statement (coped from somewhere else on this site) to emphasize that without bass it ain't no good. 16 Hz on some organs too. 60 piece bands Also room pressurization (the feel of the presentation) is definitely something I like. There is information there and I have made specific efforts to be able to play it. And I know for a fact that I can hear 20 Hz (and definitely perceive lower than that) on my system. As of yet I do not have any DSD on it. I have the equipment to do so, just other things have kept me from doing it. By the end of the year is my goal to be playing with what I have. It will be a steep learning curve, as I am not particularly familiar with computers for this use (better at using them involving monitoring parameters of what is going on in performance engines while they are performing). I typically run 800 watts at 2 ohms per sub. The amp FR is ruler flat to below 10 Hz, and well extending past the 40 kHz limit of this measurement (AMIRM) [one of my personal NAD 2200 triplets], which runs the pair of subs, the other 2 run the L & R speakers at 1.2Kw each. Right now I am at my power limit for the duel 4 Ohm voice coisl running as 2 Ohm voice coil subs. I have the power and I have the subs integrated into my system. So, why live with soft, mushy or non existent bass?
I hope I didn't come across as advocating living with soft, mushy, or non-existent bass. That would have been stupid and counter-productive, given that I'm a subwoofer manufacturer!
Regarding the thread topic, Earl Geddes has done active version of his Summa for customers who were willing to pay the upcharge. My recollection is that he switched to active in his own system, and then went back to passive, as he did not find the improvement to be worth the hassle.
At one time I was looking into making a dedicated studio monitor, so I spent a lot of time on Gearslutz and similar fora, reading (among other things) active vs passive threads. The impression I got from the posters who seemed to be the most experienced was that active was the way to go for small mixing monitors. But for the big main monitors, preference among the experienced leaned towards passive monitors, or towards active monitors with external amplifiers. The reason is, if your main monitors go down, your whole studio is severely limited (some used the words "shut down") until they can be put back into service. And with active monitors which have internal amplification, the solution involves panicked next-day-air shipping, and for the speaker manufacturer, a panicked repair/replace job. With passive speakers, when the amp dies you just pull the old Hafler out of the closet and hook it up.
Note that arguably the most important role of the main monitors is "impress the client". As a studio owner, you want to knock their socks off when you play the album you just produced for them for the first time. So you don't want your main monitors going down because one of the many amplifier modules failed.
Active gives the designer more tools to work with, but it cannot make up for fundamental shortcomings. For example, EQ cannot fix a radiation pattern discontinuity in the crossover region.
Regarding the thread topic, Earl Geddes has done active version of his Summa for customers who were willing to pay the upcharge. My recollection is that he switched to active in his own system, and then went back to passive, as he did not find the improvement to be worth the hassle.
At one time I was looking into making a dedicated studio monitor, so I spent a lot of time on Gearslutz and similar fora, reading (among other things) active vs passive threads. The impression I got from the posters who seemed to be the most experienced was that active was the way to go for small mixing monitors. But for the big main monitors, preference among the experienced leaned towards passive monitors, or towards active monitors with external amplifiers. The reason is, if your main monitors go down, your whole studio is severely limited (some used the words "shut down") until they can be put back into service. And with active monitors which have internal amplification, the solution involves panicked next-day-air shipping, and for the speaker manufacturer, a panicked repair/replace job. With passive speakers, when the amp dies you just pull the old Hafler out of the closet and hook it up.
Note that arguably the most important role of the main monitors is "impress the client". As a studio owner, you want to knock their socks off when you play the album you just produced for them for the first time. So you don't want your main monitors going down because one of the many amplifier modules failed.
Active gives the designer more tools to work with, but it cannot make up for fundamental shortcomings. For example, EQ cannot fix a radiation pattern discontinuity in the crossover region.
Last edited:
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