[Pete Schumacher]

A better question would be, why do nearly all audiophiles still use passive (crossovers downstream of power amplifiers) speaker designs?

Note that passives use crude crossovers that waste tons of power and mask the load that the amp is trying to react to while actives (one channel of amplification per driver) offer an overall less expensive solution with greatly improved dynamics, flatter frequency response, and unbelievably full/deep bass in relatively small cabinets.

With computer audio and wireless technologies becoming so popular its easy to see how an active speaker could be the ideal solution for distributing sound throughout the home.

That's a bit simplistic, and a little bit off.  Passive speakers using crossovers that are well designed don't "waste tons of power" in the crossover.  With music as the signal, the vast majority of power is concentrated  below 500Hz, and no crossover I've ever encountered wastes anything but a tiny fraction of that power in the crossover (filter inductor resistance).  Where there is potentially "wasted power" is in the mids and highs where usually more sensitive components than the woofer are used.  And even then, the power "wasted" is minimal.

Why hasn't active taken over?  Simple, to me anyway.  You have to have more amplifiers, especially as you get into 3-way mains.  And active monitors don't allow for someone's proclivities to try out other amps with their speakers.

As to why more speakers aren't higher sensitivity, most of it's been covered.  The simple answer is that in order to have some semblance of full range coverage (40Hz - 20KHz), the enclosures have to become huge if you also want sensitivity above 90dB.

Needless to say, I'm a big fan of these higher sensitivity designs.  Here's my current favorite 92dB+ system being powered by 35W SET monoblocks.

[JLM]

Active vs. passive usually breaks down to an apples and oranges debate, but years ago I auditioned Paradigm Studio 20s ($800/pair 2-way stand mounts) versus Paradigm Active 20s ($1,600/pair with the same cabinet/drivers, OK the amps added overall depth).  The comparison was over before it began.  The Active dynamics were in another league, frequency response was flat (a revelation if you've never heard before, the music just 'makes sense'), and the bass was unbelievably deep/full.  I've never seen passersby in an audio shop gobsmacked before or since, but we had it that day when they realized we weren't playing the Paradigm Studio 100s ($2,200/pair 3-way 4 driver floor standers) that would not have imaged as well.  It was one of only a few true audio epiphanies that I've experienced.

I'll stake my 40 years in audio by stating that no $800 amp would make that kind of difference.

[Letitroll98]

Active vs. passive usually breaks down to an apples and oranges debate, but years ago I auditioned Paradigm Studio 20s ($800/pair 2-way stand mounts) versus Paradigm Active 20s ($1,600/pair with the same cabinet/drivers, OK the amps added overall depth).  The comparison was over before it began.  The Active dynamics were in another league, frequency response was flat (a revelation if you've never heard before, the music just 'makes sense'), and the bass was unbelievably deep/full.  I've never seen passersby in an audio shop gobsmacked before or since, but we had it that day when they realized we weren't playing the Paradigm Studio 100s ($2,200/pair 3-way 4 driver floor standers) that would not have imaged as well.  It was one of only a few true audio epiphanies that I've experienced.

I'll stake my 40 years in audio by stating that no $800 amp would make that kind of difference.

The argument is compelling, especially when one can eliminate the "studio monitor" debate, no matter how valid or not.  My next significant purchase could be an all active speaker system.  We even have a sticky thread on them here.  As far as the "eliminates the choice of amplifier debate", do you really think you're better at picking the perfect amp for a specific driver than the guy(s) who designed the speaker?  As we go deeper in to Class D amps, we're finding they are very load intolerant and it makes sense that they be matched to a driver after the digital crossover.  Now if we could only determine a dollar value on your "40 years in audio" perhaps someone else, not me, would take you up on the wager....

[JerryLove]

A better question would be, why do nearly all audiophiles still use passive (crossovers downstream of power amplifiers) speaker designs?

You ask a lot of questions which assume answers. It's misleading. Let me try some different ones and see how they sound.

Do audiophiles worry that the amp in their speaker my break and functionally take the speaker with it?

Do audiophiles feel that it's more cost effective to purchase a multi-channel amp than an amp for each speaker?

Do audiophiles prefer running speaker wire as opposed to both RCA (with its high loss-over distance) and seperate power?

Do audiophiles prefer having a single location to go to power on-off their equipment rather than walking to each speaker or having to custom wire their outlets?

Do audiophiles the lower weight of passive speakers: especially with in-ceiling or in-wall?

Do audiophiles worry about ventilation on active speakers?

The list goes on.

Note that passives use crude crossovers that waste tons of power and mask the load that the amp is trying to react to while actives (one channel of amplification per driver) offer an overall less expensive solution with greatly improved dynamics, flatter frequency response, and unbelievably full/deep bass in relatively small cabinets.

Really?

I ask because I have a 4-way active speaker set and discovered that having to buy two active crossovers and 4 amplifiers was more expensive than a passive crossover and single amp would have been.

With computer audio and wireless technologies becoming so popular its easy to see how an active speaker could be the ideal solution for distributing sound throughout the home.

For some people it will be. For others there will be a slew of concerns including availability of outlets, wireless range, wireless quality (esp as the bandwidth gets crowded), and higher failure rate (inevitable with more parts).

[BobM]

Nobody has addressed the horn vs cone vs electrostat/panel gorilla in the room. There are just some basic physics that makes a horn efficient and an electrostat inefficient. To make this argument for just cone speakers kind of makes sense in this discussion, since the other 2 kind of dictate the levels of power (meaning current, dampening and necessary watts) needed by their inherent design.

[Freo-1]

The argument is compelling, especially when one can eliminate the "studio monitor" debate, no matter how valid or not.  My next significant purchase could be an all active speaker system.  We even have a sticky thread on them here.  As far as the "eliminates the choice of amplifier debate", do you really think you're better at picking the perfect amp for a specific driver than the guy(s) who designed the speaker?  As we go deeper in to Class D amps, we're finding they are very load intolerant and it makes sense that they be matched to a driver after the digital crossover.  Now if we could only determine a dollar value on your "40 years in audio" perhaps someone else, not me, would take you up on the wager....

I had an opportunity to buy a pair of these at a very reasonable price (considering the retail).  Still, it was a bridge too far for the budget.  They are truly remarkable.


http://www.stereomojo.com/ATC%20SCM50ASLT%20SPEAKER%20REVIEW/ATCSCM50ASLTSPEAKERREVIEW.htm


When one considers how much amps, cables, etc. costs, the price I could have gotten them for was not all that bad. 

[JLM]

You ask a lot of questions which assume answers. It's misleading. Let me try some different ones and see how they sound.

Do audiophiles worry that the amp in their speaker my break and functionally take the speaker with it?  (That's the old integrated versus separates question.  Each must answer for themselves.)

Do audiophiles feel that it's more cost effective to purchase a multi-channel amp than an amp for each speaker?  (You have to do the simple math on a case by case basis.)

Do audiophiles prefer running speaker wire as opposed to both RCA (with its high loss-over distance) and seperate power?  (How long?  Pros do it, can you?)

Do audiophiles prefer having a single location to go to power on-off their equipment rather than walking to each speaker or having to custom wire their outlets?  (Most do standby and unless you're disabled I don't have much patience for that degree of laziness.)

Do audiophiles the lower weight of passive speakers: especially with in-ceiling or in-wall?  (In wall 'audiophile' speakers??)

Do audiophiles worry about ventilation on active speakers?  (Aren't audiophiles trained to position speakers 'un-enclosed' - unlike many amps found in cabinets/racks?)

The list goes on.
 Really?

I ask because I have a 4-way active speaker set and discovered that having to buy two active crossovers and 4 amplifiers was more expensive than a passive crossover and single amp would have been.  (This seems to be a case of DIY.  My head-to-head example shows roughly comparable cost, but vastly superior advantages for active design.  My speakers are single driver and with mono blocks are active by default.)

 For some people it will be. For others there will be a slew of concerns including availability of outlets, wireless range, wireless quality (esp as the bandwidth gets crowded), and higher failure rate (inevitable with more parts).  (OTOH most audiophiles will keep their main rig wired and go wireless for secondary systems where power strips are common.  Why is a guy with 4-way speakers worried about more parts and associated higher failure rates?)

Jerry I find your arguments in this case less persuasive than usual.

[JLM]

Nobody has addressed the horn vs cone vs electrostat/panel gorilla in the room. There are just some basic physics that makes a horn efficient and an electrostat inefficient. To make this argument for just cone speakers kind of makes sense in this discussion, since the other 2 kind of dictate the levels of power (meaning current, dampening and necessary watts) needed by their inherent design.

Agreed.  All else being equal I'd take a good 2 watt amp to a good 200 watt amp.  I debated this issue for years as I wanted to love SETs but could never find a high efficiency (full range) speaker I loved to pair up (and I'm a purist 'speaker guy').  If starting over today with the MSRP of my main rig speakers, I'd have the new Omega stand mounted RS5 based single driver speakers with a swam of powered subs (an active design with properly distributed in-room bass propagation).

[JLM]

I had an opportunity to buy a pair of these at a very reasonable price (considering the retail).  Still, it was a bridge too far for the budget.  They are truly remarkable.


http://www.stereomojo.com/ATC%20SCM50ASLT%20SPEAKER%20REVIEW/ATCSCM50ASLTSPEAKERREVIEW.htm


When one considers how much amps, cables, etc. costs, the price I could have gotten them for was not all that bad.

Those look great, but be careful what you wish for as I bet they need at least 10,000 cubic feet of space to let them really sing.

[sts9fan]

A better question would be, why do nearly all audiophiles still use passive (crossovers downstream of power amplifiers) speaker designs?


Do audiophiles somehow feel that they can match amplifiers to drivers better than the manufacturer?

Do audiophiles make buying decisions based on cool (expensive) cabinets/designs?

Do audiophiles distrust/dismiss the concept (because active studio monitors are biased towards dry/highly accurate versus entertaining sound)?

Are manufacturers so segregated into speaker guy/amp guy camps that they can't/won't collaborate?


Note that passives use crude crossovers that waste tons of power and mask the load that the amp is trying to react to while actives (one channel of amplification per driver) offer an overall less expensive solution with greatly improved dynamics, flatter frequency response, and unbelievably full/deep bass in relatively small cabinets.

With computer audio and wireless technologies becoming so popular its easy to see how an active speaker could be the ideal solution for distributing sound throughout the home.

Because it's more fun!!!

Also, good job plugging your speakers Pete!

[Freo-1]

Those look great, but be careful what you wish for as I bet they need at least 10,000 cubic feet of space to let them really sing.

I'm sure they work well in that environment, but they are successfully used in studios that are often smaller in the listening area.  Besides, I get almost there with the SCM-19's, matching sub, and a high powered custom tube amp.

BTW, these speakers are not very sensitive, and they are among the very best speakers available, regardless of price. Might be a an answer to the OP's question.   

[JLM]

I apologize for not staying on topic.  It's something that irks me when others do it.   

[Tyson]

I think it's as simple as market forces. People don't want large boxes in their living space. It's a wonder sub-woofers have as much traction as they do, we can probably thank the demand for Home Theater for this. The other thing we can blame for poor sensitivity is the incorporation of baffle step compensation into many modern loudspeaker designs. A bigger baffle and a bigger woofer might go a long way towards eliminating the need for baffle step compensation.
Scotty

This!

[pslate]

I think AJ got as close to breaking Hoffman's Iron Law as anyone with the SAM-1 (now discontinued), and it's a great formula. Use a powered woofer, to make the most out of the low end in a smaller enclosure and take care of a lot of the power load, and then have a driver or combination of passive drivers that reach down into the midrange making the most of someones amp preference including lower wattage amps. There was another great series projects someone posted a while back that also took advantage of some of these properties, I think it was called the FAST project or something similar. If memory serves me correctly, a powered woofer and a passive Mark Audio fullranger. That has to be a kick ass speaker. Not all of these projects were active, but I thought I saw one that was. I would love to hear a Mark Audio driver in a SAM-1 like setup. Also the ability to control bass volume on the active woofer is outstanding, if the amp has phase control, just icing on the cake. The active bass is very satisfying.

[Freo-1]

The answer to the OP's question is basically found in the design and performance of speakers such as ATC with the super linear drivers.  VERY few speakers can get as loud with little to no distortion, speaker breakup and still be linear throughout the frequency spectrum as the ATC's, which is why they are used extensively in many of the better studios throughout the world.

It comes down to physics.  There is no free lunch here.  The tradeoff with these speakers is that they require wattage to sound their best (which is easily obtained).  The performance achieved is why they are made. 

[JerryLove]

The reason is because your speakers would become more expensive and larger (and by most eyes less attractive) to add a feature that most people don't want.

[PEB]

Here is the real answer, in simple terms. 

It all comes down to the tradeoff between cost versus electromagnetic motor strength and moving mass of the diaphragm.  In the past, rare earth magnets were not so terribly expensive.  The motor structure was designed with the super strong magnet inside a fairly large diameter voice coil, and almost all of the magnetic field was captured and returned to the air gap. 

Now we are back to ferrite magnets (or neo magnets for smaller drivers, which don't have a sensitivity "problem" to begin with). 

So .. IF you make a woofer with large magnet and iron pieces, tight air gap, large VC diameter, short VC length (= lower excursion), and lightweight cone (=less lower-frequency output), THEN you can achieve higher sensitivity.  This is precisely the formula for a pro audio woofer. 

Your tradeoff is higher cost, less bass, and lower max bass output.  (That's right - higher sensitivity does not automatically guarantee higher max SPL). 

Another approach is to use lower VC impedance, or double-up on the woofers (two 8ohm woofers in parallel for a 4ohm load, which yields +6dB sensitivity). 

Let me be clear that it is always the woofer(s) that sets the speaker's overall sensitivity. 

In conclusion, sensitivity is not an issue if you are willing to simply turn up the volume a bit more.  Why do YOU think speakers should be more sensitive? 

Philip Bamberg
BambergAudio.com
---
I looked up the definition for 'compromise' and found a picture of a loudspeaker. 

[*Scotty*]

One of the most serious consequences of using a low sensitivity loudspeaker is the specter of dynamic compression due the voice coil heating up from all those cheap watts.
 Dynamic life is one of the Hallmarks of a live performance, preserving that life during the reproduction of music in the home goes a long way towards bolstering the illusion that you are hearing a live performance. Distortion also tends to rise when any driver of low to average sensitivity has to produce substantially more SPL than it's 1 watt 1 meter sensitivity rating.
Cheap power is not necessarily the cure for a low sensitivity loudspeaker.
Scotty

[Freo-1]

One of the most serious consequences of using a low sensitivity loudspeaker is the specter of dynamic compression due the voice coil heating up from all those cheap watts.
 Dynamic life is one of the Hallmarks of a live performance, preserving that life during the reproduction of music in the home goes a long way towards bolstering the illusion that you are hearing a live performance. Distortion also tends to rise when any driver of low to average sensitivity has to produce substantially more SPL than it's 1 watt 1 meter sensitivity rating.
Cheap power is not necessarily the cure for a low sensitivity loudspeaker.
Scotty

Depends.  For some speakers, agree.  For speakers that employ these types of drivers, that is a horse of a different colour:


http://www.heliosv.nl/atc/super_linear_technical_white_paper.pdf

[*Scotty*]

AudioTechnology produces similarly high quality drivers. Here's a link to their website and a picture of a driver cut-away.
http://www.audiotechnology.dk/iz.asp?id=4|a|119|||

JBL engineers developed this type magnetic structure in the 1970's.
http://www.jblpro.com/pub/technote/tn_v1n22.pdf
Here is a paper discussing benefits of shorting rings in magnetic gaps.
http://diy-audio.narod.ru/litr/FaradayRingsVoiceCoilImpedance.pdf
Scotty