[G Georgopoulos]

Active speakers are better if they use a good (bi) amplification and active crossover.

Nearfield monitors (pro)

* But most uses cheap amps to reduce costs.

* Good amplification in class D costs money.

* Class AB many use monolithics, with low slew rate!!! 10 V/microS is very common 

* And PSU are also bad.

* Manufacturing quality has gone down a lot these years.

It is better a good passive speakers with a good second hand class AB amp or expensive like Neumann KH 120 A, Genelec... if you want to listen very good records.

mate this one is (tri) amplification!, isn't it good?

Russell,

[JLM]

It's always perplexed me as to why audiophiles who shy away from active speakers use powered subwoofers which in effect are active speakers.   

Josh, you are the man.   

[HAL]

Well the 16 channels of modified Gainclone style Class AB monolithic amps in the fully digital crossover active line arrays do a fine job for sound quality.  Runs without slew problems with a rating of 5V/uS, with 96KHz bandwidth signals.

I see most of the problems with active speakers as the use of linear phase digital systems for either or both the crossover section or the DACs.  There are some pretty convincing papers on why not to use linear phase filters in audio systems.  Have not heard a linear phase filtered DAC in many years of listening that can compare to the minimum phase filter DACs.  Since the DSP and DACs are now in the speaker for active systems, they are now the core of the sound of the speaker.

If the speaker uses all analog active crossovers and Class AB for mids and tweeters with Class D for woofers, that will do nicely, except the channel to channel matching will not be as accurate as the digital implementation.

[Saturn94]

...though a partially active system may have one amp channel for the woofer with a second amp channel driving the mid-range and tweeter through a passive crossover.  Taking the woofer out of a passive speaker level crossover provides the biggest bang for the buck.  (The woofer generates, by far, the largest back-EMF, etc.).....

This how my Soundfield Audio Monitor 1 speakers are designed.   

[Early B.]

Note that a fully active speaker system has a separate amplification channel connected to each individual driver, though a partially active system may have one amp channel for the woofer with a second amp channel driving the mid-range and tweeter through a passive crossover.  Taking the woofer out of a passive speaker level crossover provides the biggest bang for the buck.  (The woofer generates, by far, the largest back-EMF, etc.)

So a set of passive monitors with powered subwoofers is a partially active system that provides the biggest bang for buck? Oh, OK, that's what I have. I never thought about it that way. 

[G Georgopoulos]

confused here,Andrew mentions in the video 3 way fully active system,to me that means tri amping,some of you mentioned mid/tweeter common,if it is bi amping my appologies to maty...

[maty]

 Slew rate of 5 V/microS is too low. Gainclone like LM3886 has 14-15 V/microS.

To listen Beyoncé or Springsteen (by the way, BS: vey bad sound recordings) not problem. But if you would to listen an orchestal mass... maybe 15 V/microS is not enough, maybe.

[maty]

By the way, when I need ro resampler I use SoX (from foobar2000), "Best" or "Normal", but always 50% linear phase. Without aliasing.

With minimal phase the sound is always worse.

BIG Image -> http://maty.galeon.com/WP-imagenes/foobar2000/foobar2000-Nusrat-Fateh-Qawwal-party-Hum-22hz-SoX-88.png

[HAL]

maty,
Glad you enjoy it, but I do not.

For the LM3875 used in the Gainclone with it's power supplies, the range of slew rates is 5-11V/uS.  It sounds great in this application.

[maty]

The same with SSRC resampler, better like Intermediate (aka 50%).

More people say that LM3886 sound better than LM3875 but I do not know.

By the way, look the Akitika (with LM3886TF) specs and measures:

-> http://akitika.com/GT101.html

-> http://akitika.com/measurements.html

and the expensive but with very very good measures:

-> http://www.neurochrome.com/modulus-86-rev-2-1/

[JLM]

This how my Soundfield Audio Monitor 1 speakers are designed.   

Again just another passive speaker that happens to have an active subwoofer (of sorts) built-in.  And again, from the research Floyd Toole has done, ideal mains and sub locations do not coincide. 

[JLM]

confused here,Andrew mentions in the video 3 way fully active system,to me that means tri amping,some of you mentioned mid/tweeter common,if it is bi amping my appologies to maty...

I believe he mentioned that the tweeter and midrange each use the same type of A/B amps while the woofer uses a digital amp.

[HAL]

The physical positions do not coincide, but the wavefronts at the listening position should.  Time delay or large phase control range at crossover will let you do that.  This way the signal at the listening position does not have the possibility of phase cancellation.

[AJinFLA]

Again just another passive speaker that happens to have an active subwoofer (of sorts) built-in.

It's always perplexed me as to why audiophiles who shy away from active speakers use powered subwoofers which in effect are active speakers.

So you understand that there are benefits to active bass?

And again, from the research Floyd Toole has done, ideal mains and sub locations do not coincide.

I know the Harman paper you're going to quote and you've misread it. Not uncommon.
Floyd himself used Mirage M1s, full ranged stereo in his "concert hall" setup.
I've been following AES acoustics and perception research for 30+ yrs. There is no research that says that, in fact, the exact opposite. For stereo reproduction, having full ranged (down to 40hz) from the main speakers is beneficial.
Hence my M1s having that capability.

cheers,

AJ

[JLM]

Yes, AJ I'm a big fan of active speaker design.  Read my reply #3 on this thread.

All the swarm readings I've found (primarily Toole's book "Sound Reproduction") suggest multiple asymmetrical subwoofer layout is the preferred way to even out in-room bass response below the Schroeder "cross-over" frequency, something like 12", 19", 31", and 50" from corners.

[AJinFLA]

Yes, AJ I'm a big fan of active speaker design.

Me too. 
The largest benefit is in the bass, hence as you noted, there are almost zero passive subwoofers. I'm not fond of passive bass, for small enclosures, even less so. However, at higher frequencies, although active is still better, the margin is much thinner, as a great many passive speaker owners can attest to.
I personally prefer active, but I have no issue with those who have cherished love affairs with amps, etc. YMMV.
I'm surprised the other AJ didn't consider an passive/active option, but their marketing department might know far more than I.

All the swarm readings I've found (primarily Toole's book "Sound Reproduction") suggest multiple asymmetrical subwoofer layout is the preferred way to even out in-room bass response below the Schroeder "cross-over" frequency, something like 12", 19", 31", and 50" from corners.

Real rooms are acoustically far to complex for any such rules. The Welti study clearly noted this was theorectical with some assumptions. It is true that it is highly improbable that smooth amplitude can be achieved with only 2 subs at the "main" LR positions. But that is unlikely with any "2" positions. Again, statistically, at least 3 and often several more subs, will be needed for smooth amplitude over a wide area. Therefore, there is no reason to not have them at the main positions...and add as many extra spatially positioned sources as needed for smooth amplitude at many seats...if smooth amplitude only is your goal.
There is no statistic that says mains will/will not be good for 2 of the >3 positions, in real, not "theoretical" rooms.
However, all this tied to HT. For stereo, there are other considerations. One may not need a wide area, only the LP. One may also listen to content that has "stereo" bass. In that scenario, smooth amplitude mono "HT" bass may be insufficient. Dr Griesinger (Harman): http://www.davidgriesinger.com/asa05.pdf
James Johnston (Bell Labs/AT&T): http://www.linkwitzlab.com/Recording/acoustics-hearing.htm

..and where that comes from: http://www.acoustics.asn.au/conference_proceedings/AAS2008/papers/p47.pdf
I've got about 100 more, but my point is that there is plenty research to support the active subs in my M1.
By no means unique, as you noted, but done with purpose.
Ok, now back to the Elacs....a very nice design

cheers,

AJ

[richidoo]

I'm going active.  I just ordered a pair of JBL M2s and a DCi 4|600 amp.   That is 600wpc into 4 channels for biamping them.

Congrats Josh! I figured the demo would eventually push you over the edge! I can't wait to hear them for myself. I don't see in the DCi 4|600 manual any reference to built in DSP functions. What are you using for xo?



I've experimented with active crossovers in the last couple years. DCX2496, Rane RPM26z, VST xo plugins, foobar plugins, JRiver DSP studio, analog line filters passive and buffered. I've still not found the golden egg. Those attempts suffered from poor reliability and/or mediocre sound quality, or in the case of the analog attempt, inconvenient adjustability and difficult filter design compared to dsp. JRiver DSP Studio was the best for adjustment and SQ, but finding a truly audiophile quality multichannel DAC on a budget was impossible. For all the flaws presented by passive XOs, it is still the best practical solution for me, using high quality passive xo parts was better than anything I could do at line level. But my xo is 1900Hz, so the distortion and parts cost is not as big a concern. If I want to go 3way (I do) then passive bass xo at 200Hz is a different animal and the potential distortion and price of high quality parts makes active more appealing. There is a new multichannel USB>I2S adapter from diyinhk.com with mating ES9016 8ch DAC kit which I think will finally enable active dsp crossovers to achieve audiophile sound quality at a very low cost.

I am tempted by active speakers because of my reading about the technical benefits, but also I have had the good fortune to hear a couple active speakers that left permanent marks on my psyche. 2 of my top 5 listening experiences were Selah speakers using DEQX, programmed by Rick. Once you've heard what it can do, especially with linear phase filters, I don't think you will forget that. 

Some good reading about active crossovers:
http://sound.westhost.com/bi-amp.htm
http://sound.westhost.com/biamp-vs-passive.htm
https://www.amazon.com/Accurate-Sound-Reproduction-Using-DSP-ebook/dp/B01FURPS40
https://www.amazon.com/Design-Active-Crossovers-Douglas-Self/dp/0240817389
http://www.t-linespeakers.org/tech/filters/passiveHLxo.html
http://www.linkwitzlab.com/filters.htm
Legacy Wavelet
Xilica DSP
DEQX

I think the lack of active speakers in the consumer market is based on low demand. There just aren't enough hyper audiophiles to warrant development of high value, high performance, audiophile quality speakers that would sell. There are a few who use DCX, etc. Most of (all?) the commercially available active speaker systems I've seen were >$10k. For most of us, passive is good enough, and it's what we know, so turning the big ship of progress is slow going. It will always cost more because of the extra amps and the added complexity is a turn off in a hobby that's already complex enough. A commercial speaker system using simple active xo filters alone, the main benefit would be improved driver electrical damping. A benefit yes, to some of us, but plenty of us run the other direction toward tube amps specifically for the lovely sound of poor damping! More advanced implementations of active xo with dsp based linear phase filters, time alignment, room correction, pre ringing compensation, etc, etc take the active concept to a higher plane that might lure more people to try, if they could hear it. But few will take the time to talk themselves into something they've never experienced in reality by reading for 100 hours of techno babble, when they could instead be enjoying their music with passive xo speakers. Implementation of advanced dsp like that is a big hurdle, you have to understand the why to make it work and that is years of study. Great if audio tech is your hobby interest then it's fun to learn, but if your interest is Led Zepelin or Beethoven then not so much.

Last time I was at RMAF in 2008 there was a vendor who demonstrated the difference between passive and all active speakers. Everyone who attended that demo was very impressed with the result, but they were also reserved about actually taking the steps to pull it off themselves. They weren't selling an active speaker product, just trying to open minds to the potential.

For me it makes sense to try to reduce all forms of distortion to improve my listening experience. I like classical symphonies and playing them loudly with low distortion provides me with enough reward to warrant my efforts obsession. I don't want to invest the money needed to achieve that kind of sound with a big commercial passive system. Reducing the various speaker and room distortions is the goal. DSP offers opportunity to reduce speaker/room distortion by an order of magnitude. I think that's gotta be audible, but I could be wrong. Time will tell if that goose really has a golden egg or not.

Meanwhile, I thoroughly enjoy my passive XO speakers... What the hell is wrong with me?!? 

[JoshK]

Congrats Josh! I figured the demo would eventually push you over the edge! I can't wait to hear them for myself. I don't see in the DCi 4|600 manual any reference to built in DSP functions. What are you using for xo?

Actually I have the DCi 4|600n.  n version has the necessary DSP and costs a bit more.  However, it is basically the studio install version of their Itech series and thus are cheaper as they don't have to have things that make them bullet proof for touring duties.  They still apparently have noisey fans so the amp will go in the closet in all likelihood.   The dealer sent me the file to load into their DSP for the M2s.   I haven't received the M2s yet but I have received the amp. 

[Dmason]

@Josh

Now that sounds pretty interesting. What available stuff I've read about the new JBL models is uniformly positive. Pro Sound awarded two models the Best of Show recently. I have always had faith in JBL, and once shoehorned a 2226 into my Leslie, transforming it and the Hammond into a monster.

I will be returning later this summer for awhile, and will be in Toronto for upward of a month. I would trade a nice dinner out on St Clair W., for a listen to those babies..

[Russell Dawkins]

I'd love to hear the JBL M2s as well. They would appear to be Greg Timbers' swan song project, unfortunately.
I'd be particularly intrigued to hear them side by side with the Ocean Way HR4 system (at half the price), even though the latter is not one piece and meant for the console bridge with the subs out of sight below and behind:
http://oceanwayaudio.com/hr4/ system
http://oceanwayaudio.com/ocean-way-audio-now-shipping-new-high-res-near-mid-field-monitors-pro2a-hr4-hr4s/