Are active speakers still worthwhile?

[heflys20]

They will produce active speakers, just read the road map.

Yes, they said a long time ago that they planned on producing actives at some point. I was just having a dig at the assumption that products like the C6B would be the downfall of active speakers; as the first post seems to imply.

 

[alankila]

Active speakers, both eternally and externally have been my personal preference for many years. Two overwhelming aspects have led to this preference. Using my current reference speakers and previous reference which I still have. With my current speakers, which are very demanding in that they are inefficient and very low impedance, limits the amount of amplifiers to successfully drive the speaker in purely passive mode. By eliminating the the passive components, the speakers can be driven with a wider range of amplifiers. My previous reference speakers with built in DAC/PRE/AMPS are nice in that the matching of components were done at initial design phase. Eliminating the need of trying to match three different components.

I wonder if "matching" the amplifiers is a concept that actually has an operative meaning. I think in the past when output impedances were high and imperfections rife, there was much more effect from finding an amplifier with e.g. reduced treble output to pair with speaker with hot treble. But this sounds more like job for an equalizer than trying random components and hoping that their various defects complement each other.

IIRC someone took a Genelec 8351B apart and photographed the amplifier board (which turned out to be the same as with 8341A) and it looked like there was three identical class D amplifiers made of the same types of components, so I'm guessing that the exact same design worked just fine for woofer, tweeter and midrange. I know it says on the specification that they have different power handling ability on paper, but as far as I could tell, as an amateur, this was not in any way reflected in the apparent design of the actual circuit. This is a thread on ASR, https://i.ibb.co/qMnztRW/image.png is an image, from this page. https://www.audiosciencereview.com/...-8351b-teardown-2nd-disassembled.22785/page-2

 

[Bruce Morgen]

I wonder if "matching" the amplifiers is a concept that actually has an operative meaning. I think in the past when output impedances were high and imperfections rife, there was much more effect from finding an amplifier with e.g. reduced treble output to pair with speaker with hot treble. But this sounds more like job for an equalizer than trying random components and hoping that their various defects complement each other.

I don't see that as the point of the one-amp-per-driver approach. E.g., unlike those Genelecs, the Kali Audio IN models use three different amp circuits, with the one driving the woofer (60-80 watts) capable of more power than the ones for midrange and tweeter (40 watts) -- likely (just a guess!) by wiring the woofer's amp in PBTL mode and the other two in BTL. Another advantage is that, since DSP is implemented on-chip, there's no need for PFFB since since each circuit can be EQed to compensate for any load dependency of the output ICs in the context of the actual impedance of each driver -- this is especially helpful with the tweeter, since the load dependency of Class D chips tends to show up at the high end of the audio spectrum. Overall, this a far more economical design approach compared to using three identical -- and likely much pricier -- board-level modules and is at least partially why those Kali models excel as per that company's stated commitment to "value optimization," AKA "bang for the buck" when it comes to their IN and (two-way) LP product lines.

 

[Esprit]

My Adams

 

[ttimer]

Well, if you are just looking at FR and controlled directivity above 1000hz, there is hardly any difference between the best passive and active speakers.

But to be honest, those criteria seem a bit pedestrian if you are looking for „the future“. To me, that would mean stuff like advanced directivity control, maybe down to the bass region. And i know of no passive speaker with cardioid bass (e.g. D&D 8C, KII Three) or variable directivity (eg Beolab 90).
It’s hard to imagine that this would even be technically feasible with a passive design.

 

[dfuller]

It’s hard to imagine that this would even be technically feasible with a passive design.

The D&D 8C's cardioid behavior is entirely passive. It's not like a Kii where there's a bunch of multi-driver DSP delay line trickery - it's all cabinet based.

I wonder if "matching" the amplifiers is a concept that actually has an operative meaning. I think in the past when output impedances were high and imperfections rife, there was much more effect from finding an amplifier with e.g. reduced treble output to pair with speaker with hot treble. But this sounds more like job for an equalizer than trying random components and hoping that their various defects complement each other.

IIRC someone took a Genelec 8351B apart and photographed the amplifier board (which turned out to be the same as with 8341A) and it looked like there was three identical class D amplifiers made of the same types of components, so I'm guessing that the exact same design worked just fine for woofer, tweeter and midrange. I know it says on the specification that they have different power handling ability on paper, but as far as I could tell, as an amateur, this was not in any way reflected in the apparent design of the actual circuit. This is a thread on ASR, https://i.ibb.co/qMnztRW/image.png is an image, from this page. https://www.audiosciencereview.com/...-8351b-teardown-2nd-disassembled.22785/page-2

Well, you can certainly do things like, say, use an AB for treble (in which chip amps are really quite good at this point) and a D for mid/bass (and up until recently, Class D chip amps were really pretty bad going above ~2khz), or provide much more power for LF than HF (tweeters are highly sensitive, woofers with good extension are generally not).

As an example of both: The Genelec 1237 uses 500W class D for the bass, 250W class D for the mid, and 200W Class AB for the treble. It needs more power for the woofer than the tweeter, but the 200W AB amp may well just be cleaner than the Class D they're using for this for HF (I believe Pascal modules?).

 

[ttimer]

The D&D 8C's cardioid behavior is entirely passive. It's not like a Kii where there's a bunch of multi-driver DSP delay line trickery - it's all cabinet based.

Interesting! I didn't know that was possible. The speaker itself is still active, though. Is there any passive speaker with cardioid bass on the market?

 

[Purité Audio]

Amphion make or certainly made a cardiod passive, ‘Krypton’ perhaps?
Keith

 

[dfuller]

Amphion make or certainly made a cardiod passive, ‘Krypton’ perhaps?
Keith

Make, it looks like. And yeah, Krypton.

 

[bachatero]

Which active monitors need ventilation?

The KH150s specifically say to put them in a ventilated area so that the vents can pass enough air, same thing for my huge subwoofer

 

[jEDGEc0m]

Nope! Most are active, just with remote amps.


Anyway...

I see major benefits for actives.

One, they're significantly more efficient. Passive crossovers always have insertion loss just by virtue of how they work and the insertion loss increases with how complex the crossover is (hence the attempt to use as simple a crossover as you can get away with). Actives have no crossover between driver and amplifier, so there is no insertion loss. An active crossover can be as complex as you need it to be without worrying about insertion loss.

Two, the crossovers are independent of any electrical behavior of the driver itself - which changes, sometimes significantly, based on how much signal is fed into them.

Three, actives can have significantly better driver protection circuits, which are at best rudimentary.

Four, active crossovers allow for boundary correction (at the very least) to be built directly into the speaker.

Five, because the amps aren't broadband they can be different amounts of power for each way without throwing power away via a series resistor or voltage divider.

Any quantification of typically how much more efficiency might be expected?

 

[jEDGEc0m]

The answer is a big yes. Due to time alignment (very important), better dynamics, a better crossover, lower bass extension, and it opens up the door to designs that isn't possible with passive and which can improve the speaker substantially.

However, personally I think active with external electronics is the very best option.

Why is it that the dynamics would be better? and how much?

I imagine that in a volume matched comparison with no other variable, it'd likely be a difference I would fail to perceive in blind testing.

 

[Bjorn]

Why is it that the dynamics would be better? and how much?

Because much of the power doesn't reach the woofer with a passive crossover. It's wasted in the passive components.

I imagine that in a volume matched comparison with no other variable, it'd likely be a difference I would fail to perceive in blind testing.

Lack of signal aligment alone is easy to hear. Sound from drivers that reach the ear at different times is never a good thing.

 

[jEDGEc0m]

I wonder how practical would it be to convert passive speakers into active? Class D amps are readily available in various sizes. The digital equalization and crossover would be tricky tho.

I did an amateur job of it as a hobby. using a MiniDSP UMIK-1, and starting with a pair of JBL Studio 630. and pair of Fosi v3 stereo. Source is MOTU Ultralite mk5 audio interface.

In addition to some basic tweeter protection, I found there was a fair bit of tweeter hiss - improved with attenuation by resistors - the power to the tweeters to match the SPL to the mid-woofers with the same amp is still WAY less. even the mid-woofer had a somewhat surprising, but in practice acceptable amount .(listening at ~2m in a small room).

Effectively tuned them for in room response. Some time-alignment was applied and seemed mostly to help with frequency response around crossover. So I guess that was a success.

Used 48db/Octave Linkwitz-Riley crossovers. All processing is done in REAPER digtal audio workstation and windows PC. All PC Audio is "loopback" through the ASIO driver of the MOTU audio interface.

I can't really comment on the "active" improvements, as too many variables, including them ending up in a different room to when they were passive. The passive version have pretty mediocre frequency response, but directivity/dispersion is good, so they seemed to make a good candidate for the "hobby". I suppose I gained some efficiency, but again, not quantified.

TL;DR If you have the means/channels to do it, and a measurement mic, could be a fun project!

That said, I'm still keen on a pair of AsciLab and may get them... Though I'd LOVE it if they sold them with 2 sets of binding posts, no passive crossover, and they supply the crossover, eq and time alignment parameters that I can implement with my own DAC, software amps etc.

 

[dfuller]

Any quantification of typically how much more efficiency might be expected?

It's generally on average about 1dB, sometimes as high as 3. It depends on the crossover, simpler ones generally have less insertion loss.

 

[Heinrich]

I just ordered a pair of Ascilab C6B speakers and looking at the frequency curve and predicted in-room response, I'm wondering if active speakers provide any significant benefit anymore.

Bass management is a key feature of actives. Give the customer a switch to dial it in, protection included. It costs more cabeling, though, mains and signal, two lines, at least one on the heavy/stiff side, for each speaker.

 

[TLEDDY]

Haven’t they “about to launch” for over a year now?

For active you just need these power cords: Retail Price: $6,440.00 for 1.5 m

OMG!! Pulling my leg

Tillman

 

[jEDGEc0m]

It's generally on average about 1dB, sometimes as high as 3. It depends on the crossover, simpler ones generally have less insertion loss.

Thanks. 1dB is still some wattage saving, but if you're that close to limits for required SPL, I imagine one would want to seek more power anyway.

3dB is epic wattage saving! ... But still only a fairly mild volume increase-again, hopefully we're powered enough not to be that close to running out of watts.

 

[Carlton80@0]

Converted my amp killers to semi active. Removing two of the three passive networks allows for a wider choice of amplifiers that are able to adequately power the speakers.

 

[Davey]

Because much of the power doesn't reach the woofer with a passive crossover. It's wasted in the passive components.

Lack of signal aligment alone is easy to hear. Sound from drivers that reach the ear at different times is never a good thing.

Much of the power 'does' reach the woofer in a passive crossover. (DCR of series inductor(s) is usually minimal.)
And the components become high impedance out of band, so the power is not "wasted."

I wonder about statements like these. You need to be very clear with statements when talking to audiophiles so as not to confuse them.