[DVV]

For many years now, I have been (wishfully) thinking of an active speaker project - two speakers, actually, a smaller two way and a larger three way.

I first met with active loudspeakers in mid-70ies. One memorable model was RED, from UK, a smallish model, but one capable of outstanding sonic impact at the time. The other one was by Philips, using their Motional Feedback circuitry; briefly, this was used to correct bass driver membrane excursions, producing much more linear bass notes (subjectively heard as cleaner, depper bass).

Active speakers have one objective and one subjective fault; objectively, they cost more than equivalent passive speakers, often by a considerable margin, caused by built in amplification, and subjectively, they rid or deny, depending on your point of view, us of having/wanting to choose power amplifiers.

But their benefits are many. They provide for the cleanest possible dynamic driver drive, since all that stands between the power amp and the driver is a bit of wiring and nothing else, often less than 5 inches long. This in turn enables the amp to control the drivers as no other known approach allows for. Power amplifiers do not need much power, only exactly as required by the driver, as there are no lossy passive crossovers and cables in between. Furthermore, power amps can be optimized for a given driver in terms of power, so much higher class A biasing can be the norm rather than an exception. Ultimately, the crossovers themselves in this case are active, which is always a better solution than any passive gig anybody can dream up.

But if you have never heard an active speaker, there is no way I can convey to you the feeling of freedom, of sonic liberation this can bring.

I would really love to hear of other people's experiences in this field. Who knows what could come out of it?

Cheers,
DVV

[tmd]

Hi Dejan,
While I have practically no experience with them, I have been very interested it the possibilities for ages. I have posted here in the past about it. My thought was that each speaker would be fully active with as many amps as drivers and an electronic crossover. Further, it would have a DAC built in, fed optically (I think).
That way, any speaker could be 'programmed to be left, right, center, rear left etc... Also, software could adjust for room problems and distance etc. The reason for optical feed is no degradation of signal with length (I am assuming this) and no interference issues. It would be a very versatile system if it could be built.
In building the Scott Nixon DAC and GainClones, I have found simple but elegant and great sounding components which don't cost the earth. It would be a good place to start with a project like this.
It's fun dreaming these things up, isn't it?

[markC]

I have witnessed a homebuilt 3-way creation with the woofer being powered by a plate amplifier. The 8' woofer was ported and the 6.5' mid bass was sealed. The crossover was in and around 120hz and the intigration was about the best I've heard-virtually seamless. Mind you the diy project ran up into the $1700.00 range for the materials.

[JLM]

Single driver speakers are, by default active speakers.

Check out Solar HiFi here at audio circle for an example.

Everyone agrees that 80 - 8,000 Hz is the most important range, but few would believe how little you have to give up in order to have the coherency of a single point source, the ideal imaging/soundscape, lack of phasing issues with no crossovers, plus all the benefits of active speaker design (except short speaker cables, but you do keep short interconnects).

Several single full/extended drivers do much better than 80 - 8,000 Hz (which is a traditional range for such drivers).  The single Jordan 92S driver used in the Solar 1, Konus, and Carolina Audio JSM/JTM/JLM is rated 45 - 20,000 Hz without the transmission line enclosure used by each of these designs.  The 92S is a 4 inch diameter aluminum foil design and can also be used in many other cabinet types.

Fostex sells several similar drivers, from 3 to 8 inch diameter that can range 30 - 20,000 Hz or up to 96 dB/w/m without cabinets.  Lowther is perhaps the real original full/extended range driver and goes up to 102 dB/w/m, but they can get quite expensive.  As can several other non-U.S. makers (such as AER, Supervox, PHY, and Lothx).

A real fun/fustrating aspect of audio is finding the best cabinet to extend bass response for these drivers.  The cabinets can get really wild.  Most single driver speakers were developed in the days of small tube amps, so they are efficient (helped further by not having a crossover) making them a perfect match for SETs that are known for speed, liquid midranges, and imaging.

[DVV]

Hi Dejan,
While I have practically no experience with them, I have been very interested it the possibilities for ages. I have posted here in the past about it. My thought was that each speaker would be fully active with as many amps as drivers and an electronic crossover. Further, it would have a DAC built in, fed optically (I think).
That way, any speaker could be 'programmed to be left, right, center, rear left etc... Also, software could adjust for room problems and distance etc. The reason for optical ...

Wow, what you want is to compete with people like Boothroyd-Stuart Meridian and T&A. They make what you describe.

I was a little more modest. I was also prudent, because my current set of speakers, B&M Acoustics 1041 (the company is gone, but I hear rumours of this speaker's comeback?), provides for even that possibility.

It has three pairs of binding posts at the back, and the crossover inside is also split onto three separate boards. This allows for bi or triamping, and eventually going fully active. I never gave up the idea. I am currently tinkering with some power amplifiers, but it's slow work, too much to do businesswise, I just don't have the time, and it needs a lot of time. But I'll get there, it seems later rather than sooner.

Active allows for really outstanding driver integration, and with a control or two, for subjective adjustment as well. It rids me of much wasted power amplifier power, it rids me of much cable interaction (but not all!), and it allows me to use lower power amps the mid and tweeters, however biased much higher into pure class A.

However, and this is what few people realize, for true completion, this would also require a full preamp with balanced outputs - how else do you get the low voltage signal to the amps inside speakers? And a preamp is another can of worms, because evrybody wants this or that, it's almost impossible to cater for all tastes.

Then the design issues - do I use 12, 18 or 24 dB/oct filters? Butterworth, Chebyshev, Linkwitz-Reilly, what? Each has its good and bad sides. Personally, I always tend towards easier slopes with less phase shift, even in active crossovers, but I have been given hell for it.

In fact, this is a VERY complex project. And it cannot be cheap, not the way I do it.

Cheers,
DVV

[Tbadder1]

I've had exactly one experience comparing active vs. passive speakers, but it's always stuck in my mind.  I heard a Paradigm Active 20 side by side with a passive 20, first amplified with a Bryston 60 watts per, and then a Rotel 150 watts per. The Active 20 simply blew away both passive versions.  Cleaner, freer, more natural--the actives didn't sound amplified at all, they sounded like a wonderful representation of music.  The passive sounded like speakers being amplified, with all the attendant problems of constriction, beaming, etc.  The salesman said the Actives were being discontinued, and that Audiophiles want to control the quality of their amplification, so who in their right mind would buy actives.  Well, I was just getting into this audio-gig, and I felt intimidated, and passed on both even though my ears were telling me different.  The biggest mistake I ever made in audio.

[nathanm]

...

[refmedia]

The best active speakers I have heard are the Meyer Sound X10 and the Meridian DSP8000. Both are about 40k a pair. Both are active with Class A amplification. The DSP8000 are astounding and better suited to a living space. The X10's are absolutely the best sound I have heard. Clear and accurate at crushing volumes...... better have a room that can handle either of these systems. I have also used a wide variety of rienforcement and studio active speakers but every one requires a sub. My definition of full range mind you is whether a sub is needed or not. For the money I would recommend checking out Event Electronics or A Blue Sky monitors for those of us on a budget the Mackies are okay too. Or older Meridian actives, M20's (which I own) M60's etc... these are fantastic with a good sub. I still think passives are cool and when integrated with amps cables ect.. can achieve fullrange sound that rivals anything active. So it boils down to taste and how much you want to tweak.

[nathanm]

It makes sense that a speaker which was designed in conjunction with a certain amplifier would be a better match overall.  I realize much of the hobby is about tweaking and experimenting, which is cool and all but it is also frustrating at the same time IMO.  And expensive.  Active speakers give you less junk to worry about.  You only have to decide if you like them or not, none of this "oh they sound medicore now, but what if I tried this and that and the other thing..."  Then again, how many actives are out there on the market anyway? (not necessarily a rhetorical question!)

Even though I ultimately decided against using them for far-field listening, my Mackie HR-824s were far and away the most out-of-the-box satisfaction I ever got from any audio product.  They just sounded "right".  It's like, "Ahh, hell yeah, that's what it's supposed to be like!"  The bass on those suckers is so sinfully tight and powerful that I am sure my upstairs neighbor loves me whenever I play them.  The sound is so smooth and controlled they beg to be pushed louder and louder, unfortunately a luxury I cannot always indulge.  Indeed, very expensive but to me the active approach just makes all kinds of sense.  Well, based on these at least.  Unfortunately they are all business as far as asthetics go and...rectangular. *sigh*

[Andrikos]

My vote is for actively crossover-ed/ equalized passives so when you replace amps or speakers you don't need to do both at the same time (akeen to receiver versus pre/pro + amps)

[JLM]

Yes, I've heard the Paradigm Active 20s.  Amazing bass response from a small box.  Had the same bass as the equally priced floorstanding passive model of the same series, but being a two-way they were more coherent and imaged better.

But I don't care for the Paradigm sort of sound.

[DVV]

Yes, I've heard the Paradigm Active 20s.  Amazing bass response from a small box.  Had the same bass as the equally priced floorstanding passive model of the same series, but being a two-way they were more coherent and imaged better.

But I don't care for the Paradigm sort of sound.

With active technology, the designer is able to much better compensate for small speaker enclosures by tweking the electronics. However, I am not very keen on this approach because I tend to streer clear of playing games with amplification, such as slightly boosting the bass response to compensate.

I prefer a linear drive, no funnies, just straight, clean drive. Just as I prefer classic biasing to various schemes using sliding bias; my feeling is that this is a shortcut one does not need provided the amp is designed properly, because if that is so, a higher order of bias (say 120...150 mA) per device will do the job just as well in comparison with typical designs (10...50 mA) without the penalty in cost and complexity.

This is especially true in active designs, where one works with very low power levels, since one is driving the the driver directly, without the usual power robbing inductors, resistors and capacitors of the passive crossover in between. Hence, one's damping factor is very high, there is no wiring to muck it all up, and speaker efficiency is at its maximum.

Most important, speaker speed is at its best, and the inherent phase shift is TREMENDOUSLY reduced, while driver control is aboslute, as good as the amp can manage.

Cheers,
DVV

[WerTicus]

im in the process of building a 3 way active crossover at the moment!  quiet a complicated little project but not difficult by anymeans... however i dont have enough poweramps to use it anyways ... but i thought i may as well get this stage out of the way

[Kevin P]

Doing an active system is much more complicated and requires a tremendous amount of technical skill to do it right.  I'd encourage you to look into doing something that is well thought out and engineered if you pursue this route.

Sigfield Linkwitz has the best-documented and probably best-engineered solution for DIYers.  His engineering credentials speak for themselves and while I've never had a chance to hear the Orion if I were going to pursue a fully active system that is the way I would go.  I'd also not deviate from his plans if you want to get the best results.  

http://www.linkwitzlab.com/

I think the main reason active speakers have not been successful commercially is that they require the user to buy pretty much the entire system (speaker, amps and active crossover at least) and lots of audiophiles enjoy swapping gear too much to be tied into one choice.   I would normally say the cost is an issue but I see a lot of people spending more money on passive solutions than would be required to build the Orions so I don't think money is the problem.  

I'd love to do an active open baffle design similar to the Orion with some Adire XBL^2 drivers (a natural for dipole use) and the LC Audio digital amplifiers but I'm not sure there would be a market.  We would also be substantially more expensive than the Orion route due to the cost of amplification and drivers.   I'd say it would be a $8000-$10,000 product complete.   It would be a sell "one a year" speaker which seems to be half the market if you ever go to CES.

[Andrikos]

As an EE, my hat's off to Mr. Linkwitz and his incredible body of work.
His website is a fantastic resourse for knowledgeable people that need to know the (succesful) method behind the madness (i.e. speaker building).

[DVV]

Doing an active system is much more complicated and requires a tremendous amount of technical skill to do it right.  I'd encourage you to look into doing something that is well thought out and engineered if you pursue this route.

Sigfield Linkwitz has the best-documented and probably best-engineered solution for DIYers.  His engineering credentials speak for themselves and while I've never had a chance to hear the Orion if I were going to pursue a fully active system that is the way I would go.  I'd also ...

A very creditable site from one of the best established engineers in the trade indeed. I really enjoyed my first visit, but I will obviously have to go there quite a few times to get it all.

The only thing that disappointed me (a little) was the price - $3.8K is no small sum. I agree it includes the amplification and the XO, which are no small expenses when purchased separately, but I still feel this is a stiff price, the good name taken into consideration.

But I agree 100% with the comment that active speakers never really made it because of the industry pressures to change and keep changing; my experience is that it's mostly changing, and rarely truly upgrading in significant steps.

The tragedy here is that most of those people don't realize that with the active approach, so many existing problems never even make it to the final equation, so what may seem very expensive at first sight actually works out to MUCH cheaper in any 5+ year run, let alone longer.

The speed, the coherence, the clarity and soundstaging of a well made active design are quite simply unmatched by anything else out there in discrete form, or if matched, this is done at effectively 3+ TIMES the cost in money (the effort we all take for granted, some probably as the point of it all).

Cheers,
DVV

[nathanm]

So what's the definition of an active speaker; is it one where the amplifier is attached to the speaker cabinet or is it simply one with a line-level crossover and separate amps for the individual drivers regardless of where it's mounted?  Both?

[DVV]

So what's the definition of an active speaker; is it one where the amplifier is attached to the speaker cabinet or is it simply one with a line-level crossover and separate amps for the individual drivers regardless of where it's mounted?  Both?

Essentially, an active speaker is a speaker which accepts a line level signal, most often in balanced XLR format because of the wire lengths involved, and then, using the in-built electronics, send it to an electronic crossover which splits up the signal to relevant power amps, and power amps which are connected to the drivers with short runs of cable, typically around 2-5 inches. Hence, each power amp drives each driver directly, and consequently, the effect of cables is minimized, and amplifier control of the driver is maximized.

This approach allows the designer to lose the power sucking&robbing passive crossovers, to minimize crossover phase shift (since electronic crossovers do compensate what passive XOs can't) and to provide optimized power amps for their respective use. This relates to both power output and actual construction, as the designer knows in advance the part of the band each amp must cater for.

This is no small thing, Nate; for example, some power devices (e.g. MJ 15022/15023 by Motorola) can push prodigious currents into even low loads, however at lower frequencies (e.g. 5 kHz and below), but do not sound great at higher frequencies, for which one could now use for example much better behaved and linear Toshiba or Sanken devices.

However, the main benefits are much lower phase shift and incomparably improved speed (as there is no passive XO overhang), which translates to more detail and incredible response to transients. Most important, incredible here applies not so much to the rise time, but far more to the settling time - almost no overhang at all.

The result is fabulous detail soundstaging like you are not likely to hear in classic audio below $20K for speakers and as much for the power section, yet at a much smaller outlay.

In short, an active speaker is one which has the elctronic crossover and power amplifiers built in, and all it needs to play is an incoming signal; this could be from a preamp, but ostensibly also directly from a CD player, since most active speakers have at least a volume (gain) control for each driver.

Lastly, this very fact allows you to balance the sound EXACTLY according to your hearing and your room. Try that with a passive speaker - no way.

Cheers,
DVV

[Andrikos]

DVV,
You're very knowledgeable in these things indeed.
I'm going to venture a guess that you are an analog designer.

If you feel that Linkwitz is charging a stiff, as you call it, price for his design, I'm sure you're perfectly able to design your own.

That's what I'll be doing at least since I've been a designer, product, characterization and now (my BEST role by far) in Yield and Test Enhancement Engineer and it helps to have that kind of background.

Anyway, I do believe that active is the future and analog crossovers will become a kitch (tubes, vinyl etc.). Not worse, but outdated...

I work in the analog world for a company that makes the best analog IC's on the planet but I too recognize that digital will become more and more dominant. We live in an analog world, true, but analog is a mere perception.

After all, even light comes in discrete packets if you resolve enough...

Anyway, I'll be adding pictures of my active line array system in my gallery as the months go by.

Cheers,
Andreas

[DVV]

DVV,
You're very knowledgeable in these things indeed.
I'm going to venture a guess that you are an analog designer.

I'm blushing - thank you. In my defence, I can say I got hooked on audio at the age of 11, way back in 1964, and actually designed my first circuit in 1973, at the age of 20. Well, that did it, that got me irrevocably hooked, and as you see, nothing has changed since then (matter of fact, it's become worse - just ask my wife).

If you feel that Linkwitz is charging a stiff, as you call it, price for his design, I'm sure you're perfectly able to design your own.

Now, that's what I call hitting the nail on the head. You are absolutely right, and this can colour one's views. Like most audio freaks, I tend to forget that such people, Linkwitz in this case, do have a business to run. I have to blush again, because it was I who said several times here that we all make the mistake of discounting our own time and effort - so if we should do it, why shouldn't Linkwitz?

But all that notwithstanding, I can't shake off the feeling that $3.8K is a hefty price tag. Please bear in mind that over here where I am, the price system is different to the one over there, which is also a factor. As an example, a driver which costs around $350 retail in the US I can buy for around $70 simply because I know a company using them which buys them at manufacturer, not retail prices.

That's what I'll be doing at least since I've been a designer, product, characterization and now (my BEST role by far) in Yield and Test Enhancement Engineer and it helps to have that kind of background.

Anyway, I do believe that active is the futu ...[/quote]

Best op amps in the world? You work for Analog Devices? Now here's a topic to have a great flame-turned-nuclear war over.

Just kidding, of course. Like every other person with a soldering iron in his hands, I have my own preferences which I swear by, which tells you nothing of any absolutes and everything about my own personal preferences. The absolutes are in our heads only.

I couldn't agree more with your view that active is the future. And I can't wait for it.

Cheers,
DVV