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Making a Case for Active Speakers?

Now that I am hitting full stride in retirement, I find myself in a bit of a quandary. So, this month’s Roger’s Corner topic is going to be intertwined with some difficult system decisions I may need to make. Over the years, small listening rooms have been my main challenge and while downsizing my system was always something that I faced, somehow, I found a way to make the room work with what I had. That was never an easy task and luckily there was always enough storage for the leftover components. However, with my next move it is now inevitable that I downsize my system. Having a system in a dedicated listening room that is 12’ x 20’ within a multi-room 800 sq. ft. or so house is one thing, but having a system in an all-purpose room that is 12’ x 20’ in a 300 sq. ft. studio is quite another thing altogether. 

Probably the toughest part about this is that due to their wide footprint I will no longer be able to keep my Quad ESL speakers in the system. My other speakers, Stirling Broadcast LS3/5a V3.2 and Spendor 1/2e have a small space friendly footprint, and both come very close to the sound I enjoy with the Quads. If I get creative, both speakers will work in the room. I also thought of going with a headphone set up as that will certainly reduce the clutter, as well as eliminate the room from the equation altogether, but I am still too intrigued with the challenge of making speakers work in small spaces to go in that direction. So, in addition to providing useful reading material for our topic, making a case for active speakers is my effort to justify downsizing my system to suit a new listening room.

There is historical precedent for this as well. The past several years I have run a multi-channel active speaker system utilizing an outboard active crossover and multiple subwoofers set up. It was something Roger introduced me to and it was quite a revelation when I first tried it. However, as I now contemplate next steps I have recently been reading up on active speakers and I am giving them serious consideration. As a space saving solution, it removes an amp or three, an active crossover, a woofer system, some cabling, and maybe even a preamplifier from the set up if I go single source. In addition, small footprint active speakers would not take up very much space. The KEF KC62 subs I am now using are easily hidden as well. What is not to like about this? Well, I can already hear the typical audiophile commentary: 

1. There is no flexibility to “roll” amplifiers.
2. Active speakers are made for pro-audio use. They are going to sound too analytical (or some other nonsensical adjective) in a home audio system.
3. Since the amplifier is built into the speaker, it will not be as reliable, and repair requires the entire speaker to be sent in for service.

#1 is understandable and #3 has some merit. Roger designed all his components with reliability and serviceability in mind. Some of his products have been in the field over 40 years with no report of failure. Other designers have similar track records. However, any component can be subject to failure at any point during its lifespan regardless of how it was designed. So, if an amplifier fails, whether its outboard or in a speaker, you must still send it in for repair. I can also argue that some amplifiers are larger and bulkier than active speakers and as such are more troublesome to send in for repair. While I very much enjoy swapping amplifiers in and out of my system some compromises need to be made. However, as I learn more about how well designed active speakers work, the more confident I become this is a viable solution. So, I think it warrants looking into some aspects of active speaker technology a bit more.

First, the notion that active speakers reduce sound quality or are a compromise is another audiophile myth that needs to be debunked. The fact is, when designed and implemented properly, there is an increase in performance through control of driver phase. This is one of the most important contributors to sound quality and is more important than speaker vibration control or cabinet materials. Active crossovers are more accurate and allow for independent control of level and phase. As such, adjustments can be made to achieve perfect magnitude response and phase response. You cannot control driver phase with a passive speaker system as any changes you make affect both level and phase.

Second, in active speakers the amplifiers "see" the drivers directly and the active crossovers are before the amplifiers in the signal path. The same as it is in an active speaker system with outboard amplifiers and electronic crossover. This is another important contributor to sound quality due to the reduction of Intermodulation-Distortion (IMD) as the separate amplifiers operate over a limited bandwidth. In comparison to a passive speaker, or even a multi-amped passive system, active speakers can reduce IMD 15 dB to 20 dB.  In addition, passive speaker crossovers employ a combination of capacitors, resistors, and inductors to achieve filter shapes, and the crossovers are between the amplifier(s) and the loudspeaker drivers in the signal path. While passive crossovers can work very well in a speaker design, or even as an outboard crossover (Marchand and Vandersteen products come to mind) they do not always provide the most optimal sound as they do not address IMD nearly as effectively as active crossovers do.

Let us continue talking about that passive crossover. In a vast majority of speaker designs this crossover is the weakest link. Not from a design perspective per se, but most notably from the use of lower quality inexpensive parts to meet budget requirements. The spend is nearly always higher on the drivers, cabinet materials, and other exotica the manufacturer places a greater priority on. Roger often recommended to audiophiles that they call a speaker manufacturer and ask them how much of a discount they would get if the speaker was sold without the crossover. If the manufacturer deigned to answer the question the discount would assuredly not be very much. Another way to view this is to look at how little marketing effort is put into touting the passive crossover versus other speaker components, some of which are audiophile mystical nonsense. In any event, the passive crossover tends to get the short end of the stick.

Now consider that passive crossovers are more complicated to design and not as efficient as active crossovers. Also, consider the inductor that impacts bass frequencies and puts a significant amount of wire between the amplifier and speaker driver. Depending on the size of the inductor, there may be several hundred feet of wire added to the signal chain. Audiophiles routinely claim to hear differences in their speaker cables. If you think the last several feet of wire you can see between the amplifier and speaker is sonically important, imagine the other several hundred feet you cannot see in an air core inductor. The audiophile approved speaker cable costing hundreds or thousands of dollars is followed in the signal chain by a significantly longer length of generic magnet wire costing a whole lot less. I am curious as to what an audiophile thinks that magnet wire contributes to the sound, and what, if anything they hear. 

There are several more claims to support the case for active speakers, but we have covered the crucial ones. In my research I noticed there are more brands of active speakers on the market these days compared to past years. Recently, I heard the KEF LS50 and LS60 active speakers in the same system alongside a pair of passive KEF Reference 1 speakers. I have to say the little KEF is quite the bargain, especially used, and it was difficult to decide between the LS60, and Reference 1. I have also heard Linkwitz active speaker systems and would note that Siegfried Linkwitz was a master at his craft. Of course, ATC and Genelec long ago carved out a niche as premier manufacturers of active speakers. ATC even makes passive versions of some of their active speakers with customers divided on which sound better.

Now even I thought I might be compromising and losing some flexibility if I made a move to active speakers. Active speakers designed properly, or an active speaker system set up properly, provides one more important feature that a passive speaker cannot, at least not without a lot of effort and cost. In addition to level and phase controls, individual gain trims for the two or more amplifiers involved allow very simple fine tuning of the frequency response and the stereo matching. This is a feature I can take advantage of today and it is good to know I will not have to compromise on that in the future if I choose to move to active speakers. Additionally, any adjustments can often be made using a remote control, and for active wireless speakers that are now becoming more popular, through an app. It is a very elegant way to tune a system if I do say so myself. I have Roger to thank for introducing me to the idea of an active speaker system, now I am looking forward to what an active speaker can do for me. Speaking of Roger, he will be back for the next few Roger’s Corner editions so stay tuned for some interesting topics.