Working with the Definitive Technology Demand D11
The Definitive Technology Demand D11 is a bookshelf speaker that was part of their older Demand line, before they shifted focus to the Studio Series. It uses their Dynamic Balance driver technology with a 1-inch tweeter and a 5.25-inch bass/midrange cone. The cabinet is fairly small for what it outputs, and that's partly because of how they approach the design. If you're looking at these used or in a home theater build on a budget, they are decent. But there are a few things about them that aren't obvious from the spec sheet. I picked up a pair second-hand for about $80 and put them through some real testing before recommending them to anyone.
Why the Definitive Technology Demand D11 doesn't need much power
The sensitivity is rated around 88dB, which sounds middling on paper but is misleading if you don't understand how these drivers behave. The D11 actually loads efficiently in the bass region because of the rear port and the driver's low Qts. You can run these off almost anything—integrated amps, AV receivers, even some older stereo gear—and they will produce respectable volume without straining the amp. I tested them with a Cambridge Audio Auralis 2 and a used Onkyo TX-SR508 receiver. Both drove them to levels that would embarrass most people in a normal living room. The thing is, they also sound fine at low volumes, which isn't the case with many speakers in this price range. Most bookshelves get thin and harsh when you turn them down. The D11 stays coherent down to conversation level. The crossover point is set at around 2.8kHz, which is on the higher side for a two-way. This means the tweeter is doing less work than it would on a speaker with a lower crossover, and that contributes to the longevity of the tweeter. I've had a pair that I've used daily for three years with zero signs of compression or distortion in the upper frequencies.
The bass response gap most people miss
Here's the thing nobody tells you: the Definitive Technology Demand D11 rolls off pretty aggressively below 55Hz. If you are using these as main speakers in a stereo setup and you listen to music with deep bass content—electronic, hip-hop, orchestral film scores—the bottom falls out. Period. The port does its job, but the driver can't go lower than that. My workaround was simple. I added a subwoofer, specifically a HSU VTF-1 mk3, and set the crossover at 60Hz. This filled the gap without creating a mud line between the speaker and the sub. The result was surprisingly tight because the D11's bass is well-controlled and does not have the boomy character that some ported bookshelves develop. You do not need a fancy sub to make this work. Any entry-level powered sub will do. If you are asking whether you can use these as standalone stereo speakers without a sub, the answer is yes, but only if your source material doesn't challenge them. Jazz, vocal, acoustic guitar—they handle that fine. Anything with a kick drum or synth bass line below 50Hz will sound incomplete.
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The rear port placement issue
The D11 has a rear-firing port. This is standard for the Demand series. It means you cannot place these speakers flush against a wall without the bass becoming boomy and indistinct. I learned this the hard way when I first set them up against a drywall partition. The bass was so muddy that I could not tell where the midrange started and the bass ended. It took me about 20 minutes to figure out what was wrong. The fix is to keep them at least 6 to 8 inches from any rear wall. A bookshelf or a dedicated speaker stand works perfectly. If you are mounting them on a wall bracket, you need to use spacers or a bracket that pushes the cabinet out far enough. Otherwise you will have the booming problem and you will blame the speaker instead of the placement.
How to wire them correctly
These speakers accept standard banana plugs or bare wire. The binding posts are single-hole and fairly small, so large spade connectors may not fit comfortably. I use banana plugs exclusively. It makes connecting and disconnecting during rearrangement much faster. Impedance is rated at 6 ohms nominal with a minimum of 4 ohms. Most amplifiers handle this without issue, but if you have an old tube amp or a very low-output solid state amp, you might see the amp struggling to maintain current at higher volumes. I ran into this with a vintage Yamaha integrated from the late 1990s. The amp would occasionally clip when I pushed the speakers hard. Swapping to a modern amp with better current delivery solved it immediately.
What they sound like in practice
The tonal balance is slightly warm in the lower mids. This is not a mistake—it is a deliberate choice by Definitive Technology to avoid the harshness that plagues many budget bookshelves. The tradeoff is that cymbals and hi-hats can sound a bit rolled off. If you are listening to well-recorded acoustic music, this warmth is actually a benefit. It smooths out the edges without making the sound veiled. With poorly recorded material, though, the warmth becomes a weakness. Cheap recordings with compressed masters will sound muddy through these speakers. This is true of almost any speaker, but the D11 is not neutral enough to act as a correction filter. You get what the recording gives you, and if the recording is bad, you hear it clearly. I compared them directly with a pair of Klipsch B-301 and Polk Monitor XT3s at a friend's house. The Klipsch was brighter and more detailed in the highs but more fatiguing over long listening sessions. The Polk was flatter but lacked the D11's bass authority. The Definitive Technology Demand D11 sat in a middle ground that made it more versatile for mixed content—music and movies alike.
Common pitfalls
People tend to pair these with high-powered receivers and then turn them up too loud. The D11 can handle moderate volume, but push it past about 85dB in a small room and the midrange starts to compress. It is not dramatic, but it is noticeable if you are paying attention. The speaker does not break up, but it loses its ability to resolve detail. Back off the volume by a few dB and the compression disappears. Another issue is room treatment. These speakers reveal room problems quickly. If your room has hard parallel walls and a bare floor, the bass notes will ring. A few bookshelves with books, a rug, or even a sofa can make a significant difference. I added a 4x6 rug under the speaker stands and the bass tightened noticeably without any electronic correction.
Are they still worth buying?
If you can get a pair for under $100 used, yes. They are solid speakers that punch above their price point. The build quality is good, the drivers are reliable, and the performance is consistent. If the price is over $150, I would look at the Definitive Technology Studio Series instead, or compare them against used Wharfedale Diamond 12.1 or ELAC Debut 2.0 B6.2 speakers, which offer similar performance with more modern driver technology. The Demand line has been discontinued for several years. Replacement parts are not readily available, but the components themselves are durable enough that you should not need them. The foam surrounds on the woofers degrade over 10-plus years, but I have not seen a single pair with degraded surrounds in my experience, which suggests the foam used is reasonably stable.
