It’s October and as All Hallows’ Eve approaches, we explore audio’s very own… spooky phenomenon. THE PHANTOM CENTER. If you have no idea what we’re talking about, you’re about to unlock the next—enrapturing—level of listening. And for those of you intimately aware of the intoxicating effect of hearing a system that produces a holographic specter, allow us to cast a spell over the uninitiated.
It may happen by accident, or by scrupulous design, but the Phantom Center we’re referring to is when speakers disappear and the music fills the space between them. Sometimes you’ll hear a singer, sometimes a drummer, or the orchestra, or the piano—it truly depends on how it was recorded. But the speakers cease to sound distinct in space and instead produce a cohesive wall of sound.
It does sound a bit abstract when expressed via the written word. We’d much rather you heard it than read it.
And it’s reasonable to ask why someone would want a Phantom Center. Would it not haunt you? Perhaps. But we believe most people seek this out because it makes music sound more real. Instead of your left speaker sounding like a lead guitar and your right speaker sounding like backing vocals, it sounds like the guitarist and backup singers are each on stage in front of you. And depending on how it was recorded, the guitar may be directly in the middle where the vocals come from, or slightly right, or any combination of the above.
This is why we refer to it as a “holographic” specter, because the instruments and music sound like they’re happening between the speakers, even though there are only speakers on the right and left.
We do admit that this is venturing into the deep end a bit. In our experience—nearly 70 years mind you—most people are floored by how great music can sound when played through a proper pair of speakers. The Phantom Center just happens to be one of the (many) added benefits of investing in great audio. You certainly won’t find it on a spec sheet, ours included. It’s something you hear, not necessarily something you measure.
We were curious what others at KLH would have to say about the Phantom Center:
“When two speakers are properly placed in a room, they can make a holographic effect that creates sound from the area between the speakers where there is no actual speaker. The analogy I like to make is a well set up stereo can become a giant film screen of sound. Images come from a high, wide and deep soundstage. When you use a dedicated center, I feel like you begin to identify the location of the sound and it becomes less holographic.” – Josh Finkelstein, Director of Sales
One thing Josh hammers home twice in his quote is speakers need to be “properly placed” and “well set up”. Like Ghostbusters, crossing the streams (NEVER CROSS THE STREAMS) in audio can be a bad thing. Ideally, your head and ears are placed at the apex of a triangle, with the two speakers serving as the triangle’s base [see figure 1]. This helps ensure the sound from each speaker arrives at your ears at the same time (or darn close to it). When people refer to the “sweet spot” in audio, this is typically what they’re alluding to. The seat that places them right in the middle of the speakers. 
This brings about another question. Do you truly need to sit right in the middle of the speakers to achieve the Phantom Center? That answer actually has more to do with the speakers than anything else. Many speakers do indeed require careful positioning to sound just right. If you buy a $50,000 pair of speakers, you better believe they come out and install them with a tape measure and protractor. If you sit too far off axis [not in the middle], you may not experience the truly holographic effects.
But thankfully, there are speakers where it’s easier to achieve. And those speakers are typically wider. We call this a “wide front baffle”, it’s the actual face of the speaker [see figure 2]. You’ll notice that many manufacturers make their speakers skinny and deep. We—and a few others—make speakers that are wide and shallow. This helps direct more sound toward the listener, making it easier to experience the Phantom Center between the speakers, because you literally have more sound traveling towards your ears. 
“When the setup is right, a voice recorded in the middle can sound like it’s coming from a speaker that isn’t actually there. The trick is good placement, symmetry, and speakers that are well matched. When it works, the soundstage locks in and the vocalist takes the stage. That’s why people chase it. A great vocal can suddenly feel like there’s a person standing between the speakers. And the fun part is, you don’t need trained ears to hear it. Sit in the middle, close your eyes, and point to the singer. If you point at empty space, there it is.” -Adisa Nickerson, KLH Brand Manager
Adisa comes back to speaker placement too. That ‘symmetry’ and ‘matching’ he’s talking about is the ticket. But he also does a better job at helping us understand when you’re actually experiencing the Phantom Center… or some other ghoul. Next time you’re listening, heed his advice and close your eyes, put on your favorite track and point to where the musician is. Assuming everything is set up correctly, you may have just found yourself in front of THE PHANTOM CENTER.
All kidding aside (and we know we’ve fully indulged ourselves in this one), the Phantom Center is an incredible phenomenon to behold. It adds a layer of depth to the music that you simply can’t get via headphones, or when you have speakers scattered around the house. It doesn’t take expensive speakers. It takes just two good ones, set up with a little patience and someone sitting between them, enjoying the music.
The question you must ask yourself is: should you invite a phantom into your home? In this instance, and in honor of the season, we think it may be for the best…