Frequently Asked Questions
- What is Clear Filter Technology (CFT ™)?
- What is the advantage of Atlantic's Low-Resonance Tweeter (LRT™)?
- Do I need a back-box for my 14 SR or 30SR In-wall surrounds?
- How much power do I need?
- What is all this talk about Dolby Digital®, DTS® and THX®?
- How do I figure out room size if my room is open to another room?
- Where should I place my speakers?
- What about surround speaker placement in 7.1 systems?
Q: WHAT IS CLEAR FILTER TECHNOLOGY (CFT™)?
A: No quality home theater or music system is complete without the ability to effortlessly reproduce the last one-and-a-half to two octaves of sound-the deepest bass. A subwoofer and its associated power amplifier adds drama to action movie scenes, putting you front and center by making the soundtrack come alive. Powerful deep bass is what separates a great sound system from a merely good one.
Atlantic subwoofers use the same design approach in all our subs from low-priced to high, to produce consistently realistic, convincing bass effects. Our subs vary in how loud they'll play and what size room they're most suited to. But our QUALITY does not vary. Big room or small, loud or soft, the sound quality of an Atlantic Technology subwoofer is always top-notch.
But there is something most other manufacturers don't want you to know, and here it is:
In order to offer big sound that doesn't require a refrigerator-sized cabinet, most subwoofers today use cabinets that are actually smaller than the driver itself requires for best performance. To compensate for this, speaker designers must boost frequencies at the lower extremes of the speaker's operating range, in order to "trick" the driver into thinking it's playing in a larger enclosure. This is how a small powered subwoofer is able to produce deep bass.
Ah, but as we all know, there is no free lunch! If only boosting low frequencies to the woofer solved this problem, the world would be a simpler place. Unfortunately that is not the case. In fact, the small cabinet itself has a deleterious effect on the subwoofer's sound. Without getting into a lot of technical engineering mumbo-jumbo, the small dimensions of the cabinet conspire to produce audibly intrusive interference.
What does this mean to you and why should I care, you ask? It means that what you are left with is colored and unnatural bass response. To the listener, the bass will sound "slow," "muddy," and indistinct. Sure, the system may generate an impressive volume of bass, but this "box effect" makes it impossible to enjoy the program content as the artist, sound mixer or movie producer intended.
Since Atlantic Technology is at the leading edge of speaker design and sound reproduction research, we know the traditional approach of "equalizers and limiters" used by ordinary powered subwoofers is not good enough.
Therefore, we have developed an exclusive design feature called Clear Filter Technology that assures clean, articulate, musical bass reproduction at all times. Don't be fooled or confused by other companies' claims about their "limiters," "feedback loops" or other distortion reducing circuits to prevent audible distortion. These work fine as far as they go, but they don't go far enough. Therefore, in addition to taking the expected steps to reduce distortion, Atlantic has gone a very significant step farther:
With our exclusive CFT, we incorporate special proprietary circuitry into the subwoofer amplifier that eliminates the negative effects the enclosure itself has on the sound performance. That's why other subwoofers, regardless of their power ratings or limiters, can't match the sound of an Atlantic subwoofer for detail and musical accuracy.
Atlantic Technology utilizes a top down approach, which means the research and engineering that goes into our reference products is applied all the way through the line, even to our entry-level systems. This approach is clearly illustrated in Clear Filter Technology (CFT), which was initially developed for our award-winning $20,000 THX Ultra2 System 8200; but is now found in ALL Atlantic subwoofers, regardless of price.
Q: WHAT IS THE ADVANTAGE OF ATLANTIC'S LOW-RESONANCE TWEETER (LRT™)?
A: Most in-wall and in-ceiling speakers are 2-way (woofer-tweeter) designs. In-wall speakers are usually mounted well above eye level, for aesthetic reasons. Most people who choose in-walls don't want to see speakers in their room, so they mount them high up on the wall, above the sight line. That's great visually, but lousy acoustically. Ceiling mounted speakers are even worse: Invisible, but hardly an optimal acoustic situation!
So to counteract the effects of bad placement, many wall- and ceiling-mounted speakers have tweeters that can pivot or swivel, so they can be "aimed" at the listening area. Not a bad idea, but not a perfect solution either.
The problem is that the woofer in a conventional 2-way wall or ceiling speaker handles too much of the sound spectrum. The woofer in a normal 2-way speaker handles not only the bass, but it handles virtually all of the critical midrange and lower treble as well. And in the midrange/lower treble, woofers send out their sound like a flashlight beam-pretty much only straight ahead, but nothing side-to-side or up-and-down. So even if the tweeter can pivot down towards the listening area, it's not reproducing enough of the total sound to make a real difference-the listener is still missing out on large portions of the sound.
What's needed is a speaker where the TWEETER, not the woofer, handles more of the sound spectrum, because tweeters spread the sound out over a very wide area, in all directions.
Simple, right? But typical tweeters are lazy. They don't like to work very hard, so most speaker designers take the easy way out and only use the tweeter for the very highest treble notes. (Engineers call this a "high crossover point.")
Atlantic Technology is different-and better. We've engineered a special tweeter that can work very hard (a "low crossover point"), and it can play most of the middle tones as well, thereby relieving the woofer of having to do what woofers can't do. Our LRT tweeter spreads out the midrange sound ("disperses" the sound) over a much wider angle than the woofer, so our IWTS-155/30 LCR and 2400 Series cover the entire listening area beautifully in both the midrange and treble. There's nothing else like them, and it completely solves the problem of getting truly good sound without resorting to unsophisticated tweeter pivots, expensive motorized mechanisms or complicated 3-way designs.
Q: DO I NEED A BACK-BOX FOR MY 14 SR OR 30 SR IN-WALL SURROUNDS?
Here’s why: A speaker uses an enclosure (a “box”) primarily to give the woofer the proper-sized working environment to produce good bass. The 14 SR and 30 SR surround speakers are not being asked to produce deep bass—that’s the job of the subwoofer. One bank of drivers in the surrounds does have a plastic cover to acoustically isolate one side from the other, but that’s all that’s needed. No other back box is necessary.
Q: HOW MUCH POWER DO I NEED?
A: This is a tricky question. It's like trying to recommend to someone how much food they should eat for dinner. How hungry are you? What do you like? Was your lunch 3 hours ago or 6 hours ago? See? It's not so clear-cut.
The first thing to do is to look realistically at your tastes and goals. Do you want to just have an involving, satisfying movie experience in your home when watching Beyond the Sea: The Bobby Darin Story, or do you want to impress the bejeebers out of your friends when they come over to watch Terminator 3? Once you know how loud and bombastic you want your system to play, you can choose the speakers and amplification needed to do the job.
Let's begin by defining a few terms. SPL or Sound Pressure Level is a measure of the relative loudness of sound. It's expressed in dB, or decibels. Normal conversation is around 60 dB. Loud music is about 90-100 dB. If you were standing on the runway when a jet airliner was taking off, that would be in excess of 140 dB, and hearing damage would result.
Most movies in a theater have peak SPLs during crashes and explosions of around 100-105 dB. That's very loud, and it's louder than most people want in their homes.
Assuming a "normal"-sized room (about 2000-2500 cubic feet, as measured by H x W x L), a good surround-sound receiver of 75-100 watts per channel can easily power speakers of average efficiency (88-91 dB) to peak SPLs past 100 dB. A larger room or less efficient speakers will require more power.
More important than the raw power number, however, is the quality of the amplifier. Some receivers work better with lower impedance speakers (the amplifiers have higher current capacity) and it's quite common for two receivers with the "same" power rating on paper to sound quite different in the real world. If you see a receiver advertised for an unbelievably low price that promises "200 watts x 7 channels," be suspicious. Do your homework and buy good stuff. You'll be much happier in the long run.
Q: WHAT IS ALL THIS TALK ABOUT DOLBY DIGITAL®, DTS® AND THX®?
A: OK, let's make this as simple as possible. Dolby and DTS are two companies that produce movie soundtracks with a certain type of surround-sound encoding. In order for you to hear the surround effects of DVD's encoded with these surround-sound processes, you need to have electronics that have Dolby or DTS decoders built into them. Virtually all home theater receivers have these decoders. When you put a Dolby or DTS-encoded DVD into your DVD player, your home theater receiver decodes it, sends out the proper signal to the proper speaker, and Voila! Surround sound in your living room. Neat.
THX is a set of movie performance standards developed by Lucasfilm THX (the people who did the original Star Wars movie in 1977). These standards are sort of like a Good Housekeeping® seal for home theater equipment. So whether your receiver has Dolby Digital or DTS or both, if it has THX certification, it means that the folks at THX have determined that the receiver has met a very high standard of audio performance. THX is NOT a method of encoding a movie soundtrack. There are Dolby-Digital and DTS-equipped electronics components, and if they're really good, then THX blesses them with official certification. Comprendez-vous?
THX also applies a set of performance standards to speakers, and if the speakers are really good, then THX certifies them as such. Atlantic has several models that meet the stringent THX certification. As a matter of fact, Atlantic has delivered more THX-certified speakers than just about anyone else, and we're the longest-running THX-certified speaker line.
Q: HOW DO I FIGURE OUT ROOM SIZE IF MY ROOM IS OPEN TO ANOTHER ROOM?
A: This is a pretty common situation. Often the den is open to the kitchen or the living room is open to the dining room. A good rule of thumb is to calculate the cubic volume of your main listening room (H x W x L in feet), and then add to that one-half of the cubic volume of the adjacent room.
Yeah, all the theorists and acousticians out there will howl in protest, saying that if one room is open to another, then all that counts is the pure sum of the two rooms' volumes. But in the real world, it usually doesn't work out that way. If you sit reasonably close to your TV and speakers, and the opening to the next room is behind your seating position, then your ears will "think" they're in a smaller acoustic space than the two rooms' additive volumes would suggest. Judge your situation with that in mind.
Q: WHERE SHOULD I PLACE MY SPEAKERS?
A: Left/Right front speakers
Generally, the ideal locations will be located to either side of the TV screen, at least 1.5 to 2 feet away from the screen itself. It’s actually best to have the speakers a little forward of the screen and out away from the side and back walls. For the best audiophile performance and to minimize interactions with the walls (boundaries) it helps to be sure the distances from the rear wall and sidewalls relative to the speaker are different. The speakers should be placed with the tweeters as close as possible to seated ear height, about 35-40” off the floor. Experiment with them toed in towards the prime listening position or facing straight out into the room.
Ideally, this speaker should be located directly on top of or below the center of the TV screen. The center channel is arguably the single most important speaker in a home theater system, because it handles up to 80% of the movie’s soundtrack! Putting a speaker in the same plane of the TV screen does, however, cause certain problems. Sounds that would normally radiate equally in every direction from the speaker are instead immediately reflected off the television’s screen. This causes undesirable sonic "colorations" that make the center channel sound different than the left/right front speakers, even if they are precisely matched.
This is why all Atlantic Technology center channel speakers include one or more controls that allow you to tailor their sound to better match the L/R speakers. Additionally, all Atlantic center channel speakers come with an adjustable mounting base that allows precise aiming towards the prime listening position for better dialogue intelligibility.
With traditional box subwoofers, it’s best to experiment with placement, since no two rooms are exactly alike. Keep these things in mind: room boundaries—such as floors, walls, and ceilings—act like “acoustic mirrors,” and will reinforce the subwoofer’s output. Therefore, a subwoofer placed 3 feet out from all the sidewalls behind a chair, for example, will sound thinner and weaker than the same sub in the same room place directly at the floor-wall intersection.
Also keep in mind that rooms tend to have what engineers call “room modes” or “room resonances,” whereby the room’s dimensions will either reinforce or weaken certain bass notes where the bass wavelengths correspond to the room’s dimensions. The best way around this (especially if you aren’t using expensive, complicated room diagnostic tools and fancy equalization) is to locate the subwoofer asymmetrically in the room with respect to the room’s dimensions. For instance, if the sub is going to be placed along an 18-foot wall, try locating it, say, five feet out from the corner. Five and thirteen feet are mathematically unrelated, so they don’t conspire together to reinforce or cancel related frequencies. On the other hand, if you located the sub 6 feet out from the corner, then you’d be left with 12 feet. Not as good, because 12 and 6 are directly related (2:1 or 1:2), and you could get a buildup of room modes around related frequencies. 9 feet out (mid-wall) is even worse, because then it’s 9 feet and 9 feet.
You get the idea. Experiment with placement.
The exception to all this is our 10 CSB Corner Subwoofer. It’s shaped and designed to look and sound its best when placed in a corner, so that’s where it goes. Simple.
Surround speaker placement
There are several different types of speakers used for surround applications but the rule of thumb for the best location is the same: try to place them such that their sound can’t be specifically pointed to or “localized” by the listeners. The goal of surround speakers is to immerse the listening room in three-dimensional, enveloping surround effects.
For dipole surrounds (sometimes called “diffuse field” surrounds), the ideal location is directly alongside the prime listening position, well above ear height when seated, approximately 12-24 inches down from an 8-10 foot ceiling. Dipoles may be placed slightly rearward of the prime listening position on the sidewall, or even located on the back wall if absolutely necessary. For ceiling-mounted dipoles, such as our 6.3e or 8.3e Tri-Vector speakers, the best location is either directly above or very slightly behind the primary listening area. Locate them just outside either side of the sofa.
These speakers can be placed similarly to dipoles, and can even be placed forward of the listening position as well. But it’s typically more difficult to get a bipole to deliver a non-localizable sound field unless they're located fairly high on the side walls, well above seated ear level. Bipoles will work satisfactorily on back walls or ceilings, as long as they’re far enough away from the listeners so their sound can’t be localized.
Also known as direct radiators. When used for surround speakers they should be placed relatively high up on the rear or side walls, with the tweeters firing straight out from the enclosure (not angled down towards the listeners), high above the listeners’ ears. This helps to create a more believable "surrounding experience" and makes this type of speaker less localizable.
Q: WHAT ABOUT SURROUND SPEAKER PLACEMENT IN 7.1 SYSTEMS?
A: In 7.1 systems, the side speaker placement should follow the same guidelines as outlined above. For the rear surround speakers, bipoles or direct radiators are generally fine. Again, place them so the tweeters are well above seated ear level.
If you are using dipoles for the rear speakers as well as for the side speakers, pay attention now!
Remember when you installed your side surround dipole speakers? They have a “+ “ side and a “-“ side. You oriented them so that the “+” of each speaker faced towards the front of the room.
So here’s what you need to do when mounting dipoles on the rear wall to go along with dipoles mounted on the side wall: Switch the Left and Right surround speakers and mount them “backwards” on the rear wall. In other words, the Right speaker will be on the left side of the room and the Left speaker will be on the right side of the room.
Here’s why: By swapping the rear surround speakers, the rear-firing “-“ of the side surround will blend right into the out-firing “-“ of the rear surround. Then the two inward-firing sides of the rear surrounds will both be “+.” Then the out-firing side of the other rear surround is “-“, and it will blend seamlessly into the rear-firing “-” side of the other side surround speaker. Everything sounds nice and smooth, very realistic and convincing, with no abrupt, unnatural changes in the sound field.
This is pretty subtle stuff, but it’s these kinds of little things that make the difference between good-sounding and great-sounding systems