FAQ

1. Do I need a subwoofer?
2. What are some important things to consider when buying a subwoofer?
3. What if I already have a "subwoofer"?
4. What's best for me?  Cylinder or Box subwoofer?
5. What are the differences between the NSD, Plus and Ultra series of SVS subwoofers, and what about the SB?
6. Should I consider dual Subwoofers?
7. Where do I put my subwoofer?
8. What are some great movie and music demos?
9. How do I use a sound level meter to calibrate?
   

1. Do I Need A Subwoofer?

That is a good question. Let's be clear. Not everyone needs a subwoofer. But heck, not everyone "needs" a home theater either. If you and your "significant other" are content watching movies at low level, or you primarily watch VHS tape or cable TV, a high power subwoofer might be more sub than you want. Our largest offerings of subwoofers is SERIOUS bass in terms of both quantity and quality. Some people don't need it, some people don't want it. If you call the place you watch movies a "Home Theater" you almost certainly can appreciate the truly deep bass our subwoofers can bring you.

But why would you want real, deep and ultra powerful bass? Simply stated --- to capture the theater experience at home. With the advent of Blu-Ray movies and HD surround sound-tracks, such sound is finally possible in your home. Again, that's theatrical sound in both quantity and quality. Surprisingly, while there are hundreds, perhaps even thousands, of great choices in full range audio speakers (for your main, center, and surround channels), the number of subwoofers which can affordably supply both deep and accurate theatrical sounding bass are fairly slim. In fact, such bass is downright rare at prices most people can afford.

Most importantly, true, deep powerful bass is critical to realistic home theater sound. If all the surround sound was icing, bass is the cake. Some feel it's the foundation upon which the theatrical experience rests. The ".1" of Dolby Digital or DTS 5.1 surround sound is usually dedicated to subwoofers for a good reason. When an explosion rips, the tanks roll, or the pipe organs rumble, it's your subwoofer that makes the difference between "good sound", and sound you can feel too. And it should feel real.

Very few people have heard what an honest sub-woofer can do for their audio system. Those that have can't live without one.

2. What are some important things to look for when buying a subwoofer?

First and foremost, you, the customer must enjoy the subwoofer. It doesn't matter if the "numbers" or "specs" say it's perfect...if you don't like the way it sounds...what good is it? However serious subwoofer manufactureres do feel a subwoofer should meet some basic verifiable performance goals if it's going to perform well subjectively and objectively, for the majority of HT enthusiasts. In no particular order...these goals include:

• Low distortion
• Low GD (group delay)
• Flat response
• Very high output capacity

Something to consider in terms of performance...if a subwoofer can produce 110dBs (very loud) with low distortion at 40hz, we feel it should produce as close to that output as possible, right down to it's low frequency extension limits. This is called "flat" or "linear" response. Unfortunately, the vast majority of commercial subwoofers are very NON-linear in this regard. It's not uncommon for a subwoofer that produces 110dB at 40hz, to only have the ability to produce 90dB at 20hz. (or less, often much less). Keep in mind this means such a subwoofer produces roughly 6 times more acoustical energy at a relatively high bass frequency, than it is capable of doing down low.

Wonder why some subwoofers are said to sound "boomy and unnatural" when you turn them up too loud? Well, right there is a large part of the answer to that question. While it is true that there are far more instances of 40 Hz bass in most modern movie soundtracks (and music) than there are at 20 Hz, or probably even 30 Hz, we feel strongly that both should be handled with equal ease, and portray the levels and emphasis on different bass frequencies that the movie’s makers intended. Needless to say, the preponderance, or overemphasis, of mid-bass is not something most manufacturers are interested in talking about.

And flatness is only part of the picture. Flatness at the levels commercial theaters are capable of (adjusted for smaller HT rooms of course) is what you should be after. We adhere to the point of view that the two most important aspects of HT bass are headroom, and ensuring subwoofer placement and calibration so each seat is optimized to have as smooth a response curve as possible for that listener/viewer.

Many folks don't realize that the bass requirements for true Dolby Digital (DD) standardized reference level movie sound is actually quite difficult to achieve (or could previously only be done at a very high cost). If you listen to reference levels, Dolby Labs ® requires a clean 115dB at each seat...down to the lowest frequencies on the material played (usually about 21-24hz, and sometimes even lower). Most reasonably priced subwoofers don’t provide more than a small fraction of this bass.

Furthermore, if you use bass management to reroute some bass from the main speakers to the subwoofer (say you are using relatively small main speakers)...the headroom needs are increased to the 121dB range! That's 121dB/at the seats/down to 21-24hz. In a typical room...you'd need a pair of corner loaded high-end subwoofers going full throttle to approach this. As stated earlier, not everyone wants or needs true movie theater level realism, but for those that do want it, or for those few that already have it, you’ll be drawn into movies like never before. That’s what to look for in a subwoofer system... realistic sound reproduction, no matter what volume you prefer.

3. What if I already have a subwoofer?

If you have a subwoofer, and find it perfectly adequate, consider this…most "subwoofers" are really nothing more than mid-bass "woofers" that support relatively small satellite main or surround speakers. There is nothing wrong with this concept. For instance, for music only, such systems can perform quite well. The usual "Sub-Sat" arrangements generally do a fine job of providing relatively low levels of mid-bass (which we'll put in the 120Hz to 45hz range). This however is not true bass, and it's far from what's required for reproducing today's movie soundtracks the way they were intended.

True, deep bass, from roughly 20-45 hz is what you hear, and feel, when you go to a first rate commercial theater. For convincing theater sound with today's Blu-Ray movies you need effortless bass that extends to 20-25hz or even lower down to 5Hz in some cases. Many commonly available commercial subwoofers manage to squeak out a few dBs in this range, but very very few can provide adequate levels of low-distortion, high-power bass at the levels you'll hear, and feel, in the theater. This limitation applies to the vast majority of subwoofers, even those sold to augment home theater systems.

If you've drilled down from our Subwoofer Page, you already know how affordable our subwoofers are, but integrating one into your existing system (even with it's current subwoofer) is very easy to do. This is especially true if you watch Bly-Rays and your sound system is equipped with a DDD/DTS HD receiver or surround processor.

Our on-line technical support will walk you through the process from unpacking to calibration. We are so certain that adding one of our subs to your existing system will make a radical improvement in your home theater viewing (and music listening).

Please contact us today if you have any questions of which subwoofer might be your perfect choice!
 

4. What's best for me? Cylinder or Box subwoofer?

Like so many things in life - it depends.  Some folks like the cutting-edge, unique and understated elegance of our space-saving cylinder subwoofers, others value the more traditional but likewise slick simplicity of our box designs.  In fact, aesthetics ... how you want your sub to look ... is probably the most significant consideration in your decision here.  Still, there are some other "pro's and con's" to consider, and even the question of "looks" isn't as straightforward as it might seem at first.  How you  weigh these issues is clearly a personal call:   In short, cylinders tend to cost less, are noticeably taller, but at the same time lighter and easier to move.  They take up far less precious floor space too.  Boxes tend to have considerably more "heft" (requiring more "grunt" to place them; most require two people to move very far), have nice flat tops you can put things on, yet cost a bit more than the closest performing cylinder equivalent. 

Box vs cylinders within the same series is literally performing and sounding the same. Which to chose? The one you think will be best for your room/placement and which you like the most. It is only the form factor which is different as woofers, amps, ports, tuning etc is the same in both types of subwoofers.
 
 

5. What are the differences between the NSD, Plus and Ultra series of SVS subwoofers, and what about the SB series?

Starting with the NSD series where NSD is short for New Standard Driver, there really isn’t that much that is standard about the members of this family. Even though this is SVS’ entry level series, the performance is all but. 3rd party measurements have shown the members of the NSD series able to hang in with, and in many cases topple the performance of subwoofers that are considered high-end. To keep them inexpensive they follow the old T-Ford motto of being “available in any color you want as long as it’s black” and the features are kept to the bare essentials (though still better equipped than many other subs). All resources are poured into where it matters; pure performance and refinement. 

Moving up to the Plus series, you get a bit more of everything. More raw performance, more features, more finish options and more refinement. This is due to beefier and more refined drivers, larger amps, more port area and more costly enclosures. The Plus series has more features that will let you tailor the sound to your room and your liking, and the PB and PC models even has sealed modes making them the jack of just about any trade. The Plus’ carry many of the same features and much of the same quality as the Ultra series, but are kept smaller to better fit non mammoth sized rooms. 

At the top of the heap you find SVS’ Ultra series. These are high-end subs sporting the best driver and amplifier technology available, necessary to squeeze out that last drop of refinement. At the same time, and even though hard to imagine they also bring more raw performance to the table and even more features than the Plus series.  Able to fill even large rooms with tactile bass, the Ultras are the best of the best, and a marriage of performance and sophistication not seen anywhere before.

Is an SB model the right choice for me?

Our larger PC and PB models, while excelling in every other benchmark, are not particularly good at being small. The SB models, short for Small Box are built for just that particular reason. They will not be able to keep up with their larger brethren in the very deepest frequencies; this is something that holds true for any small sub, no matter if the sticker on the front says SVS or something else. Still they are some of the best small subwoofers out there, and SVS have poured every bit of know-how into making them as good as physics do allow, while keeping the size down to a minimum and making them play without any artifacts even at the limit. For smaller to medium sized rooms or where the emphasis is on music and maybe you do not prioritize the very deepest bass, and you want something that is as discrete as possible, the SB series is the right choice. For all other applications, music included, bigger IS better, and we wholeheartedly recommend the PB or PC series, or alternatively, dual SB subwoofers.
 
 

6. Should I consider Dual Subwoofers?

Absolutely! Getting real theater levels of accurate, deep and powerful bass if far more difficult than most people realize. Though whether you really need dual subwoofers depends on a few fundamental issues… primarily listening habits and room size.

First things first. How loud do you listen to your movies and music? Do you find that relatively modest levels are more than adequate when watching a movie? Maybe you live in an apartment and can’t really turn up the volume that much? If you are in a constant battle of keeping the volume low enough, then one subwoofer is almost certainly enough. In moderate sized rooms even one of our powerful subwoofers will greatly extend the bass performance of nearly any audio system, and will provide even better bass than most HT enthusiasts have ever experienced.

This is particularly true in very large rooms, or HT areas that open up into other areas of your living space. Creating effective bass requires a sort of pressure (from sound waves, propagated by moving air). Essentially, the larger the room, the more difficult it is to reach the levels of smooth, deep bass you will find it a top-rate commercial movie theater (which if top-rate can reach Dolby Labs reference levels for clean bass; or 115dBs right to the lower limits of the bass track. That’s a LOT of bass!). So if you are the sort that simply MUST be able to "take it to 11" with bass so deep and powerful you’ll think the theaters are lacking (especially if you have a large room), then we strongly urge you to plan on getting a pair of powerful subwoofers.

What can you expect with dual subs then? If you are able to co-locate two subs in a common corner of your HT, you can expect roughly 6dBs increased "headroom" throughout the sub’s response. 6dBs might not sound like much on paper, but it translates to double the acoustic energy (as you would expect). So where one subwoofer might be straining to produce the deepest bass of your Blu-Rays at high levels, dual subs can often just coast along, with accordingly less distortion too.

If you are continually giving demos of all your favorite movies, to all your favorite friends and family, dual subs are probably the best way to ensure your bass system is up to the task.

With twin subs, every movie will remind you this is what theaters aspire to sound like, we do know this is more than many folks need or want though. What sort of movie/music fan are you? If you are wondering if your room will require dual subs to hit the mark Dolby Labs has established contact us with the dimensions of your HT (and just how low and loud you want to go)… support@lsound.no

7. Where do I put my Subwoofer?

You might have noticed. Many of our subwoofers are big (yes, it's one of those instances when size does matter). There are a lot of very good reasons for this. Still, most our customers find these subs very elegant, understated, and stylish. Even in a tight corner they'll usually fit well. And corners are where you want them.

Many many theories abound regarding subwoofer placement. Their sound is essentially omni directional, and they are difficult to locate by ear. Yet for the lowest extension, and the greatest natural reinforcement of the bass sound pressure level (SPL) corner placement is nearly always best in nearly every shape room (and regardless of the brand of subwoofer).

Wherever possible, avoid placement where the sub is adjacent to openings into other rooms such as hallways, and open doors. A closed corner, relatively near the prime listening position in your home theater is nearly always ideal.  Just be certain to recalibrate (set the playback level) as you move your sub to different locations.  Moving even a foot or two (say from a wall to a corner) can have a radical impact on how the bass sounds in your listening position.  Just think of your room as another part of your speaker system.

If you have particular concerns regarding integrating a subwoofer into your room contact L-Sound. E-mail us a sketch of your current HT arrangement, and well be happy to make recommendations on sub placement for best performance.

 

8. What are some great bass demos?

This thread contains THE most complete list of bass rich movie scenes that we know of. Not only is it a list of scenes, the thread also contains a plethora of waterfall charts where you can see what was going on in the scene you just experienced.

So if you are looking for some great demo scenes, or maybe you just got shaken and is wondering how deep the bass really was, navigate over to the AVS Forum waterfall thread

9. How do I use a sound level meter to calibrate?

Proper calibration of your surround sound system, is not only easy, it's downright critical! Above is a Sound Pressure Level (SPL) meter; using one is akin to checking your car tires with an air pressure gauge. If you don't have one (the SPL meter that is), by all means stop reading this now and get one! Click here and buy one direct from L-Sound now.

Why is calibration of the levels of your surround system so important? Well, think of it this way - in the old days you could just adjust  the "Balance" knob on your stereo and get that center image (of the singer, or various instruments) "just right". Try to imagine doing that with 7 channels of a digital surround sound system for a minute! Get any of those channels out of balance by a few decibels and the complex realism of the soundstage Blu-Rays and the new high resolution music formats are capable of  goes right out the window.

Start by playing your receiver's internal test tones so you have something to measure with your SPL meter. Or better yet, a calibration disk, like our calibration discs available from L-Sound.  A test disk’s calibration tones ensure your entire signal path, from the DVD player to your speakers, is set correctly.

Make sure your receiver/processor master volume is set at "00 dB" or other easy to remember level, it will become your "reference level", one very close to that intended for home theaters by Dolby Labs. And finally, set your subwoofer amp’s volume control.  Note here, put the volume/gain knob to no more than 1/4th to 1/3rd of the way up.  It’s a good idea to check the subwoofer level control of your receiver before you begin the test tones. Keep the receiver's subwoofer output control to about 25% up or lower than "0 dB" (or say -5dB given a typical receiver channel limits of –12 dB to +12 dB) . This will allow your amp to work with the cleanest signal possible from your receiver, while still leaving plenty of downward adjustment you can use from your viewing position (using the remote). As the tones start, alternating, speaker to speaker (watching your sound meter now) set each speaker’s volume to 75 dB, depending on your tone source, using the receiver’s channel controls.

What to set the sub to? You might find that a higher level, relative to your main speakers is preferable. In other words, set to a bit higher than 75dB, depending on your calibration tone source. Tastes vary and so do movie soundtracks, but if you have a poweful subwoofer from L-Sound it is capable of tremendous levels of low distortion, low frequency bass. Take advantage of this, especially if you like action movies with lots of ".1" channel low frequency effects (LFE). Keep in mind too that the human ear is relatively insensitive to low frequencies. This, coupled with the fact most folks don’t watch movies at Dolby Digital reference level (loud!), means tweaking the bass up a few dBs usually yields a better movie sound experience.

Many of us boost the subwoofers with +2 to +6dB setting on the LFE or ".1" channel, but much depends on your room's acoustics whether you have one or more subs, and your typical listening level. With a setting like this, the VE test tone will peak about 81-83dB for the subwoofer portion of the calibration run. Because the Radio Shack sound meter is relatively insensitive at very low frequencies you'll actually be set several dBs higher than what's read.

Important Note: Use a "boost" like this only if you are watching at relatively modest levels. If you ever hear your sub bottom out (where the driver reaches its physical limits) you are set too high, at least for that movie and at that volume setting. Naturally customers with dual subs will enjoy far more "headroom" with regards to what is "too high".

As you continue to calibrate you’ll briefly need to rotate the sound meter level dial to the 80dB setting to get a good reading on the subwoofer if you go beyond the level of your main speakers as we recommend. Don’t forget that most modern surround sound receivers allow completely different subwoofer level settings, depending on the listening mode you are in. With "DVD" as your "source" use the above calibration routine. You may well find that "CD" (music) calls for a lower bass setting for the best balance in your home theater (try setting this by ear with music you are familiar with). The above is a guide, experiment!

Now if you got this far, and consider yourself an advanced user, you might want to delve a little deeper into the use of the SPL meter to flatten out response peaks in your room (using an external equalizer) or maybe just using one of the popular test disks out there to check and see just how well your subwoofer is performing. If so, you'll want to use a handy "compensation chart" to adjust the readings of your SPL meter. Its sensitivity down low is NOT uniform, but it's easy to make up for this slight flaw in this great too. This chart is ONLY good for the Radio Shack SPL meter pictured above. If your subwoofer seems to be measuring poorly with low frequencies, this chart is CRITICAL to making sure you know what's what.