does a subwoofer kill stereo sound?

I was wondering whether adding a subwoofer to a pure stereo system would cause any harm to the soundstage and other features of the system. What are your experiences? Should one buy a subwoofer to complement a great bookshelf pair (that may be lacking some bass) or necessarily one would have to buy a new par of speakers with deeper bass?
Some will tell you it will degrade the purity of the stereo image. Others will tell you how it can open up the sound. I'm with the later camp, if you can get a good blend. I have used two subs, now I use one near a corner all the way to one side. You would never know where the sub is, it integrates completely with the soundfield. Some rooms are not fullrange speaker friendly, in some stand mounts w/sub ultimately work the best.
My own experience is that it's very difficult to integrate a single subwoofer well. Multiple subs are a bit easier to get to integrate, far more effective and potentially less detrimental to imaging - again, this assumes good subs well-integrated. A poorly integrated sub can certainly hurt imaging and resolution. If I wanted more bass and was weighing adding a single sub vs going to full range, I'd look at full range. If I really wanted the depth and performance of great subs well done, I'd look at a multiple sub system like the Swarm system by Audiokinesis, paired off with Duke's speakers. If you're just looking to buy multiple subs I could also recommend used ACI Force XL's as a great alternative if you don't mind that the company is no longer in business. I've only heard AK Swarm subs with his speakers - I'd imagine they might work well with others if you just by the Swarm, but I'd consult with Duke on that. 2-3 small subs like the ACI would go nicely with monitors - again integration is still key, and your room and contents will play a bit roll there.
No. Stereo imaging is not impaired by a sub, provided that you've managed the x-over properly. Even if you screw that up, you're probably okay on the stereo separation front, so long as you're crossing resonably well below 100hz.


PS As Jax points out, a lot of things go easier with subs when there's more than one to work with.
I find the contrary to be the case, provided you have a good sub, properly integrated. The deep bass opens up the sound stage a lot as compared to a stereo that rolls off at ~50hz +, and in no way degrades the stereo separation or imaging.
When I shut my sub off, the stage gets narrower.

Sub is playing well with panels.
One of the best things you can do is add a powered sub or subs to a system. If done correctly, it frees up the amp to power the mids and highs adding much better performance.
I'm with MagFan an Stringstee, on this, I think a sub always adds to a system, no matter what the speakers.

I am shocked when I turn off the sub(s) with my Maggies, how much bass they put out. Then when I put the sub back into the system (I cross it over at 41 hz) I'm shocked again at how deep the image gets, and how much slam there is.

It does take time to set up a sub properly though, so they are not muddy, but it's worth the time.
I have full range Von Schweikert VR4sr's driven by Audio Space Ref.3.1. I felt the bottom end was mostly missing with only 42 watts per channel. I called Albert and he suggested his new subwoofer with a no questions asked 90 day in home trial. The differece is substantial. My soundstage actually opened up a great deal with much more inner detail audible. The synergy between the speakers and subwoofer makes the sub "disappear". On recordings with lots of bass, the sound is full and deep. On recordings with less bass, you can't tell the sub is in the room. As with all things audio, your mileage may vary. Happy listening.
Hi, again, Mac.
Agreed about setup. I spent about an hour doing first placement of sub.
I listened over a period of the next few days making 'little' adjustments. No joy and the bass remained 'thick'.
Finally, I turned the x-over all the way down. That is an indicated 30hz, but who really knows?
I turned it UP until I heard it again than down sightly. I adjusted the vol. again than the crossover frequency again. It's been untouched in a couple months.

the variation between recordings is a far bigger problem now than any possible improvement to the basic setup.
My final adjustment? x-over under 40hz and the sub 1 foot from a side wall and nearly 3 feet from the 'front' wall. The sub is in the same plane as the panels. When I rotated the panels around, I shut off the sub and when I had the panels properly adjusted, turned the sub back on and my bass disappeared. OOOPS! Flipping the phase switch on the sub restored the bass.

If I had the $$, time and inclination, I'd work on NOT running my panels full range. I suspect there are additional benefits in that direction, but also a whole new learning curve.
Magfan, You made this comment: "If I had the $$, time and inclination, I'd work on NOT running my panels full range. I suspect there are additional benefits in that direction, but also a whole new learning curve."

For my tastes, I found taking some of the lowest-frequency bass load off the main panels made at least as big an improvement as adding more and lower-frequency bass did. Articulation of subtle nuances (and some not so subtle) improved dramatically. My main complaint with add-on subwoofers is most just add bass and do not give the main speakers some relief where they need it the most. And you are right--it is a new ball game.
I can never get why people buy very expensive top shelf amps and then let the bass be done by amps built into the subwoofer cabinet. Is that really the best way to do things? Or do most people have a really good amp to run the subs too? How about using a seperate amp and preamp to run a subwoofer system?

As a side note, I have caught a dealer demoing SET amps but had a powered subwoofer playing hidden behind some other speakers. I am getting very good at detecting bass that should not really be there. I can tell if a subwoofer is in the system and it usually annoys me too much. imo, a sub is not really needed if you have great full range speakers AND the room to support low HZ. but they may be fun to play with and that is okay at time too.

My understanding is that high quality amplification is less important for bass than for other areas of the audio frequency band. But yes, there are certainly passive subs that let you choose the amp to use with the subs. I use a pair of passive NHT subs with 2 bridged Emotiva BDP-1s. The main advantage of this for me is the ease of dialing down the level of the bass easily for late-night listening. Most of the subwoofer attenuators are around the back. and awkward to reach for...


Your comment spoke to me . People that want more bass are really just not getting enough satisfaction from their system. They seem not to know why, so of course they seem to blame the lack of bass.

Bad move...... If the system was satisfying the bass would be the least of the problems.

You are right on.
woith some speakers only going down to ,,say 50 hz, your missing alot so maybe a sub is right in some systems.
sounds real audio; I am with you. Subs exagerate the lower end. Watching a movie great use a sub. Listening to music, NO THANKS! Take a good/great full range speaker over a sub any day.
Respectfully disagree that subs necessarily exaggerate the lower end. In my experience, the only time this happens is when the crossover is not properly set and/or the output is too high and/or the sub is not properly positioned.

Seamless integration of a sub-based system is not always simple, but once achieved, the end result is absolutely musical.
I use a passive sub so I could cherry pick the best matching amp , cables , cords , ect . I have used many different subs and set ups and found them all hard to integrate , many folks will never get it right . As to the original question , I don't feel a sub will kill stereo sound and if set up right can give a much fuller sound stage . Happy listening .
Disrespectuflly disagree that "subs exaggerate...."

Until someone has set up a subwoofer using RTA (and/or digital room correction), they should probably refrain from sweeping generalizations about what a sub does or does not do. A properly set-up subwoofer will produce measurably superior bass performance vis a vis the vast majority of full range speakers in the vast majority of rooms. Not a sweeping generalization - a fact.

There is a pretty simple reason: Most full range speakers are designed for placement out in the room. If this is where you generate your bass response, you will virtually always get serious cancellations at frequencies which can be calculated by their distance to the nearest wall and (to a lesser extent) further boundaries. A properly placed sub will mitigate those cancellations.

If a sub is exaggerating the low end, it is a poor sub and/or it has been improperly set up.

This doesn't mean that you have to prefer a sub to a full range speaker - merely that you can almost always get the sub to measure better, if you do it right.

Well first its important to understand bass is stereo not mono, and one subwoofer (unless its crossed over very low to complement a full range speaker) will collapse the soundstage. Thier really are two options, of course getting a full range speaker with enough bass on there own to satisfy you or getting two subwoofers one for the left one for the right. But to get quality bass information, carefull choice in subwoofers, cross-over adjustments, and placement are critical. It is definitely more difficult to acheive good sound with subwoofers then placing a pair of full range speakers. This takes someone with advanced setup skills to get right.

40 years hi-end audio video specialist
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Ohjoy40...I respectfully disagree with your comment. The bass that comes from a sub IS perceived as mono..whether stereo recorded or not. Bass is non=directional. What makes it seem like stereo, are the overtones, not the 30 or 40 cycle fundamental. These overtones are reproduced by the regular speaker, and thus seem directional. There is no need to spend lots of money on a "state of the art" amp to drive a "state of the art" sub. The built in "usually" class D (big power vs small size) is very good...the sub has a very limited range, without need for those subtle nuances we all love to listen to on our full range speakers.
Regarding soundstage... In my own experience adding a subwoofer seems to perceptually expand the soundstage, particularly the depth. Larry Greenhill has mentioned the same effect in his subwoofer reviews for Stereophile.

This is exactly my experience.

Further, some of the assertions made in this thread seem to be based on a "perfect world" basis where we have unlimited funds, and unlimited flexibility in our listening environment. I think when you allow for the fact that this is rarely true for most of us, a subwoofer will provide a more optimal imaging than the alternative full range floor standers that may have limited low end due to budget, or sub optimal placement due to room limitations.
Re: expanding soundstage.

I've heard the same effect, but not consistently. Most recently it's become quite apparent on Allen Toussaint's "The Bright Mississippi" which I believe - and I am speculating here - features a very large bass drum. With the subs on-line, the recorded acoutic sounds much larger when that drum is struck.

However, I rarely hear this type of dramatic evidence of this effect on most other recordings.

Isn't bass mixed to mono below.....say 80hz?
Given that bass wavelengths are longer than the longest dimension of MOST rooms, I'd say a sub was not locatable, eyes closed.

In large rooms, this may change.
I suspect that alot of information regarding a venue's acoustic space is very low frequency info that you can't quite hear on an obviouos manner, but is notable by its absence. If I had to use a subwoofer, I would only do so with close to full-range, or full-range speakers over a very narrow span with a very x-ver in the 30-40hz range. The less you ask of a sub the better it will interate and add without subtraction.
Martykl...Actually, I hear it quite differently. If you have a system that can accurately reproduce the lowest frequencies accurately (I am not commenting on your system) you will clearly hear low end pitch differentiation on those very powerful low notes. This is clearly the work of the bass player. Yes the drummer's kick drum adds some concussion when appropriate, but those lows are clearly the work of the bassist. I further speculate, that it is an old Kay plywood bass that's been electrified, and plugged directly into the recording board. In the song "Day Dream", the bass starts the tune, and the drummer comes in a couple of measures later.

I'm not sure that we're taliking about the same thing - but we might be. I'll go back and listen again, but I'm not necessarily talking about the lowest frequencies on the recording - rather a percussive sound (maybe +/- 50hz fundamental as a guess, but clearly below where a kick drum impacts) that seems to "bloom" when the subs are on.

OTOH, we might be talking about the same thing since, as I indicated in my OP I was speculating as to the source. I'll cue it up again and post back. Thanks for the insight.


Most "fullrange" speakers with really good bass response are very expensive, even in high end audio $$$. Ohjoy40 Kevin may have the luxury of a listening room where a speaker's mid/high sound and bass response both work in the same placement. I would guess many of us are not so fortunate as to have the optimum listening room and to afford a great fullrange speaker.
The subwoofer "compromise" is often used even with speakers that have impressive low end. A properly set up sub should not be heard- only missed when turn off.
I found the subwoofer to add more dimension and overall better sound. I use the Merlin TXM-mme bookshelfs on stands. I added the JL112 sub and very carefully tuned it, almost to the point you are uncertain if it is on or not. With tympanis and pipe organs I get the goosebumps! Also my preamp, McIntosh C2300 has selectable preamp outputs. With the press of a button I can have the sub in or out of the system. For the most part the sub is always playing. A vote for the subwoofer providing it is carefully adjusted, placed and matched.

I got a chance to listen to "Mississippi" again. I believe that you're right re: Day Dream, but my post was actually refering to something different, like the series of drum beats that begins less than a minute into St. James Infirmary. I believe that it's higher in pitch than the passage you reference, but removing the subs on this song causes the stage to collapse (on my system) dramatically. I do believe that it's a bass drum struck with a mallett, but can't be sure.

The same collapsing stage occurs on Day Dream, but it's more dramatic on "Infirmary" in my system - for reasons unknown.


BTW - Don't know the old Kay basses, but I have (quite recently, actually) played one of their old archtops. It was a pig and I'm not sure why anyone is fond of these things. Different strokes, I guess.
In response to the original poster, a subwoofer has a pretty simple job to frequencies in the 100 to 20Hz (or lower) range.

It's apparent you want more bass. Provided your bookshelves are capable of playing down to 80Hz or so, and you cross them over properly, there's no reason why you wouldn't enjoy the added low end reinforcement a subwoofer provides, with one caveat...some sort of EQ would provide the best integration with your room. The SVS AS-EQ1 is an amazing little piece of equipment.

So your decision really depends on your budget. A decent sub and EQ could cost from $1500-$2000. Are there full range speakers out there in this price point that interest you? If so, would they sound any better than your admittedly "great" bookshelves?

The added benefit of a sub (or my preference, dual subs), is that you can just turn them off, giving you added flexibility. Or just turn around and sell it(them) if it's not to your liking. You still get to keep the speakers you like.
There is no need to spend lots of money on a "state of the art" amp to drive a "state of the art" sub.

Disagree. Most subs (I mean 99%) simply distort so badly that they ruin the sound (at least at usable SPL's in the ultra LF range of 20 to 30 Hz).

It is EXTREMELY difficult to produce low frequencies at reasonable SPL without distortion and therefore extremely expensive to do it right (to audiophile standards).

The same can be said for speakers - it is just plain difficult to do ultra-LF well - the manufacturer may claim performance to 20 HZ on a full range speaker but what they don't tell you is that you will be hearing upwards of 10% THD at anything nearing useful SPL levels.

Distinct bass lines from drums is something that can be heard on a good system as the timbre is quite different (even if they may overlap in frequency range). The trick is to have a critically damped design as opposed to a ported resonant design. (although resonance gains efficiency and SPL it has a down side in that it destroys timbre and will make differences between bass and drums that much harder to hear)
Here is a little more why I believe resonance and THD is important in ultra LF.

Resonance is important because of "masking". Masking is what is used to create lossy MPEG files that sound almost identical to lossless files. Masking is the well known fact that loud low frequency sounds will mask higher frequency sounds to the human ear/brain system. Therefore, if you cannot hear these higher frequencies (due to LF sounds) then this detail can simply be removed from the audio files (reducing the file size dramatically), whenever there is "masking" going on. All you need is a clever algorithm to recognize when masking will occur and you can compress any file.

THD is especially important in ultra LF because your hearing sensitivity increases dramatically from 20 Hz to 100 HZ. Typically you are some 40 db more sensitive in hearing at 100 Hz compared to 20 HZ. This means that even minuscule levels of distortion in the ultra LF (20 to 30 Hz) can still amount to highly audible harmonic distortion effects at 100 Hz and above (altering dramatically the timbre of the sound). Since the distortion is harmonic it generally does not sound bad (and will not change the fundamental note) but most subs, which distort badly, will make everything sound extremely bass heavy (making it much harder to hear details) Of course, since it doesn't sound bad most people think these subwoofers are amazingly "impressive" - as they hear such heavy handed bass (deep bass they think). Actually a good precision subwoofer should not sound "impressive" at all!
I've tried at least 4 different amps ( 3 were bridged Stereo amps ) on my passive 18" sub , the better and pricier amps were very important and not just for impact , For 2 channel music .
I also tried some different crossovers , including one with room correction , hate to say it , but the more I spent the better it got .
As good as it is , We seem to listen to most music without it , but its a must for watching movies .
"Put the sub between the two speakers. Problems solved."

Umm, no. Problem is worse. A lot worse.
not in my home. but then again, i've got two wired as stereo so no threat here.
I use a Visonik of Germany, 8" sub unit in between my John Blue JB4's which are on 5" high stands.(These are full range units which do a good job with bass, for their size) My music room is very small: 10 x 15' long. The sub is turned down very low. The stereo imaging does not seem to be affected at all. When I turn it off, you definately hear that it's missing. If the idea of a stereo is to get the best sound you possibly can get in your environment, and a sub is a gain to your musical experience, Go For It! After all, how boring would it be if we all agreed.
I use two small sealed subs in my setup, equalized with the Velodyne SMS1. Both subs are situated between the speakers. I love the results. Lot's of technical info in prior posts, but one key for me was to cross over the subs to kick in BELOW the lowest frequency of my monitors, so that the subs do not overlap the monitors. Trying to integrate subs to overlap with your monitors, or to otherwise replace the low frequencies of the monitors, is a different beast and very difficult to accomplish in most rooms, in my experience. The other key, was to learn to set the subs at a modest volume level. It's tempting to crank the subs volume, but as is often said, if you can hear the subs they'rep probably too loud. This is especially true in a music only system. I can't hear my subs specifically, but if I turn them off, I immediately miss them. It took a lot of tweaking to get my subs to integrate the way I wanted, but it was worth the effort. I highly recommend the use of an equalizer or equalizing software and a good spl meter is a must. I also recommend a sealed sub - I had a ported sub previously and it was much more difficult to control in my room (YMMV).