Has anyone added a small subwoofer to 2 channel and been thrilled with the result?

The subwoofer can of worms.
I’d like to add some bass to my otherwise fine 2 speaker setup and have limited space so perhaps a single 10in?
After a few weeks of research the only conclusion I can come up with is - everyone agrees they have to be setup properly. Every brand and technology has their own following and most recommend using 2 (which I don’t want due to space concerns). My room is 12 x 13 ft with box raised ceiling.
After much research, these are the subwoofers I’m trying to pick from, for various reasons:
Rythmik FM8  - lots of hifi fans
JL audio e110 - fantastic support
REL T/9i - sort of a gold standard
KEF R400b - interesting technology, makes me grin. 

I've never heard any of these.
Hegel H160
SF Concerto speakers on stands.
Yes a sub warms up the sound...

I love my 2.1 setup with Velodyn sub. 

You won't be disappointed with a good setup.

Does your pre have a sub out?

H160 has variable Line Level (RCA) right, left and the node2i I'm adding will also have sub out.

I'd like to get both R+L into the subwoofer.

Some controversy with adding REL high level off the speaker outputs. Hegel says no don't do it and REL says they have done it at shows with Hegel.... thus the can of worms of subwoofers.

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All of my systems include a subwoofer (or two or three or...).

I have a couple off small computer systems in smaller rooms and use small sealed subs in both, a Rythmik F12 in one and a SVS SB12-NSD in the other. I love Rythmik subs and think they are hard to beat for the money, but SVS is no slouch either. The SB12-NSD is an incredible bargain right now. They have been discontinued and heavily discounted. You should add that to your list. 
Thanks, What speakers did you add it to?
It's remarkable what a sub can do for mids and highs...I use a REL S/5 SHO, but have had great success in past with small REL in small room system...
A number of the Rythmik plate amps (all but the XLR models) provide both high-level connections (on speaker binding posts) AND line-level connections (on RCA jacks). You can try the sub both ways, and use the method you prefer.
I added an Omega DeepHemp 8 to augment my Super 3i Monitors. I was really unsure if this 8" driver (down-firing, sealed design) could be satisfying. It made a world of difference. Yes, I'm thrilled. I doubt you'd be disappointed with any of the ones you're looking at. 
casteeb, if you’re asking me, I’ve had a few speakers in there, most recently Canton Vento Reference DC9 speakers, which have a surprising amount of bass for small monitors and before that, Klipsch Heresy, which despite having a 12 inch woofer in a sealed box, don’t dig very low. The sub complements both sets of speakers nicely. I also use subwoofers in my main system with legacy audio focus 20/20 speakers which have a total of 6 twelve inch drivers.
Naive question: doesn't a sub mess with the image?

Say you've got a bass guitar mic'd mostly in the left channel but then part of that instruments frequency response plays over the sub which is in the middle of the two speakers. How can that possibly sound coherent image wise? 
Many recommend 2 or more subs, I know REL does. Some depends on how low main speakers go and room. Also debate about how directional our hearing is below 35-40hz. Bass guitar goes down to 42hz. So lots of debate, and different preferences. REL likes to demonstrate subs with female vocal and acoustic guitar...
Bought 2 used RELs for peanuts (Ebay), easily helps make a good system great.
which did you get wolf ?
I wonder how much difference you would hear between 10" and 12" subwoofers?

At the frequency range the subwoofers activate the wavelengths are longer than your room.  That means the entire room is being pressurized with these low signals, so the sound from the resolved wavelength is coming from everywhere.

If you are sitting 10' from your speakers, frequencies above approximately 115 Hz will have wavelengths of under 10', so the direct sound (at 115Hz and higher) will reach your ears before any reflections.  As frequencies get higher, it becomes easier to pinpoint the direct sound from the speaker.

The reason for two subwoofers has more to do with cancelling resonance peaks and valleys than improved imaging.  You can set up one subwoofer to sound pretty good at a single listening position, but if you want the bass to sound better at multiple listening positions two subs, when placed properly, will be much better.  The sub frequencies will still be omni-directional, but will be distributed more evenly throughout the room.  Any directional cues are coming from mid bass tones and transient noises such as pick and finger noises.

One of the big advantages of subs is that you can move them around to adjust to your room resonance frequencies.  That is quite a bit more difficult with large, full range speakers that can handle sub-range frequencies.  With big speakers that can reproduce those sub-frequency sounds, you will need to resort to digital or acoustic room correction to level out room resonance peaks and valleys.
@stuff_jones  kahlenz provided a good explanation.  Suffice it to say that in any of my systems if there is a bass line coming from a particular spot in the soundstage it images correctly and I have no problem picking it out.  Most of the frequency range of the bass guitar is above where I have my subwoofers filtered off at (around 40 - 80 hz depending on the speakers) so most or all of it is coming through my speakers.
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Everybody will expound their favourites, so there is no real right or wrong choice of make. I would imagine that as long as they are not  put on "loud" almost any make will be satisfactory and demonstrate improvement. As someone posted above, 2nd hand ones are very cheap and you can improve at no great incremental costs as you see fit. I did not believe in subwoofers some years ago, basically because I had not heard any. Now I have a minimum of 2 even in small rooms, but on VERY low.
I use an older Mirage dual 8” sub with a pair of Silverline Minuets.

The sub is turned down to barely kick in and fill out the lows. I used speaker level inputs and cut the lows from the monitors. The system is for bedroom tv sound.

I’m betting you will enjoy and appreciate a sub with your monitors. Worth a try...


Yes Parts connecxion May still have a few left.
the Monitor Audio W-12 subwoofer uses a ceramic coated 
driver very fast and has Bass room correction 
was a $1600 sub retail. $950. Very musical.
I did upgrade the Fuse, built A Furutech RCA,as a decent power cord for a subwoofer,Pangea -SE  a very fast musical Bass performer.
You won't be disappointed with a REL.   My T/7i made an instant difference in my 2-ch system.
Thanks for the explanation guys, and sorry to hijack the thread.
Very happy with my REL S/3 SHO. I’ve got it tuned for just enough to fill in the lower end with some oomph and not get kicked out of my apartment. Wired up using the high level input off a class a/b amp, which it looks like the Hegel H160 is too.
I’ve had excellent luck using an old 8” 100watt Energy Sub in conjunction with a pair of Triangle Titus small bookshelf speakers driven by a 10wpc Cayin EL84 tube amp. I use the speaker level crossover in the Woofer at a 60hz crossover. This is my bedroom system and it gets used virtually every day with program sources ranging  from vinyl, CD and FM to internet radio.
Here's my transition the past few months from two speakers to a 2.1 system to a 2.2 system.

Started with a humble stereo...  Yamaha CR-2040 receiver and a pair of Advent Maestro speakers.  Clean, clear power to those donut midrange speakers- this is *great* low-buck audio! ... but you're clearly not getting the lowest of the low end.  And that's how it's going to be with many passive full-range speakers....

I don't want to shake the place- but I want the low end of the strings, percussion and brass represented completely.

Started by adding a single REL S/3.  $1000 for the sub was lots more than I had in the entire rest of the stereo.   Used the cable that taps the L and R speaker outputs.  Very significant improvement!  

Considered adding a second REL S/3...  My room is about 25 x 20, on a bass-sucking crawl space.  I could tell simply adding another S/3 would be much better... but I decided to simply cut to the chase!

Worked out a wonderful deal on a pair of REL 212/SE and I'm here to tell you.. even without using Unicorn-quality components my (formerly inexpensive) stereo sounds world class.  Not set up to boom and rattle- but the substance and dynamic power the REL's bring to the audio is unbelievable.  

Not sure having subs "in stereo" matter all that much... but having the low end filled out by one or two subs is the best tone upgrade I could have possibly made.  In essence- I took a junior varsity stereo and brought it into the major leagues with some high-quality supplemental low-end.  Best audio money I ever spent.

If the subs were boomy A-V... then absolutely not.  REL have been very musical for me and I would spend that money again in an instant for the improvements I received.
The integration of a sub(s) is one of the most popular topics discussed in these forums. Beside the choice of a particular sub the most important is placement in the listening environment. Each room is different.
You didn't state your main objective to add bass to your sound? Some like a powerful/floor shaking bass and others just want to fill in missing sound from the capability of the main speakers. What's your goal?
Maybe I missed something in your original post but I don't know what amp and speakers you are currently using? Whether floor standers or monitors. And, what type of amp you're using to drive them?
I also have a 2 channel setup using monitor speakers. I didn't want overpowering bass but just enough to fill in the complete sound. A compromise to using full range floor standers. With my setup I use the speakers with 2 10" subs. My integrated amp doesn't have any type of bass management capability. I use an Outlaw ICBM bass management unit. You could call it an active crossover. What it does is to send frequencies that the main speakers can't handle to the subs...thus relieving the mains from duty they can't handle. That's important.
Sub placement is the most important factor. If you just want to "round out" your sound then one or two subs will do the trick. Just be careful of crossover frequencies between the mains and sub.

>I’d like to add some bass to my otherwise fine 2 speaker setup
>System:>Hegel H160
>SF Concerto speakers on stands.
With little space and you want very good performance, look at the James subs.  
The answer your question yes I think adding a sub really helps. 

I the JL audio E110 is a good choice. If you have a pre-pro or dac to amp you just sit the sub between the two and use the active internal crossover (not just a low pass but a true 24 dB cross-over). Works well and makes blending super easy. 

The only issue I see is two subs are way better than one. I find one sub harder to get a good blend but it can be done. 

I have two E112s and I would say it has been my best audio perchase. Don’t be scared to try a 60hz crossover point. Many will tell you it is too high but with a cross over it is not an issue. 
I have a 10" REL that I've used with several speakers over the years and it has worked well with both stand mount and floorstanders.  I have had the best results with low crossover points, like 60Hz or lower and  running the main speakers full range.   

My dad has Concertos with a Velodyne DD10 and it's awesome for a compact system.  

Some of the newer subs have built in EQ, I would suggest looking at those first.   I'm using a Velodyne SMS 1 to EQ my REL and that coupled with a Auralex isolation platform and it delivers awesome low end .  

JL and REL are great sounding subs in my experience
A "vintage" M&K of any configuration will do wonders!!!!
Considering the size of your room, the Rythmik FM8, JL e110 and Rel T9i are all waaaaaaay more powerful than you need. You’re literally going to have the volume on any of those subs at the lowest point possible or they will overpower your main speakers.

I’m running a Rel T7 in a room a bit larger than yours (~200 sq ft) and anything above the 6th click on the volume knob is overpowering.
I’ll just say Hegel is a Norwegian Company well known in the European Audio Community and just getting a solid foot hold in North America, especially here in Canada. 
In a smaller room like that I would be looking at REL T5 or Sumiko S5. The larger subs will be difficult to tame without DSP or some type of setup with 2-4 subs to flatten out the room response.

I also don’t think that the difference between high level and line level is enough to be concerned about. I have had good results using both with REL and Sumiko. 
With KEF Ref 1s I'm using a pair of Velodyne HGS-10s low-passed at 40 Hz with 24 dB/octave slope by a SMS-1 bass manager that also does acoustic room correction.  The result is an excellent full-range sound.
Casteeb, I use the JL e110 with 2 way stand mounted speakers and it sounds great. My room is 13 x 18 x7 and the 1 sub is more than enough to fill the room. I run the speakers at full range and cross over the sub at 45Hz. My speakers are rated to around 38Hz.  The sub can be placed on either side of one speaker but at least 1 foot from the side wall. My sub is on the outside right next to my left speaker on the same plane around 45" from the front wall to avoid any booming.

The key is to set the phase on the sub which is quite simple. Reverse the cables of your speakers so they are out of phase with the sub. The play music with drums and put your ears between the speaker and the sub. Start to change the phase on the sub until the bass is basically cancelled or very low. Reverse the cables back to normal. Go back to your listening position to determine the amount of bass coming from the sub. You don't want the sub to overwhelm the speakers but to blend in. This make take a few adjustments but the entire process should take less than 15 minutes. Once you think its ok, then turn the sub off and compare it with the sub on. As I stated you don't want the sub to overwhelm the overall sound but fill in the music. The volume on my sub is only set to the 9 o'clock position but its enough to fill the room but feel the lower notes. Best wishes.
I really appreciate all the insight from folks who have implemented sub based systems and have empirical results to judge by.Very helpful for a newbee.
Thanks guys.
With the SF Concerto, rolling the low end from the mains and adding a sub will increase the 'low end precision'. Ported speakers have poor bass transient response. Consequently avoid ported subs if you want good bass transient response. Hence, a crossover for the main amp is required. It can be a simple capacitor.

IMO, a sub must have a phase control, 0 to 180° and a phase inversion switch. Crossover contour with multiple filters is a plus.

With proper phase integration, the increase in realism is way beyond the extra octave.

See http://ielogical.com/Audio/#Basement and http://ielogical.com/Audio/SubTerrBlues.php for some sub integration experiences and tips.
That agrees with what Randy at JL Audio was telling me....
JL Audio makes a great sub.  In reality the sub rally changes the mid-range and not for adding bass.  You have to find the bass node in your room to find the best placement.  Audio Physic website has good information on setting up speakers.
You have to find the bass node in your room to find the best placement.
If a sub is fully controllable and there is a prime listening position, there are many possible placement sites. For stand mounted speakers slightly ahead of the main woofer to obtain the same driver / ear path length and minimal control affectation.

As far as placing the sub in the listening position and finding the spot with the most bass, I have never got it to work, even by crawling around on my knees to find the spot at ear level.
Yes, I have done just that.  But I had Magnapan speakers at the time.  It was wonderful.  The music exploded!. I currently have full range speakers now, no need for a sub.  That said if you beside to get a sub, check out "REL".
A sound system that wants great power efficiency will definitely require you to use a subwoofer. Subwoofer has many good types, such as: JBL 728S, Martin S218, EKX118, BMB, Bose ....
Refer to the subwoofer product at http://bit.ly/2SjOdMZ
No brainer - haven’t read the other posts just be careful.  Definitely go with two subs if possible and place each one as close to each bookshelf speaker as possible to minimize any timing issues.  Just go small - 8 inch driver.  Rythmik are great so are REL T Zero’s.

I have Raidho XT-1’s and I’ve paired them with B&W PV1D’s and I would put this system up against the best full range floorstanders on the market.

I can also use this to watch movies with outstanding results due to the improved bottom end.  I cross mine over rather high at 80hz at the advise of Raidho.  Call your speaker manufacturer to get tips.

I currently have a set of KEF LS50’s in a large room, 20’ x 24’ x 9’. They are on stands and I’ve used two different configurations. The first was a set of one cubic foot Klipsch 8” driver with two passives. The second sub sat directly on top of the first. I tuned them together andnthe sound was as a single sub. One coming in lower and the other tuned just a bit higher.
Great sound but I needed to thin my gear. Sold them quick and easy, still miss them. One cubic foot with 350 watts each was a very nice sub. They were 308’s

The second setupmwith the KEFs was with a 10” sun from Klipsch again. 
Side Note; I love the PSA subs I have for my main system but they are huge and multitask for HT.

the 10” sub does a very good job as well and is set up and being used as I type.
Have fun!
I added two REL t9/i subs to my 2-channel.  Being somewhat of a dumb 2-channel purist and wanting to keep everything planar I was resistant to add the subs. 

Ive finally come to accept that I now have separate subs in the room and the sound is fantastic.  Just the right amount of room pressurization allowing for excellent slam in upper base and extension in lower frequencies.

I can try just powering a single sub to see how it compares and get back to you 
Subwoofing for 40 years now,biamp and also use an electronic crossover.....i got 5 sub woofers some big 15"some not so big10"they can really help out a system.I remember when I had KEF 101s and a subwooker ..would blow peoples mind how much music came from the KEFs,LOL,later on I showed them why ...a big subwoofer hidden away....
I wanted to post a shot of my IDEA Sub connected directly from my PassLabs XA25 amp in parallel with my PMC Twenty26 using Western Electric speaker shielded cables by TimePortal. Anyway the package of one sub and PMC sound wonderful. I couldn’t believe the results. The PMC stopped chuffing and the bass balanced beautifully. Using the sub crossover and level allows to customize to meet track needs. I’ve never looked back. Thought of trying other subs. This one is a 10” active and passive dual design. Works a treat. My bottom line? Experiment.
Ive had a set of Magnaplanars in a room of similar size to yours, and have always found large, slow 'subwoofers'i.e. Velodyne, JBL, etc just result in muddy, discontinuous sound. Not expecting very much, I tried a Martin-Logan Dynamo 300 8" powered sub and found it filled in the bottom end seamlessly. It has been superceded by the Dynamo 400 , an excellent product and an excellent value.

I couldn’t live without Subs.

I spent years box swapping.  Never satisfied.   Now I realise I’ve had a lot of very decent kit that would probably still be here if I added the missing ingredient earlier.

The JL Audio e-sub 112 has internal Hi/Lo Pass Filter.   I feed the sub from my preamp, then out to the power amp for my mains (P3ESR).   
Crossover set to 95Hz
This takes a load off the mains & liberates them.
Also removes any bass lump.   It’s seamless.  Doesn’t sound like there’s a sub.  

I definitely recommend giving this method a try.