Do I need a sub?

Would I benefit from even a small sub?

Energy rc-70s’
dual 6” woofs, bass is there, but would a sub remove the lowest freq, and give the small drivers a break, and sound better?

would it help,? I play loud once in a while, would the low freq removed from the main tower drivers make a better sound, I don’t think I would need much more than a 10 or 12” sub. 

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Search Swarm subwoofer, distributed bass array or DBA, and read posts on subs by millercarbon, noble100, and Audiokinesis, hallowed be thy name.
Hey, how big is your room?? And what are you using for electornics? Budget?
We've beaten this subject to death.  Short answer: You can have one, but you don't absolutely have to have one. Take a look at this thread:

If you feel you are missing slam, maybe look into improving the speaker placement or adding room acoustics. They may give you more for your dollar without adding a new speaker which may be hard to fit acoustically.


Large room, 16-17” vaulted ceilings.

 Left speaker (from couch) faves open hallway, staircase 
right speaker in corner,

does it matter where a small small sub goes?
I have Lansche 4.1 with two 10 inch active woofers which is supposed to go to 20hz.

But after augmenting it with two Scaena 18 inch subwoofers, it go more dynamic with stable bass foundation, wider and deeper soundstage.

The answer to “Do I need a sub?” is always yes. Even if you already have one, or two, or three, or more 😀 Multiple subwoofers is the path to high end bass and high end audio in general. Yes, if you high pass your mains they will play louder and clearer because it limits cone excursion on the lowest notes and hands that duty to the subwoofer which is designed specifically for that task. That’s what I do in my system and it sounds great. I’ve got two subs and my end goal is at least four. Not for loudness (although that’s fun sometimes) but for bass even-ness, extension and clarity. When you get a sub, invest in a MiniDSP module or something with DSP capabilities. It lets you precisely control the crossover and crossover slope, apply notch filters to help minimize room resonances, and do other things like apply Linkwitz transforms which can extend the bass lower as long as you have the amplifier watts and available cone excursion (for sealed subwoofers anyway, not sure if that works with ported). DSP and subwoofers should be married to each other in high end audio. Best of luck to you.
In my listening time (30+ years), I've always used a single sub. The important thing is finding where in your room it sounds best. In my current home, I tried moving the sub two feet and it sounded horrible! Moved back to original location and it purred like a kitten! Just got to find the right place.
does it matter where a small small sub goes?

Usually. Since you have a variety of options, put the sub where you'll listen, then walk around the room until you hear the best bass. That's where to put your sub! :)
Any speaker with 6” woofer can use a subwoofer . Its whether or not you want more . And by taking the time to soul search and realize more of an audio ambition you have likely made the decision already . So do it. Powered 10” 
powered 12” is more 
powered 15” is quite lovely 
and so forth , you get the idea. 
I added to subs and I'm glad I did.  Rounds out the sound, better sound stage (helped floorstanders to disappear.
You don't need them, you want them!
My main speakers have built in powered subs that will go down to 20 hz and I still have an additional separate servo power sub.and it adds fill and energy to the room. Requires a little work to integrate, but worth it.
Short answer, Yes.
Practical answer, Yes.
WAF answer, maybe.
Like millercarbon, I run a swarm, 2 10s and 1 12. I have a 15 in the garage, large, ugly and unused so far. I use one amp for all 3, utilizing a DBX 223XL crossover set at 40 hz. I plan to add another 12 or 10. The amp is a Denon POA 6600 mono block with 265 watts at 8 ohms.
My goal was decent bass at low level listening, without needing to turn the subs up at low volume or turn the subs down at hi volume levels. All sub boxes are sealed or acoustic suspension as we used to say in the early 70’s. To save money, the boxes and speakers are sold/used for car stereo use. All of the above except the Denon cost less than my unused Velodyne 12 dedicated sub.
I use a Lyngdorf amp to run RoomPerfect room correction. It perfectly integrates the sub to the mains, 4th order LR filters at around 75Hz. Nice.
Short answer. Any system will benefit with use of sub(s). Biggest gains will come from using high pass filtering on main amp. Let sub amp do all the heavy lifting. This will benefit SQ all the way around, not just adding hertz on the bottom end.
Arc, Mr-m has it right. Every system benefits from subwoofers unless they are already built into the main speakers. Do not bother with a single small sub. You will not be happy. Two 6" drivers can go extremely loud if you remove 100 Hz down from them. You need at least two 12" or four 10" subs to get anywhere. Most subs now come with plate amps and cross overs in them. You absolutely need a crossover with a high pass filter for your main amp as you suggest. Unloading the main speakers is one of the major benefits of using a sub. You will clean up everything else those 6" drivers carry. For those of you who do not believe in Doppler distortion just have somebody drive by you at 30 mph leaning on the horn. The sound will go from a high pitch to a much lower pitch as the car passes you. Towards you and away from you just like a woofer pumping away changing every other note it carries. 
richtruss, the Lyngdorf is a crippled version of Radomir Bozevic's original design. The Trinnov is much better but still not up to Bozevic's design in some ways.
You need 4 subs minimum! 
Zardoz....Is your dog by any chance telepathic?
I suppose most A’gonner’s live in suburban houses where bothering neighbors isn’t as much an issue for city dwellers like me. You might however have to contend with bothering people in the house.

Bass is the hardest thing to contain as bass waves are close to 30 feet or longer.

So you might want to consider the ability to easily tailor how much bass any prospective sub is putting out. It really comes in handy, in that you can fill out a bass shy recording, or add a little bass if listening at low volumes, cut it down at night if there is the possibility of disturbing other people.

All the other posts here are great advice about getting the best bass, but I thought I’d point out something else to consider.

Ok, found an absolute steal on a BIC AMERICA V1020 sub.

 A steal!!!

 My only quarrel is with my preamp, there is no sub hookup, so I will have to do the speaker wire to sub, and back to amplifier thing, which sucks.

i much prefer the rca from sub to preamp, but nope,.

is there an easier way........besides getting a new pre. My pre is wicked! McCormack LD-2 , a great pre!
First sub in 20 years.
first was a 12” cerwin vega front firing 
long times ago.

  Hoping this will add some low end.

 Even. My sanders sound pre does not have a sub iinput,
or my old onkyo p308.  
Such a shame, I. Have to do the wiring exchange for the sub.

 I very much like the rca automatic sub thing, but my gear won’t allow it.
and no I’m not changing, my stereo sounds amazing, and took me 35 years to get where I’m at these days.
Hooking up a powered sub.

 All my preamps are older w no dedicated rca to sub.

 Dislike the wiring amp to sub, then speakers from sub to amp.

is there a better way?

Yes.This is what I use:
They are very well made and snug fitting.
This works how?

two rca into sub, and a single rca into the preamp white pre out??
Amp output red and white both into the audioadvosir connector
and into the single rca of the sub?

@jtcf ,

main out rca’s from preamp into the audioquest hard Y adapter..then into the single rca input of the sub?

this is all?

 How will this hookup remove the low frequencies from the main towers,???

would it sound better to just use the speaker wire hookup style, which will actually remove the low frequencies from the towers?

or will hooking up with the hard Y adapter also remove the low frequencies from the towers?

 Thank you , in advance for all your time guys.
Get a adapter w two male 1 female , plug adapter in back of main out of preamp, then run single shielded rca to sub?

easier this way? this will just dump everything over a certain freq to sub?

 Or use the speaker terminals which will remove the low freq going to the speakers (towers) and allow a little louder volume,by not sending lower freq to the smalldual 6” woofers???
You need a sub with a high pass filter. With that BIC V 1020 you will have to run your speakers full range!
Get one or two used RELs (or a swarm system if you have the space as they're alleged to work) and don't bother with the silliness of limiting the output to the main speakers and just 'em run within their limits. I used a single REL Q150e (10" front firing 150 watts) for a couple of years bought for 200 bucks (used of course...Ebay)...still works perfectly, and added a REL Q108MKII (100 watts down firing 8") later...also 200 bucks. You don't need to do anything but hook 'em to the amp's speaker jacks, and move them around until they sound good to you (putting one in your listening seat is unnecessary, and takes some long cables). Note that good subs add air to the proceedings by sort of "charging" the room and make even bass shy stuff simply sound like real's not just about organ bass notes and EDM (although hey...).
I really kicked around the idea of a swarm set up for subwoofers.
Spent lots of time researching and reading about what it would take to do it, what parts I would need, what approach etc etc...

I decided to just go ahead and add two purportedly nice sounding subs to what I have now.

The subs I bought are HSU ULS-15mk2`s. I have the tracking numbers sitting here.
I like Rythmik and used one with some MMG`s (my daughter now has it)
but the price to performance ratio just didn`t work for me.

Anyway..I`ll have 4 subwoofers in all. A Revel Ultima15, the two 15" HSU`s and to tuck away somewhere as needed 10" 350 watt sub.
All sealed.
Should be interesting in my 3840 cu ft room
Found a great price, so I bought 4 of them.
one for my cousin.

 If I hook up via speaker wire, doesn’t this push the low freq from the main towers to the sub?
or still full range for towers?
If you don’t use a high pass filter the towers are going to run full range. If you want to add a high pass filter you can add this! I used it when I had a sub with no  high pass filter with great results!
Just checked the website, the speaker terminal hookup “is” a high pass filter.

 Monoblocks to speaker terminals on back of sub,......then speaker terminals to tower speakers.  This is how I will hook up.

 Only problem is the long speaker cable runs, 

thanks for all your help.
They label it as high level input?
Ok, talked with Patrick from McCormack audio this evening.

 I’ll set up the sub, and use a single rca from one of the main out rca’s to the single rca of the sub.

 This will b all I need, just a little bit of low end, to balance out the sound.
 Full range for the towers, and just a little bit from the sub, configured by the knob on back of the sub for the  frequency.

 I just need a little bit of low end to balance out the sound, as it sounds great as it is, so just adding a small 10” sub will balance out the sound perfectly.

thanks for all ur help guys!