2-channel audio only .. Sub or no Sub?

Your system could definately benefit from a dedicated subwoofer with it's own amplifier.

Obviously there are not right or wrong answers. Personally I am not a 'purist' when it comes to 2-channel. I love my bass and I would never have a 2 channel set up without a good sub. It just adds so much more to the music, but I like loud aggressive music anyway. Good luck

Subwoofers were effectively used in audio systems long before HT. The long organ pipes, the low string on a 5 string electric bass, the thunder and shake of the timpani... they all benefited from good response and clean acousitic power in the bottom octave.



Lots of great amps can't do much for the bottom end of your speakers.


Check this out:



Which instruments in the music you like will benefit from improved response below say, 60 Hz?

You're not the only one that uses more than two speakers on a 2ch system. I'm using 2 pairs of speakers (A & B) on my music system. And they are not even the same brand. Most of the time, I'm using just the mains with the receiver on pure direct. There are times when I use both pairs + sub

You also need to consider the room in which you have the speakers. There may be enough room reinforcement to get reasonably good extension depending on your musical tastes. Most music doesn't have much content below 40 Hz.
Low E on a bass is ~40Hz. A 5 string with low B is ~31 Hz.
Pipe organs on the other hand can go deep.

Depends what kind of music ur into of course! Hip-hop, DEFINITELY a sub. Easy listening, probly don't need it.

But why all or nothing. Just get one, and leave it off/turn it on as needed.

It is very hard to integrate a sub in a 2 channel system in a room.It can be done but most can never achive it.I prefer to go the speaker with sub in it such as Golden Ear triton 2's or 3's and other speakers like those.

Naah. Arguably its easier to add a sub to a 2-channel system than a 5.1, 7.1 or 9.1.


And the source of that sweeping statistic is where?


And thus miss one of the big advantages of a sub, which is the ability to optimize the sub's placement for good bass, while leaving the upper range speakers where they sound best.

Ironically, it's sometimes less expensive to get smaller monitors and a good sub than it is getting the top of the line huge floor standing speakers.

Way back, probably 15 years ago, I was considering Paradigm speakers. I called them to ask about their speakers. They recommended their active 20s and a sub, or their passive 20s and a sub over their monster Studio 100. Specifically for the reason Arny posted, as well as the fact that small monitor often perform better than the same speakers in a larger cabinet with bass drivers.

I've heard the comparison. They were being very honest about what's best for the customer, perhaps at some financial cost to them.

This assumes you have a dedicated room with no other furniture considerations. In a family room it is almost impossible to place a sub in an optimal position.

I don't think so. I was assuming that optimal placement of speakers might be impossible, so more flexibility would be an even stronger advantage.

Look at it this way.

There may be an optimal place in the room where both bass and the upper ranges is reproduced optimally, but for real-world reasons I can't put the full range speaker there. I may not even figure out where that wonderful place is!

By splitting up the upper range speakers from the sub, I increase my options. The fewer the constraints, the more good options that exist.

The narrower range of frequencies reproduced, the more options for placement. It just stands to reason, and IME that works out very many times in real life.

I have a pair of PSB Image T6 speakers, which most people would consider full-range speakers, and may be somewhat comparable to yours as far as bass range is concerned (Polk claims response to 20 Hz on your speakers; that is ridiculous; pure bull; they go down to 35 Hz or so at -3db; no lower).

I used them for about 6 months with no subwoofer, and they are good down to below 40 Hz, but I definitely missed some lower energy from string basses and organ music, large drums, etc.

I wanted to get one of the nice subwoofers from Rythmic, such as the F12, but I have a space problem and they just were not going to fit.

I settled on the NHT B12D subwoofer, which uses a sealed acoustic suspension design to pack a great 12" subwoofer with a 500-watt RMS amplifier into a small package (a 14" cube) that just fits my space requirement.

I watched a movie last night (The Red Baron), and the aircraft engines were so realistic that I thought I was back in the pits at the dragstrip; incredible. The visual and sound effects in that movie blew us away; very cool.

The kettledrums in the orchestra are also nicely taken care of by the subwoofer; good stuff.

I've had at least one room where the optimal location for the sub(s) was at the main L/R locations. Therefore, I mounted the mains on top of the subs.
Right now I have my subs stacked on the listening area's centerline, behind a column, between two archways. It just all depends on the rooms layout and dimensions as to what will work best.

It can take some time to find the perfect setup for any given room. I took almost 3 months to get this current room right. When you add a sub to a system, it gives you the choice to have it on/off based on the type of music you are listening to.

That chart is very accurate, except for the kettledrums.

The larger ones in the symphony orchestra are 32 Hz (Cfff), according to their manufacturer's labeling.

Another consideration is that your front mains that are producing all the bass from 50hz on down may not be in the best location for producing the best response for the listening position. A sub would give you more flexibility in choosing the best spot in the room for that.

If I recall, you have a 2 channel stereo receiver that does not have active bass management, so you would need a sub that can be connected in between the receiver pre-out and the amps that would filter the highs. I believe that the SVS SB12-NSD has a high pass filter at 80hz that would work (see page 11 of the manual). You'd then have to take the output from the SVS and use RCA splitters to send it to the separate amps. I would also imagine that there are pro audio devices that you could use to do this in conjunction with any sub and your amps. Something like this Behringer Super-X Pro CX2310 might work and would allow you to choose your crossover point, although I'm not familiar enough with this equipment to tell you definitely so.

But no active bass management like an HT receiver. So you'll probably want to set the crossover on the sub to the low frequency roll off of your main speakers to avoid double bassing between the mains and the sub. According to Polk specs, the -3db point is 35hz on the Polk RTi A7, so good guess might be around there or just above. That's going to be a problem for the Epik Legend since the lowest crossover setting is 50hz.

It does not hurt to have double bass! The OP can set the sub to 50 or 80 htz and let the RTi7s just roll off. I do that with both my systems. Its just a matter of adjusting the sub volume to get the best blend at the XO point. I'm using a HK3390 with dual sub outs. But those pre outs are full range, for one set of speakers I set the sub XO to 70; for the other set of speakers, XO to 125. That set of speakers are -6db @ 80

Must say this is a very well appointed stereo receiver. Phono for geezers, optical for the gen-Y, even has ethernet!

So it seems. Apparently, the jack labelled "Pre Out - Subwoofer" is actually a mono output.


That can work, but its less than the best that you can do with many subwoofers.

The best alternative would be to use a subwoofer with line level (typically RCA jack) inputs and outputs. The subwoofer should be hooked to the pre-out jacks on the receiver, and the output jacks on the subwoofer should be connected to a separate, additional amplifier.

Surprisingly enough this receiver does not appear to provide a means for connecting an external source to the inputs of its own amplifiers. :-(

Nice chart Arny, thanks for sharing.

While you mentioned it in your text, pipe organ seems to challenge my setup more than anything else. Bummer that it's not included in the graphic. Organ is also the only instrument that leads me to turn off my sub when listening (but then I don't have a great subwoofer).

The harp is a surprise, I hadn't thought of it as a big contributor below 60Hz.

BTW, I came up with what I feel to be a more representative graphic, with just you and pipe organs in mind:



(and if you believe that don't look at my recent post to another thread) ;-)

I'm intimately familiar with medium-sized pipe organs because I run live sound and do recording in a room with one active all the time. The medium sized ones are very strong reproducers down to abut 32 Hz, which is more than low enough to put a lot of speakers on notice. Of course, then there are the really big organs with strong output down to 16 Hz.

That method does not give you a very flat frequency response.

Yes it does, its a matter of adjusting the level of the sub to blend with the mains.
And for what it is worth, a flat response usually does not sound all that good. Setting a house curve is way better. The $30,000 Everest II has a slope of something like -10db from 45~20,000 htz.

The way I have my PT800s and sub1500s set now with the sub xo @125 and the PT800s starting their roll off @ 130 and -6db @ 80 has never sound better, compared to when I had the sub set to 80.

I think you mean full range output. Mono has nothing to do with it. But feeding a sub a full range signal is no big deal, that is what the sub XO is for.
My HK3390 has dual sub outputs, but they are not stereo, you just know they are Yed inside the box.

Maybe there is some other word you prefer for full-range both channels summed than mono? ;-)


Agreed. If there was a built-in low pass filter then we would be edging towards bass management, not that this would be a bad idea.


There to support Harman's initiative for having more than one subwoofer, as the room demands.

The way you worded the first statement, "The jack labeled Pre out-Subwoofer is actually mono." It looked like you were thinking full range, as that receiver has no bass management. The fact there is only 1 sub out would depict mono.

I agree that all receivers/AVRs should have at least two sub outs, even if they are mono outs. I've been using two or more subs for over 10 years.