It was simple for me...bass mgmt 101.

Speakers (even 'full range) do not necessarily produce full range
Effectively. Many speakers struggle to produce full range bass. They might
Not be able to produce the same db as the rest of the frequency range
Presented by the speaker. Also, distortion may start to rear it ugly head.

The positioning of the speakers in the room is dictated by the listeners
Seating place. This is not always the best place for 'ideal' reproduction
Of lower octave frequencies. The ability to place a subwoofer (hopefully)
In a different place in the room can present a much more linear frequency
Response. Proper use of bass mgmt can also 'clean up' the midrange
As the driver may not have to 'struggle' to produce bass heavy material
Along with mid-range frequencies. The subwoofer can do this much more
Effectively. (Especially true for two-way bookshelf speakers)

I also feel that many of today's towers can't reproduce the bass frequencies
That speaker of the 70's could. And if they do they are big bucks!

I feel that trying to blend a subwoofer into a system with no bass mgmt
Is a compromise...mostly because it possibly defeats all the advantages
Listed above. And then there's "double bass" when U have speakers and subs
Trying to play the same bass frequencies. (Because you have no cut off!)

My 2-channel music set up was built around my choice of the
Outlaw Audio 2150 receiver....which has analog bass mgmt.

****my opinions****

Yes man, we've all heard of bass management 101. Speakers these days can't produce full range and distortion might kick in if you don't save the day with a sub and free up the speakers to do what they do best, let the sub do what it does best, yadda yadda, etc, etc, that sermon has been heard before (many times).

But, when i start to think about it...well, there's a speaker designer/engineer out there who has many parameters available (to work with) in his design space. He may tweak a complex model and pull his hair out for months on end (something like that Elac Adante AF-61 comes to mind maybe) before he is able to perfectly marry all drivers, crossovers, bass radiators, acoustic filter, whatever he has in that speaker for the signature he delivers. But, later on, one could just waltz his way in with very little to work with...a sub, a crossover frequency, a dinky li'l 0/180 phase toggle switch, just do a li'l sub crawl and hey presto, that sub would integrate perfectly/holistically with those speakers and the listening space eh? That thought process seems overly optimistic and a bit simplistic to me man. And so many recordings out there are mixed differently when it comes to this low frequency content too... It seems like something that would lead some guys to get into severe OCD tweak levels and still never be able to get it right for various situations.

I don't know man, it seems a bit difficult for me than it was for you i suppose. I hope I get enlightened someday about all of this.

Adjusting subs to your speakers' low-end roll-off was how it was done for years. Whether towers OR bookshelves. It worked fine. Still can.

Is it the best option? For a strictly 2-channel music setup? ............................maybe?

That's interesting. I've never heard any exact numbers like that. You should run them full range and check the temps, just for curiosity's sake. Mine of course lol.

I can do that for you but, mind you, it is at my normal listening levels not my "wife is out of town" listening levels which could be dramatically different!

In My Honest Experience,
For the critical 2 channel music ear,

Careful blending of a sub with the main speaker's low end roll-off would be the less intrusive less damaging option to trial. A sealed servo controlled sub would make life easier though i feel that there aren't well engineered subs out there (in that category). It would still result in intermittent dissatisfaction/ intermittent tweaking depending on the varying content you played.

Going in with bass management/crossovers on highly resolving meticulously designed speakers is just obnoxious. If one's main speakers are sht boxes or if the listener's ears are very forgiving, it doesn't matter either way, i suppose (crossover all the way to Chinatown and it it could sound wonderful anyway!! Boom Boom Boomin).

Assuming this is for 2-channel music only, try driving your sub(s) using the speaker-level inputs instead of line level. I would never do this for home theater, but for 2-channel music, I've had much better results using speaker-level inputs. When you use speaker-level inputs, the sub sees the exact same signal the mains see. Whatever "colorization" there is in the amp will be reflected in the sub just as it is in the mains.

Some will argue (correctly) that there is a tiny bit more distortion driving the sub with the amp output than the pre-amp output, but in my experience, the uniformity of subs mirroring the mains outweighs the tiny (mostly theoretical) added distortion of the amp. In fact, I think the "more distortion" argument falls completely apart in the real world -- the more the amp output deviates (in colorization) from the preamp output, the more important it is for the sub to be driven with the same signal as the mains (since the mains communicate 95% or so of the overall sound).

Fully agree on usage of the sub's speaker-level inputs for preserving the amp's sonic signature.

I think if an amp has a audible signature it's a bad amp. I mean, that is, if one's goal is accurate, unblemished reproduction of the source signal, aka high fidelity. The founder of Stereophile magazine, J. Gordon Holt, has a term for this: "transparency". He (and Hegeman) also refers to such an amp as acting like "a straight wire with gain"*. [And in this phrase he's assuming the wire is neutral and faithful to preserving signal integrity too.]

*edit to add: According to this Peter Walker of QUAD fame coined the term. I certainly can tell you the QUAD amps I sold were indeed 100% neutral/transparent to the ear and they were carefully designed to be that way.

The speaker designer is severely handicapped by the fact that he has to put the subwoofer in (basically) the same spot as the midrange and tweeter. That handicap far outweighs any other advantage he might have over you(driver/crossover/cabinet knowledge), as bass is like 95% room placement, assuming the subs are capable.

Usain Bolt may be a better sprinter than me, but if you strap a 200lb pack to him, I bet you I could beat him in a sprint.

It's not a sermon, it's basic electrical and acoustic engineering.

Just a reminder that this is specifically the 2-Channel Audio sub-forum.

So, you're saying you can't have sub(s) in a 2 channel system? Nor use an AVR in a 2ch system? News to me.

NOPE, that's not what I said.

Then what exactly were you trying to convey?

That this is the "2-Channel Audio" sub-forum, here, and as such, simply recommending an AVR is probably not the appropriate (or best?) answer.

And, btw, I currently have a 2.1 only system driven by an AVR and I cross my SMALL speakers to my sub at 80Hz. I downgraded from 5.1 to 2.1. Were I building a '2-channel + subwoofer' system from scratch, today, though, I do not know whether I would do the same (use an AVR) or not. Maybe, maybe not. And, yes, I realize there are (very few) other 2-channel-only bass management options besides AVRs.

This hobby is driven by the needs and wants of consumers. If a conventionally bass-managed system (as in an AVR) was best for a '2-channel + subwoofer' setup then that is what 2-channel aficionados would be using. If 2-channel bass management is what 2-channel aficionados preferred, there'd be many more 2-channel-only bass-management options available. There aren't. At least not currently. And, yes, I realize that could change if there is a greater demand/need/want for 2-channel-only bass-management.

In your opinion. I disagree. Where in the rules does it say you can't recommend a certain type of equipment in a given forum?



Not high passing your mains when adding a sub almost always results in worse performance than adding the HPF to your mains. Unless you have a (2ch) pre/power, or an integrated with a pre out/main in then adding an external xover to implement the high pass is very difficult, and may be impossible for some people without a lot of fuss and/or expense. In this case an AVR with integrated xover may in fact be an easier and/or more cost effective solution. Plus an AVR can add many extra features that may be of use to the user, typically at lower cost than a 2ch unit.


I'm not going to get into the SQ argument, as I've yet to see someone pick between an AVR and 2ch integrated, settings flat, level matched and blind. There is a huge amount of snobbery around this.


FWIW, I haven't used an AVR in ages (fully active 6ch + subs system).

Fair enough.





What 'rules'? And I didn't say you couldn't. Of course you can. I just don't think simply recommending an AVR is necessarily the "best?" answer for THIS specific sub-forum.

I liked the included reasoning for your opinion.

Highlighting 1 line from a comment to make it look like you came on top... You'd fit in well at Fox News

Yeah, silly of me to think that a 2-channel enthusiast wouldn't at all be interested in an AVR.

The forum categories are more about how you are using any given piece of equipment. Plenty of people use an AVR for both movies and for music -- either because they want to (for convenience/space reasons) or because they have to (for cost/space/wife/husband reasons). The fact that AVR's also work for movies has nothing to do with discussing how they can be optimally be used for 2-channel or discussing the appropriateness of a given AVR for 2-channel use.

Please look at the sub-forum's posts. Yes, of course, there are AVR related questions. But most are related to 2-channel equipment and music. And I think that was the intent of whoever added the "2-Channel Audio" sub-forum.

I disagree. I think this sub forum is about reproducing 2ch audio.

It doesn't make your life any easier than his. Especially, a layman (or a 'self-proclaimed know it all') is more handicapped than a designer is.

Here's a clip from the overlord that might give you a hint. The code word here is "endless experimentation"

Skip to 3:25

He's not really saying anything I disagree with.

Multiple subs will always have better sound quality below 100hz or so than a stereo pair of speakers. One sub is iffy. There's not really much a designer can do at all to make good sound below a certain frequency with good consistency and flat response. The problem is they can't fix the problem with speakers, because the problem is the room, not the speakers. The only way to fix the room is to have multiple subwoofers. Andrew Jones wouldn't argue that a simple pair of bookshelves(or even towers) is capable of sounding better than multiple well position and time aligned subs.

He's talking about stereo amplifiers and trying integrate a single subwoofer while also running the mains full range. My experience with that is that the systems I've worked with usually sound better with no subs and the mains playing full range.

For pure bass quality in my setups Multi-Subs with mains crossed over at 100hz sounds by far the best. Running mains full range with no subs sounds second best(flat to 25hz in my room), and finally running subs full range with mains sounds the worst. I'd be willing to bet money that if you asked Andrew he would agree that it's almost impossible to get a stereo set of speakers to have good sounding bass relative to something like 4 well placed subs integrated with something like a minidsp 2x4.