Subwoofer meshes well with 2-channel?

>I hadn't really given it much thought before, but will a sub work well with a 2-channel system (when reproducing music)

Yes.

>or does it just muddy things up? I have full-range speakers (Tyler Linbrook Sig's) that go down to 30hz or so, and have 2 7" Seas drivers.

A couple of 7" drivers or an 8" driver are OK for upper bass (80+ Hz) but lack the excursion to play lower frequencies cleanly. Most significant is that using such drivers as mid-bass units screws up your midrange through IM distortion when you ask them to reproduce real bass at the same time.

You need at least a 3-way speaker (a sub woofer counts) to get acceptable mid-range performance if you're going to listen at reasonable levels and not restrict your musical choices (witness "audiophile" speakers that do a fine job on small ensembles but fall apart on orchestral works at subjectively realistic levels).

>If this the case, is there a particular reason that huge speakers are common, vs. a smaller speaker and subwoofer combo?

Many sub-woofers are bad, built for maximum output instead of accurate response. Most consumer speakers are built with ports to get more bass extension but this makes them harder to integrate with sub-woofers due to the inherent phase shifts and problems with excursion skyrocketing below the port tune. Most sub-woofers don't address the integration problem. So lots of sub + main speaker pairings are outright bad and there's understandable audiophile prejudice against them.

Among other things, separate sub-woofers allow you to position the units for much better interaction with room resonances and so that you don't have the quarter-wave reflection dip from room boundaries within neither the main speakers nor sub-woofers' pass band.

Avoid the problems and you literally can't do as well with a single enclosure speaker system.

My advice, as always, is in direct contradiction to Bobs, which must be derived from home theater practice. I use 2 REL Stadium subs with either Spendor SP-1s or S 100s which are full range speakers. Being full range does not imply a 20 to 20k Hz response. It refers to a speaker that is capable of reproducing music by itself. I cross mine over at 22 Hz and do not high pass. The subs are not noticeable , they add weight to the sound but you do not "hear" them. They provide a noticeable increase in the realism of the sound. A good sub will, as Alvin Gold recently pointed out in his review of the Eclipse TD 725, " if crossed over with care, without high pass filtering the satellites( i.e. around 30 Hz for floorstanders and 40-60 for more compact designs) integrates unusually well, seamlessly adding color and scale as well as bass extension." Bob does not know of the advantages of this approach because he has never tried it, I wish he would post his own system so we could see where he is getting the ideas he espouses with such certitude. Anyone who has ever run his main signal through a crossover can tell you that it degrades it. REL recommends setting up their subs as I suggested, I arrived at this approach independently almost 30 years ago when I was selling Audio Pro subs.

Dawg,

For $600 you can understand the bass shortcomings of your current speakers with a Velodyne SMS-1 sub controller (X-over, room analyzer, PEq). First, just use the analyzer portion of the SMS (no sub) to analyze your speakers in your room below 200hz. This will conclusively demonstrate that you want a subwoofer - just predicting here, but confident from my own experience.

As to Stanwal's philosophy vs. Bob Reynold's philosophy, home theater experience is not Bob's reference point here. His position is based on data from performance tests, Stanwal's on his listening experience and that of some reviewers. My own experience is too limited for me to dismiss either opinion, but I am personally more comfortable with Bob's approach. I have researched the numbers that Bob linked to and intend to audition those models that perform well. Unfortunately, i am just starting this effort...so no conclusions, yet.

Thus far, I can only ofer a few observations followed by one bit of speculation:

1) "Tight" bass seems to be a function of a spec called "Group Delay" (this is not gospel and is subject to some debate). Sealed boxes tend to minize this spec.

2) Loudspeaker distortion in the deep bass is orders of magnitude higher than elsewhere in your system. In subwoofers, a large driver in a large, vented cabinet tends to minimize distortion.

3) JL subs (very expensive) and SVS subs (less expensive to much less expensive, depending on model) both perform very well on both tests, the JL's show higher distortion but lower group delay, the SVS vice versa (per the link Bob has provided).

My observation:

The Velodyne SMS-1 will (with some work) allow smooth low frequency response below 30hz in a decent room as well as seamless integration with a variety (probably not all) of main speakers. The X-over and PEq in combination with the visual aid of room analysis are very effective tools for dialing in a seamles match.

Marty

PS - FWIW, the SVS Ultra 13 (app $2500 per pair) offer a combo of Group Delay and distortion specs that are hard to beat at any price. The less expensive SVS ($1100/pair) aren't far behind, particularly if you believe that extremely controlled Group Delay performance is not important.

To clarify, the Velodyne SMS will work with any sub you choose: a low group delay, high distortion model like Stanwal's REL or a lower distortion, higher group delay model like the SVS that Bob has recommended from time to time. Further, you can choose to use the SMS' internal x-over to filter the mains or run them full range per Stanwal's philosophy. Or, you can choose to try both approaches and see which sounds (and measures) better. I did so and choose to actively filter the mains at a higher point. However, my subs were chosen primarily for their small cabinet size (rather than optimizing performance) so I don't want to suggest that active filtering of the mains is generally a better approach, just that it worked better in my system.

Marty

I use dual subs (Dynaudio 12 inch) to augment my Dynaudio Temptations. I don't high pass the signal going to the Temps. I just add some low end 'filler' with the subs. It provides a much more realistic sound to things like kick drums, for example. The best way I can describe it is that it adds a 'fullness' to the trailing part of the notes. Without the subs, although the bass is good, the notes die too quickly to be realistic.

It is sooo much better with the subs, even though they are only augmenters (I LPF the signal to the subs at 40Hz).