Originally Posted by TheBlubbs
This is our great room and aesthetics re: placement are a priority for me as well (size is the WAF issue). It has nothing to do with me not 'having a set', but thanks for that.
Ignorant comment aside, I do appreciate that there is some real advice here. If dual subs are that finicky though, why do legitimate full-range floorstanding speakers sound so great with music? The sub drivers are attached to the midrange and tweeters in that scenario. I don't see how a placement that has the same effect would sound worse than having one subwoofer. I am, however, not an expert, so if someone can expound on this, I would be thankful.
Depending on where you cross the subs with the main speakers, localization should not be an issue. Crossed at 80Hz or below, most people cannot tell where the bass is coming from if subs are placed somewhere other than close to the main speakers. If you were to crossover higher than that, placing the subs with each main speaker would have the advantage of eliminating any localization issues. However, it is very unlikely to change or improve the frequency response. If one is interested in sound quality, a flat frequency response of +/- 3dB is generally desired. Almost always, a single source of low frequency sounds in a room will result in large peaks and nulls in the frequency response, often times +/- 20 dB or more. Remember that 6 dB is considered twice as loud, so a 20 dB swing will result in some frequencies being much louder, while some may be almost non existent. Placing two subs in front of the room on the same wall next to main speakers, rather than placing them optimally for the best frequency response, will typically make no difference, or perhaps even make worse, the FR of the single subwoofer. The reason full range speakers sound so good, quite honestly, is because the majority of people have never heard a true, flat, accurate, +/- 3 dB frequency response. You don't know what you are missing if you have never experienced it. In this case, a picture is worth a thousand words. I will post three graphs. The first shows the best frequency response that can be achieved in my room from two main speakers that play flat down to 60 Hz, paired a single subwoofer in its best possible location. The second illustrates two subs placed optimally for the best frequency response. Placing the second sub "asthetically" results in basically the exact same frequency response as the single. You will note in the second graph that most of the large null is gone, replaced by a peak. With eq, the peak, or peaks, can be pulled down to a flat response. Nulls can not be boosted. The first graph is what most people probably hear when listening to "quality" audiophile full range speakers. Granted, this could have been improved some with eq, but not fixed. The third graph is two properly placed subs, with eq. This could be completely flat had I wanted it, but the rise in the lowest frequencies was intentionally put in to provide more impact when watching movies at low volume.