2-way speaker with best bass

The other issue with bass (and yes room size and volume levels matter a great deal)is the issue of quality versus quantity. The Merlin VSM has no output below 28HZ, but is +/- 2db 33Hz to 22KHz - trust me that is a lot of bass extension for a two-way. It will not succeed at pushing a lot of air like a 15" woofer, but that would be a pretty lousy way to build a two-way. The VSM will give a lot of realistic, tuneful, and articulate bass like no 2-way I have ever heard. While I love the VSM, I would not go around touting it as a real "full-range" speaker in the ultimate sense, but when you combine its balanced performance and incredible coherency (that you rarely get a 3-way+ approach)I think it is one of the 2-way speakers that should be on anyone's list and for the most part you will be satsified with its bass output. Unfortunately, its list price is proabably going up in price to the $14K range, which may seem like a lot for a smallish two-way, but close your eyes, it is worth every penny.

Check out the Klipsch Epic CF4 for sale on this site. A 2 way speaker but with 2 12" drivers. 102dB efficient, slamming bass.

Twoleftears, I take you are looking for a refined, highly resolved system in addition to bass? That is a speaker that would also qualify as a "best in class" type speaker for overall performance. I also assume your question is regradless of cost to some extent.

Certainly Brobdingnag has the best bass. Lilliput may offer some astute, refined, defined and well behaved speakers but the greatest among them can ne'er be more than a magnified miniature.

Sonus Faber Extrema and Usher BE-718 were the two best 2-way I have owned when come to bass quality and quantity.