Single driver full range speakers

"Full range single driver" (FRSD) is often an oxymoron. Because there is no crossover,  the midrange and a few octaves on either side might be the best you ever heard, but they are lacking at the extremes, necessitating a subwoofer, supertweeter or both. Many times these are simply cobbled together and levels, timbre, phase, etc., are often mismatched. An exception would be German Physiks and a few others that do employ only one driver and achieve phenomenal extension. Most do not.

Wilson Benesch uses a 2.5 way design that direct-couples their midrange driver to the amp. This 7 inch driver’s frequency response is approximately <100Hz - >5KHz, which some might regard as full range or close to it, practically speaking. They then use acoustic or first order crossovers to mate this driver with their proprietary tweeter and woofers to yield 30Hz to 30KHz. While a subwoofer will be needed to get to 20Hz, the seamless integration of their "FRSD" with their impeccably designed, constructed and matched high and low ends yields what I think many are trying to achieve, which is a lucid midrange with transparent extension to the extremes. 

I tried a single driver speaker and while it sounded great at lower volumes it just didn't do it for me after a while.   I admit I fell in love with their presentation of vocals and imaging,   they struggled with rock at even modest listening levels.  

I used them for about a year and I'm glad I tried a single driver speaker but in the end I was missing the sparkle and air a tweeter brings to the party so I sold them and bought a sealed acoustic suspension 2 way.  Never looked back.  

Hi OP

I have encountered the same question to me by another audiophile friend, as some have posted above, the speaker I was asked my opinion was a Reference 3A De Cappo driven by JELabs 300B. those are a wonderful match but lacking lower bass power to the owner. IMHO, I thought the bass was good enough. but everyone hears differently and have their personal wants

therefore, after months to trying different things, he ended up with an external powered sub(s). nothing can be done any better. in your case, you can try different enclosures in your BASS drivers. BUT again, in IMHO, using external powered subs, you can Taylor the power output and the crossover.

MY last idea is to build a woofer enclosure, power it up with Class D amps and use a DSP (ex MiniDSP) to custom tailor the frequency match to your open baffle speakers

good luck

Several folks have recommended adding a sub, and that’s a proven way to add bass. For several years I used a Martin Logan Dynamo with my 6.5-inch FR diy speakers. But a few months ago I built a Nelson Pass -designed EQ module designed for FR speakers, plugged it in and I no longer use the sub. Go to diyAudio store.com and look for it. As I recall, Pass even posted a few customizations for particular drivers. It’s an easy project and surprisingly effective. Cheers.

I know Louis at Omega Speakers used to make a full range tower with an integrated powered sub at the bottom. I heard they were great. I personally use full range speakers, but almost always with a separate powered sub. You can use a powered sub's phase control to really dial it in and integrate it properly.