Speakers better without subwoofers? Crossover and synchronization issues? What do you do

Proper subwoofer adjustment is key, and possibly rare. There are pros and cons with everything in audio, including woofer size, mass, excursion, etc. Many, many that I’ve heard are used as the main attraction, which is fine if that’s what you like, but it’s not natural to acoustic instruments.

There are certain ranges that some woofers do well, and some that they don’t. The trick is trying to optimize what you have. Most subwoofers I’ve heard are set too loud relative to the output of the mains, and in many cases the low pass crossover frequency is set too high. The male vocal range can dip below 70 hz, which is not the best range for most subwoofers to operate in, yet many do. I try not to feature the sub, but use it only to augment what my main speakers do in the lowest octave or so. IME, subs work better set below 60hz, and when they’re barely noticeable except for passages that have deep heavy bass.

the subs in a two channel system shouldn't rock, vibrate, shock, etc. They should blend in, as if they didn't exists. When dialed in correctly they add another layer to the soundstage, and depth and punch to e.g. the drum

The DSP in current subs makes the placement issues a lot easier than in the past.  I like SVS because their subs are musical.  It isn’t the boom factor, but the way they bring out low level detail in quiet orchestral passages, and expand the sound stage 

@emergingsoul Yup those old speakers were something else. I grew up with my father's Bozaks. The problem is those large enclosures resonate like crazy. They are musical instruments. The bass drivers of the day were not capable of long excursion with any degree of linearity. Modern speakers use smaller enclosures and smaller woofers in multiples. The low bass is separated out and sent to subwoofers which have very specialized drivers able to push out huge bass in smaller less resonant enclosures. 

Many systems are better off without subwoofers, I would venture to say most because the subs are poorly integrated and/or resonate and give themselves away.  In a great system with properly integrated subs you would never know the subs were there until you shut them off.  If you are reading the specs of your speaker, flat to 28 Hz is at one meter. That is a far cry from flat at 12 feet. Not only this but getting realistic bass in a normal size room requires a 10 dB boost at 20 Hz starting at 100 Hz gradually upsloping. Every system can benefit from subwoofers but to do it right requires digital bass management which most people are not using. Integrating subwoofers with an analog low pass filter will only create a result that a seasoned audiophile will cringe at.  

@mijostyn 

the Sonos Faber il cremonese have 2 extra bass drivers Incorporated into their mains where the crossover is set at below 80. I like this idea rather than introducing a separate subwoofer, placement issues aside, if that's a concern.  Maybe it has a lot of value because it takes pressure off other bass drivers, with a crossover set at above 80.