I think the only way to tell would be to take some measurements. I don't think I tell purely by ear.
Typically the biggest problem in full range free standing speakers is the broad suckout somewhere between 100 and 300 HZ - it can be a real devil of a problem and it is near universal too. In some cases a 12 db crossover on the sub may work better than a 24 db filter typically from a pre. You need to try it and see...but I'd recommend measurements and trying all kinds of positions for your sub too - ultimately positioning may be the most important factor overall...
Typically the biggest problem in full range free standing speakers is the broad suckout somewhere between 100 and 300 HZ - it can be a real devil of a problem and it is near universal too. In some cases a 12 db crossover on the sub may work better than a 24 db filter typically from a pre. You need to try it and see...but I'd recommend measurements and trying all kinds of positions for your sub too - ultimately positioning may be the most important factor overall...