Perplexed on how single driver speakers can cover such a large Hz range

My ears say otherwise, but they can’t read.

@dlcockrum You might want to go some place where you can hear other speakers. As I pointed out earlier, it makes a big difference what sort of music you play. Any ’full range’ speaker will fall flat on its face playing a lot of the music I like to play, even if not played all that loudly. This track has a fair amount of bass in the opening section:

https://www.youtube.com/watch?v=ckM_TklU_AQ

Your speakers won’t even acknowledge that the bass notes are there. But those bass notes will cause the speaker to make distortion and sound congested. This track isn’t congested.

FWIW the speakers I’m playing are the Classic Audio Loudspeakers model T3.3, which is a bass reflex speaker flat to 20Hz employing 15" field coil woofers and field coil horns. I play bass and did so in a variety of orchestras so I expect the bass to be right otherwise I’m not convinced.

At any rate if you don’t play tracks with bass or simply don’t like bass, you might consider a filter in your system to block bass from getting to your amps and speakers- you may find they sound better as a result.

The old constraints described above for crossoverless single-driver speakers have  been nearly, if not totally, eliminated:

@dlcockrum This statement is false. I explained why in my prior post.

@marshinski15

The simple fact is no ’full range’ driver is really full range. Most struggle to get below 50Hz in an optimal enclosure. So if you want full range you will need a subwoofer.

They also are beamy on top. So only one person can sit in the sweet spot and if you want to hear everything you have to keep your head pretty still. For that reason a tweeter is nice, perhaps rear-firing, to at least correct tonal balance if you are off-axis. Nicer if forward firing with the main driver so you get better dispersion.

If there is bass excursion on the driver you get something called ’Doppler Effect distortion’ because a bass note causes the cone to move relatively slowly while much higher tones are also being produced. Those higher tones will be varying in frequency up and down as the bass notes move the cone back and forth.

This causes the presentation to sound congested.

To solve this you don’t play the speaker very loud or don’t play complex material with bass.

If you can get the bass off of the cone it will sound better immediately. So you can see that you need a crossover to keep bass out of it and something for the tweeter as well.

Put simply its best to think of them as ’extended range’ drivers at best. If the speaker is lacking a crossover you know its compromised. I know a lot of single-ended advocates will not like what I’m saying here. But I’ve had a lot of experience with these drivers over the last 20 years. The lack of a crossover is worse for the speaker than a properly designed crossover.

If you use subs, they should not be active over about 80Hz else they will attract attention to themselves so you really only need to go down to 60Hz or so and you can get a good blend. But you have to sort out how to prevent excursion due to bass notes! The lower you allow the driver to go the harder this gets.

IMO if you want full range, you start with a 15" driver of some kind that allows you the bottom octaves and cross over at 400-500Hz to your extended range driver and then roll in the tweeter at about 7-8KHz.