Feedback on Homebrew Subclass

I really like it, it's very thematic.

I feel that it's really quite underpowered, though. The bell doesn't actually do anything besides shed light until level 7, which will mean this ranger will be a torch for the entire start of a campaign. I would give the bell more features at level 3, including an offensive and a defensive option or buff/debuff. Even at higher levels, in a general dnd encounter (you just met an angry hill giant who wants to eat the town, and now he wants to eat you too, for example), this class can't offer much - it can attract creatures, but not control them. It can charm nearby creatures, but if they save then that's gone for an hour. It can shed light, which it doesn't need to, and it can open portals to the border ethereal / interact with things there, which means more work for the DM and not much guidance on what that could involve!

I would suggest:

Start by being able to summon creatures, such as swarms of beasts, using the bell, and allow them to be controlled whilst the bell is alive. This would be the level 3 ability, and I'd make it limited by CR and environement.

Then I would allow them to summon ethereal beasts, which isn't limited by environment (you want a swarm of ethereal fish in a desert? you can summon one). Such swarms are identical, except swimming speed becomes flying speed and they ignore terrain.

Also worth noting (not sure if it's intentional) but you can't seem to move your bell without a bonus action, so if you were trying to use it whilst dashing, for example, it would be left behind and destroyed.

I do like this though, it's got a nice feel to it!

I feel like it's so rarely going to be destroyed if it's immune to all damage except force that it's probably just simpler to say that it can't be destroyed. Any you can just summon it back again anyway.

I do agree with the other statements too. Maybe something like "prof times/short rest you can choose a creature in your bell's light to aid/guide or harm/blind.
Aid/Guide: Gain +1d6 to the next ability check, saving throw or skill check they make.
Harm/Blind: Reverse of aid. Maybe a save?"
Maybe the dice increases as you level like a bardic inspiration? I dunno, I'm just thinking it could be something like the guidance cantrip. Oh, maybe you just gain the guidance cantrip but can also cast it through your bell? Then maybe your bell can also harm and deal 1d6+wis radiant or force to those of your choice within the bright light prof/long(?) rest. Maybe it's a save and they take the damage and have dis on their next attack and on a success they just take half damage.

Maybe you set up Chime's at 3rd level and at 7th they each get improvements or you have say, 5-8 chimes and you can pick (prof) chimes at the end of a rest and can use them... I guess wisdom or prof times/rest.

Might also suggest giving an extended spell list here.

Ethereal Bell.

Bell is an ethereal object, can cast bright light within 10 feet and dim light within an additional 10 feet. You can move it up to 30 feet as a bonus action, but it cannot be further than 30 feet away from you. Additional things, though I wouldn't have it be breakable. I think it'd also be neat if you could have it be say, a lantern or other objects, since it seems to be doing things like sound and light? Maybe you could have it be attached to you or within you so it's not very conspicuous, but you can still gain its benefits and it moves with you? I'm not sure.

3rd level chimes. You could make it just be 'within 10 feet of the bell' instead of in the bright light so you can have it up but not be shining light, and be more about the sound.

At 3rd level, you can cause your bell to make mystical chimes; mystical intonations that your Bell can produce to grant magical effects. You gain a number of chimes of your choice equal to your proficiency modifier when you finish a long rest and can change the chimes you gain at the end of a long rest.

You can activate chimes a number of times equal to your proficiency bonus and regain all expended uses at the end of a long rest. Each chime costs a bonus action to begin and lasts for an hour, and only one can be active at a time. A chime ends when dismissed with no action cost or if you begin a new chime.

Illuminating Chime. The bell rings out with a bright, clear note and makes the hidden appear. Creatures of your choice within 10 feet (or in the bright light?) of your bell have advantage on Perception, Investigation and Insight checks.
Guiding Chime. The bell makes a gentle, patient chime and aids your allies, helping them to find their way. As an action, you can cast the Guidance cantrip, which counts as a Ranger spell for you while this chime is active, and target a creature of your choice within your bell's bright light (or just within 10 feet?).
Emboldening Chime. Your bell creates a clear, confident note that strengthens the resolve of your allies. Creatures of your choice within the bell's bright light have advantage on saving throws to resist the frightened condition and add +1 to all saving throws. 
Blinding Chime. The bell makes a loud, harsh chime and blinds your enemies. As an action on your turn, you can force a creature of your choice in the bright light of your bell to make a Constitution saving throw or take 1d6 force damage and gain disadvantage on all attack rolls until the start of your next turn.
Calling Chime. You cause the Bell to start ringing out with a strangely compelling tone. When a creature is in the bright light of your bell, you can use your reaction to force them to make a Wisdom saving throw or be unable to voluntarily leave the bright light.

At 7th level, your skill with the mystical notes of the bell improves, granting you additional benefits when you begin a chime and additional chimes you can use. 

Illuminating Chime Improvement. As an action, you can grant advantage on attack rolls to all creatures of your choice within the bright light until the end of your next turn. You cannot use this action again until you use this chime again. Or maybe creatures within the light cannot benefit from being hidden or invisible or you can banish magical darkness etc.
Guiding Chime Improvement. When you target a creature with Guidance through the chime, you can choose to target a second creature also within the bell's light.
Emboldening Chime Improvement. As an action, creatures of your choice within the bell's bright light gain 1d6 + your Ranger level in temporary hitpoints and add 1d4 to the next saving throw or attack roll they make. You cannot use this action again until you use this chime again.
Blinding Chime Improvement. As an action, creatures of your choice within the bright light of your bell must make a Constitution saving throw or take 1d6 + your Ranger level in force damage and have disadvantage on the next attack roll they make before the end of your next turn. You cannot use this action again until you use this chime again.
Calling Chime Improvement. Not sure.

New 

Soothing Chime. You cause the Bell to start ringing out with a clear, hollow song. Creatures of your choice within 10 feet/the aura of your bell have advantage on Charisma checks to interact socially with creatures. As an action, creatures of your choicethat enter or start their turn within 30 feet of the Bell must succeed on a Wisdom saving throw or be charmed until they leave the range of this chime. Creatures charmed by Soothing Chime move at half speed and cannot take actions or reactions. At the end of their turn, a creature can make the same saving throw again to attempt to break free of the charmed condition. You cannot use this action again until you use this chime again.
Relaxing Chime. If you use this chime as a part of a short rest, creatures that spend the rest within the light of your bell receive an additional (x) amount of healing. (Not sure about this one, it doesn't really follow what the rest do).

Other ideas: Strengthening Chime which might give you a bonus to athletics checks or carry capacity and as an action amp your/your allies damage (+your wisdom until the start of your next turn). Protecting Chime. Maybe advantage on stealth checks when within the aura and it doesn't need to produce light. As an action give adv on saves/dis on all incoming attacks. I dunno, go wild man.

Add some other cool, powerful chimes here. Generally I was aiming to have 1-2 ribbon abilities as the base ability that are minor abilities and aren't OP to have active for an hour. Then they get an action ability they can do in combat most likely when they upgrade or get them at 7th they can do once/chime.

11th level.
This can probably be done better by saying "you gain blindsight out to 10-15 feet" or something. Maybe you have another ability here where the aura/light your bell produces is increased or you get additional uses or gain some back on a short rest.

15th level.
Traveller's chime is pretty poor... maybe something additional happens when you activate a chime. You could also have some sort of teleport that is flavoured as going through the ethereal plane.

Not entirely sure, anyway, hope this was helpful.

I agree with some of the feedback already given -- extremely cool idea, but it needs bulking up

1) I don't see any real reason for the Bell to be attackable, either. The bonus action to send it out makes sense, as it gives you more options for AoE features, but otherwise just have the ranger wink it out and make it re-appear next to them at will

2) I would look at the Rune Knight as a template for the chimes, much like Harry did above -- give the subclass a list of chimes (with some more powerful effects it can only access at higher levels) that do various cool things, and allow the player to select some at 3rd level, then add more later on as they level up. Either less powerful chines that you can swap in and out on a long rest, or chimes you're stuck with that have a couple effects including one than you can only use once per rest, a la Rune Knight

3) Maybe some direct combat utility for the Bell? faerie fire in an area centered on the Bell at 3rd level, usable proficiency bonus times per day, for instance. Things thematically tied to 'lighting/guiding the way'

I feel like Calling Chime is strange, any reason to make it a type of creature? Because if you choose Humanoid (which is what most characters and many monsters are), that's going to be a lot of trouble. It also adds a lot of text there for not much impact and sort of just hampers readability.

You could probably do that with an effect like compelled duel, but just having 'every creature within x miles comes to you' is going to be a hassle for the DM to figure out and doesn't really make a lot of sense, why would I want every undead in the area to come to me?