Work in progress

Sonar build.

Playstyle:
Activate Silence (3), spam Sonar (2), proceed to punch or shoot foes in their now shiny unmentionables. Mostly ignore Sound Quake (4). (Activate Gloom, if available. Read below!)

Sonar damage multiplier: 10.7x
Sonar spots can overlap with weak spots (e.g. head) for extra-extra damage.

Aura:
Personal preference. Do whatever you want.

Arcanes:
Depending on the situation, spamming Sonar and keeping Gloom active can drain energy reserves pretty quickly. Energize does an amazing job in keeping me...energized. Aegis/Barrier/Guardian provides extra survivability. Feel free to use whatever you want/own.

Mods:

• [Vitality]: Feel free to replace it or upgrade it to Umbral Vitality. I prefer a bit of extra health as a buffer to survive random toxin shenanigans.
• Resonance: This is optional. It'll save you a good amount of Sonar spam and energy in missions with a high enemy density.
• Range: 145% is more than enough for Sonar (50m). One might argue that Gloom (23m) could use a little bit more, but as long as you don't sit in the middle of a wide open area this is quite alright imo. Also keep in mind that more range means more affected enemies, which increases Gloom's energy drain.
• Strength: Gloom's slow is capped at 95%, which can be achieved with 272% ability strength. Utilising [Augur Secrets] and [Growing Power] almost gets you there. Add [Umbral Vitality] for the set bonus and you got it. But unless you want to sit in a 3 hour Steel Path mission you most certainly won't need that extra slow.

Tip:
Use an intense energy color to improve weak spot visibility. (I recommend light blue...which converts nearby Grineer to shiny angry smurfs.)

Helminth abilities:
I've recently added [Sevagoth]'s Gloom (replace Sonic Boom or Sound Quake). It does consume some extra energy but BOY IS IT GOOD! Combine it with Silence and enemies are stuck in their stun animations for...well, basically until you've killed them. Dispensary ([Protea]) is another quite useful ultility skill if you're staying in one area for at least a moment.

Edit:
With the changes to armor and the addition of shield gating, [Banshee] feels less like a glass cannon now. I'm actually having a blast playing her in highlvl missions and Lich hunts!

PS: This build can surely be optimized and fine-tuned further, depending on your playstyle or mission difficulty. But since it's quite affordable and does the job, I'm fine with this for now. ;)

Questions? Feel free to message me ingame or via Discord. :)
Warframe tips and beginner's guide here.