"—hm? Oh. Anything that's sort of—sustained—like spatial effects, or holding a temporary record of a sound to be played back later, is much cheaper and easier to do with artefacts. With a spell I'd have to specify where the sound that's not being immediately relayed to me would go whereas with an artefact I can just store it in its—magical memory, I guess is the best description."

"...okay."

"And actually it might be neater if I just make it all a single artefact rather than artefact plus spell, collect and cancel sound as it approaches my ears and then play it back. I'll need to think of how to prevent that from being itself detectable, but it shouldn't be too hard..."

"I'm glad the idea is useful."

He beams. "It is! Okay I'm gonna need to write this down, it's probably gonna be complicated—" And he grabs some paper and a pencil and starts scribbling.

She flips through one of her books.

He continues writing for several minutes, every now and then muttering something to himself or making a sound to pay attention to.

Soon: "Okay I think I got something. Now I just need something to enchant—earmuffs or earplugs of some sort, better if they're connected..."

"I can pretty trivially make any shape out of wood from my tree, but I'd have to go get it."

"Oh that'd be useful. I can go through the gate and wait for you there?"

"That works. How exactly do you want it?"

"Something that covers my ears completely—if it could be soundproof or as close to it as possible mundanely that'd help."

"Okay." She inspects the size of and distance between his ears.

He stays still to let her look.

"I'll be back in an hour or so."

"Okay. See you."

Through the gate.

She is back in an hour with wooden earmuffs.

And he consults his notes and stares at the earmuffs for a few seconds and consults his notes again and—" Okay, should be done, I think." He puts them on. "Say something?"

"Something."

And half a second later he beams. "Okay let's see if this was long enough. Order me to raise my right arm?"

"Raise your right arm."

He doesn't.

He takes the earmuffs off. "I'm gonna shore up my undetectableness spell, can you make a gate to one of his courts? Or all of them, even."