Just brainstorming some new ideas drawn from classic fantasy and wondering how to implement them in Ars.
The first is an effect that targets everyone that can hear a noise generated by the caster (or item). My idea behind this is enchanted bells. Imagine a belltower with a huge bronze bell that rings out twice a day and drives off devils with a PeVi effect. Or a mighty horn that puts courage into the heart of all that hear it blown (CrMe). Certainly many magical instruments will just target a thing. D&Ds classic horn of blasting is a simple point and shoot effect that could be achieved with a voice range. But its much harder to have an effect that targets all who can hear it.
The second idea came from the first. But this time an effect that targets all who see it. Inspiration here is a battle standard that either gives enemies the willies when they see it or gives bravery to those who march under it, although you'd have some issues here targeting your effect since you don't want the other side to have the benefit/effect as your side. Maybe a better version would be D&Ds exploding runes. Essentially a trap that activates when your read the runes. I'm guessing the closest in ars would be a Watching Ward with both an attack spell and a some kind of detection spell to act as the trigger. Or would you need the detection. Could you integrate the trigger just as "Reads runes written at time of casting"?
Now sensory magic in the Bjornaer book can sort of do those things, but it has specific limits based on the animalistic nature of the magic, and is a house mystery.
Could you invent a R/D/T to do this? Does it already exist?
Since both targets exist as a Bjornaer house mystery, they can presumably be integrated into standard hermetic magic, or they may be invented with somewhat more effort as a Major (?) Breakthrough. I would assume the limitation concerning enchanted items could simply not be an issue if you invented the whole thing from the scratch, or it may be fixed as a Minor Breakthrough if you integrated the Bjornaer mystery.
I believe it would be a Hermetic Breakthrough, based on the Gruagachan section of Hedge Magic, p. 78. Improved Voice Range. Integration of the Bjornaer Mystery would probably be Major, and might then be grounds for Insight into this.
The Defixio integration in Ancient Magic might also help, if integrated. As a continuous Event? Also Hermetic Breakthrough level.
The take on bells I've had mulling around in my head is to make an item only T: Sound available as (part of?) the special/unique mystery initiation available to a Verditius confraternity of bellmakers, based in Italy. They'd maybe use Hearing the Silent Chorus (A&A pg 16) to help tune and/or enchant the bells, have a special version of Conjuring the Mystic Tower to produce campaniles (a botch of which could explain the Leaning Tower of Pisa's origins and delay, as well as providing a possible vis source - lesser enchantment vis that has a touch version of The Forgiving Earth and appears to one side of the tower).
The various ringing styles (Bolognese, Veronese, English, etc.) may not go back far enough to be historically available(?), but having an enchanted, animated plant pattern ringing enchanted bells with its vines as part of a covenants defenses may be a thing.
I've been considering a variant of the Bjornaer sensory targets for my game, and I am currently leaning toward requiring each sense to require a separate breakthrough, with a difficulty relative to the utility of the sense. Each are technically "minor" breakthroughs in terms of how easily any completed breakthroughs can be taught to others, while closer to "major" in regard to the challenge represented. Contrary to the House mystery, which only come through the caster and not ever through a device, these versions must use a physical prop or ongoing action, similar to Performance Magic or the incense magic of Soqotra. On the other hand, they can and often are enchanted into devices.
(The bare existence of the Bjornaer mystery will be known to researchers, even if they have no idea how or why it works, and knowing that something is actually possible is a huge benefit toward replicating the effect. Eventually they will succeed, in some form.)
A magical effect using scent would only continue to work while the smell (such as an incense) is present, a sound would only work while the bell can be heard ringing or the performers continue the music, and a flavor would only affect the consumer when the material reaches their tongue. In my setting, the Jerbiton are desperate to replicate the ability for a visual spectacle, so that works of art might affect viewers merely by seeing it, but so far the key has been elusive.
The existence of the Bjornaer mystery shows that such a thing is hermetically possible, however the idea of broadening it and applying it to items is somewhat... intimidating. Trying to replicate classical fantasy items is fine, though those items were designed as written, rather than crafted together from a mix of ranges, durations, targets, techniques and forms. The biggest hurdle is going to be dealing with the Limit of Arcane Connection: Hermetic magic cannot affect something it cannot perceive; however these effects are based in the exact opposite, targeting something that perceives the item. This ability is very, very powerful.
Can you imagine a crucifix that casts Demons Eternal Oblivion on anyone who looks at it? A cap that makes everyone who sees it friendly to the wearer? You don't even have to KNOW there's a target anymore.
There is HoH:TL p.73f Aura of Inconsequence: "individuals enter the influence of this spell by looking at the recipient".
This spell is grandfathered in from earlier versions, explicitly not fully Hermetic, and can not simply be generalized.
But when in a saga PC magi wish to research magic affecting " everyone that can hear a noise generated by the caster (or item)", Aura of Inconsequence and its antetype HoH:TL p.77 Veil All Eyes can provide AM p.8 Insight.