How to engineer specialized headphones

[CWilli14]

Hello,
I'm a newby at audio electrical engineering. I would like to build headphones that can do double duty as room speakers (in both situations they would be plugged into an ipod headphone jack). What I mean is, I would like to incorporate speakers that are sufficient for playing music ambiently, but then, when a (volume-limiting?) switch is thrown, the speakers max out at a certain volume that makes them able to safely be used as headphones.

Would 85db speakers be loud enough for this? Should it be more like 90db speakers? Do I need to have an amplfier built in as well as a volume limiting element?

Any help or advice would be greatly appreciated!

Thank you!

 

[berkeman]

Hello,
I'm a newby at audio electrical engineering. I would like to build headphones that can do double duty as room speakers (in both situations they would be plugged into an ipod headphone jack). What I mean is, I would like to incorporate speakers that are sufficient for playing music ambiently, but then, when a (volume-limiting?) switch is thrown, the speakers max out at a certain volume that makes them able to safely be used as headphones.

Would 85db speakers be loud enough for this? Should it be more like 90db speakers? Do I need to have an amplfier built in as well as a volume limiting element?

Any help or advice would be greatly appreciated!

Thank you!

Welcome to the PF.

This idea seems to be fundamentally dangerous, no? There are some things that probably just shouldn't be built...

Do you remember the Far Side cartoon, where the scientist is about to plug in the power cord for an 8-foot monster robot...?

 

[CWilli14]

Thanks for the welcome - and, yes, I do remember that cartoon:)

Hopefully this idea wouldn't loose similar havok. Why do you consider it fundamentally dangerous?

 

[berkeman]

Thanks for the welcome - and, yes, I do remember that cartoon:)

Hopefully this idea wouldn't loose similar havok. Why do you consider it fundamentally dangerous?

Because it seems like it would be difficult to ensure that the volume could not exceed safe headphone levels if the capacity were there for use as small room speakers. You could try putting switches on the headphones that sensed when they were being worn, but what if those switches got stuck or failed? You could put a switch on the headphones that the user sets, but then there is always user error or the switch getting bumped...

For sure if you were trying to market something like this, there would be liability issues. But even building something for yourself, it seems like the possibility of error would be enough to keep you from doing it. There probably are other, better options, I would think.