Ohms, regarding headphones.

[pietro79]

New Guy question:

Are Ohms are purposefully "put in place"/"decided" by the designer to protect speakers?

I'm looking to buy a pair of the Sennheiser HD280.
The Pro or Silver has an impendance of 64 ohms, versus the HD280-13 which has a 300 Ohms rating

I'm recording and providing foldbacks with a roland v1680 at the moment.
If I split the monitor signal (via a cheap lil' mixer) to provide more headphones, and using the same signal, what should I be careful about?

Will the signal be weakened because it's shared?

I guess the ultimate question is, if I (hypothetically, for now) bought 3 HD280 pros, and shared a monitor output, the ohms would be 16 ohms, right? ((64/2)/2=16)

Is 16 ohms dangerous? what is dangerous?

Please enlighten me! Thank you so much.

Sincerely,
pietro

 

[genob]

This is tough to answer.... the best thing to do is to use one of the outs from a mixing board into a head phone amplifier. The amplifier will tell you the loads it is capable of handling...

Generally things work like this:

If you have an amplifier that has a rating of 8 ohms on a channel. Then if you run a 4 ohm load on it, then you will be driving the circuit at twice the amount of current.

So if you have a headphone amplifier that is capable of handling a minimum of 300 ohms per channel, then you should only use 300 ohm headphones to match the impedance. The lower in ohmage on the headphones the harder you will drive the amplifier circuit to get desired volume which means more heat, which leads to burning out the amp.

It's not good to use a low ohm headphone on an amplifier not rated for that type of use... it will eventually lead to failure.

If you try to do stuff like physically tieing wires together, then you are running the headphones in parallel which will divide the load by 2 which is also bad.. again this will double the load on the amplifier of which it is probably not rated to produce that much current for such a long time.