What Helmet Intercom?

I'll be doing driving instruction this season for the first time (street cars on a road course). Yelling at my students over the in-car din doesn't seem like the best plan.

So I'm looking for a helmet intercom. I'm thinking something small, wired, battery powered. What's worked well for you?

Many will suggest chatterbox. I found the one I had to be utter crap. I've had the same Nady for a long time. It is crappy too, but I fixed a few solder joints and its been bulletproof.

In reply to asoduk:

Which Nady model?

I have a set of Sena SMH10 which we got for the motorcycle, but also work well for track days.

Dedicated earbuds would be better for volume, but the velcro-in speakers work OK. Some helmets are more amenable than others.

I bought a Nady PMC-2 some 13 years ago for our rally car, hoping to avoid the cost of a good system like a Peltor. Hugely disappointed.

That model put the earspeakers and mics for both headsets in parallel with one another going into and out of the single amp in the control unit. I suspected something like this when I noticed that with one headset plugged in the volume when speaking into the mic was two or more times that of when both headsets were plugged in. The net result was that I could not hear the other person clearly no matter how high I turned the "volume" on the control unit.

Too bad too since something like this that actually works need not cost any more and would be very handy for applications such as Luxinteriors.

I suppose it is possible that Nady fixed this with the X versions now available.

I ended up going with a Peltor FMT100 solution which works flawlessly.

So far, I'm still waiting for news of a good solution. Until then, I'm using Chatterbox/Tandem.

Be aware there is an "old" model out there which uses 5-pin headset connectors, and a "new" model that uses a single pin. Compatibility between the two is alleged, and the mnfr sells an adapter, but it doesn't work worth a hoot.

Regardless of the system, it has to adapt easily to the students' helmets or it won't matter how good it is.

You guys might also check out places like aircraftspruce.com for similar setups used in small aircraft.