I've owned 4 or 5 Fisher F19's but I don't care for them like I do other makes and models. I used to use the Teknetics G2 and Fisher Gold Bug Pro which are similar when it comes to audio circuitry design.
Generally, I have preferred several Killer B headphones, and used to use the 'Wasp' which is essentially the same as the Sun Ray Pro Gold [size=small]
(made by Killer B)[/size] and they use 150 ohm speakers. Years ago I changed to the killer B 'Hornet. model. Also 150 ohm speakers, but they use a "tank style" ear cup. I found the Wasp and Pro Gold headphones to become uncomfortable, for me, because they press too hard on my ears. The 'tank style' ear cups of the 'Hornet' model are a little larger and cover the ear better rather than press firmly on the ear.
I have a back-up set of 'Hornet' headphones in my Accessory Coil Tote and another in a smaller tote I carry in my travels that also has a spare Pinpointer and set of batteries for a detector.
I have used other brands of headphones in the past, from different makers like Calrad or Radio Shack and others, but many were using low impedance speakers, such as 8 ohm, 16 ohm or 32 ohm. I found almost all of them to not have as clean and crisp audio response and more of what you might say was a 'muffled' type of sound. The military tells me I'm deaf since '82 so as a hearing-impaired person I pay closer attention to the audio quality.
My regular-carry headphones, other than my back-up Killer B 'Hornet', is the White's Pro Star. They look and feel similar to the Hornet or Gray Ghost XP's I use with my XP ORX, in that they also have the 'tank-style' ear cups that comfortably cover my ears. They use a 50 ohm speaker, but I found the audio quality to be very good with most makes and models of detectors.
'dfmke' mentioned he also uses the Jolly Roger headphones. I had a set before and they are comfortable, but they use a 16 ohm speaker and I wasn't impressed as it, also, had more of a muffled sort of audio response with several different makes and models i used.
In the better days we had more "local" detector dealers around, and more places like Radio Shack and other electronic equipment stores. I used to just take a detector in to a shop/store and try the different headphones they offered to find what worked best. It was easier, and cheaper, than ordering in something that I wasn't going to be pleased with. I'd also contact a detecting buddy or someone in a local detecting club [size=small]
(and most of those are gone now, too)[/size] and check out headphones others are using.
If I were travelling light and w/o back-ups and only had one set of headphones to take, they would be my Killer B 'Hornets.'
Monte