Do your headphones sound a little like tin cans?

 This is why:
On the right is an oscilloscope picture of what you hear
in a set of typical narrow frequency response headphones.
 On the left is Ratphones reproducing exactly what your machine is sending.
Why not hear every signal as it was intended?
 In a comfortable,  well built, high isolation set of Ratphones!
Get up close and personal with your machine and find more targets.

The mystery of the Stereo/mono switch
(This will probably confuse most, but here it is).

Detector headphone switches are not really stereo/mono switches.
The ground conductor is what is switched to make the phones
either series tip/ring or parallel tip/ring as seen below.

TIP:
You can make your own emergency Rat Tail
with a coiled guitar cord
 and an adapter (stereo plug to mono jack) for the machine side.
Adapter not needed for Minelab or Garret machines.

Headphone specs and advertising

by Rick Viola

Impedance.

The most confusing spec to understand and advertisers make it even more confusing. Basically, you get the most power to the speakers when the headphone impedance matches the machine. What is the machine impedance? Well, it varies with the manufacturer. Many machines are 150 ohms and a few are 300 ohms. However, headphone advertisers seem to often claim 150 ohms. Well, that may be the impedance of the speakers  used, however, unless you are swinging a true stereo machine (there are very few) your headphone speakers are in parallel. This makes your so called 150 ohm headphones really 75 ohm headphones. There are also so called 100 ohm headphones that, you guessed it, are really 50 ohms when you connect to a typical machine. The further away you get (up or down) from the machine impedance, the less volume you get. This will most likely affect  distortion also, making the sound you hear further away from the sound that was intended.
Then there is Minelab. Some of their output circuits actually vary impedance depending on the headphones. They are very secretive down under!
However, impedance matching alone does not make a good sound Other features such as the speaker efficiency,  magnets, materials and durability are also important. The final judge will be your own ears. Some customers actually like a loud distorted screech!

Ratphones true 250 ohm impedance delivers more power to the speakers and matches a wider range of machines. They draw less power from your batteries with less distortion.  If you get more clarity at a higher impedance, you use less volume and less power.

Speakers. And frequency response.

This is an interesting subject. As you are searching though the specs, see how many 150 ohm (actually 75 ohm as discussed above) have a frequency response of 200 to 3200 Hz. Sound familiar? Well, most of the major brands that I took apart have the exact same speakers! Why not, they have been around a while, they seem to hold up. Yes they have been around because they were developed for telephones. We all know how bad telephones sound. Sure, nice and loud, but a bit distorted. Engineers in those days had the attitude that if the human voice was about in that range then that is all the frequency response you need. Maybe if your name is Alexander Gram Bell. Not for today’s electronics. We want to hear every nuance of the sound from soft to loud!

It’s also interesting  how some headphones are “specially made” for a certain type of detector but have the same speakers. Making phones that only work with machine “x” or "y" by removing the compatibility switch, does not make it optimized.

Ratphones frequency response is 20 Hetz to 20KHz which is the full spectrum of human hearing. Believe me, you will hear it! Since Ratphones do not need a switch, the failure rate is greatly decreased, not to mention the replaceable cord. Since the cord is reversible to make them compatible with all machines, there is no need for a switch or to produce a “special” version, except stereo, or maybe a single volume. If you want something different, just let us know.

Ear muffs.

Many headphones we see use three basic styles. They are excellent for metal detecting. No metal parts, comfortable and look stylish. There are two typical ways that earmuffs are rated, NRR (noise reduction rating, North American) and SNR (single number rating, European). They are just different standards based on different test procedures. The SNR is always a little higher that the NRR., so you will hear that number more often in advertising. The original type that appeared has SNR rating of 28 db. The ones with the added an additional plastic piece is 29db. To put that in perspective you need 2 or 3 db to notice a difference. Then there are the “lighter” cups you see that are 24 db. Do they feel lighter on your head? I don’t think anyone would really notice. You may notice the slightly more hollow sound due to the thinner plastic. Well, they cost less and are almost as good.

But that’s the three major designs. 29, 28 or 24db. That’s all. No matter what the ad says. Some like the super light home stereo phones also, which sound good, but are uncomfortable and not really made for outdoors.  In the end, it's a personal preference. I'm just saying, if they look the same, they are.

Ratphones use the popular 28 db SNR version in a handsome gloss black. They are professional looking and cartoon picture fee. (Well, just the little RAT logo).

Limiters.

This is a “circuit” that tends not to affect the lower volume sounds and prevents the loud sounds from being too loud. If you have a modulated audio machine that has weak and loud sounds, some users like this. They like to defeat all the time detector companies spend on getting the audio just right, or make up for a machine with too much dynamic audio range.

We will gladly insert our limiter circuit for free. It has a softer, more natural limiting effect. But we will still try to talk you out of it.

Switches.

Hey, who doesn’t like switches? Sometimes they are necessary to turn features on and off or to make headphones compatible with different wiring schemes of the machines. They will increase the failure rate. The better ones that fail less are very costly (and rarely seen by the way).

Ratphones don’t need a switch.

Circuitry

OK, let's call volume controls, speakers and wires circuitry. Is there much engineering here? In our case, yes.

Ratphones controls have been selected to take less power away from the speakers and still provide a  good adjustment range. They are industrial sealed controls that cost 5 times more than the typical low cost carbon commercial control. We tried the lower cost ones that the other phones used at first and we had two or three failures. Then we threw them away. The new controls will not be affected by moisture, dirt or other elements and the rotation life of these controls is much-much longer. Rated at one watt, makes them unprecedented and just not found in the industry.  The max input voltage is 8.4vac rms (4.2v single volume version), where the typical competitor is 2v or 1v for single volume models.  We like a little more headroom than that because many machines deliver 1vac rms during battery test tone!
Detents (clicks) are not needed here. They have just the right feel for continuous adjustment to get the exact setting you want. Our wiring is military/aerospace grade adding even more to the value and dependability. The Teflon insulation can endure longer soldering time to insure proper solid connections and resist stress. We even thread our own cross wires  with the same wire to insure the quality. No compromises!
 

Ratphones…something new….really.

Manufactured with a lot of care and thought by Detect USA.
No hype needed. Satisfaction guaranteed.