What is The Difference Between the Garrett AT Pro and ACE 400 Metal Detectors?

Often when searching for which metal detector is suitable for one's needs, there are some questions that come up.  At first glance when comparing the Garrett AT Pro metal detector and the Garrett ACE 400, you might think that the main differences are simply color and price.  After all, they look very similar in design. This is not the case with these two detectors. 

Simply put, the ACE 400 is better suited to beginners and intermediate and the Garrett AT Pro can accommodate beginner to intermediate detectorists and is also well suited for advanced metal detectorists.  

Similarities and Differences

Coils

Both the AT Pro and the ACE 400 use a large 8.5" x 11" Double-D coil.  Both of them are VLF (very low frequency) metal detectors.  Basically VLF detectors have two coils.  One transmitting a frequency and the other receiving it.  This happens several thousand times each second.  The term Double-D means that these coils are placed over each other in an offset method and creating a narrower detection field versus a concentric coil where the coils are basically right on top of each other.  This in turn allows for better target separation.  Smaller Double-D coils and concentric coils are available for both detectors. 

Control Housing, Controls, and Face Plate

ACE 400 Face Plate

AT PRO Face Plate

One of the biggest differences between the AT Pro and ACE 400 is that the AT Pro is waterproof up to 10 feet (the AT in AT Pro stands for All Terrain).  Whereas the ACE 400 does not have a waterproof speaker, battery compartment, or headphone port, the AT Pro does.  The ACE 400 can however be submersed in water up to the control housing allowing for shallow water detecting.  It just cannot be fully submersed.

With regards to the digital read out, the detectors are very similar.  Both have a digital target ID displayed ranging from 1-100.  Both have a target ID Segments that can be eliminated or "notched" out.  The AT Pro has 40 different notchable segments whereas the ACE 400 has 12.  The more segments, the more you are able to eliminate undesirable targets with precision.  

The Garrett ACE 400 has 5 preset search modes (zero-disc, jewelry, coin, custom, relic).  The AT Pro has 6 (custom, coin, and zero - three in standard mode and three in Pro-Mode for each). 

 Both metal detectors have 3 audio ID tones and Garrett's exclusive Iron Audio.  Iron audio is a handy feature that can be turned on or off and gives a lower "grunt" type signal when iron is present.  The difference between standard mode and Pro-Mode on the AT Pro is mostly the audio output.  Whereas in the standard mode, you get a very distinct audio signal much like the ACE 400, when in the Pro-Mode the audio is allows for more distortion.  This is a handy feature for an advanced detectorist.  Learning what different distorted sounds are can help you discriminate between a piece of aluminum and a gold ring for example.  The odd shape of the crumpled aluminum foil will put out a distorted audio signal as the radio wave is trajected at different angles and the ring will give a nice crisp signal from the uniform round shape with smooth edges.

Both have a pinpoint function and both offer the ability to adjust the frequency of the detector to help eliminate noise from other metal detectors, underground and overhead power lines, or cable lines.  Both have a sensitivity adjustment only the AT Pro has a better ability to segment exactly how sensitive it is and the ACE 400 has a little less ability to do that.  Both detectors have a target depth indicator.

Another key difference between the AT Pro and ACE 400 is the ability to manually ground balance the AT Pro.  The ACE 400 has an automatic ground balance whereas the AT Pro has a manual ground balance feature.  The ability to manually balance out minerals in the soil or on the beach make the AT Pro more flexible for a variety of different search locations.  The ACE 400 for example is not a great machine in wet saltwater beaches.  The AT Pro however can handle these extreme conditions much better.  Additionally the AT Pro offers the ability to, with the touch of a button, change the iron discrimination on the fly. 

Finally the operating frequency of the detectors are slightly different.  The AT Pro operates at 15kHz and the ACE 400 operates at 10kHz.  In a nutshell lower kHz metal detectors are better at finding larger, deeper targets, and higher kHz detectors are better at finding smaller objects.  Therefore, for instance, an AT Pro is more sensitive and will be better at finding small gold pieces (say like an earring, small gold chain, etc.)  They will both find such items as coins, relics, larger jewelry and such fairly equally.  

One thing I will say, is that the ACE series detectors do seem to more impervious to electromagnetic interference.  I have hunted next to my stepson around power lines and my AT Pro was fairly erratic and his ACE 300 wasn't phased.  So, sensitivity can sometimes be a hindrance in certain conditions. 

To sum it all up.  If you are looking to coinshoot, relic hunt, and search for the targets the "average" detectorist is looking for, an ACE 400 will work just fine for 90% of the metal detecting population.  If you are looking to detect in harsher environments and are looking for the treasure the average metal detector will miss, the AT Pro is the best choice.  Regardless, Garrett Metal Detectors makes very good metal detectors and whatever you are searching for, they are certain to have a model to suit your needs.