Garrett ACE 400 Metal Detector

The Garrett ACE 400 metal detector is the top model in the Garrett lineup of ACE-series machines, and the one we hand to detectorists who want Iron Audio, an adjustable 10 kHz frequency, and a 0 to 99 Digital Target ID without stepping up to AT-series money. Our team has run enough hours behind ACE machines to know where the 400 earns its slot. It belongs with hunters who want clean target separation in iron, predictable target ID, and an 8.5 inch by 11 inch DD coil ready for serious site work straight out of the box.

Why Detectorists Choose the Garrett ACE 400 Metal Detector

• Iron Audio reveals flattened iron like bottle caps and washers that read as good targets on most VLF machines, so we dig less trash in heavy coin and relic sites.
• The 10 kHz operating frequency lifts response on low and medium conductors such as small gold rings, lead, and thin silver, areas where the 6.5 kHz frequency on entry-level ACE machines goes quiet.
• The 8.5 inch by 11 inch DD coil ships standard, giving better depth and stable ground handling over mineralized soil than the concentric coils on lower ACE models.
• Notch Discrimination plus adjustable iron discrimination shaves the trash band out of the audio while keeping the conductive zone wide open for coins, rings, and relics.
• Camlocks hold their tension after weeks in the truck, so the three-piece stem does not slip mid-hunt.
• A Digital Target ID scale of 0 to 99 is granular enough to track a target across multiple sweeps and call it before digging.

What's in the Box

• Garrett ACE 400 control housing with three-piece adjustable stem
• Garrett 8.5 inch by 11 inch PROformance DD waterproof submersible search coil
• 8.5 inch by 11 inch coil cover
• Adjustable arm strap
• Search coil hardware kit with bolt, washers, and nut
• 4 AA batteries
• Garrett ACE 400 owner's manual
• Free Garrett buyer's guide (while supplies last)

Where the Garrett ACE 400 Earns Its Keep

Park coin shooting in trashy ground

The 400's strongest tool in tight urban parks is the combination of Iron Audio and the 0 to 99 Target ID. We run discrimination just above the iron range and turn Iron Audio on, so masked iron under a good signal still leaks a low growl into the audio. That cue keeps us from chasing crown caps that ID into the zinc penny zone. After a clean high tone hits, we drop to Pinpoint and finish recovery with our Garrett Pro-Pointer AT.

• Search Mode: Coins or Custom (notch foil and pull-tab range)
• Sensitivity: 6 to 7 of 8 in average soil, drop to 5 if EMI breaks up the audio
• Frequency Adjust: position 2 or 3 if nearby detectors or power lines crowd the channel
• Coil: stock 8.5 inch by 11 inch DD

This setup runs clean in city parks and school grounds where copper, zinc, and modern junk share the same column.

Old home sites and farm fields

Junk iron buries silver, period. The Garrett ACE 400 metal detector's adjustable iron discrimination plus Iron Audio was built for this scenario. We open discrimination wide, accept the iron grunts, and listen for the broken or partial high-tone signals tucked between them. The DD coil's narrow side-to-side detection field separates targets that a concentric coil would mush together.

• Search Mode: All Metal, or Custom with iron grunts left on
• Sensitivity: 5 to 6 of 8 in mineralized soil
• Iron Discrimination: low (around 30 to 35) so iron still reports
• Coil: stock DD; the optional 4.5 inch ACE Sniper coil tightens separation in dense iron

Slow your sweep, half the coil width per pass, and let the audio talk.

Dry beach and shallow fresh water

The control housing is not submersible, but the 8.5 inch by 11 inch DD coil and the lower stem are. We hunt the wet line with the coil dragging in damp sand. PWM audio gives crisper attack on shallow rings, which matters when a faint half-second signal is all you get on a tide-washed beach.

• Search Mode: Jewelry or Custom (notch foil out, leave the nickel zone open)
• Sensitivity: 5 to 6 of 8 on damp sand
• Iron Audio: on, so bottle caps near the water line do not waste plugs
• Coil: stock; coil and lower rod can submerge in fresh water

The Technology That Matters on the Garrett ACE 400

Iron Audio plus adjustable iron discrimination

Iron Audio is the headline feature. With a small amount of iron discrimination set, the machine still vocalizes the iron portion of mixed targets as a low grunt while keeping the high tones on conductive metals. We use it to call bottle caps before recovery and to confirm a clean coin signal is not a coin sitting on the edge of a rusted nail.

Adjustable 10 kHz operating frequency

A 10 kHz frequency is more sensitive to small low and medium conductors than the 6.5 kHz frequency on the ACE 200 and 250. Frequency Adjust shifts the channel in small increments, useful at club hunts where two or three detectors crowd the same band, and near transmission lines where EMI ruins a hunt before it starts.

Build Quality and Ergonomics

Weight, balance, and shaft

At 2.9 pounds with batteries, the Garrett ACE 400 metal detector is light enough for full-day grid work without forearm fatigue. The three-piece stem extends from 42 inches to 51 inches, and the Camlocks hold their tension well past first assembly. The arm cuff keeps the housing tight on side sweeps so the coil stays parallel to the ground.

Power and runtime

Four AA batteries (included) deliver long sessions in normal use. We carry a second sleeve for all-day hunts and have run NiMH rechargeables in the 400 without issue. A battery condition indicator on the LCD warns us before audio degrades.

Audio

PWM audio and the headphone jack

Pulse-Width Modulation audio produces sharper attack on shallow targets, which matters when reading the leading edge of a faint signal on damp ground. The 1/4 inch headphone jack accepts standard wired pairs. We prefer wired headphones on this machine, since they avoid the lag that lower-end Bluetooth packs sometimes introduce.

Coil Options

Included 8.5 inch by 11 inch DD PROformance

The standard coil is the right coil for most ground. DD coil geometry lays a knife-shaped detection field that runs more stably over mineralized soil and reduces false signals on saltwater-influenced ground. It is fully submersible to the connector.

Optional ACE-series coils

A 4.5 inch ACE Sniper waterproof coil is the one we reach for in iron-heavy colonial yards where target separation matters more than depth. A 9 inch by 12 inch PROformance coil extends ground coverage on open fields. Both are field-swappable in under a minute using the included hardware kit.

Garrett ACE 400 Metal Detector Specifications

• Operating frequency: 10 kHz, adjustable
• Search modes: 5 (plus Pinpoint)
• Sensitivity and depth adjustments: 8
• Digital Target ID: 0 to 99
• Audio tone ID levels: 3
• Target depth indicator: Yes
• Iron Audio: Yes
• Notch Discrimination: Yes, adjustable
• Electronic Pinpointing: Yes
• Standard search coil: 8.5 inch by 11 inch DD PROformance, waterproof and submersible
• Length (adjustable): 42 inches to 51 inches (1.06 m to 1.29 m)
• Total weight: 2.9 lbs (1.32 kg) with batteries
• Power: 4 AA batteries (included)
• Battery condition indicator: Yes
• Camlocks: Yes
• One-Touch Treasure Hunting: Yes
• Warranty: 3-year limited parts and labor

Why Buy the Garrett ACE 400 Metal Detector from Serious Detecting

We are an authorized Garrett dealer, so every Garrett ACE 400 metal detector ships with the full 3-year limited Garrett parts and labor warranty intact and is registered through proper channels. Our team detects with the gear we sell, so warranty support, settings questions, and coil-swap advice come from someone who has run the machine in the dirt. Free U.S. shipping, a 30-day return window, and our price-match guarantee back every order. If the 400 reads as too much detector for your goals, the Garrett ACE 300 collection covers similar ground at a lower price.