Garrett ACE 400 Metal Detector with Iron Audio and 10 kHz VLF

The Garrett ACE 400 is a straightforward coin and relic metal detector with Iron Audio, an adjustable 10 kHz frequency, a 0 to 99 Digital Target ID and an 8.5 x 11 inch PROformance DD searchcoil, built for older parks, farm fields and historical properties. Garrett calls it the top of the ACE family, and the box also holds Garrett TreasureSound headphones with in-line volume control. Our Garrett ACE 400 collection has the coils and accessories for it.

What is in the box with the Garrett ACE 400

Garrett's standard contents for the ACE 400 (Garrett part 1141260)

• Garrett ACE 400 control housing with S-shaped stem, upper and lower stem with camlocks
• Adjustable arm cuff and arm strap
• 8.5 x 11 inch PROformance DD searchcoil (submersible)
• Coil cover
• Searchcoil hardware: bolt, nut and mounting washers
• Garrett TreasureSound headphones with in-line volume control (Garrett part 1612500)
• 4 AA batteries (installed)
• Owner's manual

Why we like the Garrett ACE 400

The ACE 400 builds on the simple ACE platform and adds Iron Audio, a higher 10 kHz operating frequency and a larger Double-D searchcoil. What we like is that Iron Audio and the larger DD coil make it more interesting for someone who wants to learn how to evaluate complicated targets. We recommend the ACE 400 to beginners and intermediate coin and relic hunters searching parks, older properties and fields. We would choose it when you want a straightforward detector with better tools for investigating ground full of iron.

Iron Audio: hear the iron before you dig it

Iron Audio is one of the biggest reasons we like the ACE 400. Garrett describes it as letting you hear discriminated iron that is normally silenced, so you can avoid digging flat iron targets such as bottle caps or washers. Picture an old yard with rusty bottle caps and the occasional coin: we would use Iron Audio to investigate questionable signals rather than digging on the target ID alone. The mistake to avoid is assuming Iron Audio identifies every bottle cap correctly; rusty iron can still produce misleading responses.

Garrett ACE 400 frequency and frequency adjust

The ACE 400 operates at 10 kHz, compared with the 8 kHz of the Garrett ACE 300. Its frequency adjust offers four minor settings, F1 to F4, which Garrett provides to eliminate or minimize interference from electrical sources or from other detectors at crowded club hunts and rallies.

Digital Target ID, Iron Check and discrimination

• Digital Target ID: a numeric scale from 0 to 99 that identifies a target's conductivity, backed by three audio tone ID levels. On the display, the Target ID Legend runs from ferrous (iron) targets at the left to thick, high conductivity targets such as thick silver at the right, and the three tones split by Target ID: a low tone below 33, a medium tone from 33 to 75 and a belltone above 75. Target ID can vary widely with a target's size and thickness, and mineralized soils can cause Target ID errors, especially on small targets.
• Iron Check: four iron discrimination segments give more precise control of how much iron discrimination to apply, which Garrett says is very useful where treasure targets are masked by iron trash.
• Notch discrimination: a 12-pixel discrimination bar, adjusted with DISCRIM (+/-) and the ELIM button, so you can accept or reject individual target categories.
• Graphic Target Analyzing: the display shows a target's conductivity and the detector's discrimination pattern at the same time.
• Coin depth indicator: shows the depth of a coin-sized target; larger targets read shallower and smaller targets deeper than they are.

Five search modes on the Garrett ACE 400

The ACE 400 has five search modes, Zero-Disc, Jewelry, Custom, Relics and Coins, plus Pinpoint, and Coins is the factory default. Garrett designed Coins mode to find coins and eliminate common trash such as iron, foil and pull tabs, and the manual warns that medium-sized jewelry may be missed with that discrimination pattern. Jewelry mode is designed to find rings, bracelets, watches and necklaces while ignoring most iron trash, and Relics mode eliminates small iron pieces while detecting good targets in the lower conductivity range.

The 8.5 x 11 inch PROformance DD searchcoil

The stock 8.5 x 11 inch PROformance DD searchcoil is larger than the ACE 300's 7 x 10 inch concentric coil. Garrett's manual says the narrow detection field of the DD searchcoil allows better separation of adjacent targets, and Garrett's searchcoil guidance says a Double-D significantly outperforms a concentric coil over mineralized ground, while on non-mineralized ground it is inherently less sensitive than a concentric coil of the same size. The manual also says the searchcoil is submersible.

Coin and relic hunting with the Garrett ACE 400

For coin and relic hunting in parks, older properties and fields, target ID, discrimination and electronic pinpointing help sort signals, and Iron Audio helps you investigate a questionable one before you dig.

The ACE 400 adjusts automatically for ground minerals and lacks the adjustable ground balance of Garrett's AT series. Iron can mask a good target lying next to it, so Garrett's manual recommends using just enough discrimination to barely reject the iron trash, letting the coin and the nail be detected together. In areas with a lot of iron, the manual recommends switching Iron Audio off, because it may produce far too many signals. See our relic and treasure metal detectors.

Water, beaches and the ACE 400

The ACE 400 has a submersible searchcoil, but Garrett's manual says the control housing and connectors are not submersible and advises protecting the control housing from heavy mist, rain and blowing surf. The coil can work in shallow water as long as the control housing stays dry. For someone wanting simultaneous multi-frequency operation or regular saltwater beach capability, we would recommend the Garrett ACE Apex or the Garrett Vortex VX7; see also our beach metal detectors.

Pinpointing and recovery

Press and hold PINPOINT and the ACE 400 switches to a non-motion all-metal mode that helps locate a detected target's exact position; the display shows "PP". Accurate target location reduces unnecessary digging, which matters in maintained parks and lawns, and good recovery technique helps protect the site. The detector's pinpoint and a handheld pinpointer serve related but different purposes. See our Garrett pinpointers.

Getting started with the Garrett ACE 400

Start in Coins mode, the factory default. The settings that matter most on the ACE 400 are Iron Audio, discrimination, sensitivity and the effect of the larger DD coil. Garrett's manual recommends higher sensitivity for very small or very deep targets, and lower sensitivity when the detector behaves erratically because of heavy trash, highly mineralized soil, electrical interference or other detectors nearby.

Garrett ACE 400 compared with the ACE 300, AT Pro and ACE Apex

The Garrett ACE 300 shares the ACE 400's five modes, eight sensitivity levels and 0 to 99 Target ID, and runs at 8 kHz with a 7 x 10 inch concentric coil. The Garrett AT Pro is fully submersible to 10 feet (3 m) and offers adjustable ground balance and proportional audio. The Garrett ACE Apex offers four selectable single frequencies (5, 10, 15 and 20 kHz) plus Multi-Frequency and Multi-Salt, and adds 175 points of ground balance resolution and a rainproof control box. The differences below come from Garrett's published specifications.

Garrett ACE 400 specifications

Garrett covers the ACE 400 with a 3-year limited parts and labor warranty.

See all our Garrett metal detectors.