Apogee Duet 3 vs Audient iD24: Which Drives More Headphones?

Apogee Duet 3 vs Audient iD24

Short answer

More power: the Apogee Duet 3, with 1.18 W into 32 Ω; the Audient iD24 has 119 mW. The Apogee Duet 3 drives 6 headphones to 100 dB that the Audient iD24 cannot (Moondrop COSMO, Moondrop PARA, Symphonium Crimson, 3 more).
Hiss with sensitive IEMs: cannot be compared — neither maker publishes a noise figure.
Output impedance: 560 headphones are left alone by the Apogee Duet 3 under the one-eighth rule but coloured by the Audient iD24 (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Nio, 557 more).
Price: the Apogee Duet 3 costs $50 more; what that buys on these numbers is set out further down, under What the price difference buys.

Both are audio interfaces, $649 against $599.

The Apogee Duet 3 reaches 100 dB on 567 of the 567 models here, the Audient iD24 on 561.

Every published figure, next to each other

Specification	Apogee Duet 3	Audient iD24
Power into 32Ω	1.2 W	119 mW
Power into 150Ω	252 mW	80 mW
Power into 300Ω	126 mW	58 mW
Power into 600Ω	63 mW	52 mW
Output impedance	0.5 Ω	50 Ω
Output noise	not published	not published
Price	$649	$599
Headphones it reaches 100 dB on out of 567	567	561

Not published means the maker leaves it out, so that axis cannot be compared.

Where each power figure comes from

Load	Apogee Duet 3	Audient iD24
32 Ω	Upper bound	Derived
150 Ω	Upper bound	Derived
300 Ω	Upper bound	Derived
600 Ω	Upper bound	Recomputed

Neither column is a power rating, and the two are not even weak in the same way. The Apogee Duet 3 figures are ceilings worked out from a maximum output voltage, on the assumption that the amplifier holds it into the load. The Audient iD24 figures are worked out from figures its maker did publish — power at other loads, or the voltage printed beside it. The second method understates; the first flatters. That is the wrong way round for reading the table straight across, so a gap in favour of the Apogee Duet 3 is the one to doubt.

What the labels mean.

The headphones that tell them apart

6 headphones reach 100 dB on the Apogee Duet 3 but not on the Audient iD24 — Moondrop COSMO, Moondrop PARA, Symphonium Crimson, 3 more.

560 headphones are left alone by the Apogee Duet 3 under the one-eighth rule but coloured by the Audient iD24 (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Nio, 557 more).

561 of the 567 models here reach 100 dB on both.

Headroom and hiss on 8 models, both sources

Headroom is at a 100 dB SPL peak.

The widest gap on the list is the Shure SE846: Apogee Duet 3 has +39 dB of headroom there against +29 dB. 10 dB is about 9.5 times the power, which matters for peaks rather than for how loud the music sits.

The hiss columns are empty for Apogee Duet 3 and Audient iD24 because neither maker publishes no output noise figure.

Headphone	Impedance	Needs	Apogee Duet 3 headroom	Audient iD24 headroom	Apogee Duet 3 hiss	Audient iD24 hiss
Shure SE846	9 Ω	0.04 mW	+39 dB	+29 dB damping	not published	not published
Campfire Audio Andromeda 2020	9 Ω	4.0 mW	+19 dB	+9 dB damping	not published	not published
Audeze LCD-2 Classic	70 Ω	0.79 mW	+28 dB	+22 dB damping	not published	not published
Beyerdynamic DT 1990 Pro (250Ω)	250 Ω	0.63 mW	+24 dB	+20 dB damping	not published	not published
HiFiMAN HE400se	25 Ω	7.9 mW	+21 dB	+11 dB damping	not published	not published
Audio-Technica ATH-R70X	470 Ω	1.6 mW	+17 dB	+15 dB	not published	not published
Sennheiser HD 600	300 Ω	6.6 mW	+13 dB	+9 dB damping	not published	not published
HiFiMAN Susvara	60 Ω	50 mW	+11 dB	+5 dB damping	not published	not published

The gap in dollars, against the gap in numbers

The Apogee Duet 3 costs $50 more than the Audient iD24. Out of the 567 models here, that difference buys 6 more models driven to 100 dB and 560 more models left alone under the one-eighth rule.

Nothing runs the other way: there is no axis here on which the cheaper of the two does better.

Only published figures count here; blank axes are counted separately.