Audiomobile Encore 4412

Overall summary

In this sample and under these test conditions, the 1 volt baseline distortion run is controlled above about 40 Hz, but distortion rises as it plays lower. THD touches just past the top of the 10 percent visible window around 20 Hz, with dominant H3 distortion at the very bottom and H2 distortion also peaking in the upper 20hz. From 40 to 80 Hz distortion sits around 1%. No narrow, level invariant spikes are visible in the 20 to 120 Hz band at this drive.

At the near limit sweep of 20 volts, distortion increases as a broad rise instead of narrow peaks. H3 distortion remains most evident below about 30 Hz with H2 not far below in this lower region. H2 distortion becomes dominant from about 30 to 150 Hz. THD in more commonly used part of this passband is hovers around 7%, with the lowest octave climbing higher to about 12 percent. These changes with drive level occur without obvious level invariant spikes in the 20 to 120 Hz band, but does have elevated distortion in the 30hz to 120 Hz range with more power applied relative to the lower frequencies from the 1v to the 20v measurement.

Large signal data show a BL 70 percent one way limit of 19.11 mm (meeting the exact claim of the manufacturer of 19.1mm), CMS 50 percent not reached within the ±19.24 mm evaluation window, and the 17 percent inductance variance also beyond ±19.24 mm. BL symmetry is essentially centered at the limit (xsym ≈ 0.09 mm). Le at rest is low on this sample and Le(x) and Le(i) are stable. These LSI traits line up with the measured distortion pattern: small suspension asymmetry is consistent with even order H2 distortion, while the minimal inductance swing aligns with only a modest increase in H3 distortion as frequency approaches the very bottom.

Overall, the data shows that is a good subwoofer for its size and use case, with the only real complaints being slightly elevated distortion in the 30 to 80 Hz range on the higher voltage test compared to the 1v baseline test, and an asymmetrical suspension. No wonder I liked it when using it in the past 😊

Another thing to note, this is one of the only drivers in this testing so far that actually fully does exactly what the manufacturer claims about it via their specs and marketing. Good on them.

Manufacturer's suggested use case

The manufacturer positions the Encore series as a compact depth, high power subwoofer line using a 3 inch dual voice coil, a shaped magnetic gap with flux stabilization rings, forced air motor cooling, and a cast aluminum frame. The sheet lists 1000 W continuous power, 19.1 mm one way xmax (70 percent BL), a 4.9 inch mounting depth for the 12 inch, and a sealed alignment recommendation around 0.8 ft³; infinite baffle use is marked as approved. (Published sheet for Encore 4412.)

Our suggested use case

Based on this sample and these measurements, small sealed enclosures are appropriate. The manufacturer’s 0.8 ft³ guidance computes to about 0.700 Qtc on this sample, and a 0.77 ft³ size lands at approximately 0.707 Qtc per the project’s standard method. Distortion above 40 Hz remains comparatively low at modest drive, with the main rise concentrated below that band as excursion increases. With BL as the earliest standardized limit and inductance behavior remaining stable well past the operating region, sealed use around the 0.7 Qtc with the recommended 0.8 ft³ enclosure is straightforward.

Testing and linearity limits vs. what is advertised

What it took to reach our high-level sweep limit, and how that compares to the published specs.

High-level sweep rule: Set just under the BL 70 percent point from LSI

High-level sweep limit for this sample: 20 volts

Approximate electrical power at that limit at 20Hz: 200 watts. Real power varies with frequency and impedance. volts

Rated power (published): 1000 watts

Power used to hit the standardized limits in free air, relative to their xmax rating free air: ~35 percent. Hits 19.1 mm in free air with 345 watts of power.

Claimed Xmax vs. measured at BL 70%: 19.11 mm, ≈100.1 percent of the manufacturer’s claim of 19.1 mm.

Xmax @ 50% CMS: > 19.24 mm, > 100.7 percent of the manufacturer’s claim of 19.1 mm.

Xmax @ 17% Le: > 19.24 mm, > 100.7 percent of the manufacturer’s claim of 19.1 mm.

Manufacturer suggested sealed enclosure size (and its resulting QTC): Claimed 0.8 cubic feet nets a QTC of 0.700

Required sealed enclosure for 0.707 QTC: 0.77 ft³

Xmax @ 50% CMS: > 19.24 mm, > 100.7 percent of the manufacturer’s claim of 19.1 mm.

Overall performance snapshot

This is our subjective interpretation of the objective data. How we derive these scores can be found on the home page of the testing section.

Distortion & frequency response - TRF measurements

Method recap: Method recap: Nearfield mic positioned at 1/10 cone diameter plus 2 inches, on axis. Response measured to 1 kHz and THD to 500 Hz. 1/6 octave smoothing. Two drive levels, 1 V baseline and a high level set at 20 V per the under‑BL‑70 rule derived from LSI for this unit. In this sample at that drive level the unit reached about 14.5 mm of excursion at 20 Hz in free air, below the accepted standard of 70 percent of BL.

At 1 volt - baseline

Distortion trends upward into the lowest octave, reaching just past the 10 percent plot ceiling at 20 Hz with dominant H3 distortion below roughly 25 Hz; H2 distortion also features a pretty high spike centered around 27 Hz. From about 40 to 80 Hz, THD falls 1 percent range and remains comparatively steady. No narrow, level invariant spikes are evident between 30 and 120 Hz on this sweep.

At high level voltage (20 volts)

Distortion rises broadly with drive. H3 distortion remains most evident below ≈25 Hz, while H2 distortion becomes dominant from approximately 30 to 150 Hz, where THD climbs into averaging around 7 percent. No persistent, level‑invariant spikes are visible within 20 to 120 Hz at this level. There is a dip in the distortion around the 30hz range, possibly indicating some flex or modes in the cone.

Delta - 1 volt distortion vs. high level distortion

Compared with the 1 V baseline, the 20 V sweep shows higher THD across essentially the entire 20 to 120 Hz band, with the largest relative increase from about 30 Hz through the low‑midbass where the baseline sat near 1 percent, and the high‑level trace jumps up and averages around 7 percent. H3 distortion is still dominant below ≈25 Hz, though only slightly, while H2 distortion becomes dominant from roughly 30 Hz up through the midbass at high level. What is interesting here is the narrow H2 distortion spike centered near 27 Hz at 1 V flips to a dip in the 20 V measurement; this level‑dependent inversion may be attributed to a cone or dust cap structural mode excited at higher stroke and is most likely not tied to BL, CMS, or Le non-linearities on this sample. The broader rise in even‑order distortion with level aligns with the slight outward CMS asymmetry seen in LSI, while the limited odd‑order change is consistent with the low and stable Le(x) and Le(i).

What this means in practice

In this sample and under these test conditions, clean output is straightforward above about 40 Hz at most levels, with distortion accumulating first as content extends toward 20 to 30 Hz. As output is increased, the dominant addition is H2 distortion in the 35 to 100 Hz band, with H3 distortion most evident below roughly 25 Hz. Because BL is the earliest standardized limit and Le variation stays within tolerance beyond the evaluation window, the practical clean one‑way limit for this unit is set by BL rather than by suspension or inductance.

Motor & suspension linearity - LSI measurements

Method recap: Klippel LSI large-signal identification for this unit, cold and used for enclosure computations. Standard thresholds in this project are BL 70 percent, CMS 50 percent, and a 17 percent inductance variance criterion. Commentary below ties the large-signal behavior to the acoustic results.

Bl(x)

Bl(x) shows how much motor force a speaker produces as the voice coil moves, B is magnetic field strength and L is the wire length in that field. A high, wide, symmetrical BL curve means linear control and low distortion, a steep or uneven drop means earlier output limits and rising distortion, which is why BL(x) is often the most telling single Klippel LSI indicator of real performance.

Bl(x) window and shape

BL 70 percent is 19.11 mm one way. The BL curve shows a broad, gently rolling shelf with a gradual fall‑off toward the limits, indicating force remains well controlled through the main operating region. This correlates with the absence of pronounced even‑order anomalies tied to BL in the high‑level TRF run.

Bl(x) symmetry

Near‑limit symmetry is effectively centered with xsym ≈ 0.09 mm and the engineer note calling out “perfect BL symmetry.” This centered behavior helps keep H2 distortion down.

Cms(x)

Cms(x) is suspension compliance versus displacement, the inverse of stiffness. When the curve is broad and symmetrical, motion is linear and distortion stays low. Early roll off or offset indicates progressive stiffening or mis-centering, which adds mechanical distortion and caps clean excursion.

Cms(x) window and shape

CMS 50 percent was not reached within the ±19.24 mm window, which is favorable for mechanical headroom. The curve shows progressive stiffening only near the extremes.

Cms(x) symmetry

Centering is good over most of the range with some outward bias noted by the test engineer. That small asymmetry is consistent with the presence of H2 distortion as level rises in the 30 to 70 Hz band.

Inductance - Le(x) and Le(i)

Le(x) and Le(i) measure how a subwoofer’s voice coil inductance changes with position and current. These curves show how stable the motor’s magnetic field is under real movement and drive conditions. When inductance varies heavily, it causes distortion, uneven response, and a loss of upper-band clarity, which is why Le(x) and Le(i) are critical for evaluating how clean and consistent a motor’s behavior really is.

Level and shape

Le at rest is ≈0.79 mH on this sample, and while there is some variance on inductance over stroke, the 17 percent Le variance threshold is beyond ±19.24 mm one way, occurring later than BL and CMS in this evaluation window.

Current dependence

Le(i) is very stable across the tested current span.

Qts(x)

Qts(x) is the driver’s total damping versus excursion, combining electrical and mechanical losses. Stable, symmetrical Qts(x) means consistent control, while large variation or asymmetry signals uneven damping that can shift response, raise distortion, and cause compression.

Qts stability

Qts at center is about 0.36 cold and ≈0.40 warm. Qts drifts upward with stroke, especially at larger outward excursions, indicating gradually reduced damping as excursion increases; the trend is not strongly asymmetric near center. This is most likely caused by the asymmetry of the suspension and the two are most likely the cause of the relatively high H2 distortion.

LSI takeaway

The earliest limiting mechanism on this sample is BL, with the 70 percent limit at 19.11 mm one way. The BL shelf is broad and essentially centered at the operating limit, which helps contain BL‑related even‑order distortion. CMS 50 percent was not reached within the ±19.24 mm evaluation window and shows only slight outward asymmetry, consistent with the modest H2 distortion growth at higher drive. Inductance is low and stable; Le(x) and Le(i) do not impose an earlier limit and align with the restrained H3 distortion increase at the very bottom. Qts increases with stroke, suggesting some reduction in control at the extremes that can accompany higher drive levels.

Enclosure alignment calculations

Manufacturer sealed enclosured recommendations and the resulting QTC: 0.8 ft³ sealed nets a Qtc of 0.700 on this sample.

Sealed volume required for 0.707 QTC on this sample: 0.77 ft³

Applicable for infinite baffle? Manufacturer lists “Free Air” approval; measured Qts is ≈0.36 cold on this sample. I personally wouldn't use it for infinite baffle due to this. It excels better as a small sealed enclosure subwoofer.

T/S parameters