Overview

The Fostex PM-SUBMINI2 is a compact 5-inch active subwoofer intended for desktop studio setups. It uses a sealed enclosure with a 50 W built-in amplifier, variable low-pass crossover (60–150 Hz), a phase switch, and RCA I/O with thru outputs. Manufacturer specs state 40–150 Hz playback bandwidth and an S/N ratio of 80 dB; auto-standby draws ≤0.5 W. The model is listed as discontinued by the manufacturer but remains widely stocked. [1]

Scientific Validity

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From a measurement-first standpoint, the PM-SUBMINI2’s 40–150 Hz rated bandwidth is modest for subwoofer duties, limiting infrasonic and lower-bass extension; S/N 80 dB is serviceable for this category but not exemplary. Third-party distortion/maximum-output data have not been published; therefore this section relies on clearly labeled manufacturer specifications and will be updated if independent data emerge. Overall, performance sits near the border between “problematic” and “transparent” for small rooms where output demands are low. [1]

Technology Level

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The implementation is competent but conventional: a rigid fiberglass cone with a four-layer voice coil in a sealed box, a compact 50 W digital amp, 60–150 Hz variable crossover, and a phase switch. The 0.5 W auto-standby (now toggleable) reflects sensible power management, but there’s no proprietary acoustic or DSP innovation that would set it apart from peers. [1]

Cost-Performance

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Representative street price for the PM-SUBMINI2 is 299 USD. [4] The cheapest equal-or-better alternative we found is the PreSonus Eris Sub8, which provides an 8-inch driver, 50 W RMS/100 W peak amp, wider 30–200 Hz response, lower THD (0.05%), and higher S/N (>95 dB), with comparable I/O and filters. [2] Current market price for the Eris Sub8 is 179.99 USD. [3]
Cost-Performance calculation (cheapest equivalent-or-better ÷ review target): 179.99 ÷ 299 = 0.602 → 0.6.
Conclusion: you can obtain objectively stronger low-frequency capability for ~60% of the PM-SUBMINI2’s price.

Reliability & Support

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Fostex is an established brand with global distribution; documentation and FAQs are maintained, and parts of the PM series have long service lives. That said, the PM-SUBMINI2 is flagged as discontinued on the official page, which may shorten formal support horizons versus still-current competitors. The simple sealed design with few parts is a plus, but warranty specifics vary by region and are not highlighted. [1]

Rationality of Design Philosophy

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Prioritizing a very small sealed cabinet around a 5-inch driver keeps size and placement easy, but it imposes hard limits on extension/output. Given that multiple 8-inch studio subs offer clearly superior published performance at lower prices, the design emphasis here appears to favor ecosystem matching and form factor over measured bass capability per dollar. [1][2][3][4]

Advice

Choose the PM-SUBMINI2 only if you strictly need its tiny footprint or aesthetic match with Fostex PM satellites and are working at modest levels in a nearfield desk setup. Most users will achieve audibly deeper extension and more headroom from compact 8-inch subs like the Eris Sub8 while spending substantially less, retaining standard studio controls and connectivity. [2][3][4]

References

[1] Fostex, “PM-SUBmini2 — Specifications & Support,” https://www.fostex.jp/en/products/pm-submini2/ (accessed 2025-08-26). Key specs: sealed enclosure, 50 W amp, 40–150 Hz, S/N 80 dB, 60–150 Hz crossover, ≤0.5 W standby.
[2] PreSonus, Eris Sub8 Owner’s Manual (PDF), https://www.fmicassets.com/Damroot/Original/10001/OM_2777500105_Sub8_EN.pdf (accessed 2025-08-26). Key specs: 30–200 Hz, THD 0.05%, S/N >95 dB, 50 W RMS/100 W peak, 50–130 Hz LPF.
[3] Swing City Music, “PreSonus Eris Sub8,” https://www.swingcitymusic.com/shop/presonus-eris-sub8/ (accessed 2025-08-26). Price: 179.99 USD.
[4] Vintage King, “Fostex PM-SUB-MINI-2 Powered 5 inch Subwoofer,” https://vintageking.com/fostex-pm-sub-mini-2-powered-5-subwoofer-auto-standby (accessed 2025-08-26). Price: 299.99 USD.

(2025.8.26)