The Marshall Monitor II ANC is 32Ω with a sensitivity of 96.0 dB/mW, which is 110.9 dB/V. To reach 100 dB SPL — genuinely loud, louder than most people listen — it needs 2.5 mW, or 0.28 V across the drivers.
That puts it in the easy category. A phone, a laptop headphone jack or the cheapest USB dongle will drive it to painful levels. Of the 280 sources in the database, 270 have at least 10 dB of headroom and another 10 have enough. The cheapest portable source that does the job is the Apple USB-C dongle (US) at $9.
Sensitivity here is in dB per milliwatt. Why the unit matters.
Marshall does something unusual: it publishes 96 dB at 179 mV @ 1 kHz, an SPL at one specific drive voltage rather than per milliwatt or per volt. That is convertible — at 32Ω that voltage works out to a known power — and the 96.0 dB/mW above is the result. It is a real figure, just stated in a way nothing else in this database uses.
Source: marshall.com. How this data was built.
| As it is labelled | As printed | Tolerance | Standard |
|---|---|---|---|
| Frequency range | 20-20,000 Hz | not printed | not printed |
Marshall prints 20-20,000 Hz for the Marshall Monitor II ANC, under the heading “Frequency range”. Source: marshall.com.
No tolerance is printed with it, so “20-20,000 Hz” says nothing about how loud this headphone actually is at 20 Hz.
Only what the maker printed; maker by maker.
| Level | What it is | Power | Voltage | Current |
|---|---|---|---|---|
| 85 dB SPL | quiet background listening | 0.08 mW | 50 mV | 1.6 mA |
| 95 dB SPL | normal listening | 0.79 mW | 0.16 V | 5.0 mA |
| 100 dB SPL | loud listening | 2.5 mW | 0.28 V | 8.9 mA |
| 105 dB SPL | very loud | 7.9 mW | 0.50 V | 15.8 mA |
| 110 dB SPL | peaks on dynamic music | 25 mW | 0.90 V | 28.0 mA |
Most people listen between 75 and 85 dB; the 100 dB row leaves room for peaks.
The 15 cheapest of the 280 sources here that reach 100 dB SPL into 32Ω with at least 10 dB of headroom and no known hiss or output-impedance problem with these headphones. All 280 sources, judged for these headphones.
| Source | Type | Price | Power into 32Ω | Headroom | Verdict |
|---|---|---|---|---|---|
| JadeAudio JA11 | USB dongle | $20 | 30 mW | +11 dB | Comfortable |
| FiiO SnowSky Tiny A | USB dongle | $22 | 34 mW | +11 dB | Comfortable |
| FiiO SnowSky Tiny B | USB dongle | $22 | 34 mW | +11 dB | Comfortable |
| FiiO KA11 | USB dongle | $29 | 200 mW | +19 dB | Comfortable |
| Tanchjim Stargate II | USB dongle | $40 | 75 mW | +15 dB | Comfortable |
| ddHiFi TC35AL | USB dongle | $46 | 210 mW | +19 dB | Comfortable |
| ddHiFi TC35Air | USB dongle | $46 | 210 mW | +19 dB | Comfortable |
| Fosi Audio N3 | Bluetooth receiver | $50 | 138 mW | +17 dB | Comfortable |
| Hidizs SD2 | USB dongle | $50 | 70 mW | +14 dB | Comfortable |
| FiiO BTR13 | Bluetooth receiver | $59 | 100 mW | +16 dB | Comfortable |
| iFi GO link | USB dongle | $59 | 70 mW | +14 dB | Comfortable |
| Kiwi Ears Allegro Pro | USB dongle | $60 | 68 mW | +14 dB | Comfortable |
| ddHiFi TC35Pro (Mountain2) | USB dongle | $66 | 65 mW | +14 dB | Comfortable |
| iBasso DC03 Pro | USB dongle | $69 | 98 mW | +16 dB | Comfortable |
| DUNU DTC 480 | USB dongle | $70 | 65 mW | +14 dB | Comfortable |
Hiss. At 110.9 dB/V these are sensitive enough to reveal a source's own noise floor. The noisiest source in the database, the Schiit Mjolnir 3, would put its hiss at roughly 19 dB SPL in these headphones — clearly audible in quiet passages. Check your own source.
Output impedance. At 32Ω these want a source output impedance below 4.00Ω to satisfy the one-eighth rule; 35 of the 192 sources that publish one miss it. Check yours here.
32Ω · 111.1 dB/mW · Easy
See requirements →32Ω · 96.0 dB · Easy
See requirements →32Ω · 96.0 dB · Easy
See requirements →32Ω · 96.0 dB · Easy
See requirements →32Ω · 96.0 dB · Easy
See requirements →32Ω · 96.0 dB · Easy
See requirements →Compared with its stablemates: vs Major V.