The Beyerdynamic DT 1770 PRO is 250Ω with a sensitivity of 102.0 dB/mW, which is 108.0 dB/V. To reach 100 dB SPL — genuinely loud, louder than most people listen — it needs 0.63 mW, or 0.40 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, 264 have at least 10 dB of headroom and another 16 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.
Beyerdynamic publishes this directly as 102 dBSPL (1mW/500Hz) (1 mW at 500 Hz), per milliwatt, so nothing was converted.
Source: europe.beyerdynamic.com, north-america.beyerdynamic.com. How this data was built.
| As it is labelled | As printed | Tolerance | Standard |
|---|---|---|---|
| Headphone frequency response | 5-40,000Hz | not printed | not printed |
Beyerdynamic prints 5-40,000Hz for the Beyerdynamic DT 1770 PRO, under the heading “Headphone frequency response”. Source: europe.beyerdynamic.com.
No tolerance is printed with it, so “5-40,000Hz” says nothing about how loud this headphone actually is at 5 Hz.
Only what the maker printed; maker by maker.
| Level | What it is | Power | Voltage | Current |
|---|---|---|---|---|
| 85 dB SPL | quiet background listening | 0.02 mW | 71 mV | 0.3 mA |
| 95 dB SPL | normal listening | 0.20 mW | 0.22 V | 0.9 mA |
| 100 dB SPL | loud listening | 0.63 mW | 0.40 V | 1.6 mA |
| 105 dB SPL | very loud | 2.0 mW | 0.71 V | 2.8 mA |
| 110 dB SPL | peaks on dynamic music | 6.3 mW | 1.26 V | 5.0 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 250Ω 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 250Ω | Headroom | Verdict |
|---|---|---|---|---|---|
| FiiO KA11 | USB dongle | $29 | 26 mW | +16 dB | Comfortable |
| Tanchjim Stargate II | USB dongle | $40 | 9.6 mW | +12 dB | Comfortable |
| ddHiFi TC35AL | USB dongle | $46 | 27 mW | +16 dB | Comfortable |
| ddHiFi TC35Air | USB dongle | $46 | 27 mW | +16 dB | Comfortable |
| Fosi Audio N3 | Bluetooth receiver | $50 | 18 mW | +15 dB | Comfortable |
| Hidizs SD2 | USB dongle | $50 | 9.0 mW | +12 dB | Comfortable |
| FiiO BTR13 | Bluetooth receiver | $59 | 12 mW | +13 dB | Comfortable |
| iFi GO link | USB dongle | $59 | 15 mW | +14 dB | Comfortable |
| Kiwi Ears Allegro Pro | USB dongle | $60 | 8.7 mW | +11 dB | Comfortable |
| ddHiFi TC35Pro (Mountain2) | USB dongle | $66 | 8.3 mW | +11 dB | Comfortable |
| iBasso DC03 Pro | USB dongle | $69 | 13 mW | +13 dB | Comfortable |
| DUNU DTC 480 | USB dongle | $70 | 8.3 mW | +11 dB | Comfortable |
| EPZ TP35 Pro | USB dongle | $70 | 14 mW | +14 dB | Comfortable |
| Tanchjim Space | USB dongle | $70 | 16 mW | +14 dB | Comfortable |
| Truthear SHIO | USB dongle | $70 | 16 mW | +14 dB | Comfortable |
Hiss. At 108.0 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 16 dB SPL in these headphones — clearly audible in quiet passages. Check your own source.
Output impedance. At 250Ω these want a source output impedance below 31.25Ω to satisfy the one-eighth rule; 16 of the 192 sources that publish one miss it. Check yours here.
250Ω · 96.0 dB · Moderate
See requirements →250Ω · 96.0 dB · Moderate
See requirements →250Ω · 96.0 dB · Moderate
See requirements →25Ω · 92.0 dB/mW · Easy
See requirements →120Ω · 98.7 dB/mW · Easy
See requirements →65Ω · 96.0 dB/mW · Easy
See requirements →Compared with its stablemates: vs DJ 300 PRO X · vs DT 770 Pro (250Ω) · vs DT 880 Edition (250Ω) · vs DT 880 Edition (600Ω) · vs DT 880 Pro (250Ω) · vs DT 990 Edition (250Ω) · vs DT 990 Pro (250Ω).