What the datasheets actually say

«Sensitivity 99 dB»

The English page prints the figure with no unit. Audio-Technica's own Japanese sheet for the same product writes «出力音圧レベル 99dB/mW» — per milliwatt. Read instead as dB/V, the required voltage for a 110 dB peak jumps from 0.692 V to 3.548 V, and the verdict flips: a UA Volt 2 falls 2.4 dB short, a Vocaster 6.7 dB short, and only a desktop DAC passes. The widespread advice that the M50x «needs an amp» traces back to that missing unit, not to the headphones.

«Nominal SPL 96 dB»

beyerdynamic prints this one figure on the shared DT 770 PRO sheet, and it stands for all three impedance versions — 32, 80 and 250 Ω — which have different voice coils and are, for every practical purpose, three different headphones. The sheet also omits the unit; the sibling PRO X pages spell it out as «100 dB SPL (1mW/500Hz)», which is why we read this one as dB/mW too. Both choices matter: read as dB/V instead, the three versions look identical, and the 8.9 dB spread that decides which one your interface can drive disappears.

«Nominal sound pressure level: 96 dB»

No reference unit is printed. beyerdynamic names it on the PRO X pages — «100 dB SPL (1mW/500Hz)» — so we read this as dB/mW; read as dB/V it would mean about 81 dB/mW, which no 48 Ω headphone of this class measures. The same 96 dB also appears on the closed MMX 300 PRO page, so the figure does not distinguish the open model from the closed one.

«Nominal sound pressure level: 96 dB»

beyerdynamic prints 96 dB with no unit here, on the open MMX 330 PRO, and on the DT 770 PRO sheet that covers three different impedance versions. One figure standing for a closed 48 Ω gaming headset and an open one of the same impedance is possible only if both use the same transducer; nothing on either page says so. We read it as dB/mW because beyerdynamic spells the unit out on the PRO X pages — «(1mW/500Hz)» — and we note here that the same number appears on neighbouring products, so it cannot be used to tell them apart.

«Nominal SPL 96 dB»

beyerdynamic prints this one figure on the shared DT 770 PRO sheet, and it stands for all three impedance versions — 32, 80 and 250 Ω — which have different voice coils and are, for every practical purpose, three different headphones. The sheet also omits the unit; the sibling PRO X pages spell it out as «100 dB SPL (1mW/500Hz)», which is why we read this one as dB/mW too. Both choices matter: read as dB/V instead, the three versions look identical, and the 8.9 dB spread that decides which one your interface can drive disappears.

«Nominal SPL 96 dB»

beyerdynamic prints this one figure on the shared DT 770 PRO sheet, and it stands for all three impedance versions — 32, 80 and 250 Ω — which have different voice coils and are, for every practical purpose, three different headphones. The sheet also omits the unit; the sibling PRO X pages spell it out as «100 dB SPL (1mW/500Hz)», which is why we read this one as dB/mW too. Both choices matter: read as dB/V instead, the three versions look identical, and the 8.9 dB spread that decides which one your interface can drive disappears.

«Impedance: 32k Ohms @ 1 kHz»

Third page in Corsair's HS line to carry the kilohm figure, which makes it a template rather than a typo on one product. The value that describes a 50 mm dynamic driver is 32 Ω; that is what we store, and what Corsair itself prints on the VIRTUOSO pages. Recorded here with the date so the claim survives a silent edit.

«Impedance: 32k Ohms @ 1 kHz»

The same kilohm figure that appears on the HS65 Surround and HS55 Surround V2 pages. Taken literally it says the headset presents 32 000 Ω to the source; a 50 mm dynamic driver presents about 32 Ω, which is what Corsair's own VIRTUOSO pages print without the «k». We record 32 Ω and keep the printed line here so the discrepancy stays checkable if the page is quietly corrected later.

«Impedance: 32 Ohms @ 2.5 kHz»

Headphone impedance is conventionally quoted at 1 kHz; Corsair quotes this one at 2.5 kHz, and prints «32 Ohms @ 1 kHz» on its HS pages. For a dynamic driver the impedance curve is not flat — it peaks at the bass resonance, typically around 60–150 Hz, where it can be several times the nominal value. A figure taken at 2.5 kHz sits on the flat part of the curve and therefore says the least about the region where a high-output-impedance source actually changes the tonal balance.

«Impedance: 32k Ohms @ 1 kHz»

Read literally, 32k Ohms is 32 000 Ω — a value no 50 mm dynamic headphone driver has ever had, and one that would make the headset unusable from any consumer source. Corsair prints the same «32k Ohms @ 1 kHz» on the HS55 Stereo and HS55 Surround V2 pages, while its own VIRTUOSO pages print a plain «32 Ohms». We store 32 Ω. This matters because a catalogue that copies the number as printed would answer «no source can drive this» to a headset that any phone drives.

«Headphone Sensitivity: 114dB (+/-3dB)»

No reference is given, and unlike Razer or HyperX, Corsair names none on any of its headset pages. Read as dB/mW, 114 dB would put a 50 mm driver 14 dB above every labelled competitor of the same size; read as dB/V it equals about 99 dB/mW, which is exactly the peer cluster. We store it as dB/V for that reason and flag it here rather than hide the choice. At 32 Ω the verdict is «any source drives it» under both readings, so the risk of the ambiguity is small here — but it would not be for a 250 Ω headphone.

«Headphone Sensitivity: 116dB (+/-3dB)»

Corsair gives no reference on any headset page, so the number alone cannot be used. Read as dB/V it is about 101 dB/mW — normal for an open 50 mm driver; read as dB/mW it would be the most sensitive headphone in this catalogue by a wide margin. We store dB/V. The gap between the two readings is roughly 15 dB at 32 Ω, which is the difference between «needs 0.03 V» and «needs 0.2 V» for the same loudness.

«Impedance: 45 Ohms @ 1kHz / Sensitivity: 98 dB @ 1kHz, 1mW»

The ER4SR page carries the identical pair of figures — 45 Ohms and 98 dB @ 1 kHz, 1 mW. ER4SR is the studio-reference tuning and ER4XR the extended-bass one; Etymotic states the difference is in the acoustic response, not the electrical load. That may well be true, but it means these two numbers cannot tell you which model you are looking at, and the same pattern repeats one tier down with the ER2SE and ER2XR.

«Impedance: 15 Ohms @ 1kHz / Sensitivity: 96 dB @ 1kHz, 1mW»

Etymotic prints exactly these two figures — 15 Ohms and 96 dB @ 1 kHz, 1 mW — on both the ER2XR and the ER2SE pages. The two models are sold as different products: XR is the extended-bass tuning, SE the flat one. If the numbers were measured rather than copied, a bass shelf of several decibels would be visible somewhere in them. Either the pair really is electrically identical and differs only in an acoustic damper, or one page was filled in from the other. We record the figure as published, on both, and note that it cannot distinguish the two.

«SPL 1mW: 98»

Grado is the only manufacturer in this catalogue that labels the scale inside the specification row itself. That label is worth 14.2 dB. Taken as published — per milliwatt — a DragonFly Cobalt reaches 118.6 dB on these, comfortably above a 110 dB peak. Read the same 98 as dB/V and the identical chain yields 104.4 dB, i.e. too quiet. This is why «Grados need an amp» and «Grados run off anything» coexist in the same forum thread: two readings of one number.

«Sensitivity: 103 dB SPL»

Koss writes «101 dB SPL/1mW» on the Porta Pro and KSC75 pages and drops the «/1mW» here and on the KPH30i. Since the house convention is explicit elsewhere, we read this as 103 dB/mW. The alternative reading, dB/V, would make it about 88 dB/mW — implausibly low for a 35 Ω open driver and inconsistent with the rest of the catalogue. Same figure appears on the closed GMR-540-A-ISO page.

«Impedance: 35 Ohms — Sensitivity: 103 dB SPL — Frequency Response: 15-22,000 Hz»

Every electrical and acoustic figure on this page is identical to the open GMR-545-A-AIR: 35 Ω, 103 dB SPL, 15–22 000 Hz. An open and a closed enclosure cannot measure the same frequency response at the low end, so at least one of the two sheets describes the driver rather than the finished headphone. Treat the numbers as a driver specification shared by both products, not as a measurement of either.

«Sensitivity: 101 dB SPL»

Koss prints «101 dB SPL/1mW» for the Porta Pro and the KSC75 and the same value without the «/1mW» here. Because it is the identical number from the same maker on a headphone of the same impedance, we read it as dB/mW. This is a case where the omission is harmless — but it shows that even a manufacturer with a clear convention drops the unit on some pages, so the unit can never be assumed from the brand alone.

«Sensitivity: 123dB/Nrms (@1KHz)»

There is no unit called «Nrms». Every other Moondrop specification sheet — Aria, Aria 2, Chu, Chu II, LAN, Blessing 3 — prints «dB/Vrms», so this is almost certainly a typing slip for volts, and we record it as 123 dB/V. The alternative reading matters: taken as dB/mW, the same number would make KATO about 15 dB more efficient than it is, and every calculation of «will my source drive it» would be wrong in the direction that flatters the earphone. We store what is printed and say plainly that the printed unit does not exist.

«Impedance: 32 Ω @ 1 kHz — Sensitivity: 96 dBSPL/mW@1 KHz by HATS»

The 2022 Barracuda X carries exactly the same electrical figures as the 2021 model — 32 Ω, 96 dB SPL/mW by HATS — while the driver line changes from «Razer TriForce 40 mm Drivers» to «Customized Dynamic 40 mm Driver». Either the transducer is the same part under a new name, or one of the two sheets was copied. We record the numbers as printed for both, but they are one measurement, not two, and nothing in them distinguishes the generations.

«Sensitivity: 96dBSPL/mW@1 kHz by HATS»

«by HATS» means the figure was taken on a head-and-torso simulator — an artificial head with ear canals — not on the flat-plate or IEC 60318-1 coupler that most headphone datasheets use. The two methods differ by several decibels in a way that depends on the coupling, so this number is not directly comparable with a Sennheiser or beyerdynamic figure even though both are written in dB SPL/mW. It is still the right number for our purpose: it is the manufacturer's own, and the error it carries is small next to the 15 dB gap between dB/mW and dB/V.

«Sensitivity (@1 kHz): 118 ± 3 dB»

No reference is printed. Read as dB/mW this would be one of the most efficient headphones ever measured — 18 dB above Razer's own BlackShark V2, whose sheet does name the unit (100 dB SPL/mW). Read as dB/V it lands near 103 dB/mW, an ordinary figure for a 50 mm dynamic driver, and that is the reading we store. The same page also prints «Input/Output power: 30 mW (Max)», so the two numbers together, not the sensitivity alone, decide what you may safely plug in.

«Sensitivity (@1 kHz): 109dB»

Sensitivity in decibels means nothing until you know the reference: per milliwatt or per volt. Razer names it where it chooses to — the BlackShark V2 sheet says «100 dB SPL/mW, 1 kHz», the Kaira X «96 dBSPL/mW» — and omits it here. Read as dB/mW, this 50 mm driver would be 9 dB more efficient than Razer's own esports flagship; read as dB/V it works out near 94 dB/mW, which is exactly where Razer's labelled models sit, so that is how we store it. The two readings differ by a factor of about five in the voltage your source has to deliver.

«Impedance (without cable / with cable) 16 Ohm / 18 Ohm»

Almost no manufacturer separates these two, and Sennheiser is right to: the source is connected to the cable, not to the transducer, so 18 Ω is the load that matters and 16 Ω is a property of the driver alone. The two ohms of difference are the cable's series resistance. We store 18 Ω. The reason to record the claim is the opposite case — when another brand prints a single low number, you now have no way to tell which of the two it is, and the difference lands exactly where low-impedance in-ears are already sensitive to source output impedance.

«Sensitivity at 1 kHz — 106 dB SPL/MW»

«MW» is megawatt in SI notation; the intended unit is «mW», milliwatt. Shure prints the lower-case form in the SE215 and SE846 guides on the same server and the upper-case form in all three Aonic guides. We record milliwatts.

«Sensitivity at 1 kHz — 108 dB SPL/MW»

«MW» is the SI symbol for megawatt. Read literally, Shure would be quoting the output at one million watts into a 26 Ω armature. It is a capitalisation slip for «mW», milliwatt — and Shure's own documents prove it: the SE215 and SE846 guides on the same server print «107 dB SPL/mW» and «114 dB SPL/mW» in lower case. All three Aonic guides — 3, 4 and 5 — carry the upper-case form. We record milliwatts. The reason this is worth writing down is that a reader comparing an Aonic sheet against an SE sheet has no way to know, from the documents alone, whether two different quantities are being quoted.

«Sensitivity at 1 kHz — 119 dB SPL/MW»

«MW» is megawatt in SI notation; the intended unit is «mW», milliwatt. The same upper-case form appears in the Aonic 3 and Aonic 4 guides, while the SE215 and SE846 guides on the same server use the correct lower case. We record milliwatts.

«Sensitivity: 105±3dB @1kHz 0.179V»

This looks like a voltage sensitivity and is not one. 0.179 V across the stated 32 Ω is exactly one milliwatt — the square root of 0.001 × 32 is 0.1789 — so the figure is an ordinary dB/mW rating written in volts. Anyone who takes it at face value as dB/V will read the T3 Plus as roughly 15 dB less efficient than it is, and conclude it needs an amplifier it does not need. TinHiFi uses the same 0.179 V reference for the distortion figure on the same sheet, which confirms the reading.

«Microphone Preamps — Input impedance: 2.5kΩ / Maximum input level: +9dBu / Gain range: 56dB / Equivalent Input Noise [EIN]: -129dB typical [A-weighted]»

Arturia publishes one specification table for the whole MiniFuse range, and the MiniFuse 1 and MiniFuse 4 pages carry it byte for byte: same 56 dB gain, same -129 dB EIN, same +9 dBu maximum input, same headphone figures (+11.4 dBu, 10 ohm, 137 mW into 33 ohm). The MiniFuse 1 is bus-powered with one preamp and one headphone jack; the MiniFuse 4 has an external supply, four preamps and two headphone jacks. One headphone amplifier figure cannot describe both a single output and a pair driven together, so at least one of the two pages is describing hardware it does not have.

«Microphone Preamps — Input impedance: 2.5kΩ / Maximum input level: +9dBu / Gain range: 56dB / Equivalent Input Noise [EIN]: -129dB typical [A-weighted]»

Arturia publishes one specification table for the whole MiniFuse range, and the MiniFuse 1 and MiniFuse 4 pages carry it byte for byte: same 56 dB gain, same -129 dB EIN, same +9 dBu maximum input, same headphone figures (+11.4 dBu, 10 ohm, 137 mW into 33 ohm). The MiniFuse 1 is bus-powered with one preamp and one headphone jack; the MiniFuse 4 has an external supply, four preamps and two headphone jacks. One headphone amplifier figure cannot describe both a single output and a pair driven together, so at least one of the two pages is describing hardware it does not have.

«MAX LEVEL INTO 30R: 2.63V Peak, 1.87V RMS, 232mW»

1.87 V RMS across 30 ohms is 117 mW, not 232 mW — the printed power is exactly twice what the printed voltage produces. The same doubling holds in the other two rows (3.03 V into 60 ohms is 153 mW, printed 295 mW; 5.6 V into 600 ohms is 52 mW, printed 104 mW), so the power column is the sum of both channels while the voltage column is per channel. Audient's own iD44 sheet is self-consistent in its 30 ohm row, so this is not a house convention. Use the voltage: that is what one earpiece sees.

«MAX LEVEL INTO 60ohms: +14.2dBu 0.001% THD+N Power: 54mW / MAX LEVEL INTO 600ohms: +14.2dBu 0.001% THD+N Power: 54mW»

The 60 ohm and 600 ohm rows carry identical figures. They cannot both be right: the same +14.2 dBu (3.97 V) into ten times the impedance delivers a tenth of the power, so 60 ohms would give about 263 mW and 600 ohms about 26 mW — neither is 54 mW. The 30 ohm row above them is arithmetically sound (2.51 V into 30 ohms is 210 mW, as printed), which is why we take our figure from that row.

«Max Level Into 30ohms: +8.5 dBu, 0.00094% THD+N, 1.66Vpk Power: 86mW»

This one row states the same measurement three ways and no two agree. +8.5 dBu is 2.06 V RMS, which would be 2.92 V peak, not 1.66 V peak; and 1.66 V peak is 1.17 V RMS, which into 30 ohms is 46 mW, while the row says 86 mW — again close to twice, the same channel-summing seen on the iD24 sheet. The 60 and 600 ohm rows behave the same way. Because we cannot tell which of the three numbers is the measured one, we leave the headphone voltage empty rather than pick a flattering reading.

«Gain Range 69dB / Noise EIN (A-Weighted) -127dBu / Maximum Input Level (at minimum gain) 16dBu»

The three rackable 4th Gen Scarletts publish the same preamp block: 69 dB gain range, -127 dBu EIN, +16 dBu maximum input level, and the same headphone figures (5 dBu into 33 Ohm, 11 dBu into 300 Ohm, 11 Ohm output impedance). That is consistent with one preamp and one headphone amp design across the range, and it means a choice between them is a choice of I/O count and power, not of gain or noise.

«Noise EIN -128 dB (A-weighted)»

The 3rd Gen guides print EIN as "-128 dB (A-weighted)" with no reference — dB alone is a ratio, not a level, so strictly the number says nothing. Focusrite's own 4th Gen guides write "-127dBu" in the same table position, which is why we read the 3rd Gen figure as dBu too. If it were read as dBV instead it would be 2.2 dB better than printed, which is precisely the size of error that decides whether a quiet ribbon microphone is usable.

«Noise EIN -128 dB (A-weighted)»

The 3rd Gen guides print EIN as "-128 dB (A-weighted)" with no reference — dB alone is a ratio, not a level, so strictly the number says nothing. Focusrite's own 4th Gen guides write "-127dBu" in the same table position, which is why we read the 3rd Gen figure as dBu too. If it were read as dBV instead it would be 2.2 dB better than printed, which is precisely the size of error that decides whether a quiet ribbon microphone is usable.

«Gain Range 69dB / Noise EIN (A-Weighted) -127dBu / Maximum Input Level (at minimum gain) 16dBu»

The three rackable 4th Gen Scarletts publish the same preamp block: 69 dB gain range, -127 dBu EIN, +16 dBu maximum input level, and the same headphone figures (5 dBu into 33 Ohm, 11 dBu into 300 Ohm, 11 Ohm output impedance). That is consistent with one preamp and one headphone amp design across the range, and it means a choice between them is a choice of I/O count and power, not of gain or noise.

«Gain Range 69dB / Noise EIN (A-Weighted) -127dBu / Maximum Input Level (at minimum gain) 16dBu»

The three rackable 4th Gen Scarletts publish the same preamp block: 69 dB gain range, -127 dBu EIN, +16 dBu maximum input level, and the same headphone figures (5 dBu into 33 Ohm, 11 dBu into 300 Ohm, 11 Ohm output impedance). That is consistent with one preamp and one headphone amp design across the range, and it means a choice between them is a choice of I/O count and power, not of gain or noise.

«Equivalent input noise –133 dBV (A-weighted) / Max input level 6 dBV»

Lewitt publishes every level on this page in dBV, while essentially every other interface maker publishes in dBu. The two scales differ by 2.2 dB: 0 dBu is 0.775 V, 0 dBV is 1 V. Placed next to a competitor's dBu figure, a dBV EIN therefore looks 2.2 dB quieter than it is, and a dBV maximum input level looks 2.2 dB smaller than it is. Nothing is being hidden — the unit is printed plainly — but a shopper comparing two spec sheets side by side will get it wrong unless they convert. Our stored numbers are converted: EIN and maximum input level are in dBu.

«Equivalent input noise –129 dBV (A) / Max input level 15.8 dBV»

Lewitt publishes every level on this page in dBV, while essentially every other interface maker publishes in dBu. The two scales differ by 2.2 dB: 0 dBu is 0.775 V, 0 dBV is 1 V. Placed next to a competitor's dBu figure, a dBV EIN therefore looks 2.2 dB quieter than it is, and a dBV maximum input level looks 2.2 dB smaller than it is. Nothing is being hidden — the unit is printed plainly — but a shopper comparing two spec sheets side by side will get it wrong unless they convert. Our stored numbers are converted: EIN and maximum input level are in dBu.

«Polar patterns: Cardioid, Omnidirectional, Figure-of-eight. Open circuit sensitivity: -42 dB (7.9 mV), re 1V at 1 Pa»

One open-circuit sensitivity is printed for a microphone with three switchable polar patterns, and the datasheet does not say which pattern it applies to. The same sheet does distinguish conditions elsewhere - 149 dB max SPL, 159 dB with the pad - so the omission is specific to sensitivity. It is not a small point: on a dual-diaphragm capsule the omnidirectional and figure-of-eight settings typically differ from cardioid by two to four decibels, and Neumann publishes 20/28/22 mV/Pa for the three patterns of the U 87 Ai rather than one figure. Treat -42 dB as the cardioid value, expect a few dB of movement when the switch moves, and note that the self-noise figure of 17 dB SPL carries exactly the same ambiguity.

«The AT2020 requires 11V to 52V phantom power for operation.»

This sentence sits in the AT2035 datasheet, under Operation and Maintenance, and names the wrong model — three paragraphs above, the same document says «The microphone requires 11V to 52V». The AT2020's own datasheet says «The AT2020 requires 48V phantom power for operation» and tabulates 48V DC, 2 mA. So two documents from one manufacturer disagree about one microphone, which is why both figures circulate. For the reader it matters: a bus-powered interface that sags below 48 V will quietly cost an AT2020 level, while an AT2035 keeps working down to 11 V.

«Directional Pattern: Omni, wide angle cardioid, cardioid, hypercardioid, figure-8. Sensitivity at 1 kHz into 1 kohm: 11 mV/Pa»

One sensitivity figure is given for five switchable polar patterns, and the table does not say which pattern it was measured in. Sensitivity is not the same in omni as in figure-8: Neumann's own U 87 Ai page states 20/28/22 mV/Pa for omni/cardioid/figure-8, a spread of 2.9 dB across three patterns of one capsule. So the single number here is either the cardioid value or a typical value, and the datasheet does not distinguish. The same page prints one equivalent noise level, 10 dB-A, for all five patterns, where the U 87 Ai page prints three. In practice: plan gain for the pattern you actually use, allow a few dB either way, and treat 11 mV/Pa as a cardioid figure.

«Sensitivity | -38 dBV (12 mV @ 94 dB SPL)»

The two halves of this line disagree. 12 mV/Pa - 94 dB SPL is one pascal - converts to -38.4 dBV, not -38. The 0.4 dB gap is small, but it is not rounding of the precision printed, and it runs the same direction as several other datasheets we have checked: the decibel figure comes out flattering by a fraction. RODE's own other pages convert correctly to a tenth - the Broadcaster page reads '-34.0dB re 1 Volt/Pascal (20.00mV @ 94 dB SPL)', where 20 mV is indeed -33.98 - so the NT5 line is the outlier within one manufacturer. Note the unit too: here RODE writes 'dBV', on the Broadcaster 'dB re 1 Volt/Pascal'. We store -38.4, the conversion of the millivolt figure.

«Sensitivity (mV/Pa) - Cardioid: 29.80, Omnidirectional: 14.80, Bidirectional: 16.80. Sensitivity (dBV/Pa) - Cardioid: -31.00, Omnidirectional: -37.00, Bidirectional: -36.00»

One specification states the same quantity twice, and the two halves do not agree. 29.80 mV/Pa converts to -30.52 dBV/Pa, not -31.00; 14.80 mV/Pa is -36.59, not -37.00; 16.80 mV/Pa is -35.49, not -36.00. The gap is about half a decibel in every pattern and always in the same direction: the dBV column is quieter than the manufacturer's own millivolts. Two decimal places are printed, so this cannot be rounding. On other Shure microphones the same two columns agree exactly - SM86 gives 3.15 mV/Pa and -50.00, Beta 52A gives 0.63 mV/Pa and -64.00 - which is what makes the KSM44A row stand out. We store the conversion of the millivolt figure, -30.5 dBV/Pa, because millivolts per pascal is the quantity that gets measured and the decibel figure is derived from it.

«Type: Dynamic | Polar Pattern: Supercardioid | Frequency Range: 50 Hz - 18 kHz, +/-3 dB | Capsule: 25mm Dynamic Moving Coil | Transformer: TELEFUNKEN Elektroakustik T80 | Sensitivity: 1.54 mV/Pa, +/-1 dB | Output Impedance: 325 Ohm | Maximum SPL (for 1% THD): 135 dB»

The M80 and M81 are sold as two different microphones - different grille, different voicing, different intended sources - yet their published specification tables are identical field for field, including 'Transformer: TELEFUNKEN Elektroakustik T80' on the M81 page, which is the other model's part designation. Either the two microphones genuinely share every measured parameter and differ only in acoustic housing, or one table was copied from the other. Both readings have the same practical consequence: the sensitivity figure cannot be used to choose between them, and for gain planning they must be treated as one microphone at 1.54 mV/Pa, that is -56.3 dBV/Pa.

«Type: Dynamic | Polar Pattern: Supercardioid | Frequency Range: 50 Hz - 18 kHz, +/-3 dB | Capsule: 25mm Dynamic Moving Coil | Transformer: TELEFUNKEN Elektroakustik T80 | Sensitivity: 1.54 mV/Pa, +/-1 dB | Output Impedance: 325 Ohm | Maximum SPL (for 1% THD): 135 dB»

The M80 and M81 are sold as two different microphones - different grille, different voicing, different intended sources - yet their published specification tables are identical field for field, including 'Transformer: TELEFUNKEN Elektroakustik T80' on the M81 page, which is the other model's part designation. Either the two microphones genuinely share every measured parameter and differ only in acoustic housing, or one table was copied from the other. Both readings have the same practical consequence: the sensitivity figure cannot be used to choose between them, and for gain planning they must be treated as one microphone at 1.54 mV/Pa, that is -56.3 dBV/Pa.

«Sensitivity: 10mV/Pa Or -40dB»

'-40dB' is printed with no reference, and the word 'Or' presents the two figures as interchangeable. They are interchangeable only if the reference is one volt: 10 mV/Pa is exactly -40.00 dBV/Pa, so the arithmetic confirms the intent. Against the older 1 V/microbar scale the same microphone would be -60 dB, and a reader comparing this line with a vintage datasheet has no way to tell which scale is meant from the page alone. Two further things are missing from the same line: the load the measurement was made into, and which polar pattern it applies to - the WA-47jr has a dual-backplate K47-style capsule offering cardioid, omni and figure-8, and one sensitivity is given for all three.

«Sensitivity 30 mV / Pa (-31 dBV)»

The two halves of this one row do not agree: 30 mV/Pa is −30.46 dBV, not −31. The 0.54 dB gap shifts the gain this microphone asks of an interface by a whole decibel — 29 dB on the printed figure, 28 dB on the converted one. We record what is printed in dBV and say so here rather than silently picking the friendlier number.

«Sensitivity | 2.0 mV/Pa (-54 dB)»

The parenthesis reads '-54 dB' with no reference stated. A decibel is a ratio and means nothing until you say a ratio to what: -54 dB re 1 V/Pa describes an ordinary dynamic microphone, while -54 dB re 1 V/microbar - the older scale still printed on vintage datasheets - would be 20 dB away and describe a completely different microphone. Here the arithmetic settles it: 2.0 mV/Pa is -53.98 dBV/Pa, so the intended reference is one volt per pascal and the figure is right. The omission still matters, because the same page template is used across sE's whole range, and a reader who compares '-54 dB' against a datasheet quoting the old scale will be off by a factor of ten in voltage.

«Max. SPL Per Pair at 1 m: ≥118 dB»

ADAM quotes the T-series maximum level for a stereo pair, while its A-series pages quote «Max. peak SPL per speaker at 1 m». The difference is about 3 dB and it runs in the flattering direction for the cheaper range: a T8V and an A7V listed at 118 and 105 dB are closer than those numbers imply, because they are not the same measurement. The figure stored in this catalogue is ADAM's own, as printed — per pair.

«Maximum SPL [@ 1m] [dB] 108»

DALI prints a maximum SPL for a passive speaker without naming the drive voltage, the signal, the distortion limit or the duration at which 108 dB was reached. A passive loudspeaker has no maximum level of its own — it reproduces whatever the amplifier sends until thermal or excursion limits stop it, so the figure describes DALI's test conditions rather than the product. We keep it out of the calculable maximum-SPL field, which exists for active monitors where the amplifier is part of the box.

«Sensitivity : 89.5 dB»

The focal.com product page prints the sensitivity with no scale at all: not dB/W/m, not dB at 2.83 V, and no distance. The downloadable product sheet for the same speaker gives «Sensitivity (2.83V/1m) 89.5dB». Because the Vestia N°1 is an 8-ohm nominal design the two readings happen to coincide, so nothing is lost here — but the same page template is used across the Focal range, including models whose nominal load makes the two scales differ by up to 3 dB. Take the figure from the PDF, not the web page.

«Peak SPL ≥110 dB — Maximum peak acoustic output per pair, at 1 m distance with music material.»

Genelec prints three maximum-SPL rows for every monitor, and only one of them is measured on a pair. Read carelessly, the largest number — the per-pair peak — looks like the monitor's capability, and it is the number most often repeated in retail listings. The comparable single-speaker figure on this model is the short-term sine value, 104 dB. The catalogue stores the short-term sine figure for that reason; the per-pair peak is quoted here so that the difference is visible rather than silently corrected.

«Maximum Output 110dB»

KEF prints a maximum output figure for a passive speaker without saying at what drive level, at what distance, or over what bandwidth it was reached. A passive loudspeaker has no maximum output of its own — it has whatever the amplifier feeds it, up to thermal or excursion failure. We therefore do not carry this number as a calculable field; only the sensitivity and the impedance minimum can be used to predict level.

«Wattage: 203 Watts»

The Rokit 7 G4 product page states «Wattage: 203 Watts» in the header block and «Power Output: 145 Watts» in the specifications table lower on the same page. 203 W is the figure KRK publishes for the Rokit 8 G4, whose own page shows 203 in both places — so the header on the 7 appears to carry the 8's number. Neither figure is a level and neither can be used to compare loudness, but the contradiction is a warning about the rest of that page: the 110 dB maximum SPL printed on it has no stated measurement condition either.

«NOMINAL IMPEDANCE 8 Ohms Compatible»

The row is headed «NOMINAL IMPEDANCE» but the value «8 Ohms Compatible» states which amplifier outputs may be used, not what load the speaker presents. No minimum impedance is published anywhere on the sheet, so the document contains no figure at all from which an amplifier's safe-load question can be answered. Wharfedale words the same row the same way — the phrasing is a habit of the category, not a one-off.

«*SPL at 1M, half-space anechoic with 2.83V input, in-room sensitivity»

The footnote defining the 92 dB figure contradicts itself in six words: «half-space anechoic» is a laboratory condition — an anechoic chamber with the speaker flush in a boundary — while «in-room» is the opposite, a live room with reflections. Half-space adds about 3 dB over a free-field measurement, so this 92 dB is not comparable with a manufacturer who quotes free-field, and it is not a prediction of what the speaker does in your room either. When comparing against the KEF, B&W or DALI figures in this catalogue, allow for the boundary gain.

«Sensitivity (2.83V @ 1kHz) 87.9 dB/w/m»

One row states three things that cannot all hold. The drive condition given is 2.83 V; the unit given is dB/W/m; and the distance — the «m» the unit depends on — is replaced by a frequency, 1 kHz. On the 6-ohm load this same page declares, 2.83 V is 1.33 W, so the 2.83 V and the 1 W readings of 87.9 dB differ by about 1.25 dB. We store the number against 2.83 V because that is the only measurement condition the sheet actually names; read as dB/W/m instead, the speaker is about 1.25 dB quieter than we show it.

«Average Impedance: 6 Ohm»

On the 3000i pages Q Acoustics calls the impedance «Average Impedance»; on the 5000-series pages of the same site the corresponding row reads «Nominal impedance». The two terms are not interchangeable: a nominal impedance is a declared load class (IEC 60268-5 ties it to the measured minimum), while an average is a computed mean whose method the sheet does not disclose. Anyone comparing a 3000i against a 5000 is comparing two differently defined numbers printed in the same column position.

«Nominal impedance 8Ω Compatible»

The row is headed «Nominal impedance» but the value is not an impedance — «8Ω Compatible» describes which amplifier output taps the speaker may be connected to. The same page separately prints «Minimum impedance 4.0Ω», and that is the figure an amplifier's output devices and protection circuit actually see. Read literally, the sheet gives a compatibility claim where the nominal load belongs, and the honest load figure sits one row below.