What do dB(A), B(A) and plain dB mean on a printer spec?
Three kinds of number: sound pressure in dB(A), sound power in bels written B(A), and a plain dB that names neither, which Brother's product pages and Lexmark's brochure print.
| Number | What it describes | Who prints it |
|---|
| dB(A) | Sound pressure at one spot near the printer | Xerox, Epson, Canon, Brother's user guides |
| B(A) | Sound power, the total acoustic energy emitted | HP, Epson, Brother's user guides; Canon writes it in dB |
| Plain dB | Not stated | Brother product pages, Lexmark |
Sound pressure is the level a microphone records at one spot. Only Xerox says the spot is one metre away, and it is the number closest to what you hear at a desk. Sound power does not depend on where you stand. HP publishes it on its North America datasheets and adds pressure on some of its other sheets, while Epson and Brother publish both. A 6.1 B(A) machine is quieter than a 6.8 B(A) machine, but neither figure is a dB(A) you can hold up against Epson's 48.
Brother's product pages print a bare pair
"Machine Noise" on a Brother product page reads like "30dB / 49dB". The user guides for the same models label those numbers: the HL-L2460DW guide prints "LpAm = 49 dB (A)" for printing and cites "the method described in ISO 7779". That makes a Brother product page figure A-weighted sound pressure, with no distance stated.
On the colour models the guides attach ISO 7779 to the sound power rows only. The "40 dB" ready figure on those product pages is the number Brother's guide gives "If fan motor is functioning"; by default it lists ready as "Inaudible". Every Brother laser and its guide figures are on our Brother printer decibel page.
Lexmark publishes "53 dBA (Print)" with no quantity named, which leaves it a Lexmark-only number. For the two quantities themselves, see sound power vs sound pressure.
The working rule here is simple. Pressure goes beside pressure, power beside power, and an unlabelled figure beside its own maker's.
On printing sound pressure, the ET-4950 in colour and the HL-L3300CDW, both at 46 dB(A). Quiet Mode takes the Brother to 43 dB(A), lower than any full speed figure we found.
On sound power at full speed the ET-4950 leads at 6.0 B(A) in colour, then the HL-L3300CDW at 6.10 in colour and HP's MFP 4301fdw at 6.1, with the WF-4830 and the Color LaserJet Pro 3201dw behind at 6.2.
Those three lowest makers state three different test bases: Epson none, Brother ISO 7779 and HP a footnoted print speed. A tenth of a bel between them is too small to rank. Every HP figure, 6.0 B(A) at the low end and 7.0 at the top, is set out on our HP printer decibel page.
Xerox publishes the fullest disclosure
The B230 sheet begins: "The following measurements were made in accordance with ISO 7779 and reported in conformance with ISO 9296." It then gives "1-meter Average Sound Pressure, dBA" for three states, 53 printing one-sided, 50 two-sided and 16 ready.
A named standard, a named reporting standard, a distance, three operating conditions. No other maker here publishes all four. Brother's laser guides come closest, with ISO 7779, printing, Quiet Mode and ready rows and both quantities, but no distance, and Canon cites ISO 7779 and gives simplex and duplex separately, which still leaves the microphone's position to guesswork. HP footnotes its test configuration, "simplex printing, A4 paper at an average of 27ppm" on the M234dw, which tells you the speed but not the standard.
On the number alone, the B230 is not the quietest printer here. Its number is the one that means the most.
Canon writes sound power in dB
Move the decimal point and it reads as bels. The MF275dw's sheet gives "Sound Power: Active: 69.3 dB or less", which beside HP's "6.2 B(A)" looks like a machine from another class. It is 6.93 B, a little above HP's 6.8 B(A) OfficeJet and well within the range here.
Canon deserves credit for publishing both. Its figures are recorded as published, with the conversion noted, because a reader scanning a spec table would otherwise draw the wrong conclusion.
How loud is a printer on standby?
Only a few makers say. Xerox gives 16 dBA in ready, Brother 30 dB(A) for its mono MFC-L2820DW, and Canon and Brother's colour lasers "Inaudible".
The HL-L2460DW guide gives ready as "Up to 30 dB (A)", a ceiling, which keeps it out of any ranking. Brother's colour guides add that the cooling fan, when it runs, brings ready to 40 dB(A). HP and Epson publish no ready figure at all.
A home office printer spends almost all its time waiting, so if it shares a room with you, the ready figure describes most of your day and the printing figure only the few minutes it spends on a job. Ask for both.
Our paper shredder guide finds the opposite problem: the one maker that labels its figure measured the shredder idle.
Quiet Mode and distance go missing
Every maker but Brother leaves out a Quiet Mode figure, and even Brother leaves out what Quiet Mode costs in print speed.
Quiet Mode
Brother's laser guides give Quiet Mode rows: "LpAm = 43 dB (A)" on the colour HL-L3300CDW, and 44 dB(A) on the mono HL-L2460DW and MFC-L2820DW, with sound power of 5.81, 6.06 and 6.12 B(A). On the HL-L2460DW the setting is off from the factory, and Brother says only that "the print speed becomes slower".
Canon lists "Quiet Mode: Available" for the PIXMA G3270, and HP lists "quiet mode" among the 4301fdw's print features. Neither gives a number. 3D printer makers leave the same question unanswered, as our 3D printer guide found.
Distance
Only Xerox says where the microphone stood. Brother, Epson, HP and Canon print sound pressure with no distance, so two makers' dB(A) figures may not come from the same range.
