While 5 mV is a voltage that can be measured and confirmed, it is not
the whole story because it does not include the impedance. In this case
it can be assumed to be whatever impedance it is that the Jupiter
presents to the microphone. Ten-Tec should know better than to state a
level in dB without at least stating the reference level, and it really
should also state an impedance.
There are many kinds of "Decibels" and if you do not state which kind
you are talking about, you may as well not name a figure. News media
journalists commonly talk about sound pressure levels when referring to
noise from parties/concerts/construction sites, and they typically do
not mention the scale being used, so their data is meaningless.
Journalists almost always get science and engineering details wrong, so
we all sort of accept it as normal. Vendors of electronic equipment,
selling to a (at least slightly) technically savvy market should be held
to higher standards.
In low level audio systems, such as microphones, telephone systems, wire
line data modems, audio mixing and recording a common standard is to use
dBm, which is dB relative to 1 milliwatt, usually into 600 ohms. That is
not always the case though. Other impedances besides 600 ohms are not
unusual. (I would guess that the Jupiter mic input is not 600 ohms) And
there are many other reference levels such as dBV (decibles relative to
one volt) dBTT (dB relative to some standard Test Tone level) and many,
many others.
dB by itself is meaningless as a level measurement, though it can
represent gain or loss, or some other ratio. An amplifier may have a
gain expressed in dB or an attenuator may have a loss in dB (or negative
gain in dB) which is correctly expressed as just dB. In that case we
know the ratio is between the output power and the input power.
DE N6KB
Data taken straight from the Tentec manual.
I would comment that the mike requirements for the Jupiter is 5 mV
or -67dB.
dB relative to what? Decibels are a ratio. Without stating a
reference level decibels are meaningless as a level measurement.
Perhaps you meant dBm, which is decibels relative to 1 milliwatt.
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