Fs: Natural Oscillation frequency (resonance) of the speaker to the free

QEs: Efficiency loss factor of the outdoor speaker, considering
Only electrical losses.

QMS: Idem (Qes), considering mechanical losses.

QTS: Total speaker quality factor, includes electrical loss plots
and mechanical.

Vas: Equivalent Volume, can be understood as the volume of air that offers
The same resistance to the movement of the cone (acoustic complitance) that the
Suspension or edge.

NO: Speaker yield.

Xmax: Maximum cone excursion in one direction, so that the coil remains
Within the uniform magnetic field of the magnet. This is not the mechanical limit,
If overtaking XMAX will occur distortion in sound due to non-linearity
Of the magnetic field, but this will not damage the speaker.

Vd: Volume of air shifted by the speaker when moving within the limits
of Xmax.

BL: Magnetic flux density in the gap, multiplied by the coil length
traversed by this flow.

Sd: Effective area of the speaker cone.

Re: Coil resistance in direct current, is given in ohms as well as the
impedance, but not equal.

Le: Inductance of the coil measured in mH (milihenries).

Z: Impedance. Resistance of the coil to the passage of alternating current. Varies
Frequency, so this is the smallest assumed value.
(measured in ohms).

PE: Electrical power supported by the speaker coil, given in Watts.

SPL: Sound Pressure level – noise or sound intensity, measured in
Db. It also refers to the efficiency of the speaker, when measured at 1 meter of
Distance, being applied 1Watt.

Vb: Internal Volume of a box, in liters.

FB: Resonance frequency system box + duct. Also known as
Duct tuning frequency.

HR: Resonance frequency of a sealed box system.

F3: Frequency of which the sound intensity falls to the mety of the intensity of
Reference where the intensity falls-3dB.

QTC: Efficiency of a sealed box system, in resonance frequency. 0.71
Is the value that provides the most flat, however, and most common answer is to use
Values between 0.9 and 1 due to the severe reinforcement obtained.

See below values of the approximate diameters of the holes for speakers

8 185
10 232
12 280
15 352
18 420

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