Mackie 1620 25. SOLO MODE, 26. LEFT/RIGHT Level Meters, 27. RUDE SOLO Light, WARNING:, “Engineers who fry their ears, ﬁnd themselves with short careers.”

WARNING: The headphone amp is

designed to drive any standard head-

phones to a very loud level. We’re

not kidding! It can cause permanent hearing damage. Even intermediate

levels may be painfully loud with some headphones. BE CAREFUL! Always start with the PHONES level turned all the way down before connecting headphones to the PHONES jack. Keep it down until you’ve put on the headphones. Then turn it up slowly. Why? Always remember: “Engineers who fry their ears, ﬁnd themselves with short careers.”

25. SOLO MODE

Engaging a channel’s SOLO switch will cause this

dramatic turn of events: Any existing SOURCE matrix selections are replaced by the SOLO signal, appearing at the CONTROL ROOM OUTPUTS, PHONES and at the RIGHT METER (LEFT and RIGHT METERS when in AFL SOLO MODE). The audible SOLO levels are then controlled by the CONTROL ROOM knob (22). The SOLO levels appearing on the meters are not controlled by the CONTROL ROOM knob—you wouldn’t want that. You want to see the actual channel level on the meters regardless of how loud you’re listening.

With the SOLO MODE switch in the up position, you’re in PFL mode, meaning Pre-Fader Listen (post-EQ). This mode is required for the “Set the Levels” procedure and is handy for quick spot-checks of channels, especially ones that have their faders turned down.

With the switch down, you’re in AFL mode, meaning After-Fader Listen. You’ll hear the output of the soloed channel—it will follow the channel’s GAIN, EQ, FADER and PAN settings. It’s similar to muting all the other channels, but without the hassle. Use AFL mode during mixdown.

In either mode, SOLO will not be affected by a channel’s MUTE/ALT switch position.

26. LEFT/RIGHT Level Meters

The Onyx 1620’s peak meters are made up of two columns of twelve LEDs, with three colors to indicate different ranges of signal level, trafﬁc light style. They range from –30 at the bottom, to 0 in the middle, to +20 (CLIP) at the top.

The 0 LED in the middle is labeled LEVEL SET

to show where the level should be when adjusting a channel’s gain in the solo mode, as described in “Set the Levels” on page 5.

If nothing is selected in the CONTROL ROOM/ PHONES SOURCE matrix (20) and no channels are in SOLO, the meters won’t do anything. To display a

	The reason for this is because you want the meters to	s’Owner
	signal level, a source must be selected in the CONTROL
	ROOM/PHONES SOURCE matrix, which feeds the CON-
	TROL ROOM (40) and PHONES (24) outputs. The meters
	reﬂect the program level of the selected source prior to
	the CONTROL ROOM and PHONES (22/23) level knobs.
	reﬂect what the engineer is listening to, and as we’ve	Manual
	covered, the engineer is listening either to the CON-	Manual
	covered, the engineer is listening either to the CON-
	TROL ROOM outputs or the PHONES outputs. The only
	difference is that while the listening levels are con-
	trolled by the CONTROL ROOM and PHONES knobs, the
	meters indicated the SOURCE mix before those knobs,
	giving you the real facts at all times, even if you’re not
	listening at all.
	When a channel is soloed, the meters change to
	reﬂect the level of that channel’s signal level, pre- or
	post-fader, depending on the SOLO MODE (25) setting.
	You may already be an expert at the
	world of “+4” (+4 dBu=1.23 V) and
	“–10” (–10 dBV=0.32 V) operating
	levels. What makes a mixer one or
	the other is the relative 0 dB VU (or
	0 VU) chosen for the meters. A “+4”
	mixer, with +4 dBu pouring out the back will actually
	read 0 VU on its meters. A “–10” mixer, with a –10 dBV
	signal trickling out will read, you guessed it, 0 VU on its
	meters. So when is 0 VU actually 0 dBu? Right now!
	Mackie mixers show things as they really are. When 0
	dBu (0.775 V) is at the outputs, it shows as 0 dB VU on
	the meters. What could be easier? By the way, the most
	wonderful thing about standards is that there are so
	many to choose from.
	Thanks to the Onyx 1620’s wide dynamic range,
	you can get a good mix with peaks ﬂashing anywhere
	between –20 and +10 dB on the meters. Most ampliﬁers
	clip at about +10 dBu, and some recorders aren’t so
	forgiving either. For best real-world results, try to keep
	your peaks between “0” and “+7.”
	Remember, audio meters are just tools to help assure
	you that your levels are “in the ballpark.” You don’t have
	to stare at them (unless you want to).

27. RUDE SOLO Light

This large green LED ﬂashes on and off when a channel’s solo is active, as an additional reminder beyond the indicating LEDs next to each SOLO button. If you work on a mixer that has a solo function with no indicator lights and you happen to forget you’re in solo mode, you can easily be tricked into thinking that something is wrong with your mixer. Hence, the RUDE SOLO light. It’s especially handy at about 3 am when no sound is coming out of your monitors but your multitrack is playing back like mad.

Owner’s Manual