Each inp u t channel and the three m ain ou tp u ts have an Insert
‘A’ gau ge | jack socket, w hich | is | a | break | p oint in the signal |
p ath . It | allow s the signal | to | be | taken | ou t of the m ixer, |
throu gh an external p iece of equ ip m ent and then back into the m ixer d irectly after its original exit p oint. The Insert p oint is norm ally byp assed by the ‘A’ gau ge jack socket contacts, and
is only | brou ght into | op eration | w hen | a p lu g is | inserted . |
Typ ical | u ses w ou ld | inclu d e Effects | Processors, | Lim iters, | |
ad d itional Equ alisers | or Delay | u nits. | In ad d ition, each | ||
channel has a D irect ou tp u t w hich m ay also be u sed to feed external equ ip m ent.
The term s PRE and POST are often u sed in the context of Inserts, Equ alisers and Au xiliary Send s, and d escribe w hether
that facility is p laced | before (Pre) | or after | (Post) | another |
p articu lar section . This | is exp lained | fu rther | in the | d etailed |
d escrip tion of facilities. |
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Am ixer is often ju d ged , am ongst other factors, by the am ou nt of Headroom available. This is a m easu re of the reserve
available to cop e | w ith su d d en | p eaks in | the inp u t | signal, |
w ithou t d istortion | cau sed by | Clipping, | w hen the | signal |
becom es so high that it w ou ld exceed the p ow er su p p ly rail voltages and is as a resu lt lim ited . This com m only occu rs w here gain settings are incorrectly set or w here sou rces are im p rop erly m atched to the m ixer inp u t. If the sou rce signal is too high, clip p ing and d istortion resu lts. If the signal is too low it becom es m asked by the backgrou nd noise w hich is p resent to som e d egree in all m ixers. The d iagram below illu strates this p oint.
Clipped
Signal
Noise
If the signal level is too high, clipping distortion may occur.
SignalNoise
If the signal level is too low it may be masked by the noise.
Pa ge 5