
S-125/S-125C/S-85/S-85C page 10
7. SATELLITE/SUBWOOFER PHASINGTEST
In any system using a subwoofer separate from Satellite speakers, a phasing test must be performed to insure
good bass blending. This test insures optimum sound in the critical bass frequencies where your Subwoofer and
Satellite speakers overlap.
Playafamiliar CD, LP, or tape withsteady,consistentbasscontent through your system. Listen carefully tothe
"mid-bass"regionof75-125Hz. Thisisthepartofthespectrumwhereelectricorstringbassesanddrumspredominate.
Then reverse the phase of either the subwoofer or BOTH Satellite speakers.
If your Subwoofer has a PHASE switch on its back panel, move it either from (+) to (—) or vice versa.
IfyourSubwooferdoesnothave a PHASE switch, it takes a bit more work. YouwillhavetochangethePositive
and Negative speaker inputs on the back of BOTH Satellite speakers.
YoucandothisatthebackofbothSatellitespeakers,orattheSubwoofer'sTOSPEAKERSterminals,butnever
atbothlocations. TheleadthatwasonthePositive(+)terminalshouldbeswitchedtotheNegative(—)terminal,and
vice versa. When switching speaker wires, take care to protect your amplifier. Make sure that the wires do not touch
each other when you are making the switch. As a safety measure, we suggest that you turn the amplifier off before
making the switch.
Nowlistentothesamemusicalpassageasyoudidearlier,concentratingonthemid-bassregion. Ifyouhearless
bass, the original connection (or switch position) was correct. If you hear more bass, the new connection ( or switch)
is correct.
You need to perform this test because when Satellite speakers are located separate from a Subwoofer, each
speaker is at a different distance from your ear. In some cases, the difference will be just enough so that the output
fromthe Subwoofer arrives outof phase with theoutputof the Satellites. Whenthishappens, that critical mid-bassis
actually cancelled. You should re-do this test any time you move your speakers.
Ifyouwanttoexperimentfurther,movetheSatellitespeakerseithertowardsorawayfromyourlisteningposition,
making changes in small increments. This will "focus" the system's sound to its optimum. When you hear the best
combinationofstereoimagelocalizationandmaximumimpactandoutputinthemid-bass,youhavetheideallocation.
8. SPEAKER DAMAGE & HOWTO AVOID IT
An important factor to consider with any loudspeaker system is the potential for speaker damage. Even though
your M&K Satellites have extremely high power handling ability (especially for Satellite speakers), they still can be
damaged by relatively low powered amplifiers.
While very few M&K Satellites are actually returned for service, the vast majority of those returned are not for
manufacturing defects. Instead, they are returned because they have been overdriven, almost always because the
amplifierorreceiverusedwasdrivenintoclippingdistortion. Thisdamageisconsideredabuse,andisnotnecessarily
covered under warranty.
This clipping distortion occurs when the demands of the music are greater than the amplifier's available power.
Itcanoccurat20wattswithasmallamplifier,orat400wattswithalargeamplifier. Whenthishappens,theamplifier's
output waveform (which should look like a smooth arc) is "clipped" off, exhibiting a flat top instead of the arc.
Thisflattopcontainsmultiplesof the original amplified frequencies, sometimes at higher levels thantheoriginal
signalitself. Fortweeters,thiscanbeverydamaging,asthisdistortioniswellabovetheaudiblerange(whereyouare
unable to hear it), and where the tweeter is most vulnerable to damage.
When an amplifier clips, its sound becomes harsh and grating, and a break-up is often audible in the bass
frequencies. Itwillbecomeuncomfortabletolistento,especiallywhencomparedtoaslightlylowervolumelevel. When
you are listening at high volume levels, be aware of the onset of clipping distortion, and turn the volume down slightly
if the sound takes on the character described above.
When tone controls or equalizers are used to boost frequencies, the problem occurs much more rapidly. Even
a small boost of low or high frequencies can easily double the power requirement and lead to amplifier clipping at
moderate levels. Therefore, you should use your tone controls judiciously, avoiding extreme boosts of the bass and
treble controls, especially when you are listening at high volume levels.
The best way to avoid speaker damage is to use common sense. Use moderate boosts of tone controls or
equalizers, at the very most. Listen carefully for any harshness and break-up, especially at high volume levels, and
turn down the volume when needed. If you cannot get enough volume, you may need to consider a higher-powered