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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Subwoofer Forum => Topic started by: Michael Lawrence on June 02, 2018, 05:51:28 pm

Title: Mackie SRS1500
Post by: Michael Lawrence on June 02, 2018, 05:51:28 pm
Once upon a time, when I was but a wee lad mixing on the local audio provider's PA system, I had two thoughts about the Mackie SRS1500s:
I thought at the time that the polarity function (more accurately, lack thereof) was just a problem with our specific models.

Fast forward to today, when I decided to measure one, with the polarity switch in both positions:

The amplitude traces are offset slightly for clarity.

Clearly, the polarity switch is just there to look pretty.

Can anyone shed some light on this?
Title: Re: Mackie SRS1500
Post by: Art Welter on June 03, 2018, 01:23:06 am
I thought at the time that the polarity function (more accurately, lack thereof) was just a problem with our specific models.
Clearly, the polarity switch is just there to look pretty.

Can anyone shed some light on this?
Michael,

The manual states:
"PHASE
This switch reverses the polarity of the signal at the HIGH PASS OUTPUT jacks."


The "PHASE" switch has no effect on the THRU jack, wired straight from the FULL RANGE INPUT connector, so switching it would have no effect on your measurement.

Art
Title: Re: Mackie SRS1500
Post by: Michael Lawrence on June 03, 2018, 09:23:28 am
Michael,

The manual states:
"PHASE
This switch reverses the polarity of the signal at the HIGH PASS OUTPUT jacks."


The "PHASE" switch has no effect on the THRU jack, wired straight from the FULL RANGE INPUT connector, so switching it would have no effect on your measurement.

Art

A ha! Mystery solved. That certainly explains it. See what happens when you ASSume?

Many thanks, good sir.

EDIT: Though I will say, that seems odd. A local polarity control seems much more useful. But I guess you have to ask yourself how often people use the SRS1500 for cardioid arrays.