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Speaker phase observation and question?

Hi everyone,

After months of playing around with positive phase and reverse phase connections to my Monitor Audio Silver 8 speakers, I have made a couple of observations. When connected in positive phase (red - red, black - black), the speakers put out pretty substantial bass, but the mids and treble are somewhat subdued. Upon reversing the phase, the mids and treble open up substantially, and the bass becomes somewhat subdued. To my ears, I actually prefer the reversed phased.

Moving forward to the current day, I purchased an app that tests phase using a generated tone. In testing my speakers, both bass drivers test positive phase, but the mid and treble test negative. I had read somewhere that some manufactures wire the drivers like this intentionally, but am confused as to whether or not this is the case with my speakers, or if it's a manufacturing flaw?

Any thoughts? 
chewie70
almarg's avatar
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almarg
8,673 posts
 
From the measurements section of Stereophile's review of your speakers:
The Silver 8's step response on its tweeter axis (fig.7) shows that the tweeter and midrange unit are connected in inverted acoustic polarity, the woofers in positive polarity. More important than the polarities (see "Letters," November 2014, p.11) is the fact that the decay of each unit's step smoothly blends with the start of the decay of the next step lower in frequency, which suggests optimal crossover design.
Enjoy!  Regards,
-- Al
 

chewie70 OP
17 posts
 
Thank you Al, very informative!
erik_squires
5,268 posts
 
OP,

So, positive polarity means a + voltage causes the driver to move towards the listener and away from the cabinet.

A speaker designer may need to flip the polarity of individual drivers to get the correct frequency and phase alignment across the crossover region. It is rather rare for a flat baffle, multi-way speaker to get the drivers all lined up in positive polarity.

When this happens the convention is to wire the largest driver, the woofer, in positive phase, and then flip drivers going upwards as needed to align with the next driver down.

For instance, almost all 2-way speakers end up with the tweet reversed. My LM-1 however happen to have aligned in positive phase.

https://speakermakersjourney.blogspot.com/2016/02/the-lm-1-bookshelf-version.html

But this was a result of a great deal of luck with driver sizes, location, and crossover design.

Best,


E
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