@twoch is right. Especially minimalist tube preamps. A single stage, single ended gain stage always inverts.
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?
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?
Showing 8 responses by erik_squires
Hi Almarg, I am definitely on team "easy to drive speakers." Get easy to drive speakers and a lot of amps will sound really great. Get demanding speakers, and your amp costs may go up considerably. So make sure if your speaker is demanding that it's really worth the cost of ownership. Being able to tell amps apart is not why I buy speakers anymore. :) Best, E |
By the way, if anyone wants to learn about speaker design, and how drivers and crossovers work together I have quite a bit of documentation, including real-time simulation tools you can use to play around and look at some of these concepts. Please visit my LM-1 design page, here: https://speakermakersjourney.blogspot.com/2016/02/the-lm-1-bookshelf-version.html The files and design info are 100% free for music lovers. :) Haters have to pay. |
Man, I’m sorry I have to jump in here: In a good many speakers the phase angle is significantly different for the woofers than it is for the midrange and tweeter. If the woofer has a significant negative phase angle while the midrange and tweeter are quite positive, inverting the phase of the woofer will bring them into better coherence. This is too confusing phase angle with polarity. The polarity is either positive or negative. Applying the (+) of a 1.5V battery to the (+) terminal of a driver will result in the driver moving OUT. Reverse the battery and the driver will go IN. Because drivers as well as their crossovers result in phase angles that may not add up correctly, matching the drivers so their total output adds correctly across the crossover frequency often results in the need to invert the polarity of drivers. Something else not thought about is the time. In a flat baffle, a tweeter arrives about 0.1 My guess is that 99% of two-way systems have the tweeter in negative polarity. This is a good thing, because the alternative would be a deep null. Designers deal with driver polarity consideirng only a pair of drivers at a time. By convention, the woofer is in positive polarity. Then the woofer/midrange is considered. If necessary, the midrange will be inverted. Based on the phase angles of the midrange and tweeter the polarity of the tweeter is considered. This time the tweeter may or may not be inverted. The size, depth, placement of the drivers, the angle of the baffle, the order of the filters (1st, 2nd, etc.) all play into whether drivers will need to be inverted. For goodness sakes, no one should be inverting individual drivers, that way lies madness unless you have the right tools or background information. There are designers like old Thiel and current VanDerSteen who make polarity and phase coherense an absolute priority, and then buy or have drivers made that can work well in these configurations. It is not rocket-science, but neither is it proven to be desirable above all else, and often has risks associated with it. Best, E |
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 |