How to ensure equal tilt and measure the tilt angle

[Gordon Gray]

Hi guys,

I just posted this on another thread but thought this would be of interest to all members as a separate thread.

Following is a very simple, inexpensive way to ensure the tilt angle is exactly the same for both panels and a way to calculate the actual tilt angle.

All you need are a couple of pieces of string with a small weight (ie: a 1/4" bolt) or whatever attached at the bottom of the string.

Tape the top of the string to the exact same place at the front / top of the panel. The weighted portion should hang slightly above the floor. What you made is a simplified plumb bob with the string representing a line that is perpindicular to the front plane of your panel.

Once the string has stopped moving, measure the horizontal distance from the string to a fixed point at the bottom of the speaker. This can be a panel edge, cabinet edge or whatever.

Once the measured horizontal distance is exactly the same, the tilt of both speakers is the same.

If you want to calculate the offset angle from perpindicular (90 degrees), measure the horizontal offset and the vertical distance from the top of the panel to the point at which you measured the horizontal distance. Convert any "partial" inches" to its decimal equivalent. For example, if you measured 3/16", divide 3 by 16 and you get 0.19'.

Once you've converted the partial inches into their decimal equivalent, divide the horizontal distance by the vertical distance and then calculate the "arctan or tan-1". This calculation will give you the vertical offset angle clockwise (back) from perpindicular.

IMHO

1) Adjusting the tilt of both speakers to be exactly the same is critical to optimizing the sound of the ML's.

2) The closer the panel is to perpindicular, the better. You should hear audible improvements to horizontal / vertical imaging, as well as a better defined front / back soundstage presentation.
Good luck and have fun.

GG

 

[Craig]

A simple way to measure tilt angle is to use an angle locator.

http://www.amazon.com/Johnson-Level-Tool-700-Magnetic/dp/B00004T807

 

[Gordon Gray]

Agreed!

Craig,

I agree with you totally. However, for those who aren't tool users and / or don't wish to buy something to measure the angle, using the procedure I've outlined costs nothing and can be done with little effort.

Best regards,

GG

 

[Craig]

Since I have both an angle gauge and a carpenters plumb bob, I did a quick comparison of the two methods.

My observation: The angle gauge is simpler and quicker to use, but the plumb bob method allows for a finer measurement and therefore offers better accuracy. If you want to fine tune the tilt angle and precisely match both speakers then I would take the time to use the plumb bob and a fine ruler. As far as cost goes, the angle gauge is about $10. A plumb bob and a metal ruler; maybe a little less than $10.

Anyway, tilting the speakers forward and matching them up is potetially a good low cost tweak for Summits worth considering. Before I tilted them forward, the sweeter spot was standing behind my sofa. Now it's aimed a little lower and more forward and sounds better at the sofa position rather than behind the sofa. However, your mileage may vary.

Thanks to JTWRACE for providing the extended spikes.

 

[Joey_V]

Thanks to JTWRACE for providing the extended spikes.

Hear hear...

Thanks for the tip regarding the angle measurer, I didn't even know they made those, Craig.

 

[sleepysurf]

Ha! I actually TRIED the plumb-bob idea before I bought a digital protractor. Nothing wrong with enlisting a little science and engineering, but frankly, Craig's solution is a "no-brainer" (literally and figuratively)!

Another trick I used when installing the spikes was to lay the Summits on their side, and use a metric ruler (mm's) measuring from spike tip to the cabinet base. That got me pretty much in the ballpark for each speaker. I then did final adjustments on rear spikes once upright (for uneven floors). They are now angled ~93 degrees.

I must admit, my recent room transition, plus spikes and toe-in, have made these Summits sound like an entirely different speaker than when I first purchased them.

Lastly, I played around with the ceramic "tile under each woofer" tweak today. I found that angling the tile (diamond orientation) tightens up the bass further, by allowing MORE of the tile to be directly underneath the bottom woofer. See pic.

 

[treitz3]

Anyway, tilting the speakers forward and matching them up is potetially a good low cost tweak for Summits worth considering. Before I tilted them forward, the sweeter spot was standing behind my sofa. Now it's aimed a little lower and more forward and sounds better at the sofa position rather than behind the sofa.

Dreamer? you hear that? Hint, hint..........

Sounds like what we discovered whilst listening, huh?

 

[Joey_V]

Dreamer? you hear that? Hint, hint..........

Sounds like what we discovered whilst listening, huh?

Treitz,

Do tell! Were you guys playing with the rake angle as well?