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Laser alignment tool for speaker placement.

Vintage57

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RayDunzl

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A laser is useful.

I have a Bosch laser measure/angle device for toe and rake.

For distance, REW takes it from there, to +/-0.01ms, for microphone position/repeatability of measurement.
 

Wombat

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And then use the apparatus shown in my avatar to maintain that precision at the listening position. ;)
 

Blumlein 88

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I've used those laser levels and even a cheap one is plenty useful. I've even gotten crazy and put small mirrors (from makeup compacts those are good quality) on speaker surfaces and then bounced the laser off it in a way to get a length of light beam ratio to improve alignment by 5x or so. Accidentally tripped across the idea doing this with laser very close and bounced laser dot far away was a reasonable way to measure vibration of the panels.

Currently I do what Ray mentioned with REW. Put a UMIK at the listener position and let it measure distance to speakers acoustically. Those laser/tape measure combos just project the laser and do the distance measuring with ultrasound anyway.
 

c1ferrari

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Cool thread :cool:
I want to try that REW thing for distance.
:)
 

RayDunzl

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Those laser/tape measure combos just project the laser and do the distance measuring with ultrasound anyway.

The cheapest ones do, the "real" ones use the light. I suppose it sends out a code and reads the delay.

"The calculation is done through precision optics and laser physics using the phase-shift method, in which a laser hits an object and compares its reflection with the beam sent out, or using the time-of-flight method in which the time it takes for an optical pulse to reflect back is calculated."

Mine:

"ACCURACY: The Bosch GLM 80 Laser Distance Measurer measures distances up to 265 ft. with up to 1/16 inch accuracy"
 

Sal1950

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Does anyone have any information on a laser alignment tool like the one in this review from 20 years ago. Checkpoint is no longer active.

https://www.stereophile.com/miscellaneous/936/index.html
As the guys have said, they are plentiful today, just check your local Lowe's or Home Depot for a large assortment from about $20 and up.

For distance, REW takes it from there, to +/-0.01ms, for microphone position/repeatability of measurement.
Good thought, I'll have to check mine and see how it compares to what my Audyssey app measures.
I'll post the results when I get the numbers.
 

Fitzcaraldo215

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Audyssey measures just fine acoustically via mic. Check it once and you will forever just leave the tape measure in the toolbox. But, note that, if you are using a powered sub, chances are the mic measurement will be a fair bit greater than the tape measure distance. DSP latency/delay in the sub's input network is the cause. The mic measurement is the one to use.
 

restorer-john

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The mic measurement is the one to use.

For which ear, left or right?

Do you hang a ping-pong ball from the roof and stand right under it? I like Wombat's dungeon device for clamping one's head perfectly still.

:)
 

Wombat

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The clamping device was used by earlier photographers to prevent subject movement from blurring the long exposure shots used at the time. I saw a relationship to the audio sweet spot and 'blurring' due to head movement. :D
 

Fitzcaraldo215

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For which ear, left or right?

Do you hang a ping-pong ball from the roof and stand right under it? I like Wombat's dungeon device for clamping one's head perfectly still.

:)

Ha, ha. No, you have someone drill a hole dead center in the top of your skull, then insert the mic there for the calibration. That also saves money on tripods, mountings, etc.

As with stereo, in Mch there is only one theoretical, central geometrical reference point for symmetrical speaker setup, distance alignment, channel balance, etc. That is called the Main Listening Position or sweet spot. It provides the optimum average position. But, you need not sit there stock still in either case in order to get acceptable, enjoyable imaging. As I have said before, I find that Mch is more tolerant of variations in one's head orientation or in sitting in seats adjacent to the MLP as long as you do not get too close to one of the speaker channels.
 

restorer-john

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Yes, but the Lava Light and aquarium lighting can still stay on, right?

OK, as long as you install some old-skool rope lights that 'flow' with the music. I've got a nice Xenon disco strobe I built in the 1970s you can borrow for your next party.
 

jhaider

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For DSP-equipped speakers, there isn't a substitute for time of flight based on the impulse response, using a measurement system with loopback correction. However, for passive speakers the laser measurer works well. Mine is a Bosch, at least 5 years old.

For toe-in I use an iOS app called "SpeakerAngle." When I first bought it, it was branded Genelec. Then I think it was JBL for a while. Now it does not carry speaker company cobranding.
 

Wombat

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RayDunzl

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