Stage/phase

[khenegar]

I've had to do allot of repairs to my stage thru the years, the transformer was bad the hi-freq driver had distortion and the stage had some trips back to the factory and finally got it working and discovered that one of the bass drivers wasn't working! The wires to the bass speaker had broken off didn't know if it was me or not. Now I feel as though it sounds thin and assuming that the bass drivers are out of phase! Is there anyway I can test the stage to see if it's bass driver are in phase? Thanks

 

[jmschnur]

Can you send it pink noise with different polarity?

 

[roberto]

Hola Ken. You are going to need two people for this test. Get one 1.5 V battery type AA, AAA, C, or D size. Connect a piece of speaker wire, lets say, 1 meter (3 feet long) to the speaker terminals. Touching the - of the wire to the - of the battery, ( don't worry, you won't get any shock ) and the + of the wire to the + of the battery, you will see a momentary push out of the two woofers at the same time. If one goes inside and the other outside, the inside woofer is out of phase. Both cones should push out. Then reverse the polarity of the battery, both cones should move to inside, the push is to in...reverse again, and both will come out...the movement is fast, so keep watching the movement. Two people is better than one for this task.

 

[khenegar]

Phase

Hola Ken. You are going to need two people for this test. Get one 1.5 V battery type AA, AAA, C, or D size. Connect a piece of speaker wire, lets say, 1 meter (3 feet long) to the speaker terminals. Touching the - of the wire to the - of the battery, ( don't worry, you won't get any shock ) and the + of the wire to the + of the battery, you will see a momentary push out of the two woofers at the same time. If one goes inside and the other outside, the inside woofer is out of phase. Both cones should push out. Then reverse the polarity of the battery, both cones should move to inside, the push is to in...reverse again, and both will come out...the movement is fast, so keep watching the movement. Two people is better than one for this task.

Thank u Reberto! As usual very helpful

 

[roberto]

Please tell us how did it go!
Happy listening!

 

[khenegar]

Hola Ken. You are going to need two people for this test. Get one 1.5 V battery type AA, AAA, C, or D size. Connect a piece of speaker wire, lets say, 1 meter (3 feet long) to the speaker terminals. Touching the - of the wire to the - of the battery, ( don't worry, you won't get any shock ) and the + of the wire to the + of the battery, you will see a momentary push out of the two woofers at the same time. If one goes inside and the other outside, the inside woofer is out of phase. Both cones should push out. Then reverse the polarity of the battery, both cones should move to inside, the push is to in...reverse again, and both will come out...the movement is fast, so keep watching the movement. Two people is better than one for this task.

Reberto did as u suggested and I could not see the bass driver move in or out! I Had the speaker wires from the amp connected then. I then disconnected the speaker wires and tried a new battery , with this setup it only clicked once until I reversed the wire then it would click again still could not see which direction they were moving! I found one thing I had the D.C. power hooked up wrong had It going to the D.C. output instead of the D.C. Input! It still worked though!

 

[roberto]

1( Remove the speaker cable from the amplifier, now you have the STAGE without any connection. Put a little piece of speaker's wire with the Stage terminals, At the end of this wire, put the battery, and this wire must have enough length to come from the back to the Stage to the front, where you can see the movement. Please the battery - to the - of the wire. Now, touching several times, the + of the battery with the + of the wire, you might see the movement. If only the click sound coming from the speaker is heard, reverse the polarity, and now the movement should go inside...again reverse (now we right the polarity again) and the woofer should come out.
It moves very quickly. if you watch at the edge of the woofer, where the suspension is, its easier. You could use a wood pick. Through the hole of the grill, leave touching the wood to the surface of the woofer. Apply the DC with the battery, and if the woofer is with the correct polarity, the wood piece should come out fast. The woofer will come out with the right polarity. If the polarity is wrong, then the come will go pulling to inside, not pushing to outside.

Ken if you have whatsapp, you can reach me at 506-8888-4363. Call me, I will explained to you this better.

 

[khenegar]

1( Remove the speaker cable from the amplifier, now you have the STAGE without any connection. Put a little piece of speaker's wire with the Stage terminals, At the end of this wire, put the battery, and this wire must have enough length to come from the back to the Stage to the front, where you can see the movement. Please the battery - to the - of the wire. Now, touching several times, the + of the battery with the + of the wire, you might see the movement. If only the click sound coming from the speaker is heard, reverse the polarity, and now the movement should go inside...again reverse (now we right the polarity again) and the woofer should come out.
It moves very quickly. if you watch at the edge of the woofer, where the suspension is, its easier. You could use a wood pick. Through the hole of the grill, leave touching the wood to the surface of the woofer. Apply the DC with the battery, and if the woofer is with the correct polarity, the wood piece should come out fast. The woofer will come out with the right polarity. If the polarity is wrong, then the come will go pulling to inside, not pushing to outside.

Ken if you have whatsapp, you can reach me at 506-8888-4363. Call me, I will explained to you this better.

Roberto I Did as u instructed with the tooth pick and all it did was drop down did not come out or fall in

 

[roberto]

You do hear a click, right? This click is produce only once? You have to touch the + for a fraction of second then, disconnect the +of the battery. If you do not hear anything, reverse the polarity at the battery. Martin Logan has a DC protection for the woofers, so if you reverse, and keep doing this, then probably you will see the movement of the woofer. With polarity correct, the woofer must come out, reverse polarity, woofer goes inside.

 

[khenegar]

Reberto: I do hear a click but the tooth pick doesn't do anything but tilt down when plus is touched then nothing when reversed! It really hard to tell with the grills on looking thru the perforations!

 

[roberto]

There are tricks or ways to do this. Prepare the took pick touching the speaker suspension. That's at the edge of the cone. Turn off the light. With the aid of a flashlight, point the flash beam to that edge of the speaker (suspension). Now touch the + of the battery. Could you tell the movement? If you reverse the battery's polarity, then the cone should go inside.