How to test a tweeter...for dummies?

Klownschool

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I've got a two part question for you. I am admittedly a newbie so be gentle ;).

1. I would like to know the best way to test a tweeter I suspect may not be working. This particular speaker is a 3A adagio 06600. The one that works sounds amazing and I want to get the other up to speed without damaging anything in the process. I was hoping that I wouldn't have to swap them out to see if that is the case. It has wipers for tone so I was hoping there may be a chance that is corosion is a possiblity.

2. If it is shot, how do I tell at what ohm the speaker runs at so that I can get a suitable replacement

Any help would be appreciated,
Rick
 
two ways if you don't want to swap:

1. use a multimeter and test the resistance of the tweeter. it should read between 4 and 8 ohms. if no reading or 0 ohms, its bad

2. get a 1.5 volt battery (no higher), and some wire. connect the wire to the tweeter. connect the wires to the battery momentarily and release. You should hear a click from the tweeter. No noise = dead tweeter.

A replacement would have to be the same physical size, and have similar frequency response, impedance rating, power rating, and efficiency rating
 
Great, thanks Jordan.

Hmmm, I hope it's not shot. Sounds like finding a replacement might be tough. No markings, spec's available online. They must not have made too many of these.

Rick
 
Unless it were a $500 TAD or ribbon driver or suchlike... I personally have no qualms about applying a very low level, full-range signal to most tweeters and listening for sound. If that is beyond your comfort level, use a 2 or 4 uF NP electrolytic to block LF.
 
I agree with MHardy that you can safely test most tweeters by feeding them a very LOW LEVEL full range signal, and recommend turning the treble tone control all the way up and bass tone control all the way down (turn off any Loudness compensation) to minimize low frequency input. Some tweeters may seem to test okay but still have abnormally low level output due to physical condition issues in the spider or voice coil. Comparing the tweeter with a similar unit that is known to be working correctly is always the best way if possible.

PS - I used to work at a speaker factory in the mid to late 70's and would often conduct tweeter torture sessions during lunch time just for fun. Oem suppliers were constantly sending us samples of new tweeter models that would get tested and then set on a shelf to collect dust. I would conduct my experiments at the speaker assembly line test station which was a signal generator and low power Marantz receiver. I would feed the tweeters both sine and square waves to hear how they'd respond and then go down in frequency to see where they'd cut off. Most would just burn out after a few seconds at lower frequencies. The speaker company was using primarily Peerless cone tweeters at the time and my favorite subjects were Peerless tweeters that were rejected when holes were accidenatlly punched through the cones. Peerless used a white polyester style damping material behind the cone which would start to burn as the voice coils overheated, causing smoke to come out of the hole. It was the only situation where I've ever enjoyed seeing tweeters go up in smoke.....
 
Rick,

There is better than a 50 50 chance that the problem is in the controls. Why don't you try cleaning it first and then see if you can get some sound output.

If you are forced to replace, unfortunately, you'll probably have to buy a pair.

Regards,
Jerry
 
Hey guys, my turn to Dummy Up

I have been struggling with a gifted pair of Rogers LS7Ts and went down the wrong Rabbit Hole. Because everything worked fine before one tweeter dropped I focused on the Crossover. When I first put the other tweeter in place, it worked but must have died between then and now.

I decided to figure out how to test the tweeters with a meter and found this thread.

I did the ohm test on both, tweeter 1 had no reading for continuity. I also did the 1.5v battery test and nothing.

On Tweeter 2, the battery test is positive but the reading across the terminals read closer to 12 and not the speced 8ohms.

Tweeter 2 in both cabinets sounds like a pair of headphones sitting on the table, not over your ears. So I am assuming Tweeter 2 is also fried but has just enough life to send me chasing my tail.

Is the reading I got on tweeter 2 along with the sound symptoms I described in line with a fried but barely alive tweeter?

Thanks!
 
Did you test the tweeters out of circuit, i.e. completely disconnected from the crossover? If not this can affect impedance reading. Even so DC resistance may be different at the frequency your meter uses compared to the tweeter's response band, in other words 12 ohm DC may be normal for that unit.

Tweeter 2 in both cabinets sounds like a pair of headphones sitting on the table, not over your ears. So I am assuming Tweeter 2 is also fried but has just enough life to send me chasing my tail.

Is the reading I got on tweeter 2 along with the sound symptoms I described in line with a fried but barely alive tweeter?

Tweeters can sound like that by themselves, depending on what they are trying the reproduce. They're often only playing the top two or three octaves where there may be relatively little musical content. What signal did you feed it and what were the other test conditions (e.g. signal filtered by xover with no woofer playing)?

I suspect tweeter 2 is ok from what you've said (did it sound good when playing with the woofer?). 1 might be repairable depending on what has happened.
 
Did you test the tweeters out of circuit, i.e. completely disconnected from the crossover? If not this can affect impedance reading. Even so DC resistance may be different at the frequency your meter uses compared to the tweeter's response band, in other words 12 ohm DC may be normal for that unit.



Tweeters can sound like that by themselves, depending on what they are trying the reproduce. They're often only playing the top two or three octaves where there may be relatively little musical content. What signal did you feed it and what were the other test conditions (e.g. signal filtered by xover with no woofer playing)?

I suspect tweeter 2 is ok from what you've said (did it sound good when playing with the woofer?). 1 might be repairable depending on what has happened.

Test conditions were all done with fully assembled speakers and bi-wire cable. I was able to isolate the tweeter and woofer via binding posts thru the x-over. Music was fed thru my 2nd setup below in my sig. Also able to isolate channels via dual volume knobs.

When the tweeter is connected by itself being fed a normal signal, via Pandora, it sounds all tinny and like described above. With both woofer and tweeter hooked, the speaker has no highs. Keep in mind both of these speakers sounded fabulous for 2 days when I got them after sitting idle for years.

I may have to pull a tweeter from a pair of something I have for sale just to test sound if that is a valid next step for troubleshooting.

Is it common for a 12ohm speaker to read 12ohms?

I also did test the tweeters on the bench removed from the cabinets.

Thanks
 
As sound tests were done with the crossover in place it’s possible this is affecting sound from the working tweeter. How confident are you that this is not an issue? Swapping tweeters with a working set of approx. 8 ohm and similar sensitivity would be a good next step: how does that tweeter sound in Rogers box and vice versa. Keep in mind that newer tweeters are likely to be more sensitive.

Odd that these played well and suddenly stopped. I wonder if the caps drifted and overloaded the tweeters.

In my experience most drivers have lower DC resistance than their impedance, however there are bound to be exceptions. Is the tweeter marked as 8 ohm and how have you determined what impedance it should have?
 
As sound tests were done with the crossover in place it’s possible this is affecting sound from the working tweeter. How confident are you that this is not an issue? Swapping tweeters with a working set of approx. 8 ohm and similar sensitivity would be a good next step: how does that tweeter sound in Rogers box and vice versa. Keep in mind that newer tweeters are likely to be more sensitive.

Odd that these played well and suddenly stopped. I wonder if the caps drifted and overloaded the tweeters.

In my experience most drivers have lower DC resistance than their impedance, however there are bound to be exceptions. Is the tweeter marked as 8 ohm and how have you determined what impedance it should have?

Hang on a sec, maybe I was not clear.

I tested both tweeters on the bench, out of the box, no wires connected, no crossover
Clearly marked as 8ohm stamped on the magnet
1 tested dead with both Battery Test and Continuity
1 Tested good with Battery Test but continuity reads 12ohm and not the suggested 8

I then tested both tweeters connected to crossovers, in each box
1 tweeter produces no sound at all using just the HF portion of the bi-wire cabling
1 produces sound but at a very low and tinny volume. With both HF and LF cabled from amp, the sound is very dull and does not sound normal.

I have someone at Rogers looking into what I can replace the tweeters with.
I don't have any way to test the resistors and other components on the crossover.
I am assuming the x-overs are ok since I get the same results from both boxes, or oddly both boards have the exact same faulty part/s
 
3A Adagio's! lucky you!. Did that tweeter check ok?. Your model might have ITT tweeters, a picture would help. The dome mid is so nice in these, so is the woofer.
 
turbo, have you posted in the wrong thread by mistake?

Hyfi:
It is odd for an 8 ohm driver to read higher DC resistance. Given also weak sound perhaps the connection is poor indicating a fault. I think swapping in a known good tweeter would be a good next test.

It would also be unusual for both crossovers to develop exactly the same fault, but in another thread you mentioned faulty solder joints so who knows what is happening. Again, subbing in another tweeter (and testing Rogers tweeter with that crossover) might shed some light.

Also it might be worth disassembling the dead tweeter to look for the fault. Fairly often this is between the terminals and the voice coil, making a fix possible. Otherwise hopefully Rogers have some good suggestions. Some Rogers speakers (unfortunately I don't know which model) were my first real hifi experience.
 
turbo, have you posted in the wrong thread by mistake?

Hyfi:
It is odd for an 8 ohm driver to read higher DC resistance. Given also weak sound perhaps the connection is poor indicating a fault. I think swapping in a known good tweeter would be a good next test.

It would also be unusual for both crossovers to develop exactly the same fault, but in another thread you mentioned faulty solder joints so who knows what is happening. Again, subbing in another tweeter (and testing Rogers tweeter with that crossover) might shed some light.

Also it might be worth disassembling the dead tweeter to look for the fault. Fairly often this is between the terminals and the voice coil, making a fix possible. Otherwise hopefully Rogers have some good suggestions. Some Rogers speakers (unfortunately I don't know which model) were my first real hifi experience.

The guy who checked the board said that a tweeter by itself does not have much sound. I could do a full signal test but leery.

I am still waiting for the guy from Rogers to get back, but he has replied each time when he can. He is looking for replacements and or full specs. He thinks it is an MB Quart Titanium as that is the difference between the AS7 and AS7t along with overall mounting style and dimensions.

I have a pair of something for sale I could maybe yank out the tweeter for a test when I have more time. I will also open up the dead tweeter to see if I can determine anything.

Thank You
 
turbo, have you posted in the wrong thread by mistake?

Hyfi:
It is odd for an 8 ohm driver to read higher DC resistance. Given also weak sound perhaps the connection is poor indicating a fault. I think swapping in a known good tweeter would be a good next test.

It would also be unusual for both crossovers to develop exactly the same fault, but in another thread you mentioned faulty solder joints so who knows what is happening. Again, subbing in another tweeter (and testing Rogers tweeter with that crossover) might shed some light.

Also it might be worth disassembling the dead tweeter to look for the fault. Fairly often this is between the terminals and the voice coil, making a fix possible. Otherwise hopefully Rogers have some good suggestions. Some Rogers speakers (unfortunately I don't know which model) were my first real hifi experience.
Huh,,, OP has 3A Adagio's, made in France. The picture shows an ITT tweeter.3A-Adagio.jpg
 
Testing a speaker with a multimeter only gives the resistance with a DC current. It is not the same as a speakers rated AC impedance (even though both values are in Ohms). And to complicate matters the rated impedance of a speaker depends on the frequency. With some tones it can be much higher or lower than the overall rating. But to simplify things testing with a multimeter should give a number that is lower than the rated ohms of the tweeter. If your speaker is rated 8 ohms impedance and you get a 12 ohm DC resistance something is wrong.

For the OP.......The best way to check if a tweeter is bad is to swap it with the good speaker. If the problem swaps too the tweeter is bad.
 
I very recently bought some piezo tweeters on ebay. I connected an AA battery to one expecting to hear a little noise. Didn't hear a thing and got the same result from the other tweeter. Are they defective or is that normal for that kind of tweeter ? Thanks
 
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