Advice on SongTower tweeter issue

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gkinberg

Advice on SongTower tweeter issue
« on: 6 Jul 2015, 11:22 pm »
Hello all,

I emailed Jim about this issue but as I'm sure he is a very busy man, I thought I would query the board as to any insight. I have been having some issues with my receiver creating distortion in my right channel. I checked my cables, changed power plugs and just generally tinkered trying to diagnose the source of the problem. I don't know if it was the distortion or from operator error during my diagnosis but I realized that I had no sound coming from my dome tweeter in the right channel.  I don't know if it is fried or if something else is wrong such as loose internal wiring. I am hoping it is not blown as I assume a blown tweeter would make some sound during playback. I tried to remove the tweeter to examine it for some obvious problem but after removing the screws, it occurred to me that I didn't know how to dislodge the tweeter from the baffle. Could someone please advise a way to diagnose the problem

Thanks, Garth

ricardojoa

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Re: Advice on SongTower tweeter issue
« Reply #1 on: 6 Jul 2015, 11:52 pm »
 If you have a hard time pulling the tweeter, you can try remove the woofer and push the tweeter out from woofer opening. Just becareful and gentle as the venner can crack from the hard surface of the tweetet plater or woofer frame.

milford3

Re: Advice on SongTower tweeter issue
« Reply #2 on: 7 Jul 2015, 12:13 am »
I have replaced a few drivers in my different brands of speakers I have owned. Drivers DO go bad.  If the tweeter is not working it needs to be replaced.  Call Jim and he should just send you a new one.   

srb

Re: Advice on SongTower tweeter issue
« Reply #3 on: 7 Jul 2015, 12:13 am »
I have a handy utility hook / magnet tool that I've used to gently pry under the screw hole to break it free.

 

If you don't have that, an oversize screw gently turned in to grab and bite the bottom of the hole has also worked.

Either way, it is a good idea to hold a flat metal rule or similar tightly against the veneer at the point of extraction to prevent any lifting of the veneer as previously mentioned.

Removing the tweeter is the only way to troubleshoot this.  A tweeter could be damaged such that its voice coil is rubbing and still producing some sound, but a lot of the time a "blown" tweeter probably has a break in the fine voice coil wire and produces no sound at all.

But it certainly could be a wiring issue too.

Steve

Mudslide

Re: Advice on SongTower tweeter issue
« Reply #4 on: 7 Jul 2015, 02:35 am »
You probably did, but I have to ask...did you actually swap the left channel speaker cable with the right one (leave the cables in the receiver alone...just swap cables at the speakers)?  That's where I would start before digging into the drivers.

laulau

Re: Advice on SongTower tweeter issue
« Reply #5 on: 7 Jul 2015, 03:18 am »
^^^^

+1, except don't SWAP the cables (don't plug the speaker cable from the receiver's right speaker into the left speaker), just take the cable from the left speaker and connect it to the right speaker.  If the distortion from the receiver was enough to fry the right-side tweeter, it could do the same thing to the left tweeter. 



Mudslide

Re: Advice on SongTower tweeter issue
« Reply #6 on: 7 Jul 2015, 06:03 am »
^^^^

+1, except don't SWAP the cables (don't plug the speaker cable from the receiver's right speaker into the left speaker), just take the cable from the left speaker and connect it to the right speaker.  If the distortion from the receiver was enough to fry the right-side tweeter, it could do the same thing to the left tweeter.

Safer idea!

gkinberg

Re: Advice on SongTower tweeter issue
« Reply #7 on: 8 Jul 2015, 04:52 am »
I plugged the right speaker into the left speaker cable and no distortion but also no high frequency. Using Steve's oversized screw method, I was able to remove the tweeter. It is somehow heavier than I expected and the wiring  was still in tact. That is about the level of my diagnosis expertise. I assume if I  had the right meter, I check for resistance or lack there of. I could try to borrow an Ohm meter from someone but what would I look for that would tell me if it is damaged?

Thanks to all for your input, Garth

MichiganMike

Re: Advice on SongTower tweeter issue
« Reply #8 on: 8 Jul 2015, 12:42 pm »
You might try a simple test with a battery or borrow an ohmmeter.  See videos at links below and read the thread at audiokarma about testing tweeters for more information. 

https://www.youtube.com/watch?v=xIMHGkxw72o

https://www.youtube.com/watch?v=XpdKpnz8h64

http://www.audiokarma.org/forums/showthread.php?t=103209

You can purchase an inexpensive meter to measure ohms for about $10 from Amazon.  Harbor Freight has one on sale for $6.

http://www.harborfreight.com/7-function-digital-multimeter-69096.html

gkinberg

Re: Advice on SongTower tweeter issue
« Reply #9 on: 16 Jul 2015, 04:01 am »
I borrowed a multimeter from a friend and tried to check the resistance of the tweeter. The back of the tweeter does not have what I would say are conventional terminals. There are two separate areas that are recessed and a beige/bronze color. There are solder points on this beige surface where the wires are attached. When I place the probes of the Ohm meter on the beige area I get no reading or very high resistance but I get about 6 Ohms when placing the probes on the solder joints or the attached wires. This is with the speaker cables plugged into the back of the speakers. this surprised me because I was almost positive that the tweeter was blown. Is there an explanation as to why I would get this reading even though the tweeter is blown? I know these are probably naïve questions but I am a novice with respect to these issues.

Thanks for any help. Garth

Big Red Machine

Re: Advice on SongTower tweeter issue
« Reply #10 on: 16 Jul 2015, 11:39 am »
A blown tweeter does not mean open like a fuse. The windings inside, voicecoil, spider, etc. are many things that can fail.  I'd say the windings are the last to fail. Probably an intermittent failure that drives troubleshooters crazy. Power it on and it fails, measure it dead and it looks okay. Ugh.

gkinberg

Re: Advice on SongTower tweeter issue
« Reply #11 on: 18 Jul 2015, 05:58 pm »
Jim suggested that the by measuring the tweeter while still attached, I was probably reading the resistance of the crossover network. After snipping the wires and detaching the tweeter, my new measurement shows OL, therefore, dead tweeter. I will be ordering a new one from Jim shortly. Thanks to all for your help.

Garth