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Old 12-16-2009, 11:42 AM
andyrom52 andyrom52 is offline
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Default Trebble Tone Vanishes...

Hey All,

Firstly let me apologize for not being too tech savvy, but I'd like to explain a situation I was having with my PA at a show last night:

At one point in the show, while singing a strong note, a "loud buzz" or "crunch" was audible and shortly thereafter, all trebble tone seemed to have dissappeared. The lows and mids seemed to be uneffected, but any trace of highs or "sparkle" was gone from the tone of vocals/guitar/keyboard.

Before I dig in, I just wanted to throw this out there and see if anyone else who may have had a similar experience can point me in the right direction of what to look for with regards to diagnosis, repairs, etc...

Quick note on my gear/set-up: Guitar (Direct Input - Unbananced), Keyboard (Direct Input - Unbalanced), (3 vocal mics - Bananced). Powered mixer (Samson 910) on main bridge mode (one speaker). Speaker is an EV ZX1-90 (passive). Playing a small room (which we've played with the same set up dozens of times w/o problem) at a reasonable volume level.

Thanks in advance for the help!
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Old 12-16-2009, 09:08 PM
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I would bet you fried either the internal crossover in the speaker OR the diaphragm in the compression driver.
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Old 12-16-2009, 09:47 PM
BoB/335 BoB/335 is offline
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Sounds like the diaphram in the horn driver. Open the cab, disconnect the wires off the horn driver and remove the driver. Most drivers screw on. Occassionally they bolt on. Once you have the driver in your hand put an ohm meter across the terminals. I bet you won't get any reading which means there is an open in the coil and you need a new coil. You can buy just a coil but there is some precision in replacing a coil. I fried a coil and it was cheeper to buy a whole new driver. You will need to figure out what caused the problem in the first place.

If the coil checks good (I doubt it) then it's probably the crossover. You definitely lost the high end from your description. It's the coil or the crossover.
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Old 12-16-2009, 10:03 PM
BoB/335 BoB/335 is offline
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Quote:
Originally Posted by andyrom52 View Post
Hey All,

Firstly let me apologize for not being too tech savvy, but I'd like to explain a situation I was having with my PA at a show last night:

At one point in the show, while singing a strong note, a "loud buzz" or "crunch" was audible and shortly thereafter, all trebble tone seemed to have dissappeared. The lows and mids seemed to be uneffected, but any trace of highs or "sparkle" was gone from the tone of vocals/guitar/keyboard.

Before I dig in, I just wanted to throw this out there and see if anyone else who may have had a similar experience can point me in the right direction of what to look for with regards to diagnosis, repairs, etc...

Quick note on my gear/set-up: Guitar (Direct Input - Unbananced), Keyboard (Direct Input - Unbalanced), (3 vocal mics - Bananced). Powered mixer (Samson 910) on main bridge mode (one speaker). Speaker is an EV ZX1-90 (passive). Playing a small room (which we've played with the same set up dozens of times w/o problem) at a reasonable volume level.

Thanks in advance for the help!
I need you to clarifer something. Powered mixer on main bridge mode (one speaker). What does that mean? I'm checking the manual online and I don't see a "bridge mode". I also notice that the specs say it's rated for a 4ohm load for each channel and you are using an 8ohm speaker. I have to look further because I think it would be unusual for a mixer like that to have 4 ohm loads for each side.

Edit: I found where the setting is for "bridge mode". I don't see any specs for the ohms at the different settings.

2nd Edit: I checked the ratings for my Yamaha EMX 5000-12 which seems to have similar ratings but they are expressed much clearer. My manual states that "bridge mode" sends 1000watts to a single 8ohm load. If you in fact have a single little EV ZX1-90 that is rated to get only 200 watts continuous/400 watts program/800 watts peak, then you FRIED the voice coil in the horn driver giving it 1000 watts and could be in danger of frying the voice coil in the 8" speaker.

Who told you to hook it up that way???

Last edited by BoB/335; 12-16-2009 at 11:45 PM.
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Old 12-17-2009, 03:12 PM
andyrom52 andyrom52 is offline
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Quote:
Originally Posted by BoB/335 View Post
I need you to clarifer something. Powered mixer on main bridge mode (one speaker). What does that mean? I'm checking the manual online and I don't see a "bridge mode". I also notice that the specs say it's rated for a 4ohm load for each channel and you are using an 8ohm speaker. I have to look further because I think it would be unusual for a mixer like that to have 4 ohm loads for each side.

Edit: I found where the setting is for "bridge mode". I don't see any specs for the ohms at the different settings.

2nd Edit: I checked the ratings for my Yamaha EMX 5000-12 which seems to have similar ratings but they are expressed much clearer. My manual states that "bridge mode" sends 1000watts to a single 8ohm load. If you in fact have a single little EV ZX1-90 that is rated to get only 200 watts continuous/400 watts program/800 watts peak, then you FRIED the voice coil in the horn driver giving it 1000 watts and could be in danger of frying the voice coil in the 8" speaker.

Who told you to hook it up that way???
Thanks so much for looking into this for me.

I've had this set up since last Christmas, and I've always used it in this manner. The sales clerk from Sam Ash told me that I could use this set up as long as I'm not driving the speaker too much as it should be 450watt output (half the mixer's capacity of 900).

I just took him on his word, and (until this point) I haven't had a problem with it. I'll open the speaker up over the weekend, and check the voice coil as per your advice, then report back my findings. With that said, would you suggest that I invest in a better speaker (if so any suggestions) when running through this set up?
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Old 12-17-2009, 03:32 PM
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It is not a speaker issue....it is a setting issue. That speaker is well suited to one of the amps in that head, not both bridged.
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Old 12-17-2009, 04:07 PM
andyrom52 andyrom52 is offline
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Quote:
Originally Posted by trpullen View Post
It is not a speaker issue....it is a setting issue. That speaker is well suited to one of the amps in that head, not both bridged.
Well, obviously I screwed up here... I'm suprised that it lasted 25+ shows with this set up if it's as bad as you're saying.

Assuming that the voice coil is fried, would it be worth it to repair the speaker, if so any suggestions on where I can get the parts?
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Old 12-17-2009, 04:15 PM
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ZX1-90 Part Numbers
• 301850-001 ZX1-90, 90° x 50° Horn, Black Finish
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Old 12-17-2009, 04:19 PM
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U.S.A. and Canada only. For customer orders, contact Customer Service at:
800/392-3497 Fax: 800/955-6831
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  #10  
Old 12-17-2009, 04:20 PM
andyrom52 andyrom52 is offline
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Quote:
Originally Posted by trpullen View Post
ZX1-90 Part Numbers
• 301850-001 ZX1-90, 90° x 50° Horn, Black Finish
Thanks trpullen!
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Old 12-17-2009, 05:12 PM
Herb Hunter Herb Hunter is offline
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Tweeters are more often burned out by underpowered amplifiers driven into clipping than by a powerful one that is not driven into clipping. The tweeter didn't burn out because it was being driven by a 1000 watt amplifier. Most likely it burned out because the tweeter was defective, high frequency feedback (not mentioned), or because the volume was turned up too high for the capacity of the speaker. If the volume was turned up too much it is likely that the overall sound would have been distorted before the tweeter voice coil burned up. If the sound was clear and then a sudden, brief buzzing noise occurred just before the voice coil burned, then I'm inclined to suspect that the tweeter failed due to a defect.
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Old 12-17-2009, 09:25 PM
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Originally Posted by Herb Hunter View Post
Tweeters are more often burned out by underpowered amplifiers driven into clipping than by a powerful one that is not driven into clipping. The tweeter didn't burn out because it was being driven by a 1000 watt amplifier. Most likely it burned out because the tweeter was defective, high frequency feedback (not mentioned), or because the volume was turned up too high for the capacity of the speaker. If the volume was turned up too much it is likely that the overall sound would have been distorted before the tweeter voice coil burned up. If the sound was clear and then a sudden, brief buzzing noise occurred just before the voice coil burned, then I'm inclined to suspect that the tweeter failed due to a defect.
While technically true.....this has gotten more people in trouble than helped. Grossly underpowered is really bad but so is grossly overpowered. A pure clean tone will not roast a speaker when overpowered. any hint of square wave distortion becomes voltage and cuts through like a laser.

More than likely, you did clip something and with all that wattage, you fried it.
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