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TheSeanis

Did I just blow my Tweeters on my KG4's?

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Hey guys, I'm new here! Long time lurker and I could really use some help from the guru's

I've been using my old Kenwood km-209 power amp paired with the kc-209 amp controller to drive my vintage KG4's. The kenwood is rated at 150w although the specifications say 155+155 for both channels and says 'Music Power' Is 310w. Here's the specs:  http://www.hifiengine.com/manual_library/kenwood/km-209.shtml

I ran the volume at about 50% for about 30-35 minutes until I came downstairs to lower the volume for about 30-60 seconds and then powered the system off. When I turned the system off, I heard a pop go through the speakers. It wasn't blaringly loud, but it was loud, and concerned me. I noticed the amp was pretty warm at that time, too. After letting it cool off for about ten minutes I turned the system back on and heard a strange garbled sound coming from the speakers. When I played music through them, the tweeters weren't putting out any sound. I plugged in my EPI's to test, and their tweeters worked, so, I'm pretty sure something happened to my KG4's.

Now, I'm a little concerned.. Can't these KG4's handle some juice? I was very skeptical that I might have damaged them with this system. I am also an idiot when it comes to audio equipment so please forgive me, I'm learning. Does anyone find it peculiar that both tweeters would blow exactly at the same time, AFTER I turn the system back on at a low volume? So weird to me.

Thank you for your help!

Sean

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They sure sound blown.  Maybe things were louder than you thought since you were upstairs?

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They sure sound blown.  Maybe things were louder than you thought since you were upstairs?

It was loud, maybe I'm naive.. I don't know how much wattage those speakers can handle..? I figured they could handle 150w no problemo. 

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They are probably blown.  A pop like that can be hard on a tweeter.  

 

My KG4 tweeters blew (30 years ago) when a friend turned up the volume incredibly loud while I was out of the room.  Before I could get back to lower the volume on the 85 wpc Yamaha receiver, both tweeters had blown.  I don't know if the receiver clipped or if there was some feedback distortion through the turntable, but the tweeters did not like it.  After that I fused the output from the receiver with a 1 amp in-line fuse.  Never had another issue until about 10 years later while I was playing the movie Top Gun at high SPL. The fuse blew on one of the speakers during the first scene of the movie (on the aircraft carrier with very loud engine afterburner and tail hook landing sounds).  When I put in a new fuse, the tweeter was damaged and sounded really bad.

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They sure sound blown.  Maybe things were louder than you thought since you were upstairs?

It was loud, maybe I'm naive.. I don't know how much wattage those speakers can handle..? I figured they could handle 150w no problemo. 

 

 

It's more than just power that can blow tweeters.  If I am playing loud I turn the eq down (treble control on your amp?) on the top end so it's not so "hot."

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They are probably blown.  A pop like that can be hard on a tweeter.  

 

My KG4 tweeters blew (30 years ago) when a friend turned up the volume incredibly loud while I was out of the room.  Before I could get back to lower the volume on the 85 wpc Yamaha receiver, both tweeters had blown.  I don't know if the receiver clipped or if there was some feedback distortion through the turntable, but the tweeters did not like it.  After that I fused the output from the receiver with a 1 amp in-line fuse.  Never had another issue until about 10 years later while I was playing the movie Top Gun at high SPL. The fuse blew on one of the speakers during the first scene of the movie (on the aircraft carrier with very loud engine afterburner and tail hook landing sounds).  When I put in a new fuse, the tweeter was damaged and sounded really bad.

I ordered some repair kits from crites because of the way people on here and audiokarma raved about them. Do you think those will hold up a little better? How do I know when I'm pushing too much into a speaker? Everything sounded great, and nothing broke until after I powered it back on. Like I mentioned before, it was pretty loud so I turned it down when I went downstairs. It played at a lower volume fine for a minute or so before I decided to power the system off and it was only when I turned it back on that there were issues, and is it common for both to go at the same time like that? Thank you for all your input by the way!

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Like most of the Klipsch Heritage series the Klipsch rating across the board is usually 100 wpc max with 400 wpc peak....or something like that.

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That really doesn't mean much. I have blown 200 wpc RMS speakers with a 35 wpc receiver. The levels an amp clips at can happen in an instant and do real damage. Literally a single passage in a song or on a movie can kill your amp, your speakers or both...

Edited by teaman
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That really doesn't mean much. I have blown 200 wpc RMS speakers with a 35 wpc receiver. The levels an amp clips at can happen in an instant and do real damage. Literally a single passage in a song or on a movie can kill your amp, your speakers or both...

Thank you for your reply. This might be a dumb question, but what can I do to prevent or avoid this from happening? Do I even know that there was clipping happening? The speakers were playing fine and sounded lovely. It wasnt until I turned them on again that I heard the strange garble sound and then nothing from the tweeters.

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KG4's are rated for 100 watts continuous, 500 watts peak. Based on your description of what happened, the loud pop when you turned off the amp, is probably what killed the tweeters. Particularly since you said they sounded fine for a minute or so after you turned the volume down.

And if your amp is making that pop every time you turn it off, even with the volume turned down, it may have an electrical issue. And that could be sending some very high energy, high frequency noise to your speakers. Which could easily kill the new diaphragms you ordered from Crites.

The type of music could have something to do with it, particularly if it was bass heavy...as that may have just pushed the amp into clipping. And 30 minutes of that could kill a tweeter as well.

The main Klipsch website is being updated, so the specs for the KG4 aren't available. But here is a link to the archived specs for the KG4.

https://web.archive.org/web/20111127070629/http://www.klipsch.com/kg-4

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KG4's are rated for 100 watts continuous, 500 watts peak. Based on your description of what happened, the loud pop when you turned off the amp, is probably what killed the tweeters. Particularly since you said they sounded fine for a minute or so after you turned the volume down.

And if your amp is making that pop every time you turn it off, even with the volume turned down, it may have an electrical issue. And that could be sending some very high energy, high frequency noise to your speakers. Which could easily kill the new diaphragms you ordered from Crites.

The type of music could have something to do with it, particularly if it was bass heavy...as that may have just pushed the amp into clipping. And 30 minutes of that could kill a tweeter as well.

The main Klipsch website is being updated, so the specs for the KG4 aren't available. But here is a link to the archived specs for the KG4.

https://web.archive.org/web/20111127070629/http://www.klipsch.com/kg-4

Thank you for that. I wasn't listening to anything crazy really. Relaxing to some Eagles while doing dishes. I think the pop may have come from a sequencing error on my part, I believe I turned the pre-amp off before I turned off the power amp. I Know that the general rule of thumb for the power amp is last on/first off and I did not know that until today. 

I have a backup amp that I'm working on. My father has had a lot of really great components over the years and I'm working on a Tandberg TR 2080 receiver that I screwed up in my teenage years to repay the favor. My fear now is that maybe that Tandberg amp would clip because of the lower RMS rating -- I definitely do not want to damage his amplifier or damage my speakers any further. 

I figured that if the wattage was higher, like the 150w RMS on the Kenwood amp the Klipsch would be good to go. Is it safe to assume there wasn't any clipping occuring? It was only at 50% volume. I know those Klipsch speakers are pretty efficient but I figure that @ 50% volume it can't be drawing all 150w out of the amp and therefore would not have clipped. I could be totally off base here... I'm thinking my shut-down sequencing error might have blown the tweeters. 

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The 100 w RMS/ 500 peak dose not tell you that you only need a 1/10 or that to power the tweeters to their max if that much.

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Not sure if the sequence of turning the amp and preamp off had anything to do with it, unless your amp/preamp combo has an issue to start with. My Emotiva monoblocks are triggered on and off with the preamp power. My amps put out 600 wpc at 8ohms and I would never think I am using anywhere near that. Amplifier power output and speaker power handling are only parts of the equation. When I bought my Infinity SM150 speakers back in 1988 or so the salesman showed me what they could take by turning the Kenwood 300 wpc amp up three quarters of the way while playing a cd....then he hit pause....then he hit pay again and the music came blaring back on. He told me only two pair of speakers he sold would accept that abuse, mine and the Cerwin Vega DC-9's. Impressive to say the least.

 

Even after seeing, and hearing that I have never pushed my speakers to any limits so to speak. If the speakers begin to sound harsh you are probably pushing them too hard. My personal rule of thumb is I never turn my amps up past 40%. Anything higher and you are asking for trouble. After the 50% mark the THD starts to kick in and that is where problems come into play. 

 

Tim

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The 100 w RMS/ 500 peak dose not tell you that you only need a 1/10 or that to power the tweeters to their max if that much.

So the tweeters clipped but not the woofers? Am I understanding this right? Also, there's no surefire to way prevent tweeter clipping?

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It's hard to know what 50% on a volume knob represents... Depending on the gain structure of the amp and the input voltage driving it, it could be 20 watts or 120 watts??? So it's possible to reach an amp's limit well before the volume is "turned all the way up".

Even if the amp was just barely clipping, you might not know it. But if it went on for 30 minutes, then it could still kill a tweeter.

As you mentioned, the turn off sequence, if not followed, can easily send some loud transients through your speakers. And again, since they sounded fine for a minute or so after you turned them down, it was probably the pop that did them in... And not the volume itself.

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Woofers can usually take much higher power than tweeters. The tweeters might only accept 15 wpc, while the woofers handle 300. Woofers usually don't clip, they just blow their voice coils or the cone moves out of alignment. Tweeters usually clip, sometimes partially. You will notice the sound being "off" in the highs and mids but the sound may not be gone entirely. I usually turn the treble down and the loudness control off. This reduces the power directed to the tweeters and helps to keep the bass from overpowering the woofers.

 

Audio is a fragile and expensive hobby. My buddy had $4k Wharfedale speakers and blew both tweeters and a woofer in them in a single burst of music from his Pioneer receiver. Party music playing loud and everyone enjoying themselves one second and complete shock the next. Muffled bass from one tower was all that was left coming out. Luckily the local dealer accepted them back under warranty or it would have cost him nearly three grand to fix them.

Edited by teaman
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The amplifier is what clips... When it's asked to produce more power than it's capable. When this happens, it can generate high frequency distortion which is what can cause the tweeter voice coil to burn out.

If the amp is powerful enough, it may not clip, but will send enough voltage to physically move the voice coils too far (forward & back) which just damages the speaker.

A woofer's voice coil can also burn out, but usually from just too much continuous power (overheating). And that's if the woofer voice coil isn't already bottoming out... which can cause physical damage to the woofer.

Even though the KG4 may be rated for 100 watts continuous, the tweeter itself might only be capable of handling a few watts. The crossover sends the rest of the power to the woofers.

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The amplifier is what clips... When it's asked to produce more power than it's capable. When this happens, it can generate high frequency distortion which is what can cause the tweeter voice coil to burn out.

If the amp is powerful enough, it may not clip, but will send enough voltage to physically move the voice coils too far (forward & back) which just damages the speaker.

A woofer's voice coil can also burn out, but usually from just too much continuous power (overheating). And that's if the woofer voice coil isn't already bottoming out... which can cause physical damage to the woofer.

Even though the KG4 may be rated for 100 watts continuous, the tweeter itself might only be capable of handling a few watts. The crossover sends the rest of the power to the woofers.

Thank you for that explanation it really helped out. Do you happen to know if the crites replacements are built a little more robust? I just don't like the idea of constantly worrying I'm going to fry the tweeters.

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You'll have to contact Crites and ask them directly. I'm sure they can give you more detail about how much power their diaphragms can handle... if it's more than stock.

But most if not all of their products are essentially drop in replacements for the stock items. And built to perform as new.

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