take an extension cord, cut off the female end, strip, connect to the speaker + and - binding post... plug other end of extension cord into the wall outlet... wait until its done smoking. speaker is now bad. sell them a new one!

If it survives, however, it's just another Cerwin Vega.


Read. I said the dip was below 100 Hz, not at 100 Hz. I think it was around 40 Hz. The guy was trying to design a system with one woofer for really low bass and another for not so low bass. The trouble was that he put a 12 dB/octave low pass in front of the first woofer with the series inductor too low in value and the parallel capacitor so high in value that the impedance of the combination was way below that of the woofer, and took the system impedance down to about 2 ohms.

Once you notice that I said "below 100 Hz" it's not so WTF-worthy.


Wish I'd thought of that. After I read it, though, I came up with

Tempt it!

What do you mean "He was"?

If you want a real eye-opener, go to Audio Karma and read about what some of those people consider to be great vintage speakers and electronics from the '70s. Radio Shack? Technics? Project One?

I was typing fast. When I hit Post, I just knew that would come back to me.

Jesse Winchester R.I.P.

Simple speaker check. Ohmmeter. Speakers that match (front L&R, surrounds) should read about the same DC resistance. If one has a variation of 20% or more from the others, good chance that woofer has a wasted voice coil. Most speakers rated at 8 ohms will read about 6 ohms or thereabouts DC resistance. Impedance is apx 25% above the DC resistance.

If you suspect a bad woofer, gently push its cone in and out. No rubbing or scraping feel should be noted. You can hear it and feel it. Compare to the other speakers - they should all move freely. A bad woofer is usually the only one that will kill the amp that was just repaired. A shorted (often frozen in position) cone will wreak havoc; a rubbing cone will usually buzz at lowest volumes but be masked and sound relatively normal at moderate levels and above. A rubbing voice coil will not kill an amp.

For mids and tweeters, just listen to them. Make sure each speaker has the same clarity as the other speakers in the system. If a tweeter or mid is blown, it will be pretty apparent as long as you don't have a tin ear.

There has been a lot of odd information in the earlier posts but most has been weeded out. One poster claimed


I can assure you that amps putting speakers in series is *not* the case, and I have all the service manuals in my storage unit from the late 60's to the late 90's to prove it. Kenwood from the 80's was about the only one, cheap, cheesy amps. Earlier beefy Kenwoods did not. Pioneer, Sansui, Yamaha, Technics, HarmanKardon, Sony... no sir. You could easily tell this was the case by switching from "A" speakers to "A+B" speakers... when you only had one pair actually connected. If the amp put these in series, you got NO sound. If you got sound, they were parallel.

An impedance meter is not *required* to test speakers. It can be of help with 4-8 ohm speakers, but in the case of a 70volt system, is indispensable.

Like Bruce and Ernie, I have repaired hundreds of speakers over the last 40 years.

You absolutely can tell if they're in series by switching to A+B, but a Sony amp was what motivated me to make response measurements of different speakers in series.

This was in 1980. I worked at Marantz's headquarters. Marantz was then owned by Superscope, which had had the exclusive deal to distribute Sony tape recorders. That deal was coming to an end, so I felt it worthwhile to test to see if Marantz amps and receivers, which always put speakers in parallel, would sound better than Sony receivers, some of which put speakers in series.  It was only the cheapest receivers that put speakers in series, and that's because they could not deliver the current to parallel them. 

Not even worth thinking about. A single stray shorting would have thrown it into protect during demo with any kind of volume.


I just had an ES-500-Point 6 go bad.
System sounded like watching a movie through a cheap clock radio.
I updated the Denon firmware (no luck) Reset processor (luck) the Denon came back up in stereo mode and sounded good. Threw it on PLII and it was bad again.
Center Channel is only outputting through the tweeter.

Took me two hours to figure this out so if anyone wants to come over and punch me in the face I'll stand here and take it.

To be fair, I have over a thousand of these speakers in production homes and this is the first bad one so it was the last thing I looked at. I was sure it was a Denon issue but this time Denon wins.

Tweeter-only output is so far off our mental collection/list of things that can go wrong that it's no surprise that you didn't get it sooner, especially when other speakers were playing in the room and the bass was (I'm guessing) coming from a sub. No need to punch you in the face: you've already done that for yourself.

So, I reinstalled the Denon and tested the crap out of it for over an hour. I watched a dvd at very high volume levels, played with the mute on / off, switched over to music (at high volume) and it didn't do damn thing.
The customer sent me a text last Saturday night to tell me that it went out again.
I don't know what else to do at this point other than install a new receiver and hope it was the Denon. I checked the woofers as some of you have said to do. Played music to see if they sounded the same. Measured with ohm meter, though many of you said it really wouldn't show me anything.
What else is there to do??



Did this and got 5.3, 5.3, 5.5 ohms on the LCR's, which are 6.0 Ohms. The rears were 7.7, 7.5 and are 8.0 ohms.


Did this and no "rubbing or scratching"

Did this and similar sound on all

???

Bare with me. It is 4am. 2 year old is up with a killer fever and I am awaiting her reaction to Tylenol before I cave in and raid the ER.

What HDMI sources are connected to the avr? Is there by chance a Motorola cable box? An older one? As I read this, it conjured up vague memories of a problem I encountered where an AVR (i think it was integra) was going into protection mode intermittently, yet often. During troubleshooting, I discovered that if I left the HDMI from the cable box disconnected, the problem ceased. Tech support (for the AVR obviously, as how helpful would a call to the cable co. Have been?) Said that they had seen this issue before and it was something wrong with the HDMI stuff in the cable box. I am sorry I do not remember more detail. But a new cable box was installed and everything was fine.....probably until the HDMI board went out.....bwahaha....assuming it was an integra, that is.

Just taking swings here. let us know what you find out.....again.

Same goes with Marantz,
I've had a few with the same symptoms

It's a Fios cable system and I'm pretty sure it's a Motorola? I'll find out later today as I put in a new Pioneer Elite that I have sitting on my shelf.
The system only has a cable DVR and an LG BR player and Sonos Connect.

Do you limit the output level of receivers when you install them? I usually let the end user go to -10dB because, if they can crank it to WOT, they will and small speakers don't handle puking amplifiers anyway. Plus, it sounds really bad.

Watch the speaker cones when you crank it- at some point, the cone will begin to move wildly and that's a good way to make a receiver's protection circuit kick in. The un-damped moving cone can send current back to the amplifier.