Just fried a speaker

[olds]

I just blew the 4.5" rear firing midrange in one of my BP2006TLs. The speakers are out of warranty.
The speaker smells like it is burned but there are no obvious signs of damage. The sound that emanates from it is a crackling sound.
Is there a place where I can purchase this speaker? There are some numbers on the back: 0130A100 0209. Anyone know who makes the speakers for Def Tech?
Def Tech is closed till Monday.

 

[Snakexor]

def tech makes def tech's speakers. gl finding a replacement, however def tech should offer to fix it themselves.

 

[The Boston Dangler]

i'm sorry to hear that. i've been enjoying my def tech's for years, although i've never dealt with the factory. they are based in MD.
GL!

 

[olds]

Got one coming, $60.

 

[sdifox]

Originally posted by: oldsmoboat
Got one coming, $60.

from def tech? not bad then. maybe I should pick up a few 6.5 as spares

 

[Rubycon]

Toasted a voice coil. Amp into clipping too much?

 

[olds]

Originally posted by: Rubycon
Toasted a voice coil. Amp into clipping too much?

I have a Denon 3805.
I was wondering if it could be from a poorly recorded CD? I ordered a CD from Ebay and it fried when I played the first song on the CD.
I had it loud but not cranked.

 

[Rubycon]

Possibly.

A poor recording (lots of distortion) is no different than running a preamp/mixer/processor etc. into clipping. Amplifying such a signal can easily put much more power into the voice coil which raises the temperature dramatically.

High frequency drivers often use coils bathed in ferrofluid to take bursts of power better to avoid power compression (sudden heating of voice coils increases resistance which means less wattage drawn from the amp). It can enhance continuous power handling as well but its main role is to improve transient handling which is important with live music monitoring, special effects, and reference recordings.

Mid frequency drivers (compression drivers used in pro audio) may use FF however in most home systems the MR is direct radiating and will have xmax that may be excessive for FF application. Edgewound coils with high temperature varnish, perforated formers and vented pole pieces are often used to improve power handling. Look for fatter voice coils for better power handling in general.

Low frequency drivers use air cooling through vented pole pieces exclusively. Some may have fins on the backplate to assist in the removal of heat from the magnet assembly. The key here is to get the heat out of the gap as quickly as possible.

Most well designed speakers will handle well beyond their power ratings (for short term) to handle a snare drum hit or uzi blast in a movie at point blank range. The enormous crest factor that can be presented to the amplifier will quickly reach its power supply rail limit and go straight to clipping hell in a henbasket 99% of the of the time (with a receiver), however. This is apparent when turning up the volume and the hits don't get louder and they start sounding smeared. The speakers don't fare too well under these conditions.

If the producer haphazardly put something together and flunked gain structure in school, there's a good possibility that this could have happened and been recorded. When this is amplified - even at moderate levels - it can easily become a speaker (and ear!) shredder!

 

[olds]

Originally posted by: Rubycon
Possibly.

A poor recording (lots of distortion) is no different than running a preamp/mixer/processor etc. into clipping. Amplifying such a signal can easily put much more power into the voice coil which raises the temperature dramatically.

High frequency drivers often use coils bathed in ferrofluid to take bursts of power better to avoid power compression (sudden heating of voice coils increases resistance which means less wattage drawn from the amp). It can enhance continuous power handling as well but its main role is to improve transient handling which is important with live music monitoring, special effects, and reference recordings.

Mid frequency drivers (compression drivers used in pro audio) may use FF however in most home systems the MR is direct radiating and will have xmax that may be excessive for FF application. Edgewound coils with high temperature varnish, perforated formers and vented pole pieces are often used to improve power handling. Look for fatter voice coils for better power handling in general.

Low frequency drivers use air cooling through vented pole pieces exclusively. Some may have fins on the backplate to assist in the removal of heat from the magnet assembly. The key here is to get the heat out of the gap as quickly as possible.

Most well designed speakers will handle well beyond their power ratings (for short term) to handle a snare drum hit or uzi blast in a movie at point blank range. The enormous crest factor that can be presented to the amplifier will quickly reach its power supply rail limit and go straight to clipping hell in a henbasket 99% of the of the time (with a receiver), however. This is apparent when turning up the volume and the hits don't get louder and they start sounding smeared. The speakers don't fare too well under these conditions.

If the producer haphazardly put something together and flunked gain structure in school, there's a good possibility that this could have happened and been recorded. When this is amplified - even at moderate levels - it can easily become a speaker (and ear!) shredder!

I think it is the CD.
The CD is activating some type of shut down on the head unit in my truck.
If I crank it up, the unit powers off and back on at a lesser volume level. Any other CDs just sound like crap if I crank them too loud.
Head unit is a Blaupunkt San Jose, just for reference.
No tech help, just a follow up.

 

[The Boston Dangler]

What's the CD? I find the Black Crowes studio albums are matched by only Led Zeppelin BBC Sessions for abusive loudness.

 

[spidey07]

You might want to pull your crossover as well and visually inspect it/smell it. If it was loud enough to damage the driver, it's possible to damage the crossover.

There should be screws that hold where you attach the speakerwire, the crossover is likely on the other side of that cover.

Also, drivers aren't that expensive (as you found out) and most good speaker manufacturers will be happy to sell you one and many times just give you one for free if it's out of warranty.

Rubycon has great advice. You should immediately be able to tell the sound of clipping - it starts to smear and lose tightness. If you think it's the recording then it's quite possible the engineer sucked and actually clipped the input.

 

[olds]

Originally posted by: The Boston Dangler
What's the CD? I find the Black Crowes studio albums are matched by only Led Zeppelin BBC Sessions for abusive loudness.

Robert Plant "Now and Zen".

 

[Rubycon]

Originally posted by: oldsmoboat
Robert Plant "Now and Zen".

Any specific track or area?

I have this work (from '88) and haven't found any issues but I could run it through analysis. The version I have is probably different than a public CD though.

I remember using "Dance On my Own" and "White Clean and Neat" in sound checks on large stadium venue PA's back in the early 90's. The Crown Macro Tech's never complained but the neighborhood kids would come running fast. :laugh:

 

[olds]

It blew the HT speaker on Heaven Knows but that's the first track. It will shut down my head unit on any track.
I have the CD from the 80's some where. I didn't feel like looking for it so i ordered it off Ebay.

 

[cheesehead]

How odd. I'd presume that your amplifier is not clipping, but simply that the mid is being pushed past its limit.

Also, replacing the capacitors on the crossovers would be wise.

 

[FP]

So playing a song with lots of distortion could damage speakers? I have often wondered that. Especially when playing certain tracks that purposely add distortion (many Nine Inch Nails tracks for example).

Are you saying that playing a NIN track too loud on HT speakers with an adequate amp could still damage the speakers?

 

[Rubycon]

Originally posted by: binister
So playing a song with lots of distortion could damage speakers? I have often wondered that. Especially when playing certain tracks that purposely add distortion (many Nine Inch Nails tracks for example).

Are you saying that playing a NIN track too loud on HT speakers with an adequate amp could still damage the speakers?

Yes - even if the amp is not clipping it's still amplifying a signal that will put more power than normal into drivers not designed to handle this power on a long term basis and stress them thermally - often to the point of failure if not checked. If it sounds harsh to your ears it's a good chance it's not good for the speaker either.

In pro audio this gets a lot of folks in trouble as they feel they are safe with limiting. Problem is a limiter will indeed keep the amp from clipping however once the peaks reach the limit and the master gain is cranked higher you have the same thing going on - an elevated average level. If this average level is within the thermal capabilities of the mid/hi section of the speaker system, it won't fail but I can guarantee it won't sound good or musical.

 

[FP]

Originally posted by: Rubycon

Originally posted by: binister
So playing a song with lots of distortion could damage speakers? I have often wondered that. Especially when playing certain tracks that purposely add distortion (many Nine Inch Nails tracks for example).

Are you saying that playing a NIN track too loud on HT speakers with an adequate amp could still damage the speakers?

Yes - even if the amp is not clipping it's still amplifying a signal that will put more power than normal into drivers not designed to handle this power on a long term basis and stress them thermally - often to the point of failure if not checked. If it sounds harsh to your ears it's a good chance it's not good for the speaker either.

In pro audio this gets a lot of folks in trouble as they feel they are safe with limiting. Problem is a limiter will indeed keep the amp from clipping however once the peaks reach the limit and the master gain is cranked higher you have the same thing going on - an elevated average level. If this average level is within the thermal capabilities of the mid/hi section of the speaker system, it won't fail but I can guarantee it won't sound good or musical.

Damn... I bought the Beside You In Time HD-DVD of the last NIN tour and when I play it I can definitely hear the distortion that is present in their tracks. The audio sounds fantastic (TrueHD) though.

Do you think there is anything to worry about?

EDIT: If you aren't familiar with NIN listen to the distortion added to this track. (around 15sec). That is what I am referring to. You can definitely hear it when I crank my system to reference levels.

 

[Rubycon]

Originally posted by: binister

Damn... I bought the Beside You In Time HD-DVD of the last NIN tour and when I play it I can definitely hear the distortion that is present in their tracks. The audio sounds fantastic (TrueHD) though.

Do you think there is anything to worry about?

EDIT: If you aren't familiar with NIN listen to the distortion added to this track. (around 15sec). That is what I am referring to. You can definitely hear it when I crank my system to reference levels.

Probably not a problem - reference level is not very "loud" if the given program has wide dynamic range. It really depends on the type of drivers you have as well. Speakers with low efficiency of < 90dB 1W/1M may have problems reaching so called reference levels - especially at FOH. :Q

The important thing to remember is a speaker power rating is based on program material. Luckily music is hardly a continuous tone so it's possible to have a full range loudspeaker system with a single 15" woofer with a 4" voice coil, 6x14 MR horn with a 3" voice coil, and 4x14" high frequency horn with a 2" voice coil that can handle 1500W program, 3000W peak and not be stressed. This does NOT mean the speaker can handle a 1500W sine wave! When it comes to sine waves, the speaker is ONLY going to handle this based on its frequency. The speaker in the example given would handle a 60Hz sine wave of 600W as all the power goes in the woofer and at typical one way 8mm Xmax there will be plenty of air moving through the pole piece cooling the gap. At 1.5kHz the power handling would drop to 200W since most of this would be going to the midrange whose diaphragm may be ferrofulid cooled. Even higher sine waves of 10kHz would take the max power down even further since the drivers become more delicate and susceptible to overheating from this example. Most home speaker high frequency drivers cannot handle more than 10-20W, however this represents a 120+ wpc receiver's volume at the one o'clock position with average 10db crest factor material program with clipping at 10% in duration. That is pretty loud unless you're listening to very inefficient speakers which you would not be using a receiver anyways.

One way to tell if a tweeter or midrange even is in danger of overload is with a lightbulb. Those axial bulbs often used in automobile dome lights work well. Put it in series with the driver and crank the volume. It's normal for the bulb filament to glow on peaks. If it's glowing brightly all the time, it's too loud. You can actually leave the bulb inline as protection if you wish - in most cases it has little effect on sound and will protect delicate voice coils from frying in case of accident or amp trouble.

In pro audio these things happen far more frequently than in the home and many PA systems will have a driver protection scheme. But there are hardcore clip-light-crackheads that manage to fry them nevertheless because they feel if the bars aren't in the red, it's not loud enough. :|