So you run your 805's on the Large setting?

[RobP]

In another post, the discussion came up about running small speakers on the "Large" setting on your processor,and how long a speaker would last under those conditions, well lo and behold, I get a call today from my brother-in-law asking me to come over and check his speakers because someting sounds funny, He has four N805s in his sound system and one of them was making a nasty noise, I took off the grille of the front left speaker and found that the phase plug was loose. When I went to spin it it made a nasty grinding noise, I took it out and the thing had melted and was grinding into the VC.

I had never seen this before, I checked to see if one channel of his amp went bad, nothing, but I did find that he had his speakers all set to large and he said that sometimes when he was watching a movie the speakers would bottom out, could this have caused this? Even with his crossover set at 60hz? I would say it is very possible. Now I dont know how loud he plays them but he says not very loud at all......

[Karma]

HI Robert,
What in the world is that thing in your picture?? It certainly did not come from a B&W 805S! Could you be more specific such as speaker make and model. For all I know it came from a V8 engine except I know you would not play a practical joke on us. 8O

Sparky

[george_k]

What in the world is that thing in your picture?? It certainly did not come from a B&W 805S!

It's the phase plug, "the bullet-thingy" sticking out of the center of the kevlar cone and no it didn't come from an 805S he specifically say from a N805.

Soundgravy,

Out of curiousity, was this speaker one of the front's or one of the rears?

[Karma]

HI george,
Thanks for the clarification. I've never seen an N805 "undressed". Clearly that speaker is a totally different design than the 805S. The phase plug must screw into the magnet and is surrounded by the voice coil. In other words, the plug does not move with the cone. Also, the cone must have a hole in it through which the plug protrudes. Odd!!

I'm not at all sure that one can draw valid conclusions when comparing such very different designs. But even if you can, that voice coil was subjected to very high temperatures. I would question the statement about volume levels.

Sparky

[Race Car Driver]

Ohhh, sure looks like that voice coil sure got hot!!!
He must have been cranking them!






For quite some time to melt that plastic!

[PewterTA]

That definitely didn't happen to the speakers because of the large/small setting on his processor, that came from extremely loud and extended listening sessions with possibly using too little power to the speakers...

I've seen it before (though not to B&W 805s).

He should've have had any problems using those speakers as large and playing at normal listening volumes.

That is a nice picture though!

[RobP]

It's the phase plug, "the bullet-thingy" sticking out of the center of the kevlar cone and no it didn't come from an 805S he specifically say from a N805.

Soundgravy,

Out of curiousity, was this speaker one of the front's or one of the rears?

It came from the front left speaker.

[RobP]

That definitely didn't happen to the speakers because of the large/small setting on his processor, that came from extremely loud and extended listening sessions with possibly using too little power to the speakers...

I've seen it before (though not to B&W 805s).

He should've have had any problems using those speakers as large and playing at normal listening volumes.

That is a nice picture though!

I think it was a combonation of the two, leaving the setting on large would allow full bass signals from the processor on movies to go through these small speakers, that coupled with constant high volume spelled doom for these guys. My dealer seemed to agree with me.

[RobP]

You know what is kind of strange, This is the only speaker in the group that shows any kind of heat damage, the others look fine. I think that channel of his amp may be suspect. :huh:

[Cowanrg]

wait... what is this crap? leaving the speaker setting on large?

how do you explain stereo only setups. they dont have a setting for that, it always assumes large. its not the fault of the processor. its the owner. he bought speakers too small for his room and flat out ABUSED them. voice coils dont melt phase plugs because you had one party that got a little out of hand.

he continually clipped them and fried them. large or small processor settings have NOTHING to do with it.

[RobP]

Wow Cowanrg, it sounds as if you know everything that happened, did you visit these out of hand parties?
His system is only used for movies, and movie tracks are VERY different than music, the bass tracks and effects are usually mixed hot in regards to the normal dialouge and leaving a small speaker set on large leaves that speaker open for low frequencies that the speaker cannot reproduce without some type of distortion and or damage.

[caleb]

This won't happen with my aluminium phase plugs ! ! !

[RobP]

I know Caleb!!! You stopped making them too soon. :lol:

[EastCoaster]

I think it was a combonation of the two, leaving the setting on large would allow full bass signals from the processor on movies to go through these small speakers, that coupled with constant high volume spelled doom for these guys. My dealer seemed to agree with me.

Robert - I just checked my sub's manual again, and it says that with home theatre, the subwoofer (LFE) signal is a separate channel going directly to the sub, rather than an extension of the signal that goes to the speakers. Doesn't that sort of sounds like B&W are saying that the movie's bass effects would be going to the sub only, and not to the speakers (where they can potentially cause some nasty damage)?

Interestingly, I spent some time this evening listening to my 805S's on large, then on small, then on large, then on small, and surprisingly, I find them more pleasing on "small" :T Just goes to show me that I shouldn't always worry about how big things are... :B

[RebelMan]

This won't happen with my aluminium phase plugs ! ! !

True, they'll just turn red hot and melt the speaker! :lol:

[RebelMan]

SG, is your brother-in-law using a sub in his system? Speakers set to LARGE are going to be driven hard even with a sub in place because they will still need to produce very low frequencies.

I suspect three things happened here. One, the N805 mid/bass driver was driven past its is safe excursion limits, too much bass to reproduce. Two, the amp driving the speaker clipped, lacked the ability to deliver the necessary current. Three, the voice coil in the left channel was probably on the very edge of manufactured tolerance limits.

Just a guess but from the looks of it seems very probable.

P.S. Is the 60Hz crossover point set on the speaker side or on the subwoofer side? I would suspect that the crossover setting effects the subwoofer (low pass cut off) as most LARGE speaker settings bypass crossover settings.