[cporada]

I've come across a good deal of discussion lately on several audio forums regarding grounding the frame of drivers on loudspeakers and am curious if anyone can explain to me exactly what this does, or how it can alter/improve the sound. 
Also, with midrange and bass drivers, I understand you can just attach the ground wires to the screws on the mounting plate/rim of the driver after scraping a little paint off the metal flange, but where do you attach the wires if you are trying to ground a tweeter that has a plastic flange? Also, on a separate topic, can anyone comment on using ferrites on your speaker cable?  It seems there is a real division of opinion on whether this is good or not.  I know some reviewers from Stereophile liked this idea and others said it was a really bad idea.
Thanks for any input on these issues, Chris

[andyr]

I've come across a good deal of discussion lately on several audio forums regarding grounding the frame of drivers on loudspeakers and am curious if anyone can explain to me exactly what this does, or how it can alter/improve the sound. 

Hi Chris,

I also read some posts about this concept ... and, to me, the ideas espoused were flawed!   

Given there are some pretty heavy magnetic fields operating around the driver frame, it makes a little bit of sense (well, to me anyway!  ) that it might be a good idea to have the frame at ground.  Grounding the driver frame should minimise eddy currents in the metal driver frame, which are caused by the magnetic fields ... and who knows what effect these eddy currents have on the cone?

However, this "ground" must be the "ground" at the nearest mains wall-socket ... not the "ground/return" post of the speaker cabinet - as any signal induced in the "ground/return" post by eddy currents will feed back into the amplifier's feedback loop ... with potentially disasterous results.  Of course, if you are using a no-feedback amplifier then this won't be a problem!

Also, on a separate topic, can anyone comment on using ferrites on your speaker cable?  It seems there is a real division of opinion on whether this is good or not.  I know some reviewers from Stereophile liked this idea and others said it was a really bad idea.

Inductance ('L') opposes current thus a good-performing speaker cable - which offers minimal opposition to the flow of current to the driver - must have low L.

Putting a ferrite around your speaker cable automatically adds to the intrinsic L of the cable caused by its construction ... so I cannot see how this is a good idea!   

Regards,

Andy

[Steve Eddy]

Grounding the driver frame should minimise eddy currents in the metal driver frame, which are caused by the magnetic fields ... and who knows what effect these eddy currents have on the cone?

You talkin' shit about me again, Rosewood? 

se

[Wayner]

Adding a ground wire to the frame(s) doesn't complete any circuit. If the speaker's voice coil is damaged, then there could be a potential to ground, which would be seen by the amplifier as a dead short, causing the amp to blow fuses or MOSFETS.

I see no logic in doing this DIY.

W

[JoshK]

Wayners explanation was about my thoughts too.  If somehow the frame was electrically connected to the voice coil or had large enough charge on it that it could affect the voice coil (over the pull of the large close magnets  ) then it may.  That would have to be some serious stray currents.  The DC offset of your amp, even if small will dwarf this affect by orders of magnitude.

[andyr]

Grounding the driver frame should minimise eddy currents in the metal driver frame, which are caused by the magnetic fields ... and who knows what effect these eddy currents have on the cone?

You talkin' shit about me again, Rosewood? 

se

Haha ... Moi??     Go back to sleep, Steve!!   

Seriously, though, I would think that if "Steve currents" exist in the metal driver frame then a connection to mains earth would drain these off?  Or do I have a serious lack of living grey-matter, from imbibing too much Fosters?   

Regards from downunder.

Andy

[Steve Eddy]

Haha ... Moi??     Go back to sleep, Steve!!   

Who says I'm awake? 

Seriously, though, I would think that if "Steve currents" exist in the metal driver frame then a connection to mains earth would drain these off?  Or do I have a serious lack of living grey-matter, from imbibing too much Fosters?   

Fosters? I didn't think any self-respecting Ozzie drank Fosters. I thought that was just shit they sold to us Americans so we'd think we were big manly Ozzie men.

Seriously though, no, such a connection would not drain off those Steve currents. First, they're already flowing in their own closed loops. Second, current only flows through a closed loop. In order to have any current flowing through the frame into the mains earth, you'd have to have current first coming out of the mains earth into the frames.

.revopu morf sdrageR

se

[andyr]

Fosters? I didn't think any self-respecting Ozzie drank Fosters. I thought that was just shit they sold to us Americans so we'd think we were big manly Ozzie men.

Seriously though, no, such a connection would not drain off those Steve currents. First, they're already flowing in their own closed loops. Second, current only flows through a closed loop. In order to have any current flowing through the frame into the mains earth, you'd have to have current first coming out of the mains earth into the frames.

.revopu morf sdrageR

se

Thanks for the explanation ... makes sense! 

I guess the one good thing about Fosters, though, is that it's about 5% alcohol ... whereas I understood your Yanqui beers are only about 2%?  (yah ... wimps!  )

Actually I only drink wine or gin ... beer is bad for my diabetes!    

Regards,

Andy

[Steve Eddy]

I guess the one good thing about Fosters, though, is that it's about 5% alcohol ... whereas I understood your Yanqui beers are only about 2%?  (yah ... wimps!  )

5%? Hey, when the homeys around here wanna get shitfaced, they drink 40oz bottles of malt liquor, which can be upwards of 10%. 

Actually I only drink wine or gin ... beer is bad for my diabetes!   

Hehehe. Don't feel bad. I don't drink much of anything anymore.

se

[andyr]

5%? Hey, when the homeys around here wanna get shitfaced, they drink 40oz bottles of malt liquor, which can be upwards of 10%. 

Real Aussie blokes drink "Bundy" ... Bundaberg rum (we grow cane in the "deep North").  This is 37%.   

"Bundy and cola" is a favourite of the Aussie "sheila" too ... including my daughter!   

Regards,

Andy