Woofer Hum

[jcmusic]

What could be the possible cause for me to hear a very low faint hum in just the woofers of my k-horns? I put my ear to the mid and tweeter and hear absolutlely nothing but, when I put my ear to the side of the cabinet I can hear a very low faint hum.

Jay

[HarryO]

Your speakers aren't powered so that gives you a direction to start with.

Low freq hums are usually due to lighting or interferrence from an electrical source outside of your system.

Power Conditioner?

A year or so ago I had my DeWalt cordless drill was creating a hum ONLY when it was charging. It ran me silly for a week or so until I inadvertantly ran across the problem when I had a low floor noise when I plugged my charger in.

[Chris A]

Do you use light dimmers in the room or the rooms next to it?

Sixty Hertz power (and its low-order harmonics) will only be heard through the woofer since the crossover network routes anything below ~400 Hz to your woofers.

[jcmusic]

Ok guys I'll try and run it down!!!

Jay

[garyrc]

What could be the possible cause for me to hear a very low faint hum in just the woofers of my k-horns? I put my ear to the mid and tweeter and hear absolutlely nothing but, when I put my ear to the side of the cabinet I can hear a very low faint hum.

Jay

• I'm flabbergasted that you can put your ear to the mid and tweeter and hear nothing! Assuming that your electronics are on, they must be amazingly quiet. My Khorns have always transmitted at least a bit of hiss through the tweeters, even with my noisy preamp turned off and a power amp feeding them, inc very quiet solid state NAD, Luxman, Yamaha, and certainly tube McIntosh and Dyna.

• See if you still get the hum if you unplug the refrigerator.

[jcmusic]

Hi Gary,

I too am blown away by how quiet this new 45 amp is, I can hear absolutely nothing from the mid and tweeter even at full volume!!! This is the quietest amp I have ever heard. I would even hear a little hiss from my 300B but, not this 45.

Jay

[Guest " "]

"What could be the possible cause for me to hear a very low faint hum in just the woofers "

This is a very good question, and I'm surprised that our crossover experts did not jump in on this one.

The cause of why you only hear the hum in just the woofers, is because most hums are either 60hz or 120hz (long story on the 120hz). Your crossover in you khorns seperate sound below 400hz and sends to your woofers. 60hz is below 400hz, so that's why you do not hear the hum in you mids or tweets.

"I put my ear to the mid and tweeter and hear absolutlely nothing"

Thats right, mids produce sound between 400hz and 5000hz, tweets produce sound above 5000hz, hum is 60 hz so it never makes it though the blocking capacitors.

[LarryC]

That'd be a nice, pure 60 or 120 Hz hum, but some electromagnetic sounds are buzzes, sometimres rather raspy, and those can definitely be heard in the MR and tweeter as well as the woof. I used to get a very raspy buzz from my left K-horn from a dimmer wall switch in the next room, which the tweeter, mid horn and bass horn propagated very audibly (it's less now).

FWIW, when the room is very quiet, I get a very faint hum/buzz from all 3 drivers/horns in my right-hand K-horn -- even when no speaker wires are connected. The 150-amp electrical service entry panel is immediately on the other side of the exterior wall from the K-horn, so it must have a low-level EMI radiation possibly being picked up by the crossover coils.

The sound of these noises can be quite variable.

[jcmusic]

Fixxed thanks guys for the replys.

Jay

[HarryO]

You gonna tell us what it was?

[jcmusic]

Harry,

Do you really wanna know???

Jay

[HarryO]

Jay,

I definitely want to know. I've had my share of chasing "ghosts" and all knowledge is appreciated.

Harry