Damping factor

[Deleted User]

Going to show my ignorance again.
How come speaker manufacturers down list a recommended
damping factor for there speakers. They must have some golden
ear tuning them to something…
which leads to maybe they should partner with someone?
This would lead to bi-amping which would lead to a 4 channel amp?
I'm sure this ground must be covered but its bugging me today.

[Deleted User]

oops I see it has be answered many times.
Still bugs me.

tonyb

Doesn't really matter anyway with modern gear. As long as it isn't too low....or too high....speaking for amp specs anyway. In general though, there is just too many variables in the mix to make a speakers damping spec worth anything.

today it's more so about synergy and impedance matching within one's system. To give a technical reason as to why damping specs for speakers matter one way or another would be very confusing to most and frankly....very uninteresting.

[Deleted User]

Thanks. The reason it was bugging me was I dumpster dove
for a Architectural Acoustics Peavey IP-8.5c today and wondered
what if anything to do w/ it. It turns on and the fans pretty quite…
so I was looking at the specs and noticed the damping factor of >300
while the ole Crown I had was >1000 which lead me… to thicker
speaker wires and 14 AWG power cords!

tonyb

Like I said, just too many variables to make that a consideration. In general though, anything over 100 is pretty good. The common train of thought is the better the damping factor the more control over the speaker drivers movement. While that's true to an extent, there's just too much more involved to make that a written in stone statement.

Speaking in generals again, usually the more drivers a speaker has to start and stop, the more of a damping factor comes into play. That said, many amps today of decent quality should be well within the realm of offering a good damping factor, which is why you never hear much hupla about it. Concern yourself more with amperes peek to peek.

[Deleted User]

Thanks!

[Deleted User]

Hello,
Damping factor is really an indicator of the amount of control an amplifier has over a woofer. Since a woofer's cone has a fair amount of moving mass it can continue moving forward and rearward after the audio pulse has stopped flowing through it's coil of wire. This unwanted motion would add a muddy quality distortion to the original sound signal if not dealt with. One of the ways to damp this motion would be to temporarily short out the woofer's voice coil between the signal pulses. Next time you have a woofer out of an enclosure gently push on the cone and note how much resistance the suspension gives to your movement. Then take a clip lead or a piece of wire and short out the positive and negative terminals of the woofer. Now try pushing with the same amount of force on the woofer's cone, you should feel greater resistance caused by the shorted voice coil. In fact some of the older British speakers would have shorting wires on their terminals, when they left the factory, to limit the amount of flexing the woofer would do during shipping.
The only way to accomplish this shorting action during actual sound production is by offering the speaker a very low impedance, by the amplifier, when there isn't an audio signal being produced. This is where damping factor becomes involved, it is the ratio of the amplifier's output impedance compared to the load impedance of the speaker. The idea is to have an amplifier impedance low enough so that the speaker behaves as though the voice coil was shorted out between audio pulses.
Most transistor amplifiers have a fairly low output impedance compared to the fairly high impedance of the woofer, so mechanical damping is accomplished.
Cheers, Ken

tonyb

Here's a more in depth look...

http://www.butleraudio.com/damping1.php

After reading both pages.....refer back to my previous comments. Too techy for most and very uninteresting....but you'll get the general drift. BTW, that was written in 1967.

[Deleted User]

Thanks Mr. Swauger. As Tonyb said, I'll just have to try it and see if I like it.
It's a "Pro" amp so probably only good for bugging the neighbors for me.

tonyb

rednedtugent wrote: »

Thanks Mr. Swauger. As Tonyb said, I'll just have to try it and see if I like it.
It's a "Pro" amp so probably only good for bugging the neighbors for me.

You may be right, but since it's a dumpster find, don't be hooking it up to speakers you want to keep off the bat. Try it on something you won't lose sleep over if it toasts them.

[Deleted User]

wise idea. Thanks!

Moose68Bash

Plug it into a dim-bulb tester before you do anything else with it.

http://www.antiqueradio.org/dimbulb.htm

You can put one together in less than an hour.

[Deleted User]

Cool! Bookmarked for later.
Installed a new low flush toilet tonight. (crappy job)

Moose68Bash wrote: »

Plug it into a dim-bulb tester before you do anything else with it.

http://www.antiqueradio.org/dimbulb.htm

You can put one together in less than an hour.

F1nut

There is a chart floating around from a test someone did on damping factor effects. It was found that the difference between a damping factor of 10 and 1000 was so slight that it was a non-factor.

That said, I had an amp years ago with a damping factor of 1000, which had terrible control of the woofers. I replaced it with an amp that had a damping factor of 50, which had no problem controlling the woofers.

[Deleted User]

Didn't plug the AMP in yet, but cleaned it w/ a damp cloth.

tonyb

F1nut wrote: »

There is a chart floating around from a test someone did on damping factor effects. It was found that the difference between a damping factor of 10 and 1000 was so slight that it was a non-factor.

That said, I had an amp years ago with a damping factor of 1000, which had terrible control of the woofers. I replaced it with an amp that had a damping factor of 50, which had no problem controlling the woofers.

Jess, that's because too much is just as bad as too little. When the damping factor is too high, the woofers do their own thing and not what the signal is telling them. Kinda like when you rev the blade on a saw and it starts to wobble.

Personally I place little attention to the number unless it's super low like 20....or super high like 1000. I want to say though that 95% of the amps made today don't hit those extremes anyway. You only see really low numbers in old tube amps and real high numbers in ice amps. Those old tube amps that were used to power consoles back in the day come to mind.