damping factor, that important?

[motorstereo]

I've read somewhere that mcintosh states that there really isn't any distinguishable sound difference in df after about 30. Maybe with their speakers but I've found that a high df amp gives me much better sound on my multiple driver speakers. I consider high df very important when looking at an amp's specs.

 

[JimInPA]

You also must take into account the resistance of the speaker wire, as that more often than not puts the ceiling on DF.

For example, a speaker 10' away using 14 ga wire, is 20' (round trip) at 0.00297 ohms/ft. Resistance then is then .0594 ohms. This place a limit on the combined damping (ug) dampENing factor of 8 ohm speaker/0.0594 ohms wire of 134.

If the amplifier has an similar DF (realistic), the result would be a combined DF of 134/2=77.

A high damping factor helps the most when it is in conjunction with a VERY low cable resistance. You will likely gain more for buck using huge (but low inductance) speaker wires rather than an amp with an obscenely high DF.

 

[geiman]

Heathens.... Its "dampening factor"

Maybe, but my Technics manual says "damping"..........

I guess it's a tomato-tomatoe thing

 

[whoaru99]

Heathens.... Its "dampening factor"

It's "damping factor" according to Crown, QSC, McIntosh, Yamaha, and every other amplifier spec that I've looked at.

 

[tarior]

http://en.wikipedia.org/wiki/Damping_factor


An awful lot of many peoples favorite amps (some of mine included) have pretty low DFs and really don't spec out all that well, i.e.; nearly every tube amp, most vintage amps and receivers, and plenty of newer high end amps. There is a whole lot more to good sound than high DFs and low THD. However, many pro-type PA amplifiers have very high DFs and low THD and IM distortion. But they're not meant for home use.

 

[similost]

If you are driving large 18" subs like I am, and with some volume behind them, YES, DF is important.. lots of paper to stop from moving...

 

[mhardy6647]

dampening is what you do with a hose to the grass in the yard.
damping factor is the ratio of the load impedance to the output impedance of an amplifier. Amps with really low output impedance often achieve it by using large amounts of negative feedback. If done carefully and judiciously, this cure might not be worse than the disease. In many cases, though, the compromises are just too compromising.

Just my NSHO of course. You cannot beat actually listening to the amp you're interested in with the speaker you'd like to use it with. Speakers are (literally, in the electrical sense) reactive loads, and they will interact both with the space they're playing into and the amplifier which they are loading. The audible consequences are best evaluated empirically (again, IMSNHO).

 

[onplane]

You also must take into account the resistance of the speaker wire, as that more often than not puts the ceiling on DF.

Well, you are close. Damping factor is the ratio of the load divided by the amp's output impedance.

Problem is the "load" should be the moving voice coil the amp is attempting to control. Unfortunately, it's NOT the only load. As JimInPA points out the resistance of the speaker wire comes into play, but even more important is the coil in series with the woofer. That coil serves as the low pass filter and effectively raises the system's output impedance ... significantly.

So, what does this mean? It means that for most speaker systems the amplifier damping factor has little impact on the resulting sound.

The systems where the damping factor "could" have an impact are those systems where we have removed the coil as in active bi-amping or powered sub-woofers.

If you don't beleive this, then work out the math.

Regards,
Jerry

 

[Jon_Logan]

JimInPA is not just close. He is on the money. The speaker resistance is added to the amps output impedance. The load impedance/the amps source impedance+wire resistance+the wires insidethe capinet up to the voice coil.

 

[4.7inches]

http://en.wikipedia.org/wiki/Damping_factor


An awful lot of many peoples favorite amps (some of mine included) have pretty low DFs and really don't spec out all that well, i.e.; nearly every tube amp, most vintage amps and receivers, and plenty of newer high end amps. .

Hmm, maybe that´s why most tube and modern high-end amps sound terrible to my ears? But if you aren´t looking for transparency or neutral sound it´s nothing wrong with that of course.

Many vintage receivers and amps are underspeced and actually measures very well.

 

[onplane]

JimInPA is not just close. He is on the money. The speaker resistance is added to the amps output impedance. The load impedance/the amps source impedance+wire resistance+the wires insidethe capinet up to the voice coil.

Yes, Jon, this is true, but the sum of resistance of speaker wire + wire inside is small compared to the impedance of the low pass coil.

Until you remove that coil, damping factor can have little impact.

Regards,
Jerry

 

[Jon_Logan]

Yes, Jon, this is true, but the sum of resistance of speaker wire + wire inside is small compared to the impedance of the low pass coil.

Until you remove that coil, damping factor can have little impact.

Regards,
Jerry

Ahh the LP inductor... Damnit!!! Must Tri-Amp. Yeah, the coil might render DAMPING (not dampening) factor numbers useless. Good point.

 

[jstang]

dampening is what you do with a hose to the grass in the yard.

No.....No..... ( )

http://www.merriam-webster.com/dictionary/dampening

jk

 

[Wornears]

Thread veer on!

mhardy6647 and others are spot-on. I've been a tech editor and technical automotive writer/editor/journalist since 1979 = "damping" in engineering use. M-W is a slack-ass dictionary source for technical terminology. <G>

I will give you that since I started back in pre-word processing days, the English language has gone even more to hell than editors were whining about then! (And don't hold me to some non-mistake writing on this forum -- where I am not getting paid <G>.)

What really jacks my jaws is "dampening" being used when discussing how automotive shock absorbers work...

Thread veer off!

 

[fiddlefye]

I changed the damping on my Accuphase E-202 from 'Normal' to 'Medium' today for an experiment. I'm running it into NS-609's at the moment. Huge improvement, actually not just noticeable. Oddly, most improvement was in the midrange and lower treble, though bass cleaned up a bit as well. I also tried 'Soft' and it sounded very wooly. Now all I need to do is look up what Accuphase means exactly by 'Normal' Medium' and 'Soft'.

 

[jstang]

I changed the damping on my Accuphase E-202 from 'Normal' to 'Medium' today for an experiment. I'm running it into NS-609's at the moment. Huge improvement, actually not just noticeable. Oddly, most improvement was in the midrange and lower treble, though bass cleaned up a bit as well. I also tried 'Soft' and it sounded very wooly. Now all I need to do is look up what Accuphase means exactly by 'Normal' Medium' and 'Soft'.

Only those who have never experienced the improvement do not believe in it. But it is dependent on the speakers.


jk

 

[mhardy6647]

...utterly dependent on the load!

Not to sound like Zilch, but this is one of those concrete, at least somewhat-quantifiable areas that actually gives some definition to squishy-gooshy (damp?!) concepts like "system synergy".

You really could measure everything, if you knew what to measure.

Meanwhile, trust your ears.

 

[whoaru99]

Only those who have never experienced the improvement do not believe in it. But it is dependent on the speakers.


jk

Or, perhaps those who haven't heard an improvement already had something that already had enough of what ever it is. :scratch2:

 

[bowtie427ss]

...utterly dependent on the load!

Not to sound like Zilch, but this is one of those concrete, at least somewhat-quantifiable areas that actually gives some definition to squishy-gooshy (damp?!) concepts like "system synergy".

You really could measure everything, if you knew what to measure.

I would love to see more discussion of amplifier output impedance along with it's relationship to load impedance.

I believe it's often this relationship between amplifier and speaker that gets labeled "synergy", and i suspect the same holds true with the relationship between the output impedance of sources and pre-amp/amp input impedance.

 

[JimInPA]

Bowtie,

It does make a difference, a simple change in my mirages from running two sets of fires joined at the bi-amp terminals of the speakers to those same wires not not joined at the speakers made for a nice improvement. Why? It allows the amps DF to soak up the reverse EMF from the bass and not pollute the mids with it.

As to the voil coil/inductor resistance(impedance), that is factored into the nominal 8 ohms impedance used in the calc. The factor may get better or worse, but it IS the speaker wires that will primarily constrain it.

p.s. like the Jefferson quote - especially true in these times.