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Thread: Glass, ? on Ohms and damping factor |
    
Silver Member Username: Jwbulger79
Florida
Post Number: 251
Registered: Nov-04
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| Posted on Wednesday, March 16, 2005 - 06:11 pm: |
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hey glass, at the end of your report on amplifiers(http://www.wickedcases.com/caraudio/amplifiers.html), it reads..."Note that using 2 ohm speakers on an amplifier will degrade the damping factor as compared to using 4 ohm speakers (total load.)"
now does thim mean that, for example the image dynamics' chameleon line of components, technically the 4ohm set will have tighter sound than the 2ohm model? would the difference be so insignificant that it would be inaudible to the human ear?
thanks. |
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Gold Member Username: Invain
Michigan
United States
Post Number: 1724
Registered: Aug-04
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| Posted on Wednesday, March 16, 2005 - 06:33 pm: |
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It depends on how low it is before you start hearing a difference. I think lower DF's make the sound softer. You shouldn't be able to notice it that much, but I'm not sure. I think it's easier to notice in sub's because the punchy bass is reduced so much. |
Gold Member Username: Carguy
Post Number: 1989
Registered: Nov-04
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| Posted on Wednesday, March 16, 2005 - 08:48 pm: |
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JW, what Glass is saying is that, damping factor degrades as you decrease ohms load on the amp. Nothing to do with speaker. It's the amp itself. Some high quality amps will still maintain high damping factor even at 2ohms. |
Silver Member Username: Jwbulger79
Florida
Post Number: 261
Registered: Nov-04
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| Posted on Thursday, March 17, 2005 - 04:05 pm: |
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yeah, that's what i was getting at. i should have been more specific in my question,
assuming they are ran by the same amp, and the difference in sound would be due to the change of damping factor of the amp...
would the difference be so insignificant that it would be inaudible to the human ear, or would i notice a difference in sound quality?
thanks.
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Gold Member Username: Invain
Michigan
United States
Post Number: 1747
Registered: Aug-04
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| Posted on Thursday, March 17, 2005 - 06:17 pm: |
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It really shouldn't be that audible. Most people can't even hear audible differences with damping factors of 50. You might hear something if you go lower than that. |
Gold Member Username: Carguy
Post Number: 2001
Registered: Nov-04
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| Posted on Thursday, March 17, 2005 - 07:16 pm: |
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If you take a cheap amp like Sony/Pyraimd/Boss/Lanzar/Pyle, then yes cause those amps have very low damping factors to start with. Amps like PPI art series/PC/PCX/Zapco/JL etc have a damping factor of 250 - 1000. So even if it did drop, it's still better than lot of the amps.
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Silver Member Username: Jwbulger79
Florida
Post Number: 265
Registered: Nov-04
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| Posted on Thursday, March 17, 2005 - 08:23 pm: |
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right on. thanks ya'll. |
Silver Member Username: Fishy
TamaracFt.Laud,
FL
USA
Post Number: 692
Registered: Sep-04
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| Posted on Thursday, March 17, 2005 - 11:52 pm: |
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Damping factor determines the amount of control your amp has over its driver(s) and isn't nearly as critical for mids and highs applications.
The damping factor is most often used as an indication of the ability of an amplifier to control the motion of a driver. When a signal sent to a driver is suddenly stopped, the driver's cone continues moving back a forth for a short period after the signal has stopped. A driver with a cone that stops quickly is said to have a good transient response while a driver with a cone that does not stop quickly is said to have a bad transient response and thus is described as inaccurate.
I think it goes without saying that most people would prefer a driver with good transients and thus would prefer that the cone of the driver stop quickly after the source signal stops.
With tweeters and mid-bass drivers, this not a hard task since the cones of these types of drivers are relatively light and a relatively large motor structure can be used to control the motion of the cone. However, the cone of a low frequency driver is quite sizable and it is physically impractical to use a motor assembly large enough to obtain transient responses as good as that of a tweeter or a mid-bass driver. Thus low frequency drivers usually have relatively poor transient responses.
This is really not too much of a problem since humans are less sensitive to distortion in the low frequencies. In fact, THD of 3 to 6 percent from a low frequency driver is considered acceptable. Low frequency distortion only becomes objectionable when it gets close to 10 percent.
Since drivers are just electric motors, they become generators when their terminals are shorted. If you place an ammeter across the leads of a driver and push the cone up and down, you will see a current flowing through the ammeter. The higher that current is, the more difficulr the cone becomes to move. Thus, if a driver's cone is moving, the quickest way to stop it is to place a dead short across its leads.
The internal impedance of an amplifier is usually very small and in the absence of a source signal, it is like a short across the leads of the driver. The amplifiers with a higher damping factor will have a lower internal impedance so it will be closer to a short, thus the amplifier with a higher damping factor will cause the driver to stop quicker than the amplifier with a lower damping factor. Since low frequency drivers need all the help they can get to stop their cone from moving when the source signal stops, a high damping factor is desirable for an amplifier intended to power low frequency drivers. The damping factor is not as relevant when the amplifier is used to power mid-bass and tweeter drivers since those drivers already have pretty good transient response due to their relatively small cone size.
From Glass's site:
http://www.wickedcases.com/caraudio/ampspecs.html
Regardless, for honest specs, damping factors can give you a good idea of the quality of the equipment you have or may be buying.
-Fishy
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Gold Member Username: Jonathan_f
GA
USA
Post Number: 3498
Registered: May-04
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| Posted on Friday, March 18, 2005 - 12:15 am: |
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That's the main reason that I look at damping factor. Damping factor will give you an idea of the quality of the transistors used, doping, etc. That will hint at how good the amplifier is, or at least that portion of it. |
Gold Member Username: Invain
Michigan
United States
Post Number: 1766
Registered: Aug-04
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| Posted on Friday, March 18, 2005 - 12:39 am: |
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Jon, there's no way crappy companies can juice up their damping factors can they? |
Gold Member Username: Jonathan_f
GA
USA
Post Number: 3503
Registered: May-04
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| Posted on Friday, March 18, 2005 - 01:06 am: |
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Yeah, actually there are  . Crappy companies usually don't list damping factor anyway, so it isn't a big issue. Anyway, damping factor is typically listed at 1khz, which is way out of subwoofer range. Impedance of an amp is reactive just like a speaker is, although the impedance swings vary less. So just because brand A amplifier has a better damping than brand B, doesn't mean it will at another frequency. Some amplifiers with super high damping factors do so with a ton of feedback, though (sample of the output signal is brought back to the input signal in reverse phase, cancelling some of the gain of the amp and also reducing THD to a minor amount). While it will give better numbers, it isn't necessarily better either. The signals will reach the output uncorrected, and will only be corrected when the contents of the feedback loop reach the amplifiers inputs. It leads people to believe that this will make an amplifier "slower" and actually leads itself more to notes that change slowly over time. Either argument isn't really one I'm going to bite into, as there are too many differing opinions in audio, it's really up to your ears to determine what's right for you in the end, I try not to develop opinions on either as it would be very hard to prove how either made a huge difference over the other. Damping factor is simply one element within the chain of total driver damping, so it won't do the job by itself. |
Silver Member Username: Jwbulger79
Florida
Post Number: 269
Registered: Nov-04
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| Posted on Friday, March 18, 2005 - 10:39 am: |
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great info. thanks. |
Gold Member Username: Glasswolf
NorthWest,
Michigan
USA
Post Number: 7512
Registered: Dec-03
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| Posted on Friday, March 18, 2005 - 10:44 am: |
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just saw this.
damping factor is really only critical for subs.
you're talking about component amps here and smaller component speakers so if it's even a half decent amplifier, the damping shouldn't matter even @ 2 ohms.
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Silver Member Username: Jwbulger79
Florida
Post Number: 271
Registered: Nov-04
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| Posted on Friday, March 18, 2005 - 11:03 am: |
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cool. thanks glass. |
