I was reading upon the definition of damping factor and it occurred to me that it might actually give the sensation of less bass to the listener because an amp with a high damping factor is more in control and able to stop the speaker cones from vibrating before one with a lower. This would explain to me why in my experience (not to big to be honest) one with a lower damping factor can actually seem to have more bass when settings of bass/loudness are on 10.
What's your experience and opinion ? Am I making any sense or I must find another explanation ?
What's your experience and opinion ? Am I making any sense or I must find another explanation ?
So you add a fuse in series with your speaker and when you tally up all the series resistances it's hard to get the damping over 10 in the real world. Try series resistors to knock down the damping and hear if it really makes the difference for you. You will lose efficiency and that series resistor may get seriously hot if you crank it up but it will demonstrate your idea and for very little money.
G²
G²
You can understand damping factor if you have a loose bass speaker lying around. If you tap the speaker you will hear a certain sound and the cone will move easily. Now short the terminals on the back together and tap it again. It won't move so easily and sound much harder.
A traditional solid state amp behaves like a short. A valve amp behaves like a 4 or 8 ohm resistor in terms of damping. In other words, valve amps don't have a high damping factor.
So, in effect solid state amps have very high damping factor, valves are a bit woolly. So a bass reflex works best with solid state, a horn works nicely with valves.
What I discovered from this, is that with a transistor amplifier, you should hard solder every bit of the loudspeaker path as is practical. Because with a loose speaker wire connecting the two terminals, you get hissing noises when you press a bass unit. That's distortion! That's bad!
A traditional solid state amp behaves like a short. A valve amp behaves like a 4 or 8 ohm resistor in terms of damping. In other words, valve amps don't have a high damping factor.
So, in effect solid state amps have very high damping factor, valves are a bit woolly. So a bass reflex works best with solid state, a horn works nicely with valves.
What I discovered from this, is that with a transistor amplifier, you should hard solder every bit of the loudspeaker path as is practical. Because with a loose speaker wire connecting the two terminals, you get hissing noises when you press a bass unit. That's distortion! That's bad!
Not really, it doesn't keep flopping in the breeze, it tends to sound weak and ill defined. By all means, play with it. Try a one or two ohm 5 W resistor.
A real DF of 10? Not likely if you have a passive crossover. You would be lucky to get a loop resistance of under half an ohm. That is of course not the full story.
A real DF of 10? Not likely if you have a passive crossover. You would be lucky to get a loop resistance of under half an ohm. That is of course not the full story.
Go check out they typical coils you need. You will find them in the .2 to .5 range each. Add the cables, fuses, amp wiring, connectors and so on. Surprise!
Jantzen at parts-express
I am not saying an amp with a decent DF is not worthwhile. I might suggest amps with a published figure of 5000 may be a bit optimistic.
Jantzen at parts-express
I am not saying an amp with a decent DF is not worthwhile. I might suggest amps with a published figure of 5000 may be a bit optimistic.
For bass usually are used inductors with a magnetic core. Those are in the 0.05-0.1 ohm range.
But yes, the series resistance is a reason why 8 ohm enclosures sound better than 4 ohm ones... Even if not as loud for a given amplifier.
And why #12-14AWG wire connecting sounds better than the usual #16-18AWG.
But yes, the series resistance is a reason why 8 ohm enclosures sound better than 4 ohm ones... Even if not as loud for a given amplifier.
And why #12-14AWG wire connecting sounds better than the usual #16-18AWG.
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I have a McIntosh MC2120 with a DF of 14, it sounded a bit 'warm' in the bass.
I added a pair of 47µF bypass caps to the main filter caps, tacked in a few 0.1µF films here and there, and guess what? The amplifier now has brick-outhouse, solid slamming bass.
"For bass usually are used inductors with a magnetic core. "
Most speaker manufacturers use inductors with a DCR in the 0R2~0R5 range, for cost reasons. It also may be deliberately raising the Qes of the woofers in certain designs.
DF is largely a red herring.
The back EMF generated by the loudspeaker is in series with the DRC of the voice-coil, woofer inductor, connector, cabling, etc. Typical values of this total series DCR are around 6Ω. Explain to me why there should be a huge difference between a DF of 400 and 14? My modified MC2120 sounds tighter and slams harder than an amplifier with a DF of 400, so it can't be the DF.
It is a good idea to keep the DF above about 20, it starts changing the Qes too much, and this can affect cabinet tuning.
"A valve amp behaves like a 4 or 8 ohm resistor in terms of damping."
Not likely.
"Internal impedance less than 10% of rated impedance."
That line is from McIntosh in all their tube amp data sheets, so that means there is less than 0R4 in series with the 4Ω output tap (not 4Ω~8Ω).
McIntosh Amplifiers Part 1
I added a pair of 47µF bypass caps to the main filter caps, tacked in a few 0.1µF films here and there, and guess what? The amplifier now has brick-outhouse, solid slamming bass.
"For bass usually are used inductors with a magnetic core. "
Most speaker manufacturers use inductors with a DCR in the 0R2~0R5 range, for cost reasons. It also may be deliberately raising the Qes of the woofers in certain designs.
DF is largely a red herring.
The back EMF generated by the loudspeaker is in series with the DRC of the voice-coil, woofer inductor, connector, cabling, etc. Typical values of this total series DCR are around 6Ω. Explain to me why there should be a huge difference between a DF of 400 and 14? My modified MC2120 sounds tighter and slams harder than an amplifier with a DF of 400, so it can't be the DF.
It is a good idea to keep the DF above about 20, it starts changing the Qes too much, and this can affect cabinet tuning.
"A valve amp behaves like a 4 or 8 ohm resistor in terms of damping."
Not likely.
"Internal impedance less than 10% of rated impedance."
That line is from McIntosh in all their tube amp data sheets, so that means there is less than 0R4 in series with the 4Ω output tap (not 4Ω~8Ω).
McIntosh Amplifiers Part 1
DF is a handy number to calculate, but it really means little (outside the context of the speaker design as described above)).
DAMPING FACTOR DEBATE
DAMPING FACTOR DEBATE
Certainly damping factors over 40 or so are not really all that relevant but get much lower and apart from possible lack of bass control it will interact with the crossover to give unpredictable variations in frequency response... Obviously the extent of this will vary hugely from one speaker to another depending on crossover design and complexity....
Sometimes with a low damping factor valve amp this will produce pleasant sounding colourations which will then be attributed to "valve magic"
Sometimes with a low damping factor valve amp this will produce pleasant sounding colourations which will then be attributed to "valve magic"
DF means what it claims to mean: a measure of amp output impedance, scaled by speaker nominal impedance. It gives a rough guide to electrical damping of the bass resonance. Ignoring DF, or claiming that it is very important, are equally wrong.
Confusion may arise because as DF increases you get diminishing returns. 40 is much better than 4 (for a typical voltage-driven speaker design), but 400 is almost indistinguishable from 40. The inverse of DF would be a better measure, but some people are confused by fractions.
Confusion may arise because as DF increases you get diminishing returns. 40 is much better than 4 (for a typical voltage-driven speaker design), but 400 is almost indistinguishable from 40. The inverse of DF would be a better measure, but some people are confused by fractions.
Indeed! Well put
The effects of DF at frequencies other than the bass end seem to get routinely ignored though...
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I assume that remark was intended for me. If by 'the material' you mean the article linked from your post 11 then I hadn't read it so I had no chance to comprehend it.djk said:
I have now read it, and it appears to be saying the same thing as me. DF matters, but not that much.
So your point is ??
There is an "ideal" damping factor for each loudspeaker. It is very enlightening to hook up a range of speakers to a variable transconductance amplifier and then dial in the output impedance for each speaker.
Most loudspeakers today are designed with the assumption that the amplifier approximates a voltage source (ie damping factor >>1). THis allows the design of the loudspeaker to have wild impedance swings. It also means that that impedance is the R in the voltage to current converter (speakers are current devices)
There are good arguments for using a current amplifier (ie damping <<1) to directly provide current to operate the speaker, eliminate the nasty effects of back EMF, voice coil heating, etc.
Since most available woofers do not have adequately low Qms, one can sidestep much of the skew in the market place by using a voltage amp on the bottom (to deal with the impedance peak at resonance) and current amps elsewhere on your multiamped speakers.
dave
Most loudspeakers today are designed with the assumption that the amplifier approximates a voltage source (ie damping factor >>1). THis allows the design of the loudspeaker to have wild impedance swings. It also means that that impedance is the R in the voltage to current converter (speakers are current devices)
There are good arguments for using a current amplifier (ie damping <<1) to directly provide current to operate the speaker, eliminate the nasty effects of back EMF, voice coil heating, etc.
Since most available woofers do not have adequately low Qms, one can sidestep much of the skew in the market place by using a voltage amp on the bottom (to deal with the impedance peak at resonance) and current amps elsewhere on your multiamped speakers.
dave
I would agree. Take the speaker out of the equation and it is simply the output impedance of the amplifier.
dave
With most speaker crossovers, there's hardly any damping at the crossover frequency especially when the amp has a very high damping factor. In fact a high amplifier damping factor is worse than a low df in the crossover frequency region. (Think back emf and filters in reverse). A moderately high df is all that's needed for LF control as the woofer speech coil is in series anyway and limits current flow for the back emf.
Very high DF as a sign of bass-quality is a myth imo.
Most loudspeakers are designed to be driven by a perfect voltage-source.
Manufacturers often use the smallest enclosure possible,
and economize on the series-coil(s) of the filter preceding the woofer(s),
often resulting in an underdamped response.
Such a design needs a DF as high as possible.
When the loudspeaker is designed to perform optimally with lower DF,
driving it with a high DF will only result in an overdamped, lean bass.
The assumption that low DF by definition results in wooly bass is false imo.
Most loudspeakers are designed to be driven by a perfect voltage-source.
Manufacturers often use the smallest enclosure possible,
and economize on the series-coil(s) of the filter preceding the woofer(s),
often resulting in an underdamped response.
Such a design needs a DF as high as possible.
When the loudspeaker is designed to perform optimally with lower DF,
driving it with a high DF will only result in an overdamped, lean bass.
The assumption that low DF by definition results in wooly bass is false imo.
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