Damping Factor

[March Audio]

48 minutes ago, davewantsmoore said:

If what you are saying is that significantly adjusting the damping factor on most passive speakers (which have significant swings in the electrical impedance) would be bad for them .... then sure.

 

Yes, "most" is probably 99.9999%, so its a moot argument. 

Edited March 19, 2023 by March Audio

[March Audio]

OK, @davewantsmoore, we are actually fundamentally in agreement, just that I am looking more at the current real world situation.

 

For others reading the thread, can you explain what the specific advantages of optimised damping factor are?

 

The paper you cited talked about low end frequency response variations, but we have plenty of speakers operating without optimised DF that have flat low end responses (limited by other factors of course).

Edited March 19, 2023 by March Audio

[cafe67]

Interesting topic/threat 

 

I recently looked a ( valve) amp and the damping factor was 1. Otoh I looked a big solid state amp and the damping factor was 1000.

 

is there a point where there is too much is a problem or is a speaker by speaker consideration - the falcon 3/5 probably don’t need much where some like the big wilson floorstanders  might need alot more ? 

[MLXXX]

5 minutes ago, cafe67 said:

I recently looked a ( valve) amp and the damping factor was 1.

That'd be unusual. What model amplifier was that?

[cafe67]

Just now, MLXXX said:

That'd be unusual. What model amplifier was that?

Can’t remember  , was a low powered valve el34 design 

[davewantsmoore]

35 minutes ago, cafe67 said:

is there a point where there is too much is a problem or is a speaker by speaker consideration - the falcon 3/5 probably don’t need much where some like the big wilson floorstanders  might need alot more ? 

It's a speaker by speaker consideration.

Most speakers are design from the perspective that the damping factor will be significant (significantly high) ..... like 5+, for example.    "Too high", will not alter the frequency response... where as too low, might.

 

This is before we get into issues of settling time, and any non-linear distortion created through the speakers "voltage to current conversion" action....  but they're really topics for another thread/time, as they are complicated, and arguably small issues.

 

So the short answer to "too much a problem" is "no" .... but "more is not better" either.

 

2 hours ago, March Audio said:

but we have plenty of speakers operating without optimised DF that have flat low end responses

Of course, there are many ways to transform the low end response to be what you want (EQ, enclosure...) it to be, irrespective of the initial response of the transducer+amplifier.

[davewantsmoore]

2 hours ago, March Audio said:

 

Yes, "most" is probably 99.9999%, so its a moot argument. 

LOL it is not "moot".

 

I'm specifically responing to your statement that "it cannot be done for passive speakers" .... by showing evidence that it can be.

 

Wther it is rare or not (it is rare), isn't really the point, as oppsed to the "how / why / if" of the statement "it cannot be done for a passive speaker".    Of couse it can be done.   All that needs to happen is that the driver + amplifier has the EQ applied to it to obtain the driver response(s) needed.   Just like with any speaker that "EQ" could be a enclosure ... it could be an "active" EQ, which could be analogue, or it could be digital (DSP) ... or it could be done on a passive speaker with the right choice of filter/XO components.     The example (extreme) I provided was of a passive speaker that could be driven from any damping factor ...... but someone could design a speaker where a specific (specifically low) damping factor was needed / expected.

 

I only came in here to make the simple/blunt point that "higher damping factor (than whatever the designer expected) confers no benefit" .... none of these side issues weakens that

[March Audio]

31 minutes ago, davewantsmoore said:

LOL it is not "moot".

 

It is because that is the real world situation.  

 

If 99.9999% of amps out there are low impedance high damping factor designs then being concerned about non optimal DF is a rather pointless exercise..............unless there is significant benefit to be obtained.

 

This is why I asked what the benefits were of optimal damping factor above.

 

Without that specifically quantified it's difficult to know if this is a worthwhile debate.

 

How much does distortion reduce.  How much is transient response improved?

 

 

[davewantsmoore]

3 hours ago, March Audio said:

It is because that is the real world situation.  

The real world situation is that it can be done in passive speakers.    You said it can't.

 

3 hours ago, March Audio said:

If 99.9999% of amps out there are low impedance high damping factor designs

Yes, of course.... but you said it's not possible to "optimise the damping factor in a passive speaker" .... but that's not correct.    You can.   Whether or not it rare or common, a good thing to do, or a bad thing to do, easy to do, or hard to do.... They're all moot.   In the context of "can't" (do that on a passive speaker) .... which is what I was responding to.

 

 

3 hours ago, March Audio said:

then being concerned about non optimal DF is a rather pointless exercise

I never said I was.   

 

All I ever said was making the damping factor higher offered no benefit (and that the "right" amount of damping factor was what was "good").

 

Then you said (I'll paraphrase) "you can't optimise the damping factor in a passive speaker anyways" ... which you are incorrect about.

 

3 hours ago, March Audio said:

How much does distortion reduce.

About 10dB

 

3 hours ago, March Audio said:

 How much is transient response improved?

I don't know what that is.  

[davewantsmoore]

3 hours ago, March Audio said:

Without that specifically quantified it's difficult to know if this is a worthwhile debate.

I'm not interested in debating that here (benefits of some sort of "low" damping factor).

 

All I wanted to point out was that riasing damping factor is not synonymous with raising performance.

 

 

Saying it can't be done on a passive speaker.... is really going to corrupt people's understanding of the topic.    If you vary the amplifier "damping" a lot (which alters the response of the drivers), then the speaker will likely need a new crossover / filters...... but that's no different to an active speaker when you vary the damping factor ...  it's exactly the same for a passive.    The only difference between the active and passive is it might be "easier" to adjust the driver responses in an asctive loudspeaker (but that is obviously nothing inherent to DF itself).

 

Anyone coming into this thread just sees people arguing inanely, and probably conclude "ah well, nobody knows" and that's sad.

 

 

[March Audio]

1 hour ago, davewantsmoore said:

The real world situation is that it can be done in passive speakers.    You said it can't.

 

No I didn't say that.  I said it requires a specific design for the passive speaker and amp.  They would need to be "tuned" together.

 

The most practical way being an integrated dsp active design.

 

 

Edited March 19, 2023 by March Audio

[March Audio]

1 hour ago, davewantsmoore said:

I'm not interested in debating that here (benefits of some sort of "low" damping factor).

 

 

Well it's a discussion specifically about DF and its effects.

 

I'm simply asking what the real world benefits of optimised damping factor are.

 

 

1 hour ago, davewantsmoore said:

Saying it can't be done on a passive speaker.... is really going to corrupt people's understanding of the topic.   

 

Well all is fine because I never said that.

 

1 hour ago, davewantsmoore said:

About 10dB

 

That's actually quite specific.  Surely it very much depends on the driver design?

 

So a speaker operating at -60dB thd (0.1%), might drop to -70dB (0.03%). A drop of 0.07%. Hardly earth shattering.

 

Do you have some data that shows a design that was changed from typical low output impedance/high DF to optimised DF and what the

differences were?

 

1 hour ago, davewantsmoore said:

I don't know what that is.  

 

Sorry, I was very unclear.  I was referring to the real world effect of optimised damping/driver control. It's settling time.

What do hear different? What are you measuring to quantify it?

 

1 hour ago, davewantsmoore said:

Anyone coming into this thread just sees people arguing inanely,

 

There is nothing inane about trying to get to the bottom of what the benefits of optimised DF are.

Edited March 19, 2023 by March Audio

[davewantsmoore]

15 minutes ago, March Audio said:

Well all is fine because I never said that.

 

Quote

However, optimising DF is not an option for passive speakers without integrated amplification.

 

You can have a passive speaker which has flat electrical impedance.

You can have a passive speaker which expects a "specific" damping factor amplifier, in order to provide the correct frequency response.

 

So it is an "option".   I'm not trying to be a d!ck..... I just genuinely believe that anyone trying to understand "what is DF" is going to have a stroke trying to figure out "why does this not apply to passive crossover speakers".

 

15 minutes ago, March Audio said:

benefits of optimised DF are.

I'm not sure.

[March Audio]

55 minutes ago, davewantsmoore said:

1 hour ago, March Audio said:

Well all is fine because I never said that.

 

Quote

However, optimising DF is not an option for passive speakers without integrated amplification

 

Aaaahhh, you have misunderstood what I said and the context I said it in.

 

You indeed cannot have a passive speaker without a matched amplifier if you are tuning for optimal DF. The two have be "tuned" together, ie integrated.

 

Hence with the much higher output z and inevitable aditional frequency response variations, the only practical solution is an active dsp speaker.

 

Yes I'm sure someone can cobble some DIY solution together from a random amp and speaker with lots of modifications, but I think that would be missing the point.

 

Another question, if you have a much higher output impedance, don't you now need an amp with a much higher output voltage?

Am I reading this plot from the paper you linked indicating output impedances from 13 ohms to 170 ohms?

 

 

 

 

Edited March 19, 2023 by March Audio

[LogicprObe]

On 15/03/2023 at 12:41 PM, georgehifi said:

Not sure who quoted it to make Keith ask.

Means "Compressing" to me

"If you have no quite bits you have no loud bits" It called dynamic range as you know, and it gives the music calm/breadth/depth and startle factor when the dynamics hit.

 

Squeezing/compressing makes it all sound a bit too much like Phil Spectors "Wall of Sound" recordings, where just about everything is compressed to the same dB level. That way you don't miss out on the low level stuff if there's background noise. That's why he said he evaluated all his recordings on the cars system driving around with all the background noise!!!!

This is NO good for the quiet of the man cave with a good red a mega system. That's also why you almost never see classical music compressed, you don't want the little triangle to be as loud as guy with the big crashing cymbals.

 

Cheers George

 

That's right,,,,,,,,,Phil optimised his sound for lowfi.......................just like they did in the nineties.

 

The difference was, Phil did it in analog and then came digital, 40 years later with emulations!

[davewantsmoore]

13 hours ago, March Audio said:

You indeed cannot have a passive speaker without a matched amplifier if you are tuning for optimal DF. The two have be "tuned" together, ie integrated.

Of course (that's what I already said).

 

You can do it with a passive speaker, if:

 

You have a passive speaker which makes the expected response from ANY damping factor (ie. it has a flat electrical impedance).

You have a passive speaker which makes the expected response from a specific damping factor (in which case you need a specific amp, or an amplifier with a variable "damping factor")

 

Saying "it is only an option when using active speaker and DSP" is very confusing for people with only a cursory understanding of "what is damping factor".

 

13 hours ago, March Audio said:

Hence with the much higher output z and inevitable aditional frequency response variations, the only practical solution is an active dsp speaker.

"Practical" is subjective .... but again, not explaining how it can happen with a passive speaker is very confusing to most people, I would imagine.    They don't know it's confusing, of course.... but they just end up with a munted understanding of "what is damping factor".

 

• You can design the driver filters (and box) of a passive speaker so it presents a flat electrical impedance ..... now you can use any amplifier "DF".
• You can design the driver filters of the passive speaker to give the "right" response with a specific amplifier "DF".

 

I'm not trying to argue that it's worth doing.... simply that it can be done (which isn't a "esoteric gotcha", as opposed to being important for understanding the concept more broadly) ..... and that they key takeaway should be that converse to the "conventional wisom" which is that "larger damping factor = higher performance" ..... that the main asepct of damping factor is simply a change in frequency response if it is adusted to be significantly lower (or in rarer cases, higher) than the speaker designer expected.... with most speakers expecting a "sufficiently high" damping factor.

 

13 hours ago, March Audio said:

Yes I'm sure someone can cobble some DIY solution together from a random amp and speaker with lots of modifications, but I think that would be missing the point.

 

"Lots of modifications" is simply adjusting the driver EQ, either the passive crossover, or maybe changing the enclosure, or perhaps some external EQ.

 

There are speakers out there which are designed to be driven from "tube amps" (eg. to boost their bass response.)

There are speakers out there which have flat electrical impedance.

 

The "point" isn't that these things are good, or common, or easy, or recommended.... or anything .... other than they are possible (and exist), becuase that's how daming factor works.

 

13 hours ago, March Audio said:

Another question, if you have a much higher output impedance, don't you now need an amp with a much higher output voltage?

Sometimes.

... but typically, due to the higher efficiency in the area where the impedance rises, less "power" is needed.

 

I personally do not like to driver transducers in regions where they're particularly non-linear (eg. where they "resonante"), so it's not something I've looked much into.

 

13 hours ago, March Audio said:

Am I reading this plot from the paper you linked

What I intended to illustrate with the paper was that "using a certain amount of damping will result in a certain driver response" (except for the case where the electrical impedance is flat)  ...... which is converse to the convential wisdom often seen repeated which is "using a higher amplifier damping will result in increased performance".

[March Audio]

2 hours ago, davewantsmoore said:

You can do it with a passive speaker, if:

 

You have a passive speaker which makes the expected response from ANY damping factor (ie. it has a flat electrical impedance).

You have a passive speaker which makes the expected response from a specific damping factor (in which case you need a specific amp, or an amplifier with a variable "damping factor")

 

Saying "it is only an option when using active speaker and DSP" is very confusing for people with only a cursory understanding of "what is damping factor".

 

and I never said that it was impossible.  I said multiple times the amp and speaker need to be treated as an integrated item.  Highlighting one comment misses the context of my multiple posts.

 

Its not confusing at all because the only realistic way 99.99% of audiophiles would ever get to experience an optimised DF speaker is if they bought a commercial active DSP speaker built on those principles.  Even then I think I only know of one.

 

2 hours ago, davewantsmoore said:

"Lots of modifications" is simply adjusting the driver EQ, either the passive crossover, or maybe changing the enclosure, or perhaps some external EQ.

  So, exactly what I said; lots of modifications.

 

2 hours ago, davewantsmoore said:

Sometimes.

 

I would say every time.

2 hours ago, davewantsmoore said:

What I intended to illustrate with the paper was that "using a certain amount of damping will result in a certain driver response" (except for the case where the electrical impedance is flat)  ...... which is converse to the convential wisdom often seen repeated which is "using a higher amplifier damping will result in increased performance".

 

But you can change damping and speaker response with the cabinet design.  

 

Well we have cleared that up during this thread that increasing DF over a certain amount is not going to be beneficial, in terms of damping of the driver. There is no dispute there.  However, lower output impedance, which goes hand in hand with high DF, has definite benefits.  So, the issue is more about why high DF is good - not for the reasons people typically think, rather than higher DF is of no benefit.

Edited March 20, 2023 by March Audio

[davewantsmoore]

49 minutes ago, March Audio said:

However, lower output impedance, which goes hand in hand with high DF, has definite benefits.  So, the issue is more about why high DF is good - not for the reasons people typically think, rather than higher DF is of no benefit.

What is the benefit of a low amplifier output impedance?    Like, I mean significantly low .... vs. just low-ish.     Like let's say, 0.05 ohms vs 0.5 ohms.  (10x difference).

[March Audio]

14 minutes ago, davewantsmoore said:

What is the benefit of a low amplifier output impedance?    Like, I mean significantly low .... vs. just low-ish.     Like let's say, 0.05 ohms vs 0.5 ohms.  (10x difference).

 

As I have said previously it minimises load related frequency response variations.  Again, as I have said previously, it has diminishing returns.

 

Real world example with a not so difficult 4 ohm speaker load

 

0.05 ohms amp source impedance

 

 

 

0.5 ohms

 

 

Thats over 1dB difference in places.  As it is over a wide frequency range it would be quite noticeable.

 

More challenging and lower impedance speaker loads will give larger deviations.

Edited March 20, 2023 by March Audio

[Addicted to music]

14 minutes ago, davewantsmoore said:

What is the benefit of a low amplifier output impedance?    Like, I mean significantly low .... vs. just low-ish.     Like let's say, 0.05 ohms vs 0.5 ohms.  (10x difference).

absolute important when driving low impedance transducers,   If the impendance is say 1 ohm,  then you have 50% voltage dropped on the load and the output impedance of the devices if the output impedance is 0.5 ohms.   That’s why designers aim for the lowest possible output impedance.  Ohms law dictates this.

Edited March 20, 2023 by Addicted to music

[davewantsmoore]

2 hours ago, March Audio said:

As I have said previously it minimises load related frequency response variations.

That's reasonably significant there.

 

 

Heh, I was going to suggest 0.05ohm, vs 0.005ohm... or 0.0005ohm. (ie. incessantly rasing the DF) ... and now I wish I did. 

[March Audio]

5 minutes ago, davewantsmoore said:

That's reasonably significant there.

 

 

Heh, I was going to suggest 0.05ohm, vs 0.005ohm... or 0.0005ohm. (ie. incessantly rasing the DF) ... and now I wish I did. 

For sure its diminishing returns, plus things like speaker cables need to be accounted for. However, if asked I would always go for a higher DF.  Its not because of DF though, its because it indicates lower output impedance.

Edited March 20, 2023 by March Audio

[davewantsmoore]

2 hours ago, Addicted to music said:

If the impendance is say 1 ohm,  then you have 50% voltage dropped on the load and the output impedance of the devices if the output impedance is 0.5 ohms.

I don't see how this is an issue, as long as the speaker is designed to deliver the correct frequency response.    In many cases (eg. an off the shelf speaker) it won't be, sure .... but that's a debate about "convenience" and/or "sticking with what the designer intended" ..... as opposed to the virtues or pitfalls of some amount or ratio of "DF" (aside from the frequency response issue).

[March Audio]

7 minutes ago, davewantsmoore said:

I don't see how this is an issue, as long as the speaker is designed to deliver the correct frequency response.    In many cases (eg. an off the shelf speaker) it won't be, sure .... but that's a debate about "convenience" and/or "sticking with what the designer intended" ..... as opposed to the virtues or pitfalls of some amount or ratio of "DF" (aside from the frequency response issue).

 

The issue is the designer has no idea what amp the speaker will be used with.  The only sensible choice is to design for what the vast majority of amplifiers are, which is low output impedance SS.

 

Same with amp designers.  The vast majority of speakers are simply variable (low) impedance.  Therefore the amplifier that works best is a low output impedance design.

 

The alleged benefits of doing otherwise just dont seem to be worthwhile to justify changing tac.

Edited March 20, 2023 by March Audio

[davewantsmoore]

On 14/03/2023 at 5:42 PM, rantan said:

Is high better than low and what are the respective consequences.?

As you can see from the article I posted, and Alans charts above.... if you don't use a damping factor around what the speaker designer intended, you don't get the frequency response intended.

 

Most speakers are designed to expect a "high" damping factor.... but this isn't as high as what most "beastly" amp manufactrurers would have you think.    DF=10 is usually going to be high enough.   Any more is no benefit.

 

Using a very low damping factor is a deep topic (in terms of why it could be a benefit), but it is highly inconvenient, as you need either a speaker which can work from any damping factor (rare to non-existent on the commercial market) or you need a speaker designed for a specific (lower DF) amp, and/or you need EQ (to correct the response).    This is basically the fundamental reason why high DF is the "norm" .... so any amplifier that has a suffcient DF, can be used with any speaker... and not get unwanted frequency resposne variations.

 

On 14/03/2023 at 5:42 PM, rantan said:

I once heard an amplifier with a hugely high damping factor and it seemed to squeeze the life from the music but is this a one off or poor design

Yes.