Amplifier Output Impedance (Damping Factor) and Speakers

[Suffolkhifinut]

Not for all of us! I've never cared what anything sounds like to me, only how it measures. If it measures well, that's all I care about. If then I don't like it, that's my fault, not that of the equipment. Then, choosing equipment is easy, just buy on facilities, build quality (which I accept is subjective) and ease of service. None of this agonising over what I think something sounds like.
S.

This one certainly astounds me! So you don’t care how HiFi equipment sounds? If you go to a dealer to buy any item of HiFi equipment there’s no need to listen to it? Which measurements matter the most?
To you does digital always sound better than analogue? If you look at the output measurements of a high end turntable cartridge they could never measure as well as a relatively cheap CD player. Your take on it would be interesting to read.

 

[sergeauckland]

This one certainly astounds me! So you don’t care how HiFi equipment sounds? If you go to a dealer to buy any item of HiFi equipment there’s no need to listen to it? Which measurements matter the most?
To you does digital always sound better than analogue? If you look at the output measurements of a high end turntable cartridge they could never measure as well as a relatively cheap CD player. Your take on it would be interesting to read.

No, I don't care one jot what I think something sounds like. I've never bothered to listen to anything before choosing, just done it on the specs.
Digital does always sound better than analogue, or at least never worse, as it may depend rather more on the recording than the medium. Frankly, even a £15 supermarket DVD player sounds better (or at least no worse) than even the most outrageous turntable, depending again on the recording.

I do enjoy my turntables, as an intellectual exercise in getting the best out of a badly flawed (or at least limited) medium. It's a bit like driving a 1936 MGTC, great fun, but not a patch on a modern Fiesta.

S.

 

[SIY]

This one certainly astounds me! So you don’t care how HiFi equipment sounds? If you go to a dealer to buy any item of HiFi equipment there’s no need to listen to it? Which measurements matter the most?
To you does digital always sound better than analogue? If you look at the output measurements of a high end turntable cartridge they could never measure as well as a relatively cheap CD player. Your take on it would be interesting to read.

Peter Walker would like to have a word with you.

 

[Geert]

When it comes to HiFi the only instruments that really matter are the ones on either side of your head. Human being make subjective judgements throughout life and live by them whether it’s relationships, work, hobbies etc.

You can define room eq settings or troubleshoot amplifier distortion by ear? And you're also not subject to different kinds of bias or the limitations of system 1 thinking? If that's your believe than you don't agree with the scientific consensus on these topics and I don't understand why you joined this forum. To teach science a lesson?

 

[Geert]

If you go to a dealer to buy any item of HiFi equipment there’s no need to listen to it? Which measurements matter the most?

I auditioned my current speakers at the dealer before I bought them, and they sounded crap. Luckily I knew how they measured so I concluded I was dealing with bad room acoustics and I bought them anyway. It turned out they sound brilliant, especially after applying room eq to deal with room modes. Measurements to the rescue.

 

[Suffolkhifinut]

No, I don't care one jot what I think something sounds like. I've never bothered to listen to anything before choosing, just done it on the specs.
Digital does always sound better than analogue, or at least never worse, as it may depend rather more on the recording than the medium. Frankly, even a £15 supermarket DVD player sounds better (or at least no worse) than even the most outrageous turntable, depending again on the recording.

I do enjoy my turntables, as an intellectual exercise in getting the best out of a badly flawed (or at least limited) medium. It's a bit like driving a 1936 MGTC, great fun, but not a patch on a modern Fiesta.

S.

I enjoy both digital and analogue and at the moment am enjoying HD internet radio as much as anything. Can’t agree with your view on turntables, although I will admit £ for £ spent digital is much better. My turntable rig cost more than I could afford, yet picked up my Denon A-11 for around one twentieth of the price. Think my turntable sounds marginally better, that’s it! If I was forced to only keep one format it would be HD internet radio. In HiFi terms the worst of the three formats I use, the range of music is superb and the reproduction is very listenable.
As to your comment on not caring what something sounds like, to me it’s like picking your Wife from a mail order catalogue.
Hight
Weight
Hair colour
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[BDWoody]

I do enjoy my turntables, as an intellectual exercise in getting the best out of a badly flawed (or at least limited) medium. It's a bit like driving a 1936 MGTC, great fun, but not a patch on a modern Fiesta.

It satisfies your inner masochist.

 

[BDWoody]

Sometimes when listening it isn’t what we hear, it is what’s missing.

Usually what's missing are controls.

 

[Suffolkhifinut]

Usually what's missing are controls.

Certainly applies to my HiFi spending.

 

[BDWoody]

Certainly applies to my HiFi spending.

In a market where stuff is sold more on prose and imagination than reality, you've gotta keep both hands on your wallet!

Cutting through all that makes it much less random at least...

 

[Suffolkhifinut]

I auditioned my current speakers at the dealer before I bought them, and they sounded crap. Luckily I knew how they measured so I concluded I was dealing with bad room acoustics and I bought them anyway. It turned out they sound brilliant, especially after applying room eq to deal with room modes. Measurements to the rescue.

Glad they worked out rooms do have a major effect on sound quality. If you’re lucky enough to have an understanding dealer nearby a home trial is the way to go! It is still a subjective judgement on sound quality. As I said in a previous post we do have different tastes.

 

[Geert]

Glad they worked out rooms do have a major effect on sound quality. If you’re lucky enough to have an understanding dealer nearby a home trial is the way to go! It is still a subjective judgement on sound quality. As I said in a previous post we do have different tastes.

It's not subjective for let's say 80%, you have some wiggle room in the low end and highs and in directivity. Unless you're going for a system that's optimized for a specific music genre,.

 

[pogo]

OK, maybe I was misunderstood here. In this forum you always read that everything is known, can be recalculated or simulated. But I have not yet seen any meaningful measurement on a real chain that shows different levels, even after a few minutes of load on adequate test stimuli or dynamic music.
On the other hand, there are many statements from manufacturers and users (I count myself among them) who can clearly hear a difference and especially with different DFs.
And this does not even require level matching!

 

[Gregss]

OK, maybe I was misunderstood here. In this forum you always read that everything is known, can be recalculated or simulated. But I have not yet seen any meaningful measurement on a real chain that shows different levels, even after a few minutes of load on adequate test stimuli or dynamic music.
On the other hand, there are many statements from manufacturers and users (I count myself among them) who can clearly hear a difference and especially with different DFs.
And this does not even require level matching!

Yes, agree. Lots and lots and lots of claims. Sadly little to no evidence is the normal.

 

[sergeauckland]

I enjoy both digital and analogue and at the moment am enjoying HD internet radio as much as anything. Can’t agree with your view on turntables, although I will admit £ for £ spent digital is much better. My turntable rig cost more than I could afford, yet picked up my Denon A-11 for around one twentieth of the price. Think my turntable sounds marginally better, that’s it! If I was forced to only keep one format it would be HD internet radio. In HiFi terms the worst of the three formats I use, the range of music is superb and the reproduction is very listenable.
As to your comment on not caring what something sounds like, to me it’s like picking your Wife from a mail order catalogue.
Hight
Weight
Hair colour
* * * *

Don't forget bust size.
We've been married 48 years.

S.

 

[Geert]

OK, maybe I was misunderstood here. In this forum you always read that everything is known, can be recalculated or simulated. But I have not yet seen any meaningful measurement on a real chain that shows different levels, even after a few minutes of load on adequate test stimuli or dynamic music.

You've already received multiple serious responses on your theory in different topics, the last one being:

Calculating dynamic output impedance is challenging (yes, done it, years ago) but large-signal circuit simulators do a good job of it. As mentioned earlier it is such a small effect that it is usually neglected. Feedback handles it nicely, natch. Along with changes due to supply voltage changes, temperature changes, process variations, and a host of other factors that influence output impedance (and thus damping factor).

It again confirms it's a known thing but its effect is neglectable, hence you shouldn't expect more detailed research and measurements. If you claim your system sounds better in the dark, than do you expect engineers to jump for you and make measurements to prove their theory that light doesn't matter?

Yes, agree. Lots and lots and lots of claims. Sadly little to no evidence is the normal.

Looks like you fail to understand the answers you receive are not 'claims'. It's electronic engineers with relevant experience sharing their knowledge. Unfortunate it seems you can't differentiate the answer from an expert from that of a hobbyist.

If you want real evidence, would it help if I shared you 20 pages of math about the effect of back EMF? If that's what you want to discuss, the theory is already out there and is easy to find so maybe you can poste some very specific questions.

And taking about evidence, let's maybe take it one step back and proof difference in damping factor is audible (talking about DF > 50 at minimum) and under which conditions. Otherwise I don't know why people would spend time researching it.

 

[Suffolkhifinut]

Don't forget bust size.
We've been married 48 years.

S.

Glad to hear it we’ve been married for 42 years. HiFi here may change more often than I like to admit, Ann is here forever.

 

[egellings]

I had a vacuum tube amplifier that had a knob to continuously vary DF. The more DF I requested, the tighter the bass got.

 

[sergeauckland]

I had a vacuum tube amplifier that had a knob to continuously vary DF. The more DF I requested, the tighter the bass got.

I designed and built a valve amplifier with such a control. It allowed the output impedance to go negative! which resulted in a somewhat unstable amplifier, but if adjusted so that the output impedance was low, it worked OK. However, a lot of effort for very little benefit, and I can understand why very few manufacturers implemented this, as a risky option for the General Public without test instrumentation.

S

 

[pogo]

I keep thinking of doing some sort of transient response but the real impact of that must include a better speaker model than I am using now. It needs to include a reasonable RLC (resistance, inductance, capacitance) model for back-EMF (charge kick-back) of the driver in an enclosure. I am not a speaker designer so don't have that sort of model at hand. I can do (I think) a decent model of the steady-state impedance from the frequency response but the dynamics of speaker operation I have not looked at since my grad school days. Peter Principle.

Is there any progress on this to be able to bring the simulations closer to reality?
But also a dynamic amplifier model would be helpful here.