planet10, that's an interesting position to take. i'm not sure it's true but maybe it is. if it is true how do you determine the optimum DF for a given speaker?
wadest
wadest
1st off forget about daming factor, it is just spec sheet bling. The real spec is amplifier output impedance.
We have a couple variable transimpedance amplifiers. It is very enlighting connecting different loudspeakers and then playing with the pot that controls the amplifier output impedance.
dave
Yes we did! With the Amp at the lowest Damping Factor setting (zero?) the amp had the deepest, hardest hitting, solid bass we were able to get out of it. I remember it quite distinctly as we had my Focused Array Speakers hooked up at the time.
Best Regards,
TerryO
Last edited:
Interesting discourse.
Way beyond my simple empirical experiences.
Does make me wonder why, my experiments with bespoke 300b and 45 SE tube amps of low (no?) damping factor, proved as simply Poor/sloppy at bass and cone control.
Acceptable for one's Fender.. but little else.
Also there's the oddity of using Speaker cables with higher resistance to Enhance bass.
Seemingly 'that' alone has generated entire industries ..
Way beyond my simple empirical experiences.
Does make me wonder why, my experiments with bespoke 300b and 45 SE tube amps of low (no?) damping factor, proved as simply Poor/sloppy at bass and cone control.
Acceptable for one's Fender.. but little else.
Also there's the oddity of using Speaker cables with higher resistance to Enhance bass.
Seemingly 'that' alone has generated entire industries ..
Last edited:
Your experience (good or bad) with Low Power SETs may very well be related to the speakers you were using. Many modern speakers or Bass drivers anyway, have very rough impedance curves in the Bass frequencies which often translates to very poor bass performance with SETs. Note that we're talking about "the whole Curve", not a single frequency! The so-called Damping Factor has very little, if anything at all, to do with it!
Kill your Damping Factor and release your Bass from bondage!
😀
Best Regards,
TerryO
Mmmm ...
True - but optimum for what? Maximum power transfer? That would satisfy the classic term 'matching'; it would also be the condition for maximum distortion. Lowest distortion? That would be a different configuration.
I think the OP's question was a basic one, relating to present audio practice. There loudspeaker designers mainly assume a low amplifier internal impedance - I have never seen a loudspeaker spec. asking for a finite feeding impedance as optimal. Yes, the full scenario would include feeding with low as well as high feeding impedances. Experimental systems were demonstrated where feed was from a high-impedance source (current feed) - and it was preferred by some! But such exposition will require a full tutorial including motional feedback, other special systems et al.
Again true, but such a statement should not be applied to fuel the cable-makes-a-difference debate for all the wrong reasons. It was indicated that in just about all cases cable resistance/impedance can be neglected in practice unless someone feeds his loudspeaker away in the outhouse with flea-wire. Very close after this comes amplifier feeding impedance .... as said before. While a system, surely the engineering approach to eliminate practical negligible quantities is valid here?
Already for the uninitiated, one perhaps needs to explain that source/amplifier internal impedance is not the same as the recommended load impedance, e.g. 4 ohm or 8 ohm. Feeding impedance means the amplifier internal impedance, mostly the load divided by the feedback factor as well as driver inetrnal impedance. See, it already becomes complex!
AndrewT, i agree with you. Crown had a power amp with a DF of 10,000. of course you had to measure it at two points inside of the amplifier. by the time it got to the connectors the high DF was gone.
if DF is so important and tube amps have vey low DF then why do they sound so good.
if DF is so important and tube amps have vey low DF then why do they sound so good.
MacIntosh and Pass Labs Solid State amplifiers have "very low" Damping Factor specs and nobody that I can remember has ever mentioned their lack of Bass!
The fact is that Damping Factor and Dracula refuse to die and need to have a stake driven thru their heart!
😱
The applicability of high output impedance amplifier is heavily dependent on the speakers inherent mwchanical damping (low) and the impedance curve (flat) coupled with FR under voltage drive.
dave
Taken your concept of "real damping factor", it should be remembered that the higher its value, the closer the loudspeaker behaves as a differentiator with a 6 db/o slope in its main resonance region.
Another fact which should be made clear is that, outside the main resonance region, the damping factor does not concur to damp anything, probably even the contrary : as far as I know, cone breakups and local cone resonances do not model as RLC parallel circuits.
Optimum sonics.
You have not seen a wide spectrum them. Not many commercial speakers apply, but many diy projects do. And as diyers we can design to take advantage of the advantages inherent in a high output impedance amplifier.
But cables do make a difference.
dave
That's logical, because they should have excessive bass if their damping factor is very low and if the loudspeaker is designed for a high damping factor. The quality factor of the fundamental resonance becomes higher than the loudspeaker designer expected, hence you get some peaking around the resonant frequency.
Ok, whatever....
For those that actually have heard Mac or Pass Labs amplifiers, will probably know the difference between real Bass reproduction and "Excessive" false frequency peaking.
- Status
- Not open for further replies.