That was a clear explanation. I think that a lot of people don’t realise that just the (pure) resistance of a cable influences the frequency response by changing the damping factor. But I miss some factors in your explanation. Between the amplifier and driver is also the crossover network. That impedance is probably higher than that of the cable. The biggest impact on the damping factor however is actually the voice coil resistance itself. Heating up the voice coil is also an extra impedance, lowers the damping factor and lowers the actual electromagnetic damping. The impact is huge (and also on passive crossovers). Suppose you have an amplifier with an extremely high damping factor, no cable resistance and no crossover. One degree Celsius (1ºC) temperature rise gives 0.4% extra resistance (depending on the material). That brings down the damping factor to 250. One degree. 10ºC brings down the damping factor to 25. 100ºC brings down the damping factor to 2.5. And at the maximum rated power and maximum temperature of the voice coil (depending on the driver): 200ºC brings down the damping factor to 1.25. 250ºC brings down the damping factor to 1 (at this point the resistance is doubled, and your passive crossover is one octave off). 300ºC brings down the damping factor to 0.83. I build and use a system with a total different strategy. As the electromagnetic damping is all over the place, I eliminated it all together. I use a power amplifier with a very high output impedance (a current source), so cables and voice coil temperature has no impact on the damping (frequency response, compression, etc). The actual damping is defined by EQ (Linkwitz transformation). As the damping, frequency response (and so on) are stable now I can very precisely control the frequency response of the driver. On top of that there is no thermal compression anymore (also called power compression), IM distortion is much lower (all the IM distortion by the inductance is eliminated) and there is much lower modulated noise (all the back-emf is eliminated). (SGR Audio has active loudspeakers, the Convex series, based on the same principle).

You’re awesome keep the vids coming glad I found this channel

@stereopolice

6 жыл бұрын

I've got a follow up on damping factor coming today. Thanks for the kind words.

thanks so much sir , clear my concepts , rt now web have no more data about details information , thanks again good effort to make 2 video about that

Excellent. I'm going to recommend my son, an budding audio hobbyist, view this.

@stereopolice

6 жыл бұрын

Good for you. I became interested in Audio at the age of 7. It ultimately led to two Electrical Engineering degrees, a career in electro-optics and night vision, and eventually Intellectually Property Law, which has my career for the past 22 years. I say this only to continue to encourage your son in this direction, as a fascination with audio leads to a fascination with electronics and physics, and the desire form more knowledge hopefully will lead to a desire for higher education and a good career and life. Cheers ....

please make video on 3 way speaker driver selection and power distribution about that . i have confusion on this subject.

Love the information presented, great video. In case you or anyone else reads this, can you explain to me how can 32-50-80 ohm headphone sound good from OTL amplifier that has probably 50-100 ohm output impedance ? To be specific thinking about combinations like Focal Clear, Utopia or Meze Empyrean and Feliks Audio Elise / Euphoria ? Thank you very much.

WHAT IF: Instead of taking your amplifier's feedback voltage from the speaker output terminals, try using current feedback obtained by a very low value of resistance in SERIES with the speaker terminals, (typically a very low value of resistance, (,01 ohms), in the ground return path of the speaker to the circuit star ground point? Using current feedback, the amplifier's output voltage will change such that the current delivered to the speaker would be proportional to the amplifiers input voltage and no longer affected by the speaker impedance. The above would be the perfect scenario, where in reality you would be limited by the maximum peak to peak voltage available from the amplifier and the impedance of the speaker. OR: Took your amplifier's feedback voltage from a second pair of much smaller wires connected directly to the speaker. (Kelvin Connection)?

The highest damping factor amps I know of are an Adcom GFA-555 Mk II and mono block GFA-565. Damping factor of 1000. Also the Kenwood M2A with the split rail power supply was also 1000 but was not a high current design, but rail voltage was somewhere around 90+ volts.

What are the common things to increase and decrease damping factor in amplifiers circuits? Why does the amplifiers output impedance increase or decrease the damping factor?

@Dennis-mq6or

10 ай бұрын

All of that was actually covered quite well in his video....

Had to get mine the hard way reading a bunch and just learning lol

can i add resistance replace with bunch of wire, so that it will work or not?

It seems to me that in the case of speakers of low compliance the amplifier's damping factor can be too high.

@garywells9478

4 жыл бұрын

Good video, by the way. Thanks.

Doesn’t current capability of the amp sustain the voltage on a speaker impedance curve? How does that affect the whole equation?

how to calculate damping factor of a bridged amplifier?

How good is a damping factor of 100?

can you tell me if output impedance has any relation to the load impedance? IE, if you have a 1.2ohm output impedance as measured with a 32 ohm load.. .will that change if you used a 12ohm load? will the output impedance change at all? What if any is the relation / is there a 'rule of thumb'? Thanks

And hold that A1000 and Klipsch Forte 3 combo tight

This webpage talks of "skin effect" happening when too large a gauge is used. Apparently the inductance and capacitance is different for low and high frequencies. Maybe running 5 wires together might create the skin effect. www.empiricalaudio.com/computer-audio/technical-papers/what-makes-an-excellent-speaker-cable

@stereopolice

6 жыл бұрын

Skin effect only happens significantly at frequencies well above the audio spectrum. I recall studying this in HF communications in college. It is of absolute no consequence in the audio range, which in the grand scheme, is very low in frequency. Check me on that ... If I'm incorrect, I'd love to know, really :)

Wikipedia educated lol

@stereopolice

6 жыл бұрын

or "internet intelligent", or "web wisdom".