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Measurements - Clearly Explained

Hi Everyone,

I found a page which explain amplifier measurements which I think many would find useful on the SoundStage web site:

http://www.soundstage.com/measurements/test_amplifiers.htm

They seem to be suffering from bad links. If you get directed to "SoundstageMagazine.com" just remove the "Magazine" part.

One thing a lot of people have questions about are the impedance of "real-world" loudspeakers. This I found at the Stereophile site, here:

http://www.stereophile.com/reference/60/index.html

Of course, this is 1 specific speaker load, but it does represent the challenges posed by many 2-way, dynamic loudspeakers.

Best,

E
erik_squires
erik_squires OP
16,245 posts
 
Hi Wolf!

Those are always great finds.

But as an engineer, anything that sounds good, I'd like to know why so I could replicate it, whether or not it goes with established dogma.

Like, maybe it adds plenty of 2nd order distortion, or has noise in the treble which enhances digital recordings.

Best,

E
wolf_garcia
6,714 posts
 
Had does go on about the 2nd order harmonics inherent in this amp, and regarding "dogma," the entire SET (or SEP in this case) world has its own dogma it seems, and I'm all for it as it's a thing that has transformed my thinking about such things (although I've used relatively low wattage guitar amps for many years…including a hand made single ended amp with a tube rectifier). Regardless of all that, this amp "seems" to have less distortion of ANY kind at even louder levels, and the openness and apparent clarity may be the amp simply fooling me, which as long as I like the results is just fine.  As Fremer said in a recent article, "my hearing gets worse, but my listening gets better," which certainly applies to my old person self as I continue to produce and mix concerts and play music. Had's new stuff since retiring from Cary seems like an assault on convention (and pricing), and if he makes a remote preamp I'm in with one of those too! Note no measurements are around for the Fire Bottle amp unless somebody else has tested one, but Had certainly measures things and his idea of what sounds good might just be the same as mine.
erik_squires OP
16,245 posts
 
@wolf_garcia

Nothing wrong with that at all in my mind. :)

I just don't like influence/idea peddlers promoting ideas about power and impedance not supported by facts.

Buy and listen to what you like!! :)

Best,

Erik
rotarius
431 posts
 
Erik, Agon has always been big on "alternate" facts, long before the term came about.  Where else can you find clever lil clocks and pebbles?
erik_squires OP
16,245 posts
 
Here is a paper I just discovered an excellent paper on Damping Factor from Wikipedia:

https://en.wikipedia.org/wiki/Damping_factor#cite_note-3

which also references a paper from Nelson Pass discussing how matching the amplifiers to specific speakers (lots of full-range and high efficiency drivers could be useful):

http://www.firstwatt.com/pdf/art_cs_amps.pdf

While the paper focuses on HE speakers and using current source amplifiers (i.e. very high impedance output)  I think it's a great way to dive in deep into speaker / amplifier interrelationships.

I'm not sure if I can create a current source amp in Xsim, but it is a fun challenge. :)


Best,


E
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