CALCULATING THE PERFORMANCE OF AN AMPLIFIER/SPEAKER COMBINATION

BlueFoxBlueFox Posts: 9,145
An application note from Benchmark dealing with their new amps.

While mainly an ad for their amps, I suspect it is applicable to any amp/speaker combo.

I like this part since Magico CEO and chief designer Alon Wolf basically told me the same thing after I blew up my S5 MKI speakers. LOL

"One word of caution: This combination is so clean that you will need to keep an eye on the sound pressure level. They effortlessly reach high sound pressure levels and therefore are much louder than they sound. Keep an SPL meter nearby until you get accustomed to the clarity of this system."


https://benchmarkmedia.com/blogs/application_notes/calculating-the-performance-of-an-amplifier-speaker-combination?utm_source=Benchmark's+Application+Notes&utm_campaign=9b8bed5219-EMAIL_app+note+74+5-17-16&utm_medium=email&utm_term=0_7c8c792ee5-9b8bed5219-34688693
Bud

Lumin S1
Sony XA-5400ES SACD
Pass XP-20 pre, X600.5 amps
Magico S5 MKII Mcast Rose speakers, SPOD spikes

Shunyata Triton v3/Typhon for source, Denali 2000 (2) for amps
Shunyata Z Anaconda XLR analog ICs, Z Anaconda speaker cables
Shunyata Sigma HC (2), Sigma Analog, Sigma Digital, Z Anaconda (3) power cables
Revelation Audio Cryo-Silver Reference DB-25 umbilical power cable for preamp modules

Mapleshade Samson V.3 four shelf solid maple rack, Micropoint brass footers
Three 20 amp circuits.

Comments

  • mhardy6647mhardy6647 Posts: 14,335
    I may be missing something -- they show an impedance plot for a real loudspeaker load:

    PMCIB21impedanceandphasechart_large.jpg?v=1493328752

    ... but then they show the THD+N as a function of power (measured as dBu which, if I am reading correctly, is a reference voltage of 0.775VAC RMS) of their amplifier... driving a four ohm load. Presumably a pure resistive load; the loudspeaker in the plot above isn't a "four ohm load" -- even if it has a nominal impedance of four ohms.

    THDvsPower_4Ohm_bridged_mono.JPG?v=1493322575

    I mean, the amp may drive the speakers perfectly well to any reasonable (and perhaps even unreasonable) SPLs in a real-world room... and it may sound great, or not, doing so... but the two graphs are essentially unrelated from my perspective.

    Drive a load that looks like that loudspeaker (a mixture of fixed DC resistance, and frequency-dependent capacitive and inductive reactance) and show me that curve (i.e., THD+N as a function of power) for a number of frequencies: 20 Hz, 45 Hz (those two resonance peaks in the LF of the loudspeaker), 200 Hz, 1kHz, 10 kHz and 20 kHz and let's see how the THD+N plots for those conditions would look.

    Unfortunately still won't tell you much about how the pair sounds.

    Sorry to be the grumpy old man -- now, excuse me while I go chase some punk kids offa the lawn ;)

    ;)



    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

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