K-Horn power need per PWK

[Zim.]

x

[tube fanatic]

I know many guys who have invested a great deal of money in very high power solid state amps and tube amps based on their mistaken belief that they need huge amounts of power for their super high efficiency Klipsch speakers.  And they can’t understand why they can hear high frequency hiss all the way across the room when no music is playing, among other things.  Also, if a person’s typical listening level requires only 1/10 watt, what’s the point of using a 100 watt amp when one  which can provide 10 clean watts will give them the 20 Db head room needed for most program material?   It’s like buying a car which has a 400hp engine and only driving it down Main St. at 25 mph.   Aside from this, it is instructive to know that a fairly inexpensive amp can provide the desired listening experience which frees up money for improvements elsewhere in the system.  
 

Maynard

[Zim.]

 x

 

[Khornukopia]

I have not done the test,  but while reading its instructions,

• Use the highest setting you found when playing back music really loud and leave the volume there for the following measurement.
• Playback the test tone and measure the voltage at your speaker terminals. Measure at the amp or at the speaker, either is fine.
• Post the voltage you measured.

I considered that full range, dynamic music will need more power than a steady state, single frequency 220Hz test tone at the same volume control setting. The test might be more realistic if the voltage is measured while comparing the music setting vs. pink noise at matching SPLs.

[Khornukopia]

Yes I read the part about using a single frequency tone for the sake of the common volt meter, but I wonder about the perceptual bias of the results of the test, based on the different loads. 

[tube fanatic]

2 hours ago, Zim. said:

  Noise (hiss) should never be tolerated anywhere in the audio chain.   It's caused by many things,  but I wouldn't put amplifier power alone as a culprit. 

 

Perhaps the 100 watt amp (400 hp engine) sounds better.

Hiss is often a function of amplifier gain.  For example, the Krell KSA-250, in spite of its 2.3V input sensitivity, produces a great deal of hiss with Heritage series speakers.  Contrast that with the dead silent Quicksilver Horn Mono with a 9V input sensitivity and a power output of 10 times less than the Krell.  
 

As far as the power measurement test goes, it is designed to provide guidance as to required power.  I find it to be quite accurate.  The bottom line is what PWK said is needed to satisfy in-home listening requirements with Khorns.  My own experiences mirror this completely.  
 

 

Maynard

 

[garyrc]

Dynamics and the leaning edge of big peaks.

• Back when I had a small room (about 1,000 cu ft) & Khorns, the built-in meter in my Yamaha power amp usually read less than a watt or two, but 6.3 watts on very loud, very brief, peaks.  Once, though, at the end of a Mahler symphony, at a realistic level, it reached 25 watts for just a moment. 
• For the last 15 years, I have had a large room  (4,257 cu. ft.) & Khorns, along with a Belle center, and Heresy II surrounds and crossing over at 80 Hz to a Klipsch  RSW15 sub, with all kinds of boundary gain, to play PWK's Wide Stage Stereo (3 channels), or SACD Multichannel music (5.0 or 5.1), or Blu-rays (5.1).  I no longer use a power in watts meter, but with an SPL meter, C wt., "Fast," big, unusual, very brief peaks in music very occasionally reach 110 dB for just an instant (this would be at the end of The Great Gate of Kiev, or the Crystal Clear Records version of Fanfare for the Common Man -- not the brass, but the tympani, bass drum, Tam-Tam, etc. -- and Mahler, again).  For explosions in movies, a reading of 115 dB is conceivable, since that is THX's fs for the sub channel.  It's doubtful, though, because I always set movie SPL for normal dialog (not screaming or whispering) ASAP in the film, and that dialog usually ranges from the mid '70s in dB to the mid '80s.  This results in a Main Volume setting of 5 to 7 dB below THX/Dolby/Cinema reference level, as set in an Audyssey calibration.  In my THX portfolio, it states that the greatest SPL recorded 1/2 way back in their test theater for The Empire Strikes Back was 110 dB in the bass, with a nominal test SPL (I refuse to call it an average!) of 88 dB (rather than the 85 dB settled on later, to allow for 20 dB peaks up to the fs of 105 dB when above 80 Hz, and 115 dB below 80 Hz).  For movies, my usual 5 to 7 dB below reference, set for dialog, gives me about 110 dB below 80 Hz, and 100 dB above 80 Hz.   Un-coincidentally, that gives me THX peak levels for a room my size (for home-sized rooms, because of early reflections, and other "small" room phenomena, THX reduces their recommended level); at this lower level, in the small room, the movies "sound like" they have theatrical level brief peaks, even though they are 5 to 7 dB lower in measured SPL.  At 13 feet away from the listener in my 4,257 cu.ft. room, it takes just below 4 watts through 1 Khorn to produce 100 dB.  If I were to put the bass below 80 Hz through the Khorn (which I don't, except for the slope the crossover to the sub allows) and produce the needed 110 dB, 1 Khorn would take about 32 watts.  But this is neither here nor there -- who knows how many watts the sub is requiring from its built-in, 650 watt continuous, 2,400 watt "dynamic power" amplifier?   I hear no clipping.
• As many of us know, SPL is the hopefully objectively measured physical pressure at the location of the meter (or the ears), loudness is a perceptual phenomenon, influenced by many factors, and volume originally meant volume!  In a room of high volume in cubic feet, one would turn up the control marked volume, and in a less voluminous room, one would turn that knob down.
• Instantaneous peaks of 100 dB probably wouldn't bother OSHA much; they allow much more continuous machine noise at that level for 2 hours!  Likewise, 110 dB is allowed for 1/2 hour, and even 115 dB for 1/4 hour.

 

[ClaudeJ1]

On 11/14/2019 at 12:50 PM, babadono said:

And that requires headroom out of your amplifiers. Of course it ALL depends on how dynamic your source material is.

The most I have ever measured thus far is 62 db from a Dolby Atmos 4k Blue Ray Movie. Most of the power came from the subs, but still pretty impressive, from conversation level up to BOOM.