Does anyone know what the actual sensitivity of the Cornwall IV is?
I know Klipsch says something like 101 dB but I remember the Klipsch sensitivity of the Heresy IV was higher than when tested. I just can't remember where I read that.
I also read that Klipsch uses a different testing procedure for sensitivity.
I apologize for all of the "I read this somewhere" stuff. I figured some of you guys/gals might know about this.
Thanks in advance.
Dave
ps The reason for the curiosity is that I have a 2A3/45 amp incoming.
Your question addresses one of my pet peeves in this industry. Something I have, rightfully, bitched about for over 47 years.
Marketing departments have always picked the
Highest numeric value possible from Engineering. Not a lie, but an exaggeration.
That goes for PEAK Speaker Sensitivity as well as Power Amplifiers.
So if Klipsch Corporate Marketing can choose a point on the magnitude/frequency r(true exaggeration) in order to get the Highest Number to advertise with. Truth in Advertising is a great expression for a false concept, eh?
Same is true for Power Amps. I remember, as a kid, reading electronic catalogs that claimed 200 watts
Peak to Peak Power per channel receivers in the '60's, with bold type (15 watts RMS) in smaller type. total bs
I have wished for amplifiers to be rated in dbWatts, where 0 dbWatts is 1 Watt, 10 dbWatts is 10 Watts, 20 dbWatts is 100 watts, and 30 dbWatts is 1,000 Watts and so on.
Never gonna happen!
So, this problem calls for a little Elementary school Arithmetic and some High School use of Logarithmic Math.
If the Cornwall IV is rated at 101 decibels, likely a peak value in the Midrange, and you have TWO speakers playing together in Stereo, you now have to add 3 db for a total of 104 db SENSITIVITY. Now if we subtract a peak 4 db's worth of "real world exaggeration," our REAL working number is now 100, OK? So far so good.
Now your upcoming amp is 1.5 watts Per Channel, so 2 channels TOGETHER is a total lof 3 Watts, assuming that peaks do not go beyond this. Tubes clip very gradually (softly) and it's harder to hear them when they happen, so let's ignore them for now, as it will depend on your music source anyhow and how much compression they use in the recordings.
So according to my HP calculator,
you will be using a 4.77 dbWatt amplifier, both channels driven into a 100 dbWatt sensitive pair of speakers.
We are not done yet. Now we need to talk about the most IMPORTANT and most expensive part of all, your ROOM!
In a typical living room, say, listening approximately 3 meters away from the speakers (10 ft.) depending on wall reflectivity/absorption you can measure (typically) 7-9 db less than the 1 Meter Industry Standard Distance, approximately.
Now if we look to another industry standard of
85 db sound pressure as "reference" which is pretty darn loud for OSHA and Home Theater Standards as our worst case scenario, we can complete the Arithmetic.
We take the agreed upon 100 db/Watt Speaker number for the Cornwall IV's and add the 4.77 dbWatts of your 2A3/45 Stereo Amplifier we get 104.77, rounded up to 105 db Loudness at a theoretical 1 Meter, OK?
Now we subtract a worst case 9 db loss for Distance to the Listening Position, we get 105-9=
96 db of sound pressure level with an SPL Meter to verify (you don't really need one).
My own personal preference is to meter an average of 83 db for as loud as I can stand, on average for most music. OSHA says you can listen to 85 db for 8 hours without creating Hearing Loss! I like to be more conservative that that, so 83 or less is my target. What is YOURS?
When I started measuring horns in the new Millenium, I dound that 160 Milliwatts was sufficient to give me that 83 db number in MY Room! So unless your live in a huge warehouse, you will be happy with your average room being similar to mine for this purpose.
So, back to you numbers. You can reach 96 db with your amps, which is what I call "stupid loud," which should be reserved for PEAKS!
Working back to "average" power levels, means you will have 13 db of headroom with those amps which should be fine for most music.
When I told Paul Klipsch that I was using a 10 db crest factor for Headroom, as measured with pop/rock/jazz music with my Khorns, he said "make it 17."
Realize, of course, he ONLY listened to his own recording of Symphony Orchestras, of which he had Hundreds at his house.
One year ago, I attended a live, Full Symphony Orchestra Concert with a peak db meter from a really sweet listening spot in a large Church. The peak ready was actuall 17 db, like he said. PWK was right about many things.
In my experience with non-Symphonic, COMMERCIAL recordings, 10 is a great number and you have 13, so no worries.
Since you have 1.5 Watts per channel to work with, and 13 db less POWER is all you need, that translates back to 20X less power than FULL.
So, 1.5 watts divided by 20= 80 milliwatts per channel is all you need to get to the 83 db SPL at your Listening Position!
Plug and Play and let us know how it goes!
