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Help a newbie understand

So the pandemic had me listening to a lot more music and as a consequence, I sold my 30-year-old but still functioning Snell c2 mk4 speakers and Adcom GFA 555 200 watts per channel amp which together sounded great ( to my uneducated and now failing hearing ) playing my digital library of CDs.I wanted to try something different.
I replaced them with Canton reference 9k monitor speakers ( which can handle 200 plus watts and a Technic su g700 integrated amp. max. 70 watts a channel. These also sound great in many different ways. By the way I bought both on Audiogon.

What I miss in the new system is its ability to play loud( I'm old and going hard of hearing) this has led me to play the amp at levels between -10 and 0 per the amps "wide range scale peak power meters"  and at those levels, the needle occasionally spikes into the region slightly above 0  for fractions of a second to a second or two but not ever reaching +6( the next demarcation on the meter) per the integrated amp's meters.

My fear is frying my speaker's voice coil etc. by clipping when I play at the above level so I have two questions. First, is the headroom sufficient to prevent frying my speakers given the listening level and the volume's slight venture into going over 0 on the meter and second how do I read this "wide range scale peak power meter"?
The peak power meter's main demarcations are as follows-50/0001,-40/001,-30/01,-20/.1,-10/10, 0/100,+6/200.and under those numbers is the symbol db/%. 
So I went online but could find nothing that I could understand relative to how to read this type of meter. For example, if the relationship is dB/% what does  -50 represent and the % 0001?, what about 0/100,+6/200?The top numbers make no sense to me -50? -50 what no watts who's on first.
Thank you in advance for your time and expertise.
scott22
elliottbnewcombjr
5,515 posts
 
I must inform you, you choose speakers that need a LOT of power, they are LOW Sensitivity.

sensitivity = 1 watt in; mic 1 meter away; how loud _____ db???

Your Cantons, given 1 watt, only produce 87db of sound 1 meter away.

I, and many others recommend high efficiency speakers, at least 90db 1w/1m ... (sensitivity +3db above the Cantons)

+3db is the amount of additional sound level needed to just perceive a bit more loudness.

It takes twice as much power to make just +3db sound level.

then twice more to reach 93; twice that to reach 96db, twice that again to reach 99db.
...................................

I would sell those Cantons, and buy speakers 90db sensitivity, or more, 91, 92, to get more volume out of your existing amp. I prefer that to getting more amp to push the in-efficient Cantons to loud levels.

Horn tweeters, horn mids, conventional cone woofer are the most efficient; or horn tweeter, cone mid/lows are efficient, always check specs, sensitivity or efficiency rating.

btw, Canton website specs do not mention efficiency, deplorable, I had to go elsewhere to find the answer.



scott22 OP
265 posts
 
Wow guys thank you so much nekoaudio, elliotbnewcomb, and fuzztone for your explanation and advice very much appreciated. I'm playing at different levels depending on the cd and even song .the "Who" Zepplin, Stones Beatles, Tull,   etc. the needle is bouncing as high as going anywhere from a little below  -10 to 0( on average) with spikes  I'm guessing +2. Jazz, blues   Dexter Gordon,  John Coltrain, Art Pepper, Bill Evans, Mile Davis, Chet Baker, etc.  -20,-10 those number and in the late evening even less power,-20,-30 on average. Classical on Telarc, Deutsche, Grammophon Mozart, Brahms, Beethoven, Schuber, Bach, I'm playing back at the -10 to  0 levels unless late then again much -20,-30. I'm listening about 7 ft from the speaker.

millercarbon's avatar
millercarbon
12,531 posts
 
First of all the meters are superfluous. Even peak meters lag a great deal. But the way to read yours is 0dB is 100 watts. Every 3dB up or down is twice or half the power. +6dB and 200 watts is just wrong. Sorry, but it is. +3dB is 200 watts. So your meters aren't even right. Like I said, superfluous. -10dB is 10 watts, at least they got that right.

You may wonder how it is that a 70 watt amp has 100W and 200W. This is because of all the different ways we measure power. If you look at your spec page https://www.technics.com/us/products/grand-class/stereo-integrated-amplifier-su-g700.html#specs you will see FTC output power with 70 and 140 watts at 8 and 4 ohms. Its that FTC thing we're concerned with. Amplifiers can put out really high power for a short time- peak power. They get hot being played loud and heat lowers their power output. FTC came along and said no more bragging peak power, you can only say what the amp can do continuously, and after being warmed up.

This is all important stuff to know because most guys just look at the number without really understanding what goes into that number. In reality you play your music at whatever level sounds good. The amp clips or doesn't, gets hot and shuts down or doesn't. If you can play it loud enough to be happy, it still sounds okay, its not getting too hot- and the meters aren't pegged a lot- then don't sweat it. 

Its only if you're running it into clipping a lot- the meters are pegged a lot- that you would worry. In that case the answer is not more power. Your speakers are too inefficient. Because of the fact power doubles every 3dB then to go only 6dB louder you're going to need at least a 300 watt amp. The better answer is much more efficient speakers. Anything 95dB or higher and you'll have plenty of volume and no power worries at all.

jjss49's avatar
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jjss49
6,612 posts
 
good thread, and excellent responses!!

scott, have fun... enjoy! 
scott22 OP
265 posts
 
Millercarbon Thank you I'm learning a lot. Darn really like those Cantons but then again I really only have a couple of frames of reference. Sad all the local stereo stores have died off. As a kid I used to go to Soundex( spelling ?) in Willow Grove Pa Woo was that fun to visit you could hear so many levels of goodness depending on your disposable income.

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