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Re: Building a home theatre incrementally
JohnK #265742 07/09/09 12:51 PM
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Well, couldn't each of the decibels the new amp puts out be just a teensy bit louder than each decibel his old amp put out?

Re: Building a home theatre incrementally
pmbuko #265745 07/09/09 01:27 PM
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Decibel Lite.

I still want a big-azz amp someday.


::::::: No disrespect to Axiom, but my favorite woofer is my yellow lab :::::::
Re: Building a home theatre incrementally
Ken.C #265759 07/09/09 05:58 PM
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Worm Alert!

 Originally Posted By: kcarlile
90dB is lower volumes?!

For critical listening, yes, it is lower than the 95db average or 105 peaks that are common in my room for really getting into the layers of a song. I'm not saying it is quiet. How do you critically compare the reproduction of a guitar or piano or horn or drum if the peaks are 20db to 40db below the real thing? And if 90 is so reckless, why do some many people enjoy live music that exceeds this level every time - including many kinds of music.

 Quote:
I hope it was total kidding, because that just ain't the way that amplifiers work.

Right, I get that; 80 wpc is enough for all the listening you do. But given the dynamic peaks of classical music, have you tried a separate amp, you might shock your calculations, even at the top edge of sanity...about 88db?
As the article Alan wrote details, getting even near real instrument volumes- say 105db peaks (10db off from real), takes more dynamic power than my Denon 3300 can dish out at my 15ft listening position without distortion - simple fact of math which I assume must be accepted by the group. So while I don't doubt that you are right John, that amplifiers don't work "this way", the below fits my experience perfectly and I trust it is accurate mathematically.

Whatever it is I'm not understanding about how amps work, I'm fine with, since the simple fact more power has increased my enjoyment of music (not so much for theater). Most seem to enjoy the benefits of clear dynamic peaks, even if it is all unicorns and pixie dust. ;\) Give it a try, toss out the slide ruler for the day and just slop around in Chopin's dynamic range!

The below is from Alan's article. The bracketed comments are mine, in order to give my opinion the appearance credibility, and to confuse the reader. Enjoy.

 Quote:
But if it were a real-life orchestra playing at full tilt, and you wanted to reproduce the illusion in your living room of standing next to that grand piano, then peaks of 109 dB would be required. So getting from 96 dB to 106 dB will require ten times as much power again (10 x 10) or 100 watts per channel [comment: without distortion]. The goal, remember, is real-life reproduction of that grand piano, so now we only need 3 dB more (subjectively "somewhat louder") to hit 109 dB [dynamic peak] in the living room. But twice as much power is required for a 3-dB increase (100 watts x 2 = 200 watts). All of a sudden our A/V receiver or amplifier has run out of power! [at 12 feet!]

Of course, it's just a brief peak, lasting perhaps 200 milliseconds (one-fifth of a second), but the amplifier must have sufficient reserves of power to properly reproduce that momentary peak without distorting. If the amplifier has 3 dB of dynamic headroom, it will make it, and output the required 200 watts per channel for a fraction of a second, with no clipping and no distortion. But the truth is that most A/V receiver amplifiers have little or no dynamic headroom, so the receiver runs out of power, the distortion rises, and audible distortion intrudes, ever-so-briefly. The piano then "sounds too loud," to our ears because of the nasty distortion components, so we turn down the volume just short of our goal, because our amp didn't have enough dynamic headroom to handle the instantaneous peak power requirement. [Clean 95db is very nice, distorted 95db is too loud, I agree! Thus, I can now listen louder, but cleaner.]
If your speakers are 3 dB less sensitive than the M80ti's, [which mine might be?] or you are another three feet back [which I am], then twice as much power (400 watts) again would be needed to hit that goal of 109 dB SPL [peak]. It doesn't tax our arithmetic skills to realize that aiming for rock concert peak sound levels of 115 dB (if the neighbors could stand it), is beyond our capabilities. Most of our amplifiers and receivers do not have enough dynamic headroom to deliver this kind of power output without sounding strained. (To finish the example, using M80ti's to reach 115 dB at 12 feet would require 6 dB more output, or four times the power that the 109-dB level required, so 800 watts per channel would be needed.)

 Quote:
So the better the transformer and the better and larger the power-supply capacitors, then the better the dynamic headroom is. [As happens when you get a good separate amp compared to my Denon AVR.]

"The problem with many amplifiers and A/V receivers designed for economy (the most watts for the dollar) is that they make the transformer just big enough to produce the voltage output they need [to meet sustained power output measurements into an 8-ohm load], and just big enough capacitors to supply the sustained, continuous voltage and current they need for continuous power, and then the amplifiers quit, so those amplifiers have no real headroom. On top of this, the power may be calculated to be the rated output for one channel at full power and the other five at 1/8 power. So a 100-watt six-channel A/V receiver actually only has 162.5 watts of total power or 27 watts per channel with all channels driven. [how does that 100db peak sound now, with 27 watts?] The better amp builders, who design for performance (reproductive accuracy for the dollar) rather than economy, will install these big transformers with huge capacitors, so then they have all these joules of energy in reserve to produce the dynamics necessary for the music."


For anyone new to the forum, know that I have learned a great deal from JohnK and respect his opinion very much. Don't read the cold transcript without the bar-room-banter atmosphere my comments deserve!

John, your serve.


Panny 3000 PJ, 118" Carada, Denon 3300, PS3, Axiom QS8, PSB 5T, B&W sub, levitating speaker wire
Re: Building a home theatre incrementally
pmbuko #265760 07/09/09 05:59 PM
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 Originally Posted By: pmbuko
Well, couldn't each of the decibels the new amp puts out be just a teensy bit louder than each decibel his old amp put out?


Now that's just silly.


Panny 3000 PJ, 118" Carada, Denon 3300, PS3, Axiom QS8, PSB 5T, B&W sub, levitating speaker wire
Re: Building a home theatre incrementally
Zimm #265787 07/10/09 01:40 AM
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Charles, Peter's tongue-in-cheek comment about bigger decibels really isn't any more silly than claiming that at a level using only a few watts an amplifier with a much higher maximum output capacity has more "impact" than a lower powered amplifier which isn't close to its maximum output. Equal volume is equal volume. If 5 watts are being used(roughly what your speakers would use at 90dB), a 1000 watt amplifier can't result in any more impact than a 10 watt amplifier.


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Re: Building a home theatre incrementally
Zimm #265799 07/10/09 02:23 AM
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 Originally Posted By: Zimm
I don't want to open the worm farm, but I was surprised that even at lower volumes (say 90db) how much more impact my towers had with the new amp. (Crap, there go the worms! JohnK will be around soon to put them back in their cages.) But this amp can unleash 500 watts without clipping, where as my Denon was rated at 110 (and started clipping at 84 according to lab test). In short, those 16db peaks Alan describes require a ton of instantaneous power, and are delivered unclipped now, whereas they were being clipped from the Denon. (Still happens in 5ch mode as the Denon clips the highs to the center causing some thinness/shrill that I used to get from my towers.)

Got my amp for under $500 and have not regretted it once. Unlike that "special" speaker wire JohnK sold me. He said it was all about the wire. \:o


Just kidding John. ;\)
So in the future, if I'm looking to upgrade my receiver. What exactly should I be looking for? I bought my 607 before I bought my speakers. To be honest, it was the 7.2 that drew me in despite the fact that I doubt I'll ever have or have a need for 2 subs. I did a little (but not much) research prior to the purchase of my receiver and speakers because the more research I do, the more things tend to cost me and I end up with a hobby rather than a simple purchase.

Re: Building a home theatre incrementally
Scott64 #265800 07/10/09 02:42 AM
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Scott, just to point out that the "7.2" is at best just a minor convenience factor and shouldn't have been a significant factor in a purchase. There's still only one .1 sub channel and this is simply an internal splitter that provides two outputs of that one channel. The same result can be achieved with any receiver having a sub output by plugging in an external splitter that might run $2-$3.


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Re: Building a home theatre incrementally
JohnK #265801 07/10/09 02:51 AM
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 Originally Posted By: JohnK
Scott, just to point out that the "7.2" is at best just a minor convenience factor and shouldn't have been a significant factor in a purchase. There's still only one .1 sub channel and this is simply an internal splitter that provides two outputs of that one channel. The same result can be achieved with any receiver having a sub output by plugging in an external splitter that might run $2-$3.
Yeah, I know. That shouldn't have been a deciding factor. I didn't even know it was an internal switch (good info). And paired with the receiver getting some really good "best bang for the buck within it's price point" reviews, I thought I'd do well to pick one up while they were on sale at http://www.electronicsforless.ca. And maybe it would have been sufficient with different speakers.

By no means am I saying the combination sounds bad, I'd just like to be able to reach higher volumes and still have the speakers sound the way they're supposed to sound.

Is there a sub-$1000(CAD) receiver that will do these speakers some actual justice at reasonably high volumes? If so, I might pull the trigger on one and kijiji the 607.

Last edited by Scott64; 07/10/09 02:51 AM.
Re: Building a home theatre incrementally
Scott64 #265802 07/10/09 03:10 AM
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Scott, I wasn't indicating in any way that the 607 wasn't a good buy, just that two wires coming out of the sub channel rather than one isn't a big deal. You already have a receiver that can drive your M80s to dangerously high(to your hearing)sound levels. More expensive receivers with a little more maximum power capacity would simply allow about 2dB more volume on brief split-second peaks. For example, a peak that could be played now at 106dB could be played at 108dB. Relax and enjoy the sound.


-----------------------------------

Enjoy the music, not the equipment.


Re: Building a home theatre incrementally
JohnK #265803 07/10/09 03:19 AM
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It was just your comment about "Anywhere near full power and you are clipping hard, which is part of the reason you are lacking some bass" that made me think that maybe I would benefit from a more powerful receiver.

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