Power Question for Experts

Alright, but wait a second. Say I'm listening at to something averaging 86db with a watt. What music jumps 20db up from that average? 106db is really freaking loud. Is there some material out there I don't know about? Or do I just not notice because the jump is so brief? Also, don't much smaller amplifiers (rms wise) also have "peak capability?" Doesn't this peak capability allow them to handle these very brief bumps in power? If this is true, is the only real benefit to a 150wpc amplifier to ensure constant SNR / THD numbers even during those peaks? (not trying to argue, just trying to understand how much of a practical difference there is between a 150wpc amplifier and a 60wpc amplifier for moderate listeners)New Project: 2003 Pathfinder

No Worries. I'm kinda an older guy myself and I most likely don't listen to my music any louder then you do. My home system has VERY inefficiant speakers ( DCM Time Windows and AR 12" subs ) I run it with a Luxman ( read Alpine ) pre amp power amp combo with wattage output meters. The amp is rated at 350 RMS X2 and when I get a wild hair up you know where, I can use all that power. Sustained bass notes ( pipe organ? ) will not be covered by peak power.

What you guys are talking about is dymanic head room.  The ability of an amp to cleanly reproduce "peak" sounds.  Most amps using a high speed switching power suppy cannot react fast enough for musical transitions.  High quality amps will have 2 or 3 times power avalible to hit these peaks.  Usually done by having more capacitants and bigger power supplies (higher cost), result no clipping.  (Ever wonder why your Alpine v12 mids amp sounds better with a 1 farid cap attached).  Easy way to tell is if the amp double its power output when impednce is haved.  Most amps only increase 50-60%,( 100w @ 4ohm, 160 @ 2ohm)  There are two solution if you building amps, build it right with big power supplies and caps, or use a bigger amp at lower levels.  Personnely, the better built power supply sounds better even with less ulimate power.

Hmm... Ok. I wonder if Haemphyst's friends at Harman have an opinion on this. Harman seems to favor the better built power supply with less ultimate power too. What I want to know is this. With most well-engineered cd's, how often do we experience these ~20db peaks in music? If often then 300wpc+ headroom starts making financial sense. If not often then it makes diminishing sense. New Project: 2003 Pathfinder

kfr01 wrote: s there some material out there I don't know about? Or do I just not notice because the jump is so brief?

You probably don't notice it's so loud because it is only sustained for usually less then a second.Note that a Popped Balloon can produce upwards of 150dB!

kfr01 wrote: Also, don't much smaller amplifiers (rms wise) also have "peak capability?" Doesn't this peak capability allow them to handle these very brief bumps in power?

Many descent quality amplifiers have the ability to put out peak power between 2 and 3 times the RMS rating. THD? THD and peak power don't really play well together.

KFR01 wrote: What music jumps 20db up from that average?

Have you ever listened to any music that starts out kind of quiet and then all of a sudden a clash of the cymbal is heard(or some other high dB instrument) that really stands above/out from the rest of the music? This would be one case of a dynamic peak.

Dyohn, thanks for weighing in. So, here's my question. As a fellow "crazy power is not necessary" audio guy, do you ever feel that you miss anything during these transients? This is off topic as I'm really talking more about home audio here. Basically I was thinking about buying one of these: http://www.bryston.ca/b60_m.html It seemed like a fantastic investment for 2-channel audio. 20 year transferable warranty, more power than mathematically I thought I'd ever need. Ultra clean. Small. Price isn't too crazy. After hearing that statement from the "horse's mouth," so to speak, regarding power, I'm having second thoughts. From the Bryson employee's post it seems like, money being not too large a hurdle, that 300wpc+ is the only "not messing around" solution. :-) True? False? How much, in your opinion, is there to gain sound quality wise, during these transients, comparing a similar quality 150wpc amplifier to a 300wpc+ amplifier? Anyway, thanks for the input. That 10-12db of headroom is a lot less than 20. :-) Incidentially, I respect your opinion quite a bit, so I'll ask another non-car audio question, if that's ok... what are your favorite bang/buck sound quality brands in home audio. I know you own sunfire. A hearty recommendation there? Those new Anthem amplifiers from paradigm look nice. That Bryston 20 year warranty calls my name for some reason. New Project: 2003 Pathfinder

Interesting... (Sorry, I was not ignoring you, I was out celebrating my promotion with some friends...) I am a fan, as most of you know, of "overpowering" my systems. There is NO substitute for headroom, wether it is mechanical (106dB efficient horn systems) or electrical (3kW on a 85dB efficient subwoofer). (I may digress, but I am slightly inebriated, so bear with me, please...) I am a fan of running an amplifier BELOW it's rated impedance i.e. 4 ohm rated, load it with 8 ohm speakers. This allows a lower THD, better S/N ratio, better damping, and better efficiency. It WILL hit you in the headroom arena, as you amplifier will be putting out less power (on an RMS basis) than it is spec'd for. This will mandate buying TWICE (at least) the power you are really looking for... Bob Carver (of the TFM amplifier fame) really is responsible for my point of view. While developing his power supplies for his amplifiers, he was doing very secret experiments, (which later surfaced in some of the better audio magazines) as to how much power is REALLY necessary to reproduce a waveform from a loudspeaker. I cannot tell you WHERE I read them, (it was while I was in high school - a few years back) but he said that it takes at least than 3600 watts to reproduce (accurately) the "snip" of an ordinary pair of scissors. This was where his 1.0t amplifier came from. In Bob's words - "The last amplifier you will ever need." (Please note that he then developed the Amazing Loudspeaker system, with an efficieny rating of 81dB - they wanted a 1.0t bridged to each one!) Much like horsepower in a car, you may never use it, but it's nice to have it. Beat 'em! I have 2.7kW running a single 12 in my trunk, and I have never needed more power. I usually run on the order of 100 to 150 watts to it, but because of the headroom available, I don't ever suffer clipping from the sub. Whether you are running CD or vinyl, (of which I posess plenty) there is really no substitute fo headroom. Clipping is FAR more noticeable than you might think, even with VERY short durations. The more power you have, without exception, the lower your overall distortion will be. Yes, 106dB is loud, but you cannot notice HOW loud it is until it plays for pretty significant periods of time. It is VERY important to have adequate headroom for these transient periods. The current view at Harman is "What we have is good enough", but my buddy is trying to change all of that. the amplifiers from Harman are good pieces, but he does not care for where efficiency numbers are heading today. His goal is to produce higher efficiency with other specs remaining where they are right now - low Fs, high power, long throw, etc. Difficult at best, as we all know (with WHAT we know today) we always trade off extension for efficiency or efficency for extension. I am not at liberty to speak of what he is working on, but suffice to say, he is trying to fix what is wrong with loudspeaker technology today. :::::EDIT::::: I do VERY much like the Bryston gear, the old school Carver stuff is good, NAD "Power Envelope" stuff... Anything with Adcom on the front panel is still good gear (though not as good as it USED to be) The Sunfire amps are top notch, and YBA is nothing short of the BEST solid state power amp I have ever heard in my LIFE... but VERY expendy.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."