Axiom Home Page Forums General Discussion Technical Questions Amps and Power, for Micah

We know, we know...

Fred, as we discussed a couple years ago, I don't care for that Crown calculator. If it's used without the correction for the room effect the result comes up about four times too high, and there's no hint of this on the calculator page itself. On the discussion page it doesn't appear until an "Other Considerations" section near the end. Even then, instead of suggesting that the figure from the calculator be divided by four(and a smaller amp be bought), the suggestion is made that it be used for added headroom.

On another point, if a correction for the room contribution(either the one suggested by Crown or another)is applied, then the in-room figure for speaker sensitivity(e.g., 95 dB for the M80s)shouldn't also be used, since this would be counting the room effect twice.

When a peak of as much as 20dB is mentioned, this is almost always referred to the average, rather than the minimum, level. For example, listening at a comfortably loud 80dB average, on some material a peak as high as 100dB might take place. The total dynamic range(quietest part, but not silence, to the loudest part)on a few of my classical CDs is as much as 60dB, which would mean listening over a range from about 40dB(nearly inaudible)to about 100dB. On the other hand, one of the pop recordings used in a speaker stress test described in my AES Journal was so uniformly loud that the total dynamic range was essentially 0dB.

Okay, enough of this miserable typing with the board in this condition.

JL W6 V2's are definately the SHIZNIT!!!

So many of my friends thought they had to have the W7's, but those are just absolute insanity. The W6 V2's are head and shoulders above the W7's IMO.

Ah, so it's not just me eh??? THANK GOD, I've been wondering what the hell was up with my computer for the past two days.

*Hint*

What I've found works is writing something out, then start a sentence a few lines above it and write out the rest of my post from there. Then I simply cut it out and paste it at the end of my post.

P.S. So if any of my posts seem out of order... then I obviously forgot to cut and paste it.

Well, I didn't think I'd mentioned it in a few days, so I wanted to refresh everyone's memory.

Micah, at least at the moment neither of the problems that I mentioned(the jumping and disappearing bottom lines and the big lag in key response)have reappeared.

Mica –

Well…. to understand your perception holistically, the answer to your question is a mutually exclusive dichotomy of emotion and logic. Your perception is a mix of real and non-real and both. Depending on what perception you are referring to, it may just be an emotional response, or it may be very real. If you are referring to dynamic peaks at an already loud SPL, it probably is real. If you’re referring to constantly moderate SPL with little to no dynamic peaks, then it’s probably a perception based on some form of emotional response.

When speaking to the peaks, and why an outboard amp would have “real” gains over an integrated amplifier that is housed in an AVR such as your Denon, there are a couple possibilities that are logically supported. The outboard amp more than likely has a more robust power supply. Just take a look at the PSU in the Krell dakkon posted above. Remember, the power supply is where the amp(s) get their power from. Amps do not generate power; they simply change the amplitude (add gain) of a millivolt signal they receive from the pre-amp, (which in some instances converts a sine wave that represents frequency, into millivolts). The PSU converts power from the electrical wall outlet to usable power for the amps. As the sine wave goes up and down, the power requirements to match it will follow.

Voltage will dip and rise with the sine wave due to an instantaneous flow of electrons being allowed to pass to the speaker drivers, through the coils and back to ground. (think of your thumb holding back a steam of water in a garden hose with each water droplet being an electron under pressure from the water main). The recovery of voltage (pressure) is dependent on the current being supplied by the power supply. The variance of this dip and rise is determined by the potential current supplying capacity of the power supply and what type or level of capacitance it has (think of current as the number of electrons, or water droplets in the garden hose and water main). As you apply gain to the sine wave, the domino effect is more needed electrons at each speaker driver. When the power supplies current supplying potential has been met, clipping occurs. Obviously, when there is a greater supply of available current for the amp sections, clipping will occur later, verses sooner.

Then of course there’s always the individual rating of each component. Without looking real hard at the score card and spec of each, it’s hard to determine exactly how much “real” power each amp can supply. A rating of 100 WPC is completely meaningless without supporting measurements.

I’m obviously not an expert of amp design, electrical theory, or philosophy, but a student of all. In other words, I don’t fully appreciate what I don’t know that I don’t know. However, I do know I don’t know shit and you should take what I say for what it is, which isn’t much.

I love a good disclaimer.

It doesn't start for me until I get down to about the third paragraph...