Re: Uli Behringer of The Music Group Q&A
Dear John,
Many thanks for your question and your patience in awaiting my answer. As I have said earlier, I spent the last month traveling with the acquisition of Turbosound and of course the Infocomm show in Las Vegas.
Your question about power amplifier ratings is an interesting one for several reasons. Although over the years there have been attempts at standardizing the way power amplifiers are measured and rated, it appears to me that even in the face of legislation, there continues to be no consensus in the pro audio industry.
Forgive me for stating what you already know John, but for some readers a bit of history may be in order.
There was a time when the accepted method for measuring amplifier power was to inject a sinusoidal signal (usually 1 kHz) and measure the output just as the sine wave began to distort. This type of measurement assumed that the amplifier would be operated in that manner, although we were all aware that actual program material was very different to a sine wave. Regardless, this RMS measurement became a standard.
While there have been several variations on this theme, the net effect of standard practice has always been that power measurements have been based on a continuous sinusoidal signal applied at the input. As imperfect as this system may have been, it did allow consumers to compare one amplifier to another and conclude which one had a higher rated power. Sounds good? Not so fast.
The problem with this method is, as most manufacturers and users discovered over time, that it measures a parameter that may not necessarily be the best predictor of actual amplifier performance. Real program material, whether it be music or speech, is very different from a sine wave and it is a leap of faith to correlate one to the other. Imagine a car that is capable of pulling a heavy load up a mountain compared to one that accelerates aggressively; which one is more powerful? It depends on what your objective is.
I believe that this disparity between what was measured and what was really needed was driven by the measurement technology of the day. In fact, the use of a steady-state sine wave is a throw-back to a time before digital oscilloscopes and programmable signal generators, when pretty much any technician could replicate the measurements on their test bench. Regardless of whether it was the “right” measurement, it was at least a measurement that almost anyone could make.
In the last 10-15 years we have seen the emergence of a whole new breed of amplifiers with power ratings in the thousands of watts, not just hundreds. Respected brands such as Lab Gruppen and Powersoft have led the way into this new realm not by measuring amplifiers the “old” way using a steady-state sine wave but by other means that more closely mimic the dynamics of real program material. The objective is to better quantify the performance of their products in the actual environment where they will be used.
Inherent in this approach is a lack of agreed measurement standards and definitions. I have yet to see published documentation on the precise measurement methods and techniques used by these and other manufacturers claiming specifications based on "maximum output power".
I can only assume that capable engineers are using good judgment in creating test routines that inject impulse signals of sufficient amplitude and duration along with periods of reduced energy to arrive at their power ratings. In any event, most manufacturers must consider this proprietary IP as they are not publishing such data currently.
This brings us to the iNUKE series of power amplifiers that BEHRINGER introduced just over a year ago. iNUKE amplifiers were the culmination of extensive research and development in our engineering team around power efficiency. As I have said in other posts we proudly operate one of the most capable power engineering teams in the industry with extensive experience in both SMPS and Class-D amplification.
Our new patent-pending "Class Zero" technology that combines power supply and amplifier into a single stage was in fact a direct outcome of the research the preceded the iNUKE range. With this new "Class Zero" technology, we have been able to design amplifiers with up to 94% efficiency (AC to AC), which is a remarkable increase of 10-15% compared to the most efficient SMPS and Class-D designs. The final component count and cost will have to be seen until the mature design stage, but energy efficiency in light of carbon footprint reduction and green energy is definitely worth pursuing.
I am proud to say that iNUKE amplifiers have become a tremendous commercial success and are now outselling even our EP4000; one of the most successful power amplifiers of all time. They have also earned the praise of users and the press, who have conducted their own independent testing.
Allow me to post the "Tools4Music" review of the NU3000:
http://www.behringerdownload.de/_pdf/Tools4Music_Review/NU3000DSP tools4music English review_2012-03-13_Rev.0.pdf
You'll see that the reviewers confirmed, with rigorous testing, that the NU3000 actually delivers even more than its rated power! That is gratifying to see as it mirrors our own in-house test results.
Thanks again for your question John, as you have touched on an important but seldom-discussed topic in our industry. While we always support standards and also ensure that all of our products are UL listed and FCC compliant, even though many of our competitors skirt the law (try searching www.fcc.gov to see who has been fined for non-compliance), it appears that power amplifier measurement standards have not kept up with measurement technology.
If such a standard does come to pass, then rest assured that we will follow it right along with venerable competitors such as Lab Gruppen, Powersoft, Crown and QSC among others.
Warm regards and again sorry to keep you waiting.
Uli
