I have to admit some confusion on this point, since this specifically refers to "combination self-powered speaker systems," which does not apply to anything Outlaw manufactures - they're talking about HTIB systems with separate amps dedicated to distinct and separate parts of the audio spectrum.

In this PDF are some details on this issue, about halfway through the doc. Important is that they distinguish these systems' ratings from standard amp power ratings, because they figure a sub or sat amp in a HTIB system wouldn't necessarily tax the power supply to the detriment of the other amp at peak levels, since unlike stereo amps they each cover different freqs. This refers to the fact that the Amplifier Rule requires testing to be done for both channels of an amp simultaneously, not just one, since one channel will have higher and cleaner output independently (and would be misleading).

To my knowledge, the FTC Amplifier Rule has not been updated specifically for multichanel amps, so "all channels driven" should still mean that all channels are driven with the same test tone simultaneously.

Greg: very interesting!!

Go to page 32 and read what they state about multi-channel amps. My opinion is that only 2 channels MUST be tested simultaneously!!

And, I think this is the key to FTC ratings versus RMS ratings.

I believe that the 7100 specification is consistent with the FTC rule. The reason that the word "simultaneously" is not in the spec is because the 7100 was rated with only 2 of the 7 channels running at full power.

I do not believe that the cost of an amplifier necessarily scales linearly with the power. I think that the primary reason that the 770 costs so much more than the 7100 is that it is more "rugged" to comply with the RMS and "simultaneous" ratings.

The text on p. 32 states the opposite: "the manufacturer’s rated minimum sine wave continuous average power output, in watts, per channel (if the equipment is designed to amplify two or more channels simultaneously) at an impedance of 8 ohms, or, if the amplifier is not designed for an 8-ohm impedance, at the impedance for which the amplifier is primarily designed, measured with all associated channels fully driven to rated per channel power." Subsequent to that, they only exempt HTIB systems from the "all associated channels" rule for the aforementioned "different portions of the audio frequency spectrum."

FTC regulations require that the specifications provided to consumers conform to this. How manufacturers word it (i.e., with or without the word "simultaneously") is irrelevant, because the FTC requires the underlying testing to be the same either way. This prevents companies from doing what you suggest - comparing "apples to oranges" in their power output claims.

greg: Nope, I disagree. Look at the last sentence of the first paragraph on page 33 (I couldn't copy and paste, for some reason). It CLEARLY states that all channels DO NOT have to be driven simultaneously.

You mean this one:

"when measuring maximum per channel output of self-powered combination speaker systems that employ two or more amplifiers dedicated to different portions of the audio frequency spectrum, such as those incorporated into combination subwoofer-satellite speaker systems, only those channels dedicated to the same audio frequency spectrum should be considered associated channels that need be fully driven simultaneously to rated per channel power."

I don't see how you can derive your conclusion from this. What this refers to, "combination subwoofer-satellite speaker systems" and the simultaneous testing of ALL associated sat-only channels separately from sub-only channels, has nothing to do with standalone multichannel amps.

What you say it "clearly states" is neither stated or implied, and must be taken entirely out of its context to infer. If you wish to misinterpret what is made abundantly clear in the document, I don't see a need to discuss further.

that and the fact that the Outlaws "clearly state" it is "All Channels Driven" which is either a lie (I doubt it) or the truth (which I believe) so where do we go from here???
Bill

Ratpack - Thanks for the great info on how watts relate to sound levels. I wasn't aware of the equation.

My browser allows me to see the product pages, but won't let me drill down on the Specs or Gallery or Manual or About sections.

Typically, a higher power amp has a higher damping factor, right? Does the 770 have a higher damping factor than the 7100? And the damping factor is a measure of how well the amp controls cone movement? I'd be happy to look that up myself, but as I said my computer isn't cooperating on the pages within each product description.

What are the differences between the 7100 and 770 besides 100wpc vs 200wpc? Clearly, the "simultaneous" and "all channels driven" discussion is important, but it doesn't look conclusive regarding what Outlaw means with the 7100.

Wharf Rat's comments about wanting the 770 but being happy with the 7100 are MOST helpful. I want the 770 just be sure I get the most out of my gear, but I'd really rather save the money.

Does the 770 do anything more for the sound than just add 3db? That is, does it do a better job of channel separation or cone control or something else? I'd agree that I'm not likely to listen at 110db, much less 113db. But if the 770 is has more immediacy or is more dynamic or other desireable characteristics, I'd love to know about it!

Since I'm building a new system, I'm probably not going to try it with the old system. It would require HUGE effort to pry my B&K out of the current set-up. I'm just going to buy a 7100 or 770 and see what I think. I'd like to make the best choice possible. I'm leaning towards the 7100 to save the $$.

I listened to the B&Ws at ListenUp in Denver through a Rotel pre-amp/amp rated at 100wpc. there seemed to be plenty of volume.

Further info on the diffences between the 7100 and 770 welcome!

Greg: I believe that the following means the front pair, or the center surround pair, or the rear surround pair.

"only those channels dedicated to the same audio frequency spectrum should be considered associated channels that need be fully driven simultaneously to rated per channel power."

One of my links contains this language:

"allow the subwoofer and satellite amplifier sections in combination self-powered speaker systems to be driven to full rated power separately, rather than simultaneously, during the power rating tests.


I don't think that it applies to the rears or subwoofer on a 5.1 system, or side surrounds on a 7.1 all at the same time. The key is the audio that comes out of the sides, rears and subwoofer is not the same audio spectrum. Of course, I guess that you could say that about the audio spectrum that comes from the right and left of each pair.

But, if I have a chance tomorrow, I am going to pose the question to the Outlaw technical support. They should be able to tell us one way or another.

This has been a most interesting dialogue. Thanks!

Bill: where do we go from here?

Well, I'll tell you.

I'll ask Outlaw if all seven channels are simultaneously driven to 100 watts.

That should settle it one way or another.

ratpack, I was going to ask the same thing. Please let us know what you find out.