True power output?

[bassbrother666]

Hey, so i have recently been seeing a TC Eletronic BH550 and many people here on TB have been talking about how they "would wait to see if 550 watts was it's true output power or if it just sounds like 550 watts"
Can someone explain this to me ?

 

[ahc]

There was a controversy when the RH450 head was tested and was found to put out something like 240 watts into 4 ohms (I think). TC responded that they did some electronic trickery or used compression (or something) to make the head sound bigger. If you search on it you'll find the info. After this happened folks have doubted TC's wattage claims.

 

[Korladis]

I remember that happening. People were pretty (rightfully) pissed off.

 

[Downunderwonder]

When you electronically cut the nuts off bass signal it takes away a lot of power requirement. The remainder of the signal getting the other half of the power sounds like a full range bass with all the power, except it doesn't.

 

[ThisBass]

As far as this effect can be explained in easy understanding words.
The attack of the bass guitar signal needs much more power then the average. As the attack of the signal is very short in time duration compared to what is perceived by ears as a sustained note, so attack itself does nearly nothing contribute to loudness.
If only attack is reduced means the average (the loudness) remains nearly steady. But once attack is reduced (inaudible) then the whole signal (the average) can be gained to higher levels.

In an very abstract view the mechanism is comparable to the functioning of a compressor.

 

[cfsporn]

Did anyone ever do a test of TC's newest amps? I'd like to think they learned their lesson…

 

[Jazz Ad]

I haven't and don't think I will. I need amps I can trust, the way I trust my 35 yo TC SCF.
The stupidity of these sale dept guys is abysmal.
How can you be stupid enough to ruin the reputation of an established pro level semi-boutique brand with impecable records, only to sell underpowered units in plastic shells ?
I think they might as well close the case of their bass amps at this point. Even if they make something great there will be a taint over it.
Accugroove comes to mind.

 

[ThisBass]

So in conclusion we should blame any manufacurer when an amp can't produce same watt rating for sine waves and bass guitar or/and audio programs.
In this case we have to blame every manufacturer because they don't tell us that power rating will be reduced in practice with more realistic signals.

 

[Jim Carr]

...we have to blame every manufacturer because they don't tell us that power rating will be reduced in practice with more realistic signals.

But at least we know this applies to every manufacturer. What TC Electronic did was much more than that. Also, don't underestimate the importance of transients as determinants of instrumental timbre.

I recommend the classic work by Risset and Wessel, Exploration of Timbre by Analysis and Synthesis in "The Psychology of Music (D. Deutch, ed.) 1982 Academic Press, Inc.

 

[ThisBass]

Also, don't underestimate the importance of transients as determinants of instrumental timbre.

Sure. And indeed that is an rather important and essential characteristic especially with acoustic instruments.
My thoughts refered mainly to electric bass guitar. In this case it's impressing to recognice how much amount of the attack part can be "altered" while the timbre (and also dynamic feel) remains audible the same.

Indeed it was not correct what TC did, it was not correct the way how they tried to get market shares.

There are some things that I don't really understand. It was clear that sooner or later this "marketing trick" will be unmasked. I insinuane TC has taken this into account.

I suppose TC used bass players all around the world as unbiased test persons to figure out if the new development really works. If DC had done it in a different way like:

"this amplifier provides a new technique that provides considerably more power than rated"

then I claim most bass players would have argued that THIS is impossible, and every bass player testing the amp the very first time had been biased by an imagination of a new technique that can't operate in an oversimplifying view of things, like most folks do. Some folks hear grass growing where there is no grass.

No doubt it was not correct what TC did, but at the other hand the way how they introduced this technique was a sharp clou because they duped lots of (self made) experts and even those who believed they are able to hear clearly a difference of 1 dB.

Makes me no wonder that a lot of folks was pissed off.

I'm not employed by TC, neither do I own TC products, neither do I sell ones but, if I was an engineer signing responsible for this technique I'd feel proud to have developed a product that was finally unmasked by bench mark testing, but NOT by (pro) bass players.

 

[cfsporn]

I think another thing that pissed off TBers was that the RH450 and RH750 produced the same (real) watts. That really irked me.

 

[nashvillebill]

The standard for measuring a conventional amplifier has been around for decades: the amp is hooked up to a non-inductive dummy load, then a sine wave is input to the amp, and power output is measured at a chosen distortion point. For those of us who do not have expensive distortion analyzers, we look at the sine wave on an oscilloscope to see when the sine wave starts to clip; those folks with more expensive test equipment can measure THD directly. Regardless, this is a pretty good benchmark, and allows us to get a pretty good feel for the amp's performance compared to other amps. Sure there will be some variation of actual measurements, but when a manufacturer claims his amp will put out 250 watts continuous into a certain load, our own measurements generally come pretty close, often even just a tad higher.

So when a manufacturer comes around claiming "X" power--but it produces some 40% less when actually measured in independent testing--most of us were rather miffed. We then wonder how many OTHER things were exaggerated by that manufacturer.

 

[/\/\3phist0]

I haven't and don't think I will. I need amps I can trust, the way I trust my 35 yo TC SCF.
The stupidity of these sale dept guys is abysmal.
How can you be stupid enough to ruin the reputation of an established pro level semi-boutique brand with impecable records, only to sell underpowered units in plastic shells ?
I think they might as well close the case of their bass amps at this point. Even if they make something great there will be a taint over it.
Accugroove comes to mind.

Well Behringer owns TC Electronic now so the "new" wattage rating for the RH450 will be 4kilowatts

 

[Scottkarch]

I think another thing that pissed off TBers was that the RH450 and RH750 produced the same (real) watts. That really irked me.

Your only definition of "real" watts, is a sine wave through an amp measuring RMS. Fine, but you should define it that way. I recommend you read the documents describing their power/output section. They did not design their amps to output sine waves. They designed them to output signals made by someone playing a bass guitar. Lots of transients and brief spikes. Their output is closer to a peak power rating than an RMS rating. The RH750 IS louder than the RH450 when someone is playing a bass through it. Maybe maxing out a 800Hz sine wave at max power they will likely end up at the same volume. Nobody ever has or ever will do that, so that's just not relevant to me.

I am curious about the output of the hew 550 and 800 heads and I'm guessing they when to a more typical output section..

So, to answer your comment. They may output the same maximum RMS into 8 or 4 or even 2.8 ohms, but they 750's power section outputs more power in it's peaks than the 450. So, I'd say that in terms of REAL output ( someone playing a bass through their amp ), they do not output the same power. The 750 puts out more than the 450. RMS can be a helpful measurement, but it's not useful in all instances. I get what you're saying, but I think you're too hung up on RMS values.

 

[nashvillebill]

Except their original documents even claimed the power was RMS, not some mystical "peak power".

 

[Korladis]

The standard for measuring a conventional amplifier has been around for decades: the amp is hooked up to a non-inductive dummy load, then a sine wave is input to the amp, and power output is measured at a chosen distortion point. For those of us who do not have expensive distortion analyzers, we look at the sine wave on an oscilloscope to see when the sine wave starts to clip; those folks with more expensive test equipment can measure THD directly. Regardless, this is a pretty good benchmark, and allows us to get a pretty good feel for the amp's performance compared to other amps. Sure there will be some variation of actual measurements, but when a manufacturer claims his amp will put out 250 watts continuous into a certain load, our own measurements generally come pretty close, often even just a tad higher.

So when a manufacturer comes around claiming "X" power--but it produces some 40% less when actually measured in independent testing--most of us were rather miffed. We then wonder how many OTHER things were exaggerated by that manufacturer.

Exactly. If they had claimed that the amp was 450 watts, and then it clocked in at like 438 or something when measured, I think people might have been very slightly annoyed, but that the general attitude would have been "eh, they fudged it a little, but who cares?" The issue was that it wasn't even close. It wasn't like 12 or 20 watts off. It was a couple hundred watts less powerful than the manufacturer claimed. It's not like they put in fine print that they were talking about peak power, either. They claimed it was 450 watts RMS, and it turned out to be a huge amount less than that.

 

[Thumper19605]

Marketing, It happened back in the 70's as well.
Always research.

 

[bobcruz]

I try not to buy gear from liars. Guess what? I don't buy very much gear any more....

 

[brian1e]

Marketing, It happened back in the 70's as well.
Always research.

The FTC got involved in the early 70's forcing the manufactures (aimed primarily at low/mid home audio) to clean up their act regarding wattage claims. The rules were withdrawn sometime in the 80's.

 

[JimmyM]

As far as this effect can be explained in easy understanding words.
The attack of the bass guitar signal needs much more power then the average. As the attack of the signal is very short in time duration compared to what is perceived by ears as a sustained note, so attack itself does nearly nothing contribute to loudness.
If only attack is reduced means the average (the loudness) remains nearly steady. But once attack is reduced (inaudible) then the whole signal (the average) can be gained to higher levels.

In an very abstract view the mechanism is comparable to the functioning of a compressor.

Not so abstract to me. That's exactly what it is. They also subtract ultra-lows and ultra-hi's, but most definitely there's compression going on.