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Seems like the new thing for playing live is speaker sims, attenuator with line outs, and so forth. Does anybody do this?

I'm looking at weber attenuators and they are very nicely priced. And then there's the new torpedo captor, which is also nicely priced.

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There have been 3 that I have heard of, 2 of which I have tried.

I tried an older Marshall Power Brake.
It was awful and I do not recommend it.

I tried a THD Hot Plate.
It was pretty decent.
Only minimal tone colouring and very smooth sounding attenuation.
I suspect the minimal tone colouring was the result of there being nothing to simulate an excited speaker vs a speaker only half awake.
Drawback was a separate unit for each impedance and power level.

Heard of the Weber but never tried it.
Weber make quality products

There is a 4th alternative but it's not the same kind of technology.
The Rivera Silent Sister is a speaker cab you drive at full volume but the whole thing is inside a soundproof isolation chamber and there's a mic inside.
The plus side is that you're not altering the signal with resistors and you're still exciting the speaker properly.
The down side is you are getting your sound from a mic cable and that introduces a whole second set of variables.
 

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This is an awesome demo by Pete Thorn with a good explanation about resistive vs. reactive loads around the 10 minute mark, including sound samples. He uses an IR he creates in the first half of the video and then compares the speaker itself as a load, a THD Hotplate, Airbrake, Suhr reactive load, Two Notes Torpedo, and a Fryette Power Station.

 

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This is an awesome demo by Pete Thorn
EXCELLENT! I was so impressed by his explanation AND the results.
This IS the future of recording, IMO.

Made me laugh when I thought about the resistive (dummy) loads I built in the past.

Thanks for posting this.
 

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I tried a THD Hot Plate.
It was pretty decent.
Only minimal tone colouring and very smooth sounding attenuation.
I suspect the minimal tone colouring was the result of there being nothing to simulate an excited speaker vs a speaker only half awake.
Drawback was a separate unit for each impedance and power level.

.....There is a 4th alternative but it's not the same kind of technology.
The Rivera Silent Sister is a speaker cab you drive at full volume but the whole thing is inside a soundproof isolation chamber and there's a mic inside.
The plus side is that you're not altering the signal with resistors and you're still exciting the speaker properly.
The down side is you are getting your sound from a mic cable and that introduces a whole second set of variables.
This is an important point. While many would like the sound of their amp cranked at a lower volume, only part of that sound is what the amp itself is doing at higher output levels. Another part is how the speakers behave at those higher levels. Most speakers will have a different frequency response at different SPLs; they do not maintain the same reproduction qualities from 500mW to 5oW. And if the speakers are being pushed less forcefully by a strangled amp, then they don't behave the same.

That doesn't mean anything other than an isolated-and-mic'd cab is a waste of your time. But many may find that what they have come to love about their amp may well disappear (or at least recede) if fed through some form of power soak. There are better and worse ones, that vary in the manner at which they provide an actual impedance, rather than simply a DC resistance. I suppose some folks might find that a different speaker choice compliments their use of an attenuator better than the speakers they would normally use without an attenuator. So, for example, if you found that an attenuator robbed you of some of the sparkle, then using a speaker with more top end might work better. IN other words, select the speaker that works best with the attenuator.

Alternatively, see if an EQ unit or use of the amp's EQ can restore what an attenuator seems to remove.
 

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There are better and worse ones, that vary in the manner at which they provide an actual impedance, rather than simply a DC resistance.
Would you please expand a bit on this statement to assist me to understand the concept and subsequently enhance my education in electronics theory. I am wondering how actual impedance would be provided in these circuits?

Thanks in advance.

You are such an excellent teacher and write so clearly and professionally.
 

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Thanks Dave. I wish I knew how it worked. All I know is that they somehow attempt to mimic the way in which the load presented by a speaker changes, depending on the frequency.

Bear in mind that the coil in a speaker does provide a fixed resistance, as a simple length of wire, when it is sitting still. But the moment it moves back and forth over the magnet structure, the value that takes will change. Take your voltmeter to an 8ohm loudspeaker and you will see that at rest it generally measures less than the 4 or 8ohms printed on the speaker or listed in its specs. The manner in which that value changes as a function of the coil's movement is part of what provides the resonant frequency of the speaker, along with the physical properties of the cone. Magnetism is something I've never really properly understood, so I'm afraid we've come to the perimeter of my knowledge.
 

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I think these companies are using a circuit of resistors, inductors and capacitors to replicate a dynamic speaker. It is a simplification, to be sure, but requires no moving parts and can be tweaked (i.e. the two switches on the load side of my PowerStation allows for 9 varieties of tone shaping).

I've heard of companies trying rotary motors and other dynamic devices to replicate a speaker load, but I'm not aware of any that have caught on as well as the good RLC reactive loads. There are quite a few of those out there, now.
 
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There are some sorts of conditions under which a simple power soak can come very close to the normal speaker functioning at a lower level. For instance, if one generally uses a single 8ohm speaker, inserting an 8ohm power resistor in series with the speaker, and a 16ohm power resistor in parallel with that, one will have mimicked replacement of a single speaker with a 4-speaker cab, and divided the output over 4 "drivers", three of which are real. Of course the power resistor in series with the speaker will not behave like a speaker, but at least the speaker will.

But again, there is the matter of whether reducing the power fed to a speaker will make it behave like a speaker pushed harder.
 

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There are some sorts of conditions under which a simple power soak can come very close to the normal speaker functioning at a lower level. For instance, if one generally uses a single 8ohm speaker, inserting an 8ohm power resistor in series with the speaker, and a 16ohm power resistor in parallel with that, one will have mimicked replacement of a single speaker with a 4-speaker cab, and divided the output over 4 "drivers", three of which are real. Of course the power resistor in series with the speaker will not behave like a speaker, but at least the speaker will.

But again, there is the matter of whether reducing the power fed to a speaker will make it behave like a speaker pushed harder.
I've done that. I built an 8 ohm, 40 watt dummy load (four 10 watt 33 ohm resistors in parallel) and ran it in parallel with a couple of my big amps, to take 3 dB out. It worked, but of course 3 dB isn't that much, and when I plugged it in I heard a bit of harshness that didn't seem to be there without it. May have been the extra resistive component, may have been the change in impedance and how the amp was loaded. I don't know.

It became quite irrelevant when I bought the PS so no more research was done.

As to your last point, it would be illogical to think off-loading the power to a specific speaker would make it behave as if it had the same or more power (pushed harder). The amp would be pushed slightly harder though.
 

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My suggestion, perhaps not clear enough, was to divide the same output over two parallel paths providing the same load to the amp. So, the amp would not be working harder (unless turned up higher), but a chunk of the output would be lost to heat in the power resistors. That is, of course, why one can use something like a 4x10 speaker complement for a 50W amp even though each speaker is rated at only 25W; the output is divided/shared amongst the four loads, such that no single speaker receives the full output power, butonly some of it. Were one to substitute 3 additional power resistors for the 3 speaker of a 4x10 (or 4x12) cab, the same thing would apply; some of the output current would be dissipated as heat through the resistors. Clearly the value and wattage of the resistors matters.
 

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I getcha now. A driver that, on it's own, would be under-rated for the amp (say a 25 watt speaker and a 50 watt amp), and then using something like my dummy load to dissipate the other 25 watts. So the driver sees a power level closer to it's limit, making it work/push, while the amp is also closer to it's limit as well.

In your example though, 3 of the 4 drivers would be purely resistive. Considering I found it a tiny bit harsher when 50% of the load was R, I think it would be even more noticeable (and undesirable) if 75% of the load was pure R.
 
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