Your "World's Best Audio System" . . . 2012 Edition

[Phelonious Ponk]

Although this is outside the scope of this thread, what amplifier parameters should be tuned for a specific driver? Power?

Yes. By all its meanings -- watts, volts and current. You can match an amp to the requirements of each driver instead of picking an amp over-engineered enough to deliver everything the resistance characteristics of the tweeter demand while feeding the woofer's much more ample hunger, to put it simply. It's not that passive cannot be effective, it can. But it is typically a lot less efficient. Then of course, beyond the issues of amplifier efficiency there is the inefficiency of passive crossovers. There are some really good networks out there, don't get me wrong. But putting a nest of resistors and capacitors that typically have pretty widely varying impedance across the range, right between your amps and your transducers is not a good thing, theoretically or practically. Audiophiles spend thousands of dollars minimizing such things in the signal chain, then passively (pun intended) accept a big wad of it in their speaker systems. The love of metal boxes and a passion for switching and upgrading has to be very strong to have kept active design from becoming the audiophile standard years ago.

Tim

 

[JasonI]

Oh, but you can do active externally, so more metal boxes!

 

[microstrip]

Yes. By all its meanings -- watts, volts and current. You can match an amp to the requirements of each driver instead of picking an amp over-engineered enough to deliver everything the resistance characteristics of the tweeter demand while feeding the woofer's much more ample hunger, to put it simply. (...)

Tim

I am not sure if building three power amplifiers with different powers, implying different supply voltages
and current needs will be really cheaper than building a large amplifier. And most people in the high end business will tell you that putting active electronics in the vibrating speaker boxes is a technical nonsense.

 

[Jeff Fritz]

A forum discussion will hardly convince people to change opinion on their favorite approach to "perfection", so my two cents are to go back to "play" with Jeff on its game.

I came to the conclusion a long time ago that there are many paths to enjoyment within this hobby. I think when I first started out as a writer 13 years ago I wanted to tell people what they should buy, based on what I would buy. I still do that for people that don't see audio as a hobby, but as simply a one-time purchase much like a stove. Ultimately, enjoyment is the goal, and I would not criticize anyone for following their ears to that destination.

Where the debate comes in is when accuracy is part of the discussion. Now this can still be debated because there are many different parameters that could be argued are more important than others. For me, I like accurate loudspeakers, those that meet the criteria that I have seen many designers that I respect shoot for, and which seem to be indicative of sound quality based on the research. This has taken me down an unexpected path in some cases in that it has attracted me to some brands that others might feel are not the most high profile. I wrote about Rockport speakers when very few folks seemed to know Andy Payor outside of turntables, for instance. The other unexpected turn was understanding that engineering expertise, complete design conceptualization, and the eventual quality of execution was far more important than how much it cost: there is no question that some high-priced speakers just plain stink (in terms of accuracy).

Sorry to ramble, but the point here is that accuracy is the ultimate goal for me, and from that I derive my enjoyment. The second thing is that accuracy might come in a different shape than what you might expect. For instance, as much as I loved my Boulder 2060 amplifier (still #2 for me), I found the Gryphon Colosseum more musically engaging. From a technical standpoint both companies know what they are doing, although some of the numbers might favor the Boulder. But then diving deeper, to issues like the use of negative feedback (the Boulder uses it, the Gryphon does not) or pure class A versus a sliding-bias technique, perhaps some of the technical elements do favor the Gryphon.

So in the end, it is about the complete picture, not just the numbers. But it’s also important to have the numbers, too, particularly if accuracy is the ultimate goal, which it is for me. So I really want, in the speaker, all the technical parameters that I have espoused on this board and elsewhere, and at least high enough sensitivity that I have a reasonable selection of amplifiers from which to choose. Maybe 90dB would be a good number, knowing that 86dB is about average.

 

[Phelonious Ponk]

I am not sure if building three power amplifiers with different powers, implying different supply voltages
and current needs will be really cheaper than building a large amplifier.

And yet, when done properly, it is. Kinda makes you wonder where the money is in high-end amps.

And most people in the high end business will tell you that putting active electronics in the vibrating speaker boxes is a technical nonsense.

What negative effects are you expecting from placing SS amps inside speaker cabinets? Give me specifics and together we can search for the evidence of those detrimental effects in some of the world's finest active studio monitors through independent measurements and reviews in pro magazines and web sites. If we know precisely what we're searching for, it shouldn't take long to root out the precise technical nature of the nonsense.

Tim

 

[Bruce B]

What negative effects are you expecting from placing SS amps inside speaker cabinets? Tim

Don't high-end speaker manufacturers go to great lengths to isolate even the crossovers from vibration? There must be a reason.

 

[Phelonious Ponk]

Don't high-end speaker manufacturers go to great lengths to isolate even the crossovers from vibration? There must be a reason.

That's exactly what need: The reason. The specific impact of not isolating from vibration. Once we have that identified, we should easily be able to find the detrimental effects in active monitors. Or not.

Tim

 

[docvale]

...
So in the end, it is about the complete picture, not just the numbers. But it’s also important to have the numbers, too, particularly if accuracy is the ultimate goal, which it is for me. So I really want, in the speaker, all the technical parameters that I have espoused on this board and elsewhere, and at least high enough sensitivity that I have a reasonable selection of amplifiers from which to choose ...

I trust that everyone would agree with this statement.
Numbers may not be sufficient to produce a great result, but, at least, they can dissuade to go for certain matches.
In the end, it's only a matter to pick a speaker (or a series of speakers, being now before the final setup assembly): then picturing which typology of amps would be suitable will be more intuitive.

After a listening session at the Axpona NYC with the TAD CR1 I'd like to propose the TAD Reference 1 to my personal bucket list. The CR1 were impressive, so I trust that the TAD Ref1 could be suitable for such a prestigious role Additionally, I know in Italy they've been demoed with the tubed Viva amplification, so they could be a speaker set that could play with several partners...

 

[Ron Party]

... most people in the high end business will tell you that putting active electronics in the vibrating speaker boxes is a technical nonsense.

Do you have any data to support this claim?

 

[Phelonious Ponk]

Do you have any data to support this claim?

"most people in the high-end business" appears to be the technical data.

Tim

 

[microstrip]

And yet, when done properly, it is. Kinda makes you wonder where the money is in high-end amps.

For those I own happily I know where money goes ...

What negative effects are you expecting from placing SS amps inside speaker cabinets? Give me specifics and together we can search for the evidence of those detrimental effects in some of the world's finest active studio monitors through independent measurements and reviews in pro magazines and web sites. If we know precisely what we're searching for, it shouldn't take long to root out the precise technical nature of the nonsense.
Tim

Microphony, the name usually given to electronic microphonic effects in electronics. Many manufacturers well considered in this forum, such as Burmester, openly refer to it. Apologies, I am not interested in doing research "through independent measurements and reviews in pro magazines and web sites". Crosschecking opinions from credible people who have a long record of well know quality products and industry recognition is enough for me and is my main interest in this forum. Specially when they are members of this forum.

 

[Phelonious Ponk]

For those I own happily I know where money goes ...


Microphony, the name usually given to electronic microphonic effects in electronics. Many manufacturers well considered in this forum, such as Burmester, openly refer to it. Apologies, I am not interested in doing research "through independent measurements and reviews in pro magazines and web sites". Crosschecking opinions from credible people who have a long record of well know quality products and industry recognition is enough for me and is my main interest in this forum. Specially when they are members of this forum.

I know what microphony is, and I'd be happy to check into it myself if someone can just tell me what the effects of this microphony are. Noise? Distortion? What kind? If it's audible, it has shown up somewhere.

Tim

 

[microstrip]

I know what microphony is, and I'd be happy to check into it myself if someone can just tell me what the effects of this microphony are. Noise? Distortion? What kind? If it's audible, it has shown up somewhere.

Tim

This was taken from a recent PhD thesis I own: Design of CMOS analog integrated circuits as readout electronics for High-TC superconductor and semiconductor terahertz bolometric sensors - Vratislav Michal

3.2.4 Non-Electrical Noise Sources
Random noise signals can arise as well, from fluctuations in the environmental conditions. This interaction can be limited by a correct design, for instance by a good shielding of the circuit. A most common external perturbation is the electromagnetic radiation caused by natural electromagnetic signals (atmospheric noise) or being the consequence of human activity. This latter may arise from 50/60 Hz power lines or radio station signals, for instance. There are also non-electrical effects which should be considered as noise: the ambient temperature variation which affects the device parameters, acoustical noise related to the wellknown
“microphonic effects”, high energy (ionizing) particles (e.g. cosmic radiations), or the components’ aging.

Another reference at IEEE
Electrical noise generated from the microphonic effect in capacitors
R. Nelson, L. Davidson
Dept. of Electr. & Comput. Eng., North Dakota State Univ., Fargo, ND, USA;

Electromagnetic Compatibility, 2002. EMC 2002. IEEE International Symposium
on. 09/2002; 2:855-860 vol.2. DOI: 10.1109/ISEMC.2002.1032708

Enjoy - I will go for the fun now - music time!

 

[fas42]

What negative effects are you expecting from placing SS amps inside speaker cabinets? Give me specifics and together we can search for the evidence of those detrimental effects in some of the world's finest active studio monitors through independent measurements and reviews in pro magazines and web sites

Apart from microphony the other word is piezoelectric. Many things when shaken generate voltages, the more you vibrate the greater the spurious voltage, which if it affects an element of an audio circuit will obviously be a distortion. You can get piezo mic's which directly exploit this behaviour. And of course there is a whole sub-industry which markets products to isolate and damp those vibrations. There is technical info galore on this mechanism, so it is not a "voodoo" behaviour.

Of course, in a speaker driven hard with electronics inside, if there is distortion or it doesn't sound quite right, then you can always point your finger at the driver or the room acoustics rather than the electrical side of things ...

Frank

 

[Phelonious Ponk]

Perhaps I wasn't clear. Conjecture is conjecture whether it comes from Frank or a PhD. I was looking for data, something indicating a measurable and/or audible effect of this microphony, limited to the kind of vibration that might be found inside a speaker cabinet, rather than "shaking." If this is a real effect that causes real distortion that is eradicted by design techniques being employed by high-end manufacturers, it must be both measurable and audible, or they don't know what they're addressing and whether or not their efforts have been successful.

Hearing alone? There are tens of thousands of highly trained, deeply experienced recording engineers out there making records with active monitors every day; the records you're playing back on your systems. If this was an audible problem, I trust they'd hear it, and active monitors would be diminishing in popularity in pro recording instead of taking an ever-greater share of the market.

Tim

 

[FrantzM]

Hi

I don't have much vested in active speakers.. I do however like the idea of active digital crossover... It is possible with digital crossovers to correct speakers anomalies in ways impossible with analog.. .Arbitrary slopes without the limitations of analog filters.

Microphony is often invoked in many an audiophile discussion. A real case of serious and measurable microphony occurs whenever a turntable is placed inside the listening room ... Airborne vibrations (vibrations in general but I am supposing one has taken great pain to suppress those coming from the floor, a huge assumption) will reach the TT and there isn't much you can do against this unless you place the TT in a different, isolated room; something I have seen (in pictures) some audiophiles, for the most part Japanese do ... Most people even the most vocal about microphony place their tubes ampolifiers next to speakers capable of serious bass ...

Now about piezo electricity in this context, the least said about it the better ...

 

[fas42]

Now about piezo electricity in this context, the least said about it the better ...

Interesting comment, why say you that (perhaps in another thread ...)?

The key thing in all this is that vibrations by whatever physical mechanism is involved, cause electrical components to behave at less than their optimum capability, sufficient to possibly cause measurable distortion to occur. A good designer will attempt to avert this, by using good isolation and vibration damping; I would imagine better examples of active speakers would have this aspect addressed fairly comprehensively ...

Frank

 

[Phelonious Ponk]

This is a huge distraction from the purpose of this thread so I'll say this and be done with it unless someone wants to start a separate thread on the subject: There are two "high-end" audio markets: One very small one made up of hobbyists, many of whom seem to believe that otherwise undetectable ground-born vibrations (we're not talking about rattling cabinets or buzzing circuit boards, ie: piezo-electric effects) can cause audible (if not measurable) distortions in electronic components. The other, much larger one, is made up of professional recording engineers and musicians who have, for a couple of decades now, increasingly chosen to use professional monitors with the amplifier electronics actually mounted inside the speaker cabinets.

I take the latter as evidence that the former is nonsense. Add to that my listening experience -- the cleanest, clearest, most resolving speaker systems I've heard were all active -- and I give this issue no more thought. YMMV.

Tim

 

[JackD201]

That's not entirely true Tim and you're using the same logic as Micro when you invoke the Pro world. There are many vibration isolation products for speakers and equipment for pros and they are gaining in popularity. Auralex makes the MoPad, Adam ships with their own set of pads, potting is common for quite a few onboard components. New potting agents for high temperature instrumentation are popping up regularly and can be bought in bulk. What one has to take into account with pro gear is that electronics are usually rackmounted and these enclosures help protect the chassis of the equipment and the mounting couples the equipment (the heavy faceplates do have a reason for being there. Meanwhile, soffit monitors are decoupled and near field monitors are now getting either pads or joint and elbow devices. They know the problems exist and they are addressing them. That the domestic market beat the pro world to the punch is more a function of the domestic market simply needing it more. $40 Tim, give them a shot with your monitors if you aren't using any yet and let us know if they work or if the Pro world is just trying to carpet bag the pro market.

 

[Jeff Fritz]

Most designers that I've spoken with tell me that active is ultimately the best configuration for a loudspeaker. I think there are inherent advantages there that are easy to understand.

However, the best speaker manufacturers in the home market seem to have gone farther in terms of driver development, cabinet resonance control, and perhaps other areas where the pro market seems to be lagging. Fot instance, I still see a fair number of poly drivers in pro speakers. Whereas the prevailing wisdom with the best drivers is that the primary break-up mode of a cone be two octaves outside of its passband. A poly driver won't do that. Laurence Dickie of Vivid made pro drivers when he left B&W, but has really optimized his designs in his current line of home speakers.