[JohnR]

The question was about measuring synergy.

Hi Kevin, that's why the challenge is to build a whole system. You can't have synergy with just one component

[Kevin Haskins]

The question was about measuring synergy.

Hi Kevin, that's why the challenge is to build a whole system. You can't have synergy with just one component

The line we draw for components is arbitrary.   You could put the amplifier, preamp & loudspeakers all in one box and then I could design something with synergy with just the measurements. 

[rollo]

With synergy in mind, would it make sense to purchase from one manufacturer? Choose the sound of the manf. you like and buy their components. Same for cabling. For example all AudioNote. Amp, Pre, CDP Speakers, cables.
      You would think there is synergy with each other. Makes sense to me.
 What is your opinion?

  rollo

[JohnR]

The question was about measuring synergy.

Hi Kevin, that's why the challenge is to build a whole system. You can't have synergy with just one component

The line we draw for components is arbitrary.   You could put the amplifier, preamp & loudspeakers all in one box and then I could design something with synergy with just the measurements. 

OK, so what specifically would you be measuring?

[Kevin Haskins]

The question was about measuring synergy.

Hi Kevin, that's why the challenge is to build a whole system. You can't have synergy with just one component

The line we draw for components is arbitrary.   You could put the amplifier, preamp & loudspeakers all in one box and then I could design something with synergy with just the measurements. 

OK, so what specifically would you be measuring?

Good question... It would start with some design goals.   How big is it, how much is it going to cost, what frequency range you want it to cover, what type of playback environment is it going to be used in etc...

After you answer those questions then you move on to the design choices (what components to use).   If I really had the money I'd design the drivers in question from scratch and optimize the motor, & suspension components.   You do so with computer models and measurements.   I've got a pretty good handle on the motor, the suspensions have been more trial and error.   Use Klippel measurements to evaluate changes and sample a lot until we have a frequency response and Kms/Cms curve we can live with.   You find these properties by measurements.   Since the transducer is the single largest source of error in the playback system it makes sense to focus a lot of energy on the raw driver design to optimize it as much as possible.     We then measure distortion curves to evaluate how our fundamental design choices (motor/suspension/inductance) effect the outcome of measured distortion.   I'd take even order products over high odd-order harmonics and we need a measured frequency response in the desired acoustic environment (the enclosure we plan to use) that we can work with.    If the first phase of development was done well (good fundamental motor & suspension design) then the rest kind of takes care of itself. 

Tweeters I'm not much good with.   I'd depend upon someone else for a the driver design and just measure the finished part to fit my design goal.    Distortion curves, off-axis performance and a frequency response I can work with.    I like systems with lots of dynamic range so I like to measure all drivers at higher signal levels to see where they start to fall apart distortion wise.   

After I'm happy with the drivers I'd move on to crossover and optimizing the box design.   I like sealed enclosures because they are easy to design for.   Especially if you are doing an active design where you can EQ the bottom-end.   They theoretically have higher measured distortion down low because the port/PR gives you another half octave of usable output typically and lowers drive excursion in that area.   These days our drivers are much more linear (we can see because of measurements) and capable of more output, I prefer using a sealed box because I can dial in whatever Q & F3 I want using a Linkwitz Transform.    The smooth roll-off and tight transient response of a sealed box is almost always more musical.   There is something about how it couples with the room that just works.   For the top-end I'd design the enclosure to deal with as many diffraction issues as possible.   This mainly shows up on the measured tweeter response.   Depending on how you design there are methods to deal with it.   

Once I'm happy with the layout of the front baffle I'd measure FR & impedance for crossover design.    I'd import those into LSPCAD for crossover modeling.   I like using as simple of a crossover as possible.   I prefer about 4th order acoustic responses which I can usually obtain with 2nd order electrical solutions.   Every situation is different though and I measure on/off-axis during the crossover evaluation to make sure I'm optimizing off-axis as well as on-axis.    Typically at this point I use LSPCAD to listen to the crossovers.   Since I'm not allowed to listen though I'd just optimized the off-axis measurements as much as possible. 

Final analysis is a distortion measurement of the finished system at low & higher levels to make sure we designed the crossover appropriate to the driver's needs.

For a preamp I'd just use a passive on my amplifier input.    The Bent Audio relay based resistor networks measure well.     For an amplifier I'd cheat and use something I know sounds good (from the measurements of course).   The Hypex UcD modules work really well!   Measures great!   I'd design the input stage right at the input of the amplifier so I wouldn't have issues with driving long cables.   

For a source.... that is tough.  I don't have any experience designing either CD players or IPODs.   I've built several turntables and I'd happily use one of the Well Tempered prototype units I have.   Oh!  By the way.   Bill designed his turntable with MEASUREMENTS.    He found that WOW/Flutter closely match subjective preference.   Most of his fine tuning of the design has been with the wow/flutter meter measurements and it has led to good results.   

I don't want to get goofy (maybe too late).   My main point is that virtually everything we design has a measurement attached to it.   We measure almost every property of a product before building and selling it.   Do we listen?  Yes.... but most audio engineers (the vast majority) don't design by ear.    Engineering is an art whereby we quantify things to move forward.   Without a measurement we are nothing more than Alchemist and a village Shaman.    Engineering by definition is process of understanding and optimization through quantification.   Otherwise we have no idea on how to move forward and design better products. 

[miklorsmith]

All these elements which measure great I have gone away from in the interest of system synergy.  Weird.

[rajacat]

Kevin,

Nice synopsis of your design process.

How do you predict a loudspeakers depth of soundstage? Is this related to your dispersion numbers?

Raj

[Kevin Haskins]

Kevin,

Nice synopsis of your design process.

How do you predict a loudspeakers depth of soundstage? Is this related to your dispersion numbers?

Raj

A lot of the subjective properties are hard to tie to one measured property.   If I had to guess I'd say it is a combination of the dispersion characteristics and controlling early refection's.    The room also plays a major role.   

On another note, my 300B SETs open up the soundstage considerably when used with appropriate loudspeakers.   Since they have NO effect on either the dispersion or diffraction effects I'd guess that in this case it has more to do with the distortion spectrum.    I don't know enough to classify why though.

[miklorsmith]

I have a completely unsubstantiated thought that the distortion characteristics of tubes mimic instrumental vibration which is lost in the recording process.  While technically adding distortion to the recording, the result is actually closer to the live event.

I'm sure it's hogwash, but fun to think about.   

[JohnR]

For an amplifier I'd cheat and use something I know sounds good (from the measurements of course).

Well, that's not true. You know it sounds good (I'll take your words at face value) because you listened to it.

You're still being very... non-specific about what exactly you would measure in order to determine synergy between the various parts of this all-in-one-box system. While I'm now quite comfortable with the spelling of the word "measure" and it's variations, I'm less comfortable with this insistence on "measurements" as a concept without (apparently) much idea of what exactly to measure or what criteria determine good vs bad measured performance. For instance, what about the slew rate that Karsten mentioned above? Would that factor into your design?

[Kevin Haskins]

For an amplifier I'd cheat and use something I know sounds good (from the measurements of course).

Well, that's not true. You know it sounds good (I'll take your words at face value) because you listened to it.

You're still being very... non-specific about what exactly you would measure in order to determine synergy between the various parts of this all-in-one-box system. While I'm now quite comfortable with the spelling of the word "measure" and it's variations, I'm less comfortable with this insistence on "measurements" as a concept without (apparently) much idea of what exactly to measure or what criteria determine good vs bad measured performance. For instance, what about the slew rate that Karsten mentioned above? Would that factor into your design?

Oh come on John.   Your not going to let me off the hook are you?    I don't know what to measure to determine synergy.   There... I've said it!   

I think measuring synergy is about like measuring many of these other subjective characteristics.   They are hard to nail down to one measurement.   With enough money and time we could do research to better quantify what people prefer and tie that back to several measurements but it isn't real practical.   For one I don't have the time or money to do that.    Also, most of the basic research points to the fact that our hearing and preference are not real reliable.   In other words the only way to study it is via statistical methods and you would have no guarantee that the research would be valid for a given individual. 

So... we would be right back where we started with people swapping componets to find synergy. 

[miklorsmith]

Dammit!   

[Daygloworange]

If I had all the options open and means available for someone to aid me in building a complete system from front to back, I would enlist the aid of persons like Kevin and Dan et al, to assemble such a system. No way would I enlist someone who does it predominantly from a subjective standpoint.

I have every confidence that that would achieve superior results to the latter. Not to say the latter would fall flat on his face, but, nevertheless, fall short.

Cheers

[miklorsmith]

If you like the sound they're going for, that would be an excellent choice.  If you liked horn speakers or SET amps or NOS DACs and THEY asked YOU what kind of sound you were going for, that would be very smart.  If they TOLD you what kind of sound you'd be getting, that would be ill-advised.

[Karsten]

This is a hard one. To go a little further with the "slew rate/micro dynamic speed theory" another observation is that a turn table will sound good in most systems, and I have yet to hear it go really harsh in the highs, in most any system. For some this leads to the conclusion that "digital sucks" although some digital recordings do sound good in most systems as well. However the turntable will always limit the maximum slew rate/micro dynamic capability because of physical limitations in the technique.... By this the slew rate/micro dynamic speed is limited already from the source, which again means that downstream components will have an easier job to do..... Maybe a controversial theory, but food for thoughts

Regards,
Karsten

[JohnR]

I think measuring synergy is about like measuring many of these other subjective characteristics.   They are hard to nail down to one measurement.   With enough money and time we could do research to better quantify what people prefer and tie that back to several measurements but it isn't real practical.

So far, the discussion has been about measuring individual components. Since we are concerned about "synergy," why not measure the whole system, all at once? For example, you would presumably take a CSD of a loudspeaker you are designing -- why not take a CSD of the whole chain, from digital test signal, through DAC, preamp, poweramp(s), crossover (active or passive), and drivers?

You mentioned earlier, for instance, measuring an amplifier with reactive loads (I think). But if it's synergy we are interested in, then why not measure the amplifier with the speaker at the same time? If there are problems with that amp and speaker, then there must be a way to show that up by measuring both of them at the same time. Or to turn it around, SETs and single drivers are considered to be synergistic, or you will see written that a particular speaker is "tube-friendly." So rather than simply speculating about what goes with what, can't we measure them together?

Before I go further, let me point out that I am following Kevin's "engineering approach to design" he explained above. I am not suggesting that measurement will tell us if a particular system will sound good or be to someone's taste, but that if you (Kevin, as the designer) see measurements that are different than what you expect, that is a sign that there is something going that you need to investigate.

So, to look at Karsten's example. If there is a "slew rate mismatch" between components, this will surely show up as IMD if you were to measure the components together. That would then give you (Kevin, the designer), pause to wonder why the IMD measurements are not what you expected, and hopefully further investigation would reveal the cause.

What do you think of this idea so far, Kevin?

JohnR

[opnly bafld]

Sometimes I think synergy comes down to what some of the measurement (only?) guys have mentioned, a component does not measure well, but we like it so much in certain areas that we try to match other components to it to get a desired overall sound.
Case in point: mcgsxr just posted in the Gravity Well thread that he has had Visaton B200s on open baffle for 2 years, obviously he likes some things the drivers do very well and he has tried several different amps with them. He mentions synergy with a couple of the amps, now these are my words not his, but I assume the reason he says this is that the synergistic amps LET the B200s do what they do best without interfering and the amps COMPLIMENT the B200s in the areas where they lack.
Therefore, maybe some of the guys that believe in and use synergy are getting something they would not get with components that measure well.
Nothing wrong with either preference.

BTW to steal the opening spoken words from a Police song written by Stewart Copeland: I have 273 posts and I am sure there is a least ONE good one, "the others are complete b...s...".

Lin

[miklorsmith]

Nice post, very concise.  I know for a fact you have far more than one good one.

[Daygloworange]

Is synergy measurable?

You'd have to get a clear consensus on what constitutes an exceptional sounding audio system, and what it should sound like.

You'd have to overcome that obstacle, get a clear definition of what constitues "synergy". If you could do that, then the answer is yes, you could measure it, and I'm sure you could define the parameters to a high degree.

Till then, I suspect synergy will always be an elusive, solitary goal.

Cheers

[Thebiker]