"What a refreshingly honest blog about listening to music through hi-fi. So happy to see views based upon the enjoyment of music rather than so-called sound 'quality'." - Peter Comeau, Director of Acoustic Design at Mission / Wharfedale

Monday 25 January 2021

System Synergy and Expectation Bias

A couple of phrases you might hear or read from time to time when researching or in dicussion about music playing hardware.  What are they about, and why would I be writing about them right now?

Sometimes how to phrase an audio experience is very elusive.  Some readers might say that continues to be the case, even for published posts!  This particular case has been more elusive than usual - its been a year since I made my notes on this project. How to frame those notes have been through about 6 iterations and I'm not sure I'm there yet. But a lot of time and effort went into this, and its time to just put it out there, good or bad, as the products involved might be old hat before I'm content with the wording.  I wanted to not just list the reviews, but to try and put them into some kind of relationship - finally settling on the synergy and expectation bias frame to hang it all from. So here it is, some kind of a review from circa Christmas 2019:

A 6 week or so period of frenzied (at least by my standards) box swapping, mostly for research purposes, but also to inform some purchasing options, mainly not for me, but for a good friend of mine, who's system features here. And it's all given the opportunity for another few blog posts too.  Elsewhere on the blog you'll soon find some impressions of some of the products involved so I won't go into huge amounts of detail here, but will cover a "flavour" of the systems involved. Long form, no photos and no apologies for that.

Coming to Terms

What do these words mean, in an audio system context?  Well, let me have a go at describing how I would use them, so these aren't definitions as such, but more setting the context of this post.

System Synergy - when putting together a whole series of components into a system - CD player, turntable, amp, speakers, cables, the room - do they work together in the way you would like them to?  Or do they lead to some kind of imbalance in a system?  Do you hear a coherent musical message, or is there something that grates like a bloated bass when you wanted tight tunefulness or a laziness to the sound where you wanted pace and energy?  Well, when it all comes together to meet your hopes, that, to you, would be a system that displays good synergy - the components complement each other to give an overall positive result.  If it doesn't work, the synergy's not there, then there needs to be a further search to find what's causing the imbalance, to work out what needs changing or improving.  Note that there is no mention of cost in this description - it has nothing to do with cost, it has to do with balancing characteristics of components to get a good result.

Expectation Bias - we'd probably all like to think we're impartial and can evaluate what we're hearing without regard to what we think we're going to hear or prefer.  Are we going to prefer one brand over another because its been a favourite for years? Are we going to like the sound of the component that has the nicest finish or a preferred species of wood on the front? Will we expect the more expensive bit of cable to sound better than the cheaper one?  Of course we all have these biases - its part of what makes us human.  I think its possible to try and minimise them by being concious of the issue, but probably not to eliminate it.  Blind testing (where you don't know which component is playing) is often advocated, but it just introduces different problems (such as an unnatural focus on the listening process), so I don't consider it to be the answer.  Just accept that a level of bias is inevitable and that it influences your opinion, but try to minimise this as much as possible.  That's one of the reasons why this blog is just opinion - there's nothing scientific about most of it, and that's just the way I prefer to keep it - the disclaimers make this clear.

So How?

If we're susceptible to expectation bias, how do we know if a system really has good synergy or if we're just expecting it to have good synergy?  Well I don't think there's a way to be totally objective (objectivity is restricted by the measures used anyway, as there's no way of knowing if a set of measures is comprehensive or relevant enough, that's why science keeps evolving) so just embrace the subjective and try to deal with it.  Its also worth noting that listening to music is meant to be an emotional experience and therefore, to me, it seems that choosing a system on some level of emotional evaluation is entirely reasonable.


Mustn't leave the room out of the equation either.  Lots of impact on the way a system sounds comes from the room and the interaction of the speakers with the room, so I've included that in these musings to try and cover a little of the less obvious.  Where possible (ie with the Linn front end) SPACE optimisation was set up for each system.  What is often referred to as "Tune Dem" or "Tune Method" was used to position speakers and adjust SPACE.


I'll go straight into listing the systems that I listened to over those few weeks a year back and that have fed this post, along with my expectation bias - as without that the rest of the post will be a bit meaningless.  The premise of the post being that my expectation bias wasn't met and I'll describe where and in what way.  Perhaps this is part of trying to be aware of my own bias and trying to rationalise how I have, at least partially, probably, tried to put it to one side and listen to what's actually going on. Still a big "if" though.


I won't go fully into every detail of the systems here, such as precise cables etc., but the main components that differentiate the systems.  I suppose its fair to say that my expectations are in comparison to my everyday system.  They're based on a mix of hearing 2 of these systems frequently and hearing the other components in other systems. It is fair to say that every single one of the components in these systems is highly respected, so there are no "duds" at all, and that's where the synergy element becomes so intriguing.

System 1: 

Melco N1ZH server, Linn Akurate DSM / Exaktbox Katalyst streamer, 3x Lejonklou Tundra Stereo 2.5 power amps, PMC Twenty.26 converted for active use, medium size pretty much rectangular room. This Exakt system uses filters for the PMCs available from SpeakerFilters.com, not the standard versions.
Expectation Bias 1: this is my everyday listen - its taken a long time to get to this system - it has a great deal of  detail but also a very musical flow to it.  Its not the last word in dynamics and slam but I can listen to it for hours (and do so, most evenings), following the tunes, enjoying the emotional impact of the music.  Its not perfect, no system ever is, but its what works very well for me.  What's my expectation?  Well, its more a reference point for comparison than an expectation really, but I would say that I expect it to be very difficult to beat in this evaluation with other systems having some benefits but not the overall balance of this system.

System 2: 

Melco N1ZH server, Linn Akurate DSM / Exaktbox streamer, 2x Lejonklou Tundra Stereo 2.5 power amps, Kudos Titan 505 on their dedicated stands and configured for active use, medium size pretty much rectangular room
Expectation Bias (comparative to System 1): more detail, a more dynamic presentation, a touch of brightness. Perhaps a little looseness in the bass.

System 3:  

Melco N1ZH server, Linn Akurate DSM / Exaktbox streamer, 2x Naim 250DR power amps, Kudos Titan 505 on their dedicated stands and configured for active use, medium size pretty much rectangular room
Expectation Bias (comparative to System 1): more detail, a more dynamic presentation, a touch of brightness, possibly assertiveness approaching aggression, more impact in the lower frequencies.

System 4:  

Melco N1ZH server, Linn Akurate DSM / Exaktbox streamer, 3x Naim 250DR power amps, PMC Twenty.26 converted for active use, medium size pretty much rectangular room
Expectation Bias (comparative to System 1): a more dynamic presentation, a touch of brightness, probably assertiveness approaching aggression, a loss of musical flow.

System 5:  

Naim NS01 server, Naim NDS streamer with 555DR PSU, Naim 252 pre with PSU, SNAXO crossover, 2x Naim 250DR power amps, Kudos Super 20 configured for active use, a medium sized room but L shaped, using the larger part of the L, which is smaller than the other listening room.
Expectation Bias (comparative to System 1): a system I'm already very familar with - a more dynamic presentation, too bright for my taste, assertiveness approaching aggression, a loss of musical flow somewhat compensated for by the enthusiasm.

System 6: 

Naim NS01 server, Naim NDS streamer with 555DR PSU, Naim 252 pre with PSU, SNAXO crossover, 2x Naim 250DR power amps, Kudos Titan 505 on their dedicated stands configured for active use, a medium sized room but L shaped, using the larger part of the L, which is smaller than the other listening room.
Expectation Bias (comparative to System 1): a more dynamic presentation, slight brightness, assertiveness approaching aggression, perhaps retaining the music flow, extra weight (because of the smaller room mainly), more information delivered.

So there we are, cards on the table. Something else worth mentioning - those who say "all competently designed solid state amps that measure within a gnats whisker of measurement-of-the-week all sound the same".  I have an expectation bias about that too - its just not true - I've heard far too many amplifier changes in systems to know that this is not true.  Unless I've only ever heard incompetently designed amps with bad measurements, which is also not true.


So here we go, here are the descriptions of systems 2 to 5 and a conclusion, that's not what I thought it was going to be:

System 2: the biggest suprise for me really.  The Titans give a far more detailed presentation than the PMCs, its suprising how much more they reveal in the recording. The extra brightness is certainly there, as per expectation, but is this just brightness or is it more detail too?  I'm going with the latter as there's more expression too in the vocals.  In fact the greatest strength of the Titans in this and the other systems is their vocal expression - its quite outstanding by any standards of the many systems I've heard.  Another element that was as expected is that, compared to the Titans driven by the Naim amps, there is a softness in the bass with the Tundras.  And here I think we see the first of the synergy issues - perhaps the Tundras and the 505s don't sit all that comfortably together as there was another element here that I wasn't expecting as the Tundras have never sounded like this in any other system I've heard - a sense of relentlessness.  Not shouty aggression, just a bit too much going on and losing some of that lovely flow that the Tundras present in partnership with speakers such as the PMCs and Graham Audio LS5/9. That, juxtapositioned with the lack of pace in the bass lines, meant that this wasn't the best of the combinations compared here.  There was a fair bit of experimentation with toe-in with the Titans in this room as there's definitely not the width or precision of soundstage compared to the PMCs. Don't get me wrong, we're talking about a decent sounding system, but in absolute terms, it lacked the right synergy.

Expectation bias 0: Systems 1

System 3: its long been a thing, a Linn front end with Naim amplification into a pair of speakers of choice.  Traditionally, of course, that was an LP12 and a passive Naim pre-power combination. Here we bring the tradition up to date with Linn streamer/pre and Naim power. Yep, more impact in the lower frequencies, no doubt about that - nearly reaching as low frequencies as the PMCs too - impressive. Mind you, the 505 standmounts on their dedicated and structurally massive stands are actually much more intrusive in the room than the much more constrained PMCs (which I always use the the grilles on). Definitely more detail from that (very) expensive tweeter - is it too bright? Its touch and go and track dependent, sometimes just tipping over the edge. But here's the thing - music, because listening to the music on this combination was very engaging - but its different to the regular system 1. There's an immediacy without shoutiness and that detail mentioned earlier but there's not the same musical flow that a Tundra delivers (in partnership with speakers they work happily with!). Whilst the Titans have very impressive bass power and immediacy, they still didn't quite fill the room like the PMCs do. Vocals are excellent again and there's plenty of engagement into the meaning of the music. This is good, but is very much along the lines of the expected.

Expectation bias 1: Systems 1 

System 4: before I go any further, just consider this: moving from Tundra to Naim power amps is a 50% price hike in amplification prices. And they do have a very different mix of abilities. I can also say that the Naim NAP250DR is a heavy beast.  Not too easy to lift onto a shelf and keep the shelf edges in pristine condition.  Those massive toroidal transformers are very heavy indeed. And noisy, good grief they're noisy. Not through the speakers, no issues there at all. But my goodness do they hum. I know my incoming mains typically carries about 2.5% distortion (the PS Audio regenerator displays this information) - I'm not sure if that's high, typical or low, but its certainly enough to get the NAPs a buzzin'. Just to be clear - neither of the power amps in this sequence of tests were plugged into the PS Audio, only the low current source electronics are fed from the regenerator. So there is no doubt that the 250 boxes have a tighter grip on the PMCs. There is more slam, there is more immediacy. There is a little more enthusiasm in the upper frequencies but it never becomes wearing in this system. All of this as expected.  What I didn't anticipate at all was the way everything hung together as a piece of music in very much the same manner of the Tundras into these speakers. Even that very taughtly controlled bass didn't disrupt the ability to follow the tune. Very good indeed. Except for gaps between tracks when the boxes from Salisbury irritated me significantly. Expection or surprise - calling this one a score draw.

Expectation bias 2: Systems 2

System 5: nearly all change.  Change of front end, speakers and room. As I'm very familiar with this system as it as grown and developed over the last 5 years with the Super 20s, then my "expectation bias" notes above are really all you need to know - they're more about experience than expectation. So let's call this one a no score draw!

Expectation bias 2: Systems 2

System 6: Would we expect (or have a bias!) that the 70% more expensive 505 with their stands would have a family feel when contrasted with the Super 20 floorstanders? Would there be a family resemblance from the North East parentage? Yes. And No. The Titans have that same family immediacy but the way they feel more "grown up" was far greater than my expectations.  Especially in the treble - where the Super 20 appears to major on detail, I find it gets too much after a while. What seems to be the case with the 505 is that the detail is real and it knows that it doesn't have to try too hard. I was a little worried about the size of the bass that comes with the upgrade to Titan (yes, the standmount has far more bass output than the floorstanders, in part due to their isobaric loading) in this smaller room, but it worked very well indeed - and there's an important reminder that system synergy includes the room.  Here, of course, there is no SPACE optimisation to make the best of the room so its all down to component choice and speaker positioning. What was just a touch underwhelming from these speakers in the bigger room is just right here. I don't get the same sense of ease of musical delivery compared to the Linn front end with Naim amps and these speakers, but I can see how their immediacy could appeal. No stridency, no experience of fatigue.

Expectation bias 2: Systems 3


So you can now decide if any of this tells you anything about expectation bias or system synergy (which needs to include the room).  I certainly was surprised that the weight of the 505 could work in the smaller room, that the Tundras and Titans just didn't get on together at all and that I'd enjoy the Naim power amps in my regular system anywhere near as much as I did.

I wish the Naims amps didn't have 2 faults: that hum I can't just dismiss nor excuse, and their price. So I shall continue to be extremely happy with the Tundras as they work very well indeed with the PMCs.  As for my friend with the largely Naim system - he bought the 505s and has them working even better now the speaker cables are Super Lumina.

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