So, "synergy" in a system is another audiophile claim that I've heard a number of times. Recently, in the Monoprice HTP-1 thread, its sensitivity control setting has been generating some questions. These questions have led me back to questioning how important "synergy" is. Thus, first I want to speculate a bit (please correct me), then explain some signal chain items, give some examples, then turn it over to y'all to educate us.
Incoming speculation --
You know the age-old argument, "if you spend x on speakers you better spend y on amps and z on your pre-amp (and whatever other stupid number on cables, lol)". So, allow me to contend that I often perceive a trend among "boutique" expensive speakers which is that they tend to be very insensitive and hard to drive (have crappy, poorly engineered, impedance curves). If you take this for granted, then sure, to reach high output levels (or have lots of dynamics) you'll need a powerful amplifier (expensive, at least more than a less powerful amplifier) and (possibly) to drive that amplifier you may need more input voltage. Thus, this moves the goal-post up again to the pre-amp, which now needs beefier line drivers. Thus, if we contend that more expensive speakers require more powerful amplifiers and more powerful amplifiers require more input voltage and more input voltage can only be provided by more expensive pre-amps then...well...looks like the statement "works!"
Of course, if it all starts at the speakers, then this is a "problem" created by a cottage industry of boutique brands. Worse, this cottage industry tends, IMO, to be full of garage-educated "EEs" that often can't design their way around anything using actual math and physics, preferring instead their uneducated school of hard-knocks and unscientific design methods. Unfortunately, though, if I'm right, the cottage industry has created a problem which it then solves by "making" you spend more money -- the reasoning above tells you why you have to and some of us sip it right up and reproduce the dogma!
That said, I have "no idea" (I couldn't care less, honestly) if these "trends" are factual. I speculate only why the "cost synergy" argument could
be made. However, it's not really "cost synergy" I'm here to discuss. I'd prefer to look at the actual numbers that mean something -- those things that may actually impact synergy in some meaningful way.
Ok, so now on to our signal chain --
For this example, I'll presume it all starts at the pre-amp (who cares the source, it's digital anyway, haha!). Now, in the Monoprice HTP-1 thread
there were statements
made regarding the performance degradation that would have been incurred if Monoprice decided to make their product produce an 12v max output vs. the 4v they settled on. Their supposition was that by settling on 4v, they could make it perform better for more people than had they chose 12v. However, since this specification is "up in the air" and "not adjustable" on just about all consumer gear, it's the first piece of our puzzle. It will determine how hard you can drive your amplifier. If it's "too much" then, if we take the Monoprice statements as fact, you may
be giving up performance in the lower end of the volume control where you'll be relegated so as not to overdrive your amplifier. If it's "too little" you'll never drive your amplifier to its maximum output (which, if your speakers can't handle it, or you don't want those volume levels, or the music you listen to never demands it, then it won't matter).
Ok, so now the amplifier. Again, way too often consumer amplifiers have no (or little) adjustability (personally, I won't buy an amplifier with fixed settings, but that's me -- there's a reason pro-amps have controls, I can't say the design compromises that are made to include them, though). Regardless, the fixed input sensitivity and gain go hand in hand to determine the maximum voltage the amplifier can output. This voltage, combined with the amp's current capability and your speaker's impedance curve, will determine how "well" the amplifier can drive your speakers. Since these are all fixed, if your amplifier needs, say, 2v to reach 500W on a 8ohm load then if you have a pre-amp with an 8v output you're going to cook it (unless you keep your volume level down on the pre). If your pre-amp can't hit 2v (say it's a cheaper unit whose outputs can't reach above 1v) then you'll never get 500W into an 8ohm load.
And, finally, we reach our speakers; arguably the most important
thing you can chose! There's a reason that many modern speakers have high sensitivity and are easier to drive -- science progresses. However, if you should chose a speaker that has low sensitivity or is hard to drive, then you best start looking at your amplifier selection and relating it to your listening habits. The speakers you chose will have the largest impact on your signal chain, IMO. Not just because they have the largest impact on what you hear, but because they set the goal-post that every piece of the equipment must reach if you want to produce the full dynamic range of the music you listen to!
Alright, so some examples -- note: here, I have to take the manufacturer's specs at face value...oh well.
First, let's say we have three pre-amps:
- Pre-amp A can reach a modest 1v output
- Pre-amp B a "better" 4v
- Pre-amp C a whooping 8v.
Now let's pick a few amplifiers (honestly, this was harder than I thought, most amplifiers either don't list specs or list (or I compute) a 29dB gain):
- Amplifier A; Emotiva XPA-DR1: 2.4v in -> 640W @ 8ohm (about 72v, they list gain as 29dB, every 6dB is a doubling, so can we do 2.4 * 2^(29/6) = 68v, about 72....).
- Amplifier B; QSC GX-5: 1.2v in -> 500W @ 8ohm (about 63v), they list gain as 34.4dB, using the above that also works out around 63v).
- Amplifier C; Boulder 3050: this is a BIG amp, it doesn't list the required input voltage, but it lists the gain, we'll have to assume their output power is accurate, so with 26dB gain (which, as you can see from the other amplifiers is NOT a lot, especially for such a big amplifier) to produce its (claimed) 2100W @ 8ohm (about 130v) with 26dB gain, you'll need x * 2^(26/6) = 130; x = 6.4v.
Alrighty! So, now I'd love to pull out some real speakers and specs, but there are a lot of variables that are NOT
listed for speakers (point me to a manufacturer provided impedance plot for any boutique speaker...). However, I can at least pick two at some extremes which have been measured by stereophile.
- Speaker A; MBL 101E Mk.II: 81dB measured sensitivity, 3.3ohm measured minimum impedance, this thing isn't going to be an easy-to-drive speaker nor is it very sensitive ("wonderful" combo, lol). Unfortunately, I don't know how I'd compute in-room SPL with this speaker, it's omni-nature probably makes it fall off less than normal as distance increases. Regardless, it's at enough extreme to make a point.
- Speaker B; GoldenEar Triton One.R: 91dB measured sensitivity, 3.1ohm measured minimum impedance, also not easy to drive, but it's pretty sensitive, so it'll require less power.
So, let's look at some combinations:
Pre-Amp A -> Amplifier C -> Speaker A -- This is not looking very good is it? This probably won't be able to get the MBLs moving none-the-less get any kind of dynamics out of them. The paltry voltage out of Amplifier C with Pre-Amp A's putrid .9v won't make much dent at, say, 40hz; don't try to play back EDM, lol.
Pre-Amp C -> Amplifer C -> Speaker A -- Much better!
Pre-Amp A -> Amplifier C -> Speaker B -- humm...well, Amplifier C is probably overkill for Speaker B, so...in this case, maybe the .9v limit isn't so bad? Or is it? I mean, Amplifier C can handle a lot of voltage, how well does it behave with .9v? What's its noise floor? If it has such low gain, how well does it handle lower signals? I can't answer any of that, but...this combination doesn't make a lot of sense, IMO.
Pre-Amp B -> Amplifier C -> Speaker B -- if the previous was overkill, this is too, right? But, at least we can put more voltage into the amplifier...we won't need it, though, unless we feel like watching Speaker B launch its cones across the room, lol.
Pre-Amp A -> Amplifier B -> Speaker B -- looks a bit better "matched".
And we can go on and on.
Now, the biggest question is, can all those signal chains be "matched" to provide the same levels of dynamics with some external devices? If so (and I presume so), are these devices hampering the overall signal-chain? Do we end up reducing the dynamic range of both systems to an equivalent level just to equalize our test?
Plus, there are amplifiers like: this Benchmark
which can be set to have an 8v input sensitivity for 100W output!?! I don't know what the point of that is (I tried to make that point in the Monoprice thread), but...if it needs 8v to output 100W, what the heck is it going to do with the paltry .9v of pre-amp A into something like Speaker A? Of course, at least this amp is adjustable, so we can set it to a higher gain (which requires 2v) and use pre-amp B happily, but does it have the "heft" to drive Speaker A to "reference" given its "horrid" sensitivity?