How do you know if a speaker is any good?
The answer should be obvious.
If you like the way it sounds, then it is good.
Im not here to tell you what you like doesnt actually sound good.
But Iamhere to help you make more educated purchases.
So how can you tell if one speaker is better than another without direct comparison?
Thats when you turn to speaker measurements and objective data.
Knowing how tounderstand frequency response graphs is one of the most valuable skills an audiophile can have.
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This same graph can tell you what some of the speakers audible coloration and flaws might be.
This guide will hopefully help you understand how to correlate that data with your own impressions too.
Okay, so why should I care about measurements?
Cant I just read the review?
Some audiophiles believe listening to a speaker is theonlyway to know if a speaker is any good.
We all have different tastes in music, after all, so surely speakers are the same?
The problem is, when it comes tosoundreproduction, not music, youre probably not that special.
The gold standard of this preference research is the double-blind comparison.
And these are just two studies of many suggesting similar results over the past few decades.
Though the research isnt without flaws, these areremarkableresults.
With speakers, we have that rare luxury.
Meanwhile, properly performed measurements can be replicated across different measurement rigs to a high degree of repeatability.
Knowing how to read measurements gives you a much better chance of buying something that you know youll like.
So which speakers are the best?
It usually doesnt matter what jot down of listener you are.
Personal taste doesnt completely disappear, but the best speakers do trend toward having the above qualities.
It doesnt matter if theyre studio monitors or hi-fi speakers.
The basic acoustic principles remain the same.
What does a great frequency response look like?
Thats it?
I mean, basically.
So why arent all speakers flat?
Because its really hard to do right.
Also, some designers dont agree with the science mentioned so far and prefer to tune things by ear.
And most speakers cant extend all the way down to the lowest bass frequencies.
This is fantastic performance; flatter than this and you are pushing the limitations of my measurement system.
Heres another one, albeit with less bass output:
There are some things you should know though.
I use the latter method because I aint got that kind of money.
How do I understand deviations from flat?
Frequency response is typically divided into the lows/bass, mids, and highs/treble.
If it is higher, that region will be more audible.
A few more things to keep in mind.
Firstly, its worth noting peaks in the frequency response are generally a bit more audible than similarly-sized dips.
There also isnt much music content up there.
I saw a manufacturer post a super smooth frequency response!
This aspect ratio highlights flaws more than most measurements posted online.
You shouldalwayslook at the Y-Axis scale before making an assessment about a measurement.
Smoothing
Its exactly what it sounds like: smoothing out the frequency response.
Combine a tall vertical scale with smoothing, and you could easily clean up a messy speaker.
Here is the same measurement again with both a compressed Y-axis and exaggerated smoothing.
Smoothing can be useful for assessing trends while ignoring harmless minor deviations, especially for in-room measurements.
But when it comes to anechoic measurements, it should only be used in conjunction with higher resolution measurements.
Luckily, its usually pretty easy to spot smoothed measurements because they look unnaturally smooth.
Even the best speakers have some jagged bits to their measurements.
It makes sense if you think about it and not just with speakers.
After all, why dont we hear all the reflections when someone is speaking in a small room?
Its because thatd be annoying and we could never understand each other or pinpoint where sounds are coming from.
you’re free to learn more about this phenomenon by reading up on theprecedence effect.
it’s possible for you to hopefully now see why having high-quality early reflections is important.
Nonetheless, when people say smooth directivity, theyre usually focusing more on the horizontal portion.
What does smooth directivity look like?
There are many ways of displaying a speakers directivity performance.
The most basic way and my preferred method is by simply graphing a speakers frequency response at different angles.
Usually, only the front hemisphere is included because it makes the largest contribution to the sound.
Heres one more situation.
What happens if the direct sound is awful, but the directivity is still good?
In practice, this would likely lead to a speaker with uneven tonality but a good soundstage.
Its worth noting that a speaker can have good directivity in different ways.
Other speakers have narrow directivity, which means a more tilted off-axis response.
Narrower directivity speakers may have more focused imaging, but a smaller soundstage.
Heres an example of a great speaker:
it’s possible for you to read more about thesehere.
Frequency response and directivity together: What is a spinorama?
The On-Axis is measured with the speaker aimed directly at the microphone.
It also helps eliminate inaudible deviations in the frequency response that sometimes only show up when the microphone isexactlyon-axis.
The other curves, meanwhile, represent the off-axis sound the sound that will reflect off your walls.
The Early Reflections curve (blue, top) is particularly important, as discussed earlier.
The Sound Power curve (red, top) represents an average of the speakers sound in all directions.
It is, in a way, a refinement of the ER curve.
These are calculated by subtracting the Sound Power and Early Reflections curves from the Listening Window, respectively.
Smooth DI curves are a quick and easy way to assess directivity performance.
This line in particular should be very smooth for a good soundstage.
An ideal spinorama might look something close to this:
But again, no speaker is quite this good.
So are frequency response and directivity everything?
No, but they sure get youreallyclose to the full story.
You mightve noticed Ive said nothing about distortion so far, the classic audiophile bugbear.
Thats because quantifying what qualifies as bad distortion is really hard.
Moreover, the types of distortion measurements available to most reviewers are fairly rudimentary.
They do not correlate because they ignore any characteristics of the human receptor, itself an outrageously non-linear unit.
The excessive simplicity of the signals also remains a problem.
Music and movies offer an infinite variety of input signals and therefore an infinite variety of distorted outputs.
The only meaningful target for conventional distortion metrics is zero.
When it comes to distortion, I personally only worry about it if I can clearly hear it.
Lastly, I want to reiterate that this article is about a speakers anechoic performance.
Ill have a separate write-up on optimizing a speakers performance in-room.
Id like to learn more!
So if you want to learn more, I cant recommend Dr. Tooles book enough.
It provides an incredible wealth of knowledge with myriad citations.
Better yet, the amount of available speaker measurements is increasing all the time.
Its a great time to be an audiophile at least one who sees value in the data.
