Dispelling Myths About EQ

[mas]

Attached is an article that touches on quite a few topics of rescent interest.

Of particular note might be the common understanding of some basic principles that some of the whosits here have yet to grasp.

So, while EQ may be the topic, what is even more significant are some of the concepts underlying their positions.

Hopefully this will stimulate a few who don't already know it all to explore the topics a little more deeply, to put down the hopelessly lost audiophilia and home theater mags that have yet to understand or address the basic physics of sound and to explore better sources of information that seek to explain more and sell less.

[pocket.change]

Interesting read and on track for SR application(s).  Not mentioned was most of the results are monitored by someone connected with the group to insure they are at spec and typically changed (athough not always) during a performance. 

But what does it have to do with a sound reproducing (not producing) system and dealing with less than positive recorded sources?  

I typically find playing with EQ a positive on alot of the older (and some of the newer stuff too) recorded material.  

If you are lucky enough to have a good home system, I agree most of the time things sound good right out of the box.   

I put jelly on my peanut butter sandwiches too... go figure.

[jacksonbart]

I have heard from the trolls down at the local audio store that Unicorns use Equalization very effectively. Anyone got a Unicorn?

[Groomlakearea51]

I liked the one comment:

Hales: " If you have quality equipment.... very little (if any) EQ should be required...... Don't get me wrong here, if I need to use the graph (graphic type) or PEQ (parametric type), I will, but I strongly believe that equalizers are the most misused piece of gear in existence....

I think (correct me if I'm wrong... as usually can be the case....) that their point relates to the sound provided; and eq should only be used sparingly after the sound has been adjusted for the "house curve". Assuming in our applications that the "house curve" is what we have after treatment, etc.?

Gotta run and go grasp my whosit...[:|]

[mas]

First of all, as mentioned, EQ can be used.

But note WHERE and HOW it is used! It is used on the mic inputs to vary the direct source quality. Something that does not even enter into a home listening environment.

They are NOT using the EQ to correct for speaker or room anomalies. Nor does it have anything to do with your use of tone conrols.

Now compare that to the primary use of EQ proposed by many on this forum!

Anyone gather why EQ is used on the monitors? And consider that their energy will bleed into the source mics. Considering gain before feedback issues and the distribution of frequencies, and the proximity effects of micing, the sum of the various direct signals is adjusted to minimize the summing of signals to prevent resonance peaking and stimulating feedback. Thus parametrics may be used to selectively notch a resonant frequency(ies). Again, they are addressing only the direct sound feed as a component of what is necessarily a potentially an excessively regenerative system.

Again, how many here are using their home listening systems in a potentially regenerative environment? If you are not using it for Karoake, you have no business even thinking about this or the use of EQ to adjust this issue.

But is the post really even about EQ? Only in a derivative sense.

EQ is actually a red herring. After all, as I mentioned, while the application was SR EQ, the underlying contributing concepts had little to do with SR or even EQ. Rather you will find that each employed a more basic and fundamental understanding of acoustical behavior to address fundamental issues rather than simply running for the EQ except where it is used appropriately.

And the result is a very sparse use of EQ.
(And BTW, no one who has a clue is riding an EQ in a live application!)

And in fact, if you remove the unique SR aspects, it further serves to remove additional legitimate uses for EQ and increases the focus upon acoustical fundamentals for those who will see and not begin by dismissing the notion entirely.

Now, lets take a step back and take a very quick look at what was mentioned about polar responses of speakers.
What about the speakers and passive crossovers contribute to anomalous polar responses and major off axis dips? Any guesses?

Lets see, what do we know about the artifacts caused by the superposition of two sources reproducing a common passband? Hmmmm. Oh yeah, comb filtering and polar anomalies! And what are the sources of superposition which have phase differentials resulting in anything other than a linear summing of magnitude (without the correlative comb filtering and polar anomalies)? Signal mis-alignment in the time domain.

And note the problem with using EQ to remediate the response of the monitor speaker. By using the too limited L & C phase characteristics of the EQ circuitry to make small phase adjustments that result in the polar anomalies, they have simply shifted and moved the problem around a bit.

So what fundamental approaches are effectively utilized to minimize this? New caps? Hardly!
Rather it is the practical application of coaxial drivers and bi-amplification utilizing active crossovers that not only allow minimal passband overlap, but also provide superior signal alignment to minimize the resultant comb filtering and polar lobing anomalies.

Thus, a better understanding of the underlying fundamental are what is most important. And simply replacing components, interconnects, and any number of other relatively speaking placebo remedies do not.

So, as you may recall, Heyser pointed out a fundamental issue with the acoustical offsets in the KHorn resulting in arrival times of individual drivers arriving with such an extreme offset that they arrived AFTER the first order room reflections (meaning that the physical offsets where greater than the reflective paths in the room!!), and practical remediation to solve the preponderance of the problem is actually rather simple.

What are the appropriate responses that address the fundamental acoustical issues necessary to remediate the problem? Is it simply a matter of running for the latest toy claiming to magically fix a complex problem? Or is it better addressed by examining the fundamental issues that contribute to create the problem in the first place?

So while some miss the point and begin by short circuiting the thinking process entirely by dismissing the fundamental concept of using a system to reproduce source material and instead focus on the system as an artistic tool for creating FX and thus begin by a cessation of thought without asking how and why things occur, others would be better served by realizing that there is more to acoustical behavior than replacing cable and yellow or orange components with blue or red ones. After all, for some who choose to think, there is more to accurate sound reproduction than learning how to make peanut butter and jelly sandwiches. So I guess sandwich makers just might want to move their chairs closer to the receiver so that they may more easily ride the tone controls. .;-O

But with a slightly more inquisitive approach that encourages a creative examination of the fundamentals, especially as new methods and models have arisen to replace or to radically extend old limited models in the past 35 years, much greater results may not only be expected, but realized,

[bodcaw boy]

sorry....i still believe in the myths of eq.....

have a blessed day,

roy

[mas]

sorry....i still believe in the myths of eq.....

No surprises there.

Just more of the usual insights.

I mean it should be obvious, what with a speaker with greater than a 9 foot acoustical center offset with a passive crossover! with no signal synchronization...!?

[bodcaw boy]

THANKS![8-|]

have a very blessed night,

roy

[mas]

You're welcome.

If only it were a compliment...

[bodcaw boy]

THANKS![8-|]

have a very blessed night,

roy

[ZAKO]

Some times diplomacy comes off looking like a persimmon.

[DrWho]

What's a persimmon? Surely you don't mean the fruit?

[IB Slammin]

sorry....i still believe in the myths of eq.....

No surprises there.

Just more of the usual insights.

mas,

You have a PM.

tc

[JJkizak]

There are no myths with my equalizer. It works just fine balancing the low end of the K-horns to the sub and eliminating some room nodes. There are no myths with my compander/expander which can pump a huge amount of power into the low/high end. If I didn't have the equalizer/compander/expander I probably would have the Bose table model radio. I have no problems with ancient tube technology and degradation as my SS is the same year after year. I have no vinyl or turntable problems either. No hiss, no scratches, no hum, no feedback, no pops, no 24 hour warm-ups. And instead of replacing tubes every 6 months the money saved goes to purchasing newer and better big buck SS items with this and other hobbies. The problem that I do have is the vibration of the walls, windows, doors,ceiling, and the small room and the nic-nacs vibrating into different positions.

JJK

[sunnysal]

frequency dips and peaks caused by my room cannot be reduced or eliminated no matter how great my equipment is, only my equalizer can help do that (since I cannot move the speakers around in the room, k-horns ya know). so this purist garbage that EQ is somehow a patch for poor equipment really doesn´t fly round my place. YMMV. Tony

btw: howdy Roy nice to see you posting.

[bodcaw boy]

hey tony,

how are you doing?

have a blessed night,

roy

[mas]

frequency dips and peaks caused by my room cannot be reduced or eliminated no matter how great my equipment is, only my equalizer can help do that (since I cannot move the speakers around in the room, k-horns ya know). so this purist garbage that EQ is somehow a patch for poor equipment really doesn´t fly round my place. YMMV. Tony

If you think EQ as a patch for poor equipment is nonsensical. the notion that EQ can correct for superposition induced comb filtering and polar lobing in non-minimum phase multi-source environments (speakers and rooms) is even more so.

But, by all means, have fun.

I always marvel at how folks like NASA can't overcome the limits imposed by physics, but audiophiles seem to have absolutely no problem in doing so.

But to quote Disraeli, "Where knowledge ends, religion begins." Which perhaps explains much of the resurgence in popular religion. But I can't help but wonder, if he were alive today, if he wouldn't add 'consumer audio'.

[Marvel]

Hope we can keep this on track and keep religion out of it.

Have a blessed day!

[JohnA]

So just WHAT is the great revelation here? Playback systems
should be neutral? Use good gear and don't screw it up with
EQ? Duh!

I don't even have tone controls.

[Marvel]

My system with the La Scalas has no tone controls (Merlin pre and Moondogs), and I am more than happy with the sound in the room. My Heresies re hooked up to my HK430, and I have the bass up a tittle bit, but only because I have the speakers 30 inches off the floor. That puts the midrage and tweeters about ear level when I am sitting in bed reading or... whatever.

Later...

John, I still need to get your crossovers back to you...

Bruce