Recently in some of the discussions in this circle, I found that there some persons and companies who use room generated reflection to generate a "flat" response.
In one posting it was said that I must be running my speakers "very hot" in order to not be victim of "HF attenuation" and "sonic black holes".
Such is not the case. While it is true that my speakers are "adjustable" in the mid and highs, and that many who hear them think I am running them a "little hot" (which I do since high end hearing tends to reduce with age
)
BUT...the actual "settings" I use on the speakers, (which is 12:00 or less), is lower than the suggested settings by the designer himself.
Soooo....I'm actually running them "cool", but they have a very clear and extended high end.
How can this be? Read on.
I have also noticed that some discussions are now occuring about certain room measurement software to be used in the "attempt" to generate a flat response from the speaker room combination.
It is my understanding that specific "test tones" are generated for a few seconds and or a slow sweep tones are run through the speakers and are then "measured" by a microphone.
The recorded decibel level of each frequency is then shown on a graph.
I would say that most all professional acousticians use some sort of device and software to help us "move toward" a "FLAT" room.
Gee that sounds very scientific and should work...or should it?
Recently George AKA Zybar (Hi George
) made the comment that it was amazing that his system "sounded" so good, yet "measured" so bad.
I'm not sure that is a bad thing..
I have also "on occasion" heard some speaker designers say that measured frequency response, is really not a good indicator of whether or not their speaker will sound good or not.
I'm sure many think this is just a "copout" if their speaker doesn't measure "FLAT". And of course if it doesn't measure flat it couldn't be accurate (this I say with tongue in cheek
)
For years we have been told that "flat" frequency response is the ultimate goal and it is always measured in a way that "DOES NOT" really show us how a speaker plays dynamic music. (unless you listen to slowly changing organ tones)
What am I getting at?
In a room, when playing test tones, the sound leaves the speaker and moves out in most every direction, like the ripples of a stone thrown in a quiet pond. Now the intesity of these ripples may be greater or lesser based on the speaker type or dispersion pattern, but all the air in the room is "energized" with sound by the speaker.
Just stand behind one of your speakers sometime and see just how much sound is generated well off axis.
By the time the initial wave reaches the listener (and or measuring microphone) it is being "chased" and bombarded by early and late reflection, the "sum total" of which are measured by the microphone to give us a "db" rating/reading of that frequency.
The ear brain will generally "filter" the following signals to a degree in forming the perception of sound and amplitude of the sound, if the interfering signals are not too great. (This is called the "precedence" effect)
Front wall, ceiling and other reflections are generally lower in amplitude and later in arrival.
While these late arrivers will be recorded by the software and mic as part of that moments total amplitude, they may not be "heard" and perceived as same by the ear/brain.
Even using "tone bursts" the primary signal and its "real decay" is poluted with the reflection and the room decay.
In my exchange with some others in another post, I suggested seriously treating the front wall with acoustic treatment to reduce as much as possible contributing reflections from that surface.
One individual stated that in order to have a soundstage, that the front wall "MUST be reflective". It was said that these reflections were "very valuable" and that I would have no soundstage, "black holes" and HF attenuations.
In fact, it is just the opposite. Removing these "later and lower level" signals is more like "cleaning up" the signal (that we have worked so hard to preserve) and the crystal clear highs are even more sharp.
I have the best soundstage I have heard in 35 years of listening, my highs are great and who knows what a "black hole" is, but I certainly have deep blackness between instruments, when it exists, and a very thick "wall of sound" when it is on/in a recording.
Much like reducing reflected light in a front projection TV system improves the perception of detail and "black level" the reducing of these room artifacts does the same for sound.
Will they measure "flat" with continuos test tones or sweeps? NO they won't, but I don't see that as important since "dynamic music" is NOT steady tones or sweeps. It is a constantly changing group of multiple frequencies and attacks and decay.
To acheive measurement of this type of response, the attack and decay of a signal would have to be measured so that the reflected room response did not "skew" the actual measurement.
Lab instruments that I am aware of do not have the ability to discern the precedence of signal and disregard the lesser room signals as our brains do.
Anechoic measurement is the only true way.
Again, what does this mean to you at the sweet seat?
It means that reducing the frontal and side reflections (which boost equipment perceived high frequencies) will, in fact, make the "primary" signals heard by the ear/brain more clear, discernable, and lifelike.
This means you will hear them better and cleaner.
It also means that simply harvesting primary and reflected frequencies and summing them to acheive a higher db reading will not nessessarily lead to a "perceived" increase at the ear/brain perception level.
Now again much of this will depend on your speaker type and system. Line Source and or ribbon speakers will be different in this aspect than systems of high dispersion.
So when that cymbal is playing from somewhere in the left side of the soundstage. That instantaneous tranmsission, is sent on its way to your "left" ear (I know stereo is a balance of left and right but for simplicity let's just say left)
The primary edge of that soundwave reaches your ear first and with greatest amplitude followed by the delicate decay of that sound. If we allow the "first reflection" sounds from the floor, ceiling, side walls and front wall to "also" come at us, then the delicacy and inner detail of that "decay" or subdued trailing detail is "smearded, smudged, fogged, and any other fuzzed out term you can think of".
While some hear this "sonic haze", and think it "air" since it is highly dispersed and "fills" in what is supposed to be "blackness" or nothingness (or I guess I should say "soundless" space).
This is how singers and musicians and instruments take on "edges" and "shape". By "filling in" this "space" with room sound we are not only losing the ability to hear "into" a recording, but we are "creating" additional sound that was not on the recording.
It usually smooths out a recordings imaging and reduces depth.
Now don't get me wrong, this can sometimes be "very" beautiful and enticing. And with some studio engineered recordings it really is a moot point, since they cannot be reproduced as the real event anyhow.
But, in a live recording in an actual venue, with a good sound engineer, it is a beautiful thing.
So, in the end my point is that, using unusual means to produce a "machine measured" FLAT response in your room, may not be that, at all.
In fact, one of the first "excuses" you get from one so inclined as to want to be "FLAT",or who has acheived it, is that "It may not sound good to you, but it is flat".
I'm really wondering what is accurate for "truly accurate" reproduction.
In all areas of our world, there are many things that are thought of as "certain". That is, you or "some expert" is certain about this.
Just look at where diets have been over the last 30 years. Carbs, protien, fats, cholesterol, simple carbs, complex carbs, yada yada.
Let me assure you there exists a term called "mistaken certainties". I find new ones in my map of the world everyday.
I simply put forth the supposition that "maybe flat isn't really flat and it ain't what it's cracked up to be in audio"
And in a parting shot "do" be aware that I am not saying "truly flat response" is not a goal, because it is. What I'm saying is that I think maybe the current methods used to measure and produce "flat" may not be so at all.
Remember Columbus
OK, be gentle on me I'm old and frail
