Do we REALLY want a flat response? (1 Viewer)

[jeff lam]

Sorry Vince,
I missunderstood your post. I understood it as you were saying that a house curve isn't nessasary and a ruler flat response is ideal because a human engineered it and the human ear compensation has already been accounted for.

Which is a valid point but when my system was set up this way (ruler flat), it sounded weak! The lower frequencies were clearly much softer than the midrange/midbass frequencies.

 

[Dave Koch]

This is a very interesting discussion... I had a thought to add:

Remember that the materials you're listening to were prepared by a human being. Therefore, the curve of human hearing is already built into the material.

Yes.... at the VOLUME LEVEL it was mixed at.
I think a point that might have been overlooked here from the original post is that we are less sensitive to Highs and lows (compared to mids) as volume decreases.
So, yes, I can see wanting a flat response AT 75 db or whatever you ref your system to.
BUT would it make sense to have a non-linear volume control (probably not the right word, but I am using it!) What I mean is, as you take the volume down 10 db, maybe the highs and lows are only taken down 9 db or something.
I am sure this is all very impractical... but it was just the thought I had while reading through all this!
BTW, I do know that I do adjust my SUB + 1 or 2 db when listening at lower levels (and have for some time.... maybe I am ahead of the curve!

 

[Stephen Houdek]

Lets not forget our hearing isn't equal either......Some have far more sensitive and wider range hearing than others.......Take a hearing test sometime and you may be surprised at the range of scores for different frequency ranges.

Some folks are nearly deaf above 10K and the high frequencies drop off significantly for most people as they age.....Something to keep in mind. Perhaps speaker manufacturers can start a marketing campaign for the geriatric crowd....

Next time you buy a set of speakers think about it....It may not be the speakers......It may just be you're now officially an old fart.

 

[Kevin C Brown]

For instance, you could add an equalizer into the signal chain and get the flattest frequency response you want, but this would probably negatively impact the system's phase response.

I guess I implied proper phase. In other words, why go through all the trouble of trying to get to a flat frequency response in your environment, if you wouldn't also properly adjust the phase between all your speakers, and between all your speakers and the sub?

And, IMO, plotting the freq response below, through, and above any crossover's (at least between separately adjustable drivers and speakers), is the best way of properly adjusting phase. I've tried the signals on Avia, S&V's disc, and VE, I couldn't do it by ear. Show me a graph of discretely measured values? Piece of cake.

And yes, freq response of course needs to be considered with other parameters that not many magazines publish any more. Impact response, distortion, ringing, shoot there are more, but not coming to mind ATM...

 

[Rich Kraus]

since ive been pointed to this topic and its one of my favorites....

we all agree that video has a standard (color temperature, brightness, contrast...) that should be calibrated to.

when we get a piece of video software that has poor black level we call it what it is, a flaw in the software, we dont immeadiatly reach for our brightness level.

audio on the other hand seems to be an all together diffrent story. what are the refrences? now for me its 80/20 movies/music, so my system is calibrated to be as flat as possible, at my refrence level volume (about 10dB below dolby refrence level.)

if i get a piece of source audio that is bass heavy or overly bright (as was sighted above, yes i have cd's like that too) i consider the problem to be the source material, not a deficency in my system. we have ALLOWED the studios to send out flawed material (with no apparent standard for response) for years.

...more later...

 

[Vince Maskeeper]

Kevin- I think the poster was referring to phase shift from using a equalizer.

This does not make on speaker "out of phase" with another- rather all EQ devices are known to create a "phase shift" in certain bands with their filtering. This is the issue that makes the question of using an EQ a sticky one for some people- you can certainly balance the system flat within a DB- however extreme use of an EQ will have an negative effect on the over sonic quality of the signal.

-V

 

[Mark Seaton]

The problem here is that everyone is talking about a flat display on an RTA. Unfortunately there are many ways to measure a system, and an RTA integrates all the direct and reflected energy. Mostly flat response from the direct sound does in fact sound quite good, if you then consider the reflected energy to know which direction to err. With total energy, listeners tpyically preffer a downward slope on an RTA which approximates a pink noise response. What and how you are measuring can make a world of difference. Again, it is a mistake to get too caught up in the shape of the F-M curves, but it is the DIFFERENCE in the shape of the curves which is significant.

 

[Saurav]

And, IMO, plotting the freq response below, through, and above any crossover's (at least between separately adjustable drivers and speakers)

Agreed. However, what about the crossovers that you do not have control over? That's basically what I'm trying to say - everyone knows about frequency accuracy, so they buy speakers which are frequency-flat. Very few people know about phase accuracy, so no one cares to check a speaker's phase response before buying it. In the end, I could end up with a speaker that's less frequency-flat than yours, but more phase-flat. Since nobody measures phase, everyone will tell me that I'm intentionally choosing a colored sound to suit my tastes, I don't like accuracy, blah blah blah. In reality, my speaker may be the one that's more accurate, when all parameters are taken into consideration
Just something to think about, IMO...

 

[Kevin C Brown]

Saurav- I actually agree with everything you just said! And, that's why I am now the proud owner of Vandersteen 2Ce Signatures (since 2 weeks ago). Wanted to try a pair of phase correct/time aligned speakers myself. (Switched from bipolar Def Techs. Mated with a Vandy V2W sub.)
Takes a little longer to set them up to get the right imaging, but man, what a difference. The "wall of sound" from the Def Tech's is gone, but there's a lot more nuance, subtleness, and depth to the music.
Once you fall on to the slippery slope of phase and time alignment, unfortunately there are not a lot of designs to choose from...

 

[Saurav]

Once you fall on to the slippery slope of phase and time alignment, unfortunately there are not a lot of designs to choose from...

This is one of those "sad but true" statements. I've heard Vandersteens, though not extensively, and they definitely sound more 'right' than many other speakers. Like you said, once you hear phase/timing done correctly, your ears are opened to what the others aren't doing, and it's hard to settle for less.

 

[Stephen Houdek]

Saurav,

I technically understand what you're saying and it makes sense.......

A couple of questions, how does one measure the phase at frequency X and then compensate for these differences across 5.1 speakers? What is an acceptable sample range of frequencies to measure? Every 10Hz? 100Hz? What is the typical phase variance of an average HT setup?

What is the obvious result when everyhing is phased properly? Is it like the upsampling setting on my Onkyo that makes no difference to my ear? Or, is it more dramatic? Is it one of those things that is only readily apparent on certain types of recordings?

 

[Saurav]

Is it one of those things that is only readily apparent on certain types of recordings?

Again, hard for me to say. I don't have that much experience with phase coherent speakers to know what effect they'll have with different kinds of music.

 

[Chris PC]

You want most of your equipment to be able to reproduce a flat curve, but then allow for adjustment from that flat point. Not currently in vogue, are equalizers, but they mess up the sound a bit. Loudness curves help. Remember, that your room should boost the bass quite a bit, and then its just a matter or boosting the bass with a tone control to taste. Usually a properly calibrated subwoofer matches with room gain so that the result is a very good seemingly 'flat' response. While a rooms response is anything but flat, what I mean to say is that it does not have the low frequency drop off that you would expect given the low end hearing response mention in the first post.