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Skeptico Saloon: An Objectivist Joint - Page 42  

post #616 of 1671
Quote:
Originally Posted by mikeaj View Post
 

 

I'm not sure if I'm reading you correctly either, but if the focus is just on missing bass response through the body, that's a separate issue (not what I'm talking about). I'm talking about response at the eardrum. You can read about the so-called "missing 6 dB effect" from headphones not giving you bass response through the body in various papers and discussions. Some people think it's valid to compensate on headphones by boosting bass; others don't and say the lack of bass felt through the body is how it is with headphones and can't / shouldn't be addressed. I'm sure there are other thoughts on it too.

 

 

I haven't fine read the reports, but wasn't this basically what Sean Olive and Harman found through their studies?

Other than that, what you are saying about our anatomy colouring our response to sound, and that headphones bypass some of these features, are basically what I was trying to get at.

post #617 of 1671
Quote:
Originally Posted by limpidglitch View Post
 

 

I haven't fine read the reports, but wasn't this basically what Sean Olive and Harman found through their studies?

 

Hm, I don't think so. Or rather, the suggestion is that a little extra bass is correct, but not for the reason you state.

 

The hypothesis is this:

Quote:
 Since stereo recordings are optimized to sound best through loudspeakers in rooms...

.. stereo recordings will sound best when reproduced through headphones that simulate the in-room response of a well-designed loudspeaker system calibrated in a reference listening room.

 

and see this:

Quote:
Typical listening rooms are neither diffuse nor free field but somewhere in between, containing both direct, early and late reflected sounds Listening rooms provide bass reinforcement from standing waves and boundaries effects that are not accounted for in the diffuse and free-field target responses Therefore, headphones calibrated to DF and FF target responses will sound too bright and too thin in the bass.
post #618 of 1671

Ah, room gain. Gotcha.

post #619 of 1671
Quote:
Originally Posted by limpidglitch View Post

I'm sure you are aware of the corporal effect of low frequencies, how they're picked up by your body and travels through flesh and bone to your auditory system. This is mostly conjecture, but it seems reasonable to assume that different body types do this in slightly different ways. Big vs. small, short vs tall, fat vs. muscle etc.

The way I evaluate bass is to put on music with descending bass patterns. Reiner's Marche Slav is great for this. I listen for spots where a bass line that should be even all the way down suddenly becomes louder or softer. I even those out and with speakers, I have to finesse the handoff at 80Hz between the mains and the sub.

When it's smooth, then I balance the relative volume using orchestral music... making sure the bass doesn't stand out in front of the higher frequencies. Sub bass, bass, upper bass, lower mids, mids, etc... all hands off to each other smoothly.

Once all this is done, the corporal element you talk about should just fall into place naturally, but there is one more thing you need to do with speakers. Rooms have their own resonant frequency in the sub bass. You'll find a particular bass note that will make the walls shake. A quick notch right there fixes it. The lower the frequency the less EQ matters. At some point, bass stops being a musical note and becomes just rumble. The last octave or so just has to be balanced in overall volume, not so much for EQ. (the same goes for the last octave at the top end.)

With the Oppos, I was amazed at the bass, because it seemed to be perfectly balanced with all the other frequency ranges and the handoff in descending runs was perfectly even. I tried a few corrections, but ended up erasing them after listening to other recordings. I've never seen anything like it before. Usually the bass isn't that controlled. When my buddy ran tones on it, he started at the bottom and started working up octave by octave... no corrections. He determined that they were stone flat from 28Hz all the way up to 1.6kHz. That is a huge chunk of sound to have absolutely perfect!
Edited by bigshot - 4/7/14 at 4:45pm
post #620 of 1671
Quote:
Originally Posted by mikeaj View Post

No, this is not true. Let me back up. Why are all relatively neutral headphones actually balanced roughly like this (raw response)


with the huge treble spike 2-4 kHz or so? That's because strapping speakers to your head essentially bypasses the gain of your ears that they naturally have (based on the shape) when sounds are coming from a distance. Hence, you need to compensate for that missing anatomical gain  by boosting the headphone response accordingly.

That graph is made using a microphone, so you have to apply a correction curve. If you determined the response by ear using tones, the sound of the tones would be even all the way across... no correction needed.... measured flat vs audibly flat. If you graph audibly flat, it's a straight line- correction built in.

I always EQ by ear, so Fletcher Munson and ear canal shape doesn't matter. All of that is already incorporated into my hearing. Simpler that way.
post #621 of 1671
Quote:
Typical listening rooms are neither diffuse nor free field but somewhere in between, containing both direct, early and late reflected sounds Listening rooms provide bass reinforcement from standing waves and boundaries effects that are not accounted for in the diffuse and free-field target responses Therefore, headphones calibrated to DF and FF target responses will sound too bright and too thin in the bass.

Again, if you tune by ear, all this is built in to your normal human hearing. The baseline would be audibly flat, whether or not a microphone would measure it as a flat line.

It's really SO much easier to EQ by ear. It removes a lot of guesswork and theory and arguments over what correction curve is right and what is wrong. You use your ear to listen to a tone all the way across and the correction is all built in.
post #622 of 1671

Just to be clear, I'm agreeing you want to EQ audibly flat for yourself. But that it's not necessarily quite as accurate if given to someone else to listen to (on headphones).

 

The original context was the not-quite-so-hypothetical that someone were to release a headphone that ended up with a tuning that sounds flat to you. Now others wonder how it might sound for them. I'm saying that you can't guarantee that it will sound flat for them based on what you heard, even though it sounds flat for you. It'll probably be close or perhaps match even better than that for some others, but there is some error tolerance level or uncertainty due to how these things work. And perhaps more so, if you allow that nobody can tune headphones perfectly at every frequency, and your by-ear tuning could readily be a dB or two off here and there. I don't think you can dismiss a bit of skepticism out of hand, like you could if you did the same on speakers.

 

 

By the way, these days pretty much all the popular planar magnetic headphones are flat from ~30 Hz until the 1 kHz region or so. It's a feature of the competitors too. Apparently with a large enough magnet array and the technology, that's what you get without an incredible amount of effort. It's the rest that's difficult, seemingly.

post #623 of 1671
Quote:
Originally Posted by mikeaj View Post

Just to be clear, I'm agreeing you want to EQ audibly flat for yourself. But that it's not necessarily quite as accurate if given to someone else to listen to (on headphones).

I don't think that's the case. Audibly flat is audibly flat.

If I have normal hearing and I use an equalizer to balance response using a tone, playing music through those cans will sound natural to me and everyone else, even those with less than perfect hearing. I can't say that headphones tuned to flat response would sound flat to someone with a hearing defect... but I can say that it would sound natural... the same as any other sound in the real world through their ears. And that is the goal of headphones. Headphone curves can't be expected to act as hearing aids to correct biological audio imbalances.

The only time that tuning to tones wouldn't result in natural sound is if the person doing the tuning has a hearing defect themselves. When I EQed the Oppos, my buddy and I checked each other to make sure we were both hearing the same thing. The only range we can't speak for is above 15kHz, because our hearing may not be flat up that high any more, but those frequencies really don't matter to music.
post #624 of 1671

IEM and CIEM manufacturers must have it really rough. If the sound is not being affected at all by the user's pinnae or HRTF and going straight into the ear canal, then who knows what people are going to hear. In that case flat to one person could be drastically not flat to another if their ear shapes are drastically different.

 

I am assuming based on the theories expressed here. I am not expert at all.

post #625 of 1671
I would think the closer the transducer is to your ear guts, the easier it would be to control. Speakers are tough because of all the space around them in the room. Headphones would be much easier than that, because there is no space between the ears and the transducer. In ear would be even easier, because you're bypassing the outer ear entirely and shooting the sound straight at the eardrum.
post #626 of 1671
Quote:
Originally Posted by darinf View Post
 

IEM and CIEM manufacturers must have it really rough. If the sound is not being affected at all by the user's pinnae or HRTF and going straight into the ear canal, then who knows what people are going to hear. In that case flat to one person could be drastically not flat to another if their ear shapes are drastically different.

 

I am assuming based on the theories expressed here. I am not expert at all.

Either:

1. they use an averaged HRTF, which does not apply to everyone

2. they use an 'expert' who 'tunes' it to their ear (not yours)  without a good reference

3. They string parts together and stick them into a housing and sell it to some poor fellow

 

However, the expectations of IEM users are low enough that 3 is considered an acceptable practice.

 

The deviation in HRTF is not really that big - Hammershoi and Moller in 2008 looked at a whole bunch of studies with 10-50 people measured, and they were pretty consistent below 2khz, with a standard deviation of around 3dB at most.


Edited by higbvuyb - 4/8/14 at 5:19am
post #627 of 1671
Quote:
Originally Posted by bigshot View Post


Again, if you tune by ear, all this is built in to your normal human hearing. The baseline would be audibly flat, whether or not a microphone would measure it as a flat line.

It's really SO much easier to EQ by ear. It removes a lot of guesswork and theory and arguments over what correction curve is right and what is wrong. You use your ear to listen to a tone all the way across and the correction is all built in.

 

How do you refute the premise in this earlier post (the two paragraphs starting from "A flat response out in free space")?

http://www.head-fi.org/t/670056/skeptico-saloon-an-objectivist-joint/600#post_10436276

 

Short version: every person's HRTF is different, so the real-world "baseline" to aim for with headphones varies by person. The "correction" is not the same for each person, so anyone correcting for themselves doesn't necessarily correct it for anyone else. (not by a huge amount but by some whole numbers dB maybe in the treble)

 

If you have the time, I'd appreciate you going through the argument to pick through it, ask for clarifications, and/or point out what's wrong, rather than handwaving the whole thing off. Also, see above post by higbvuyb.


Edited by mikeaj - 4/8/14 at 8:24am
post #628 of 1671

didn't olive&welti's work this last year also show that most people hear flat "pretty much" the same way without regard of age or continent? 

post #629 of 1671
Quote:
Originally Posted by mikeaj View Post

How do you refute the premise in this earlier post (the two paragraphs starting from "A flat response out in free space")?

Oh man! That second paragraph is a doozy! I can't make head nor tail out of that, I'm afraid.

Personal hearing differences and defects are like a personal filter on sound. It colors what we hear the exact same way everywhere... in headphones, in the real world, with speakers... everything. Flat response is flat response. It's what the tweeting of a bird or the roar of a jet engine sounds like in real life. We might hear it filtered through our own hearing defects, but it doesn't change what the sound itself is. When we hear that natural sound, it is always filtered through our personal coloration the same. So if we take natural sound through our personal filter and compare it to a response curve we've balanced through our personal filter, the sound will be exactly the same.

Again... Hand me a set of headphones and an equalizer, and I will balance the sound through my own filter, but I will be aiming at a target that is real life through my filter. The two filters will cancel each other out and underneath my own personal perception, I'll end up with an audibly flat response curve through anyone's personal filter.

People with relatively normal hearing don't vary all that much anyway. A dB difference here or there makes no difference at all. When I was EQing the PM-1s using tones, my friend would do a sweep through an octave and he would hand the headphones to me so I could hear what he was hearing. We both were hearing the same thing. When we were all done, the corrections we made evened out the response and it sounded flat to both of us. We both have normal hearing, so that shouldn't be surprising.

There are people who have a vested interest in claiming that flat response isn't an achievable goal. Most of them are manufacturers who can't build to the tolerances required, or home stereo fans who don't want to expend the effort to do it. Achieving a balanced frequency response isn't something you flip a switch and it's there, and it isn't something you can go out and buy. The only way you can get it is through work, analytical listening and experimentation.

But I can tell you from personal experience that achieving an audibly flat response *is* possible, and once I achieve flat for me, it's flat for all the friends who listen to my stereo too. Music played with a flat response sounds a LOT better than randomly imbalanced too. It really is worth the trouble.
Edited by bigshot - 4/8/14 at 11:17am
post #630 of 1671
Quote:
Originally Posted by bigshot View Post



There are people who have a vested interest in claiming that flat response isn't an achievable goal. Most of them are manufacturers who can't build to the tolerances required, or home stereo fans who don't want to expend the effort to do it. Achieving a balanced frequency response isn't something you flip a switch and it's there, and it isn't something you can go out and buy. The only way you can get it is through work, analytical listening and experimentation.

 

Users of Audyssey room correction and Anthem's ARC may dispute this: it can be bought, and comes standard issue with most current AVR's, with varying degress of accuracy.

 

for the record, I prefer your method.

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