[12v]

Ok, maybe some have read my posts before, and some of you haven't. I am relatively new here... though I have been reading posts on this forum for over 3 years. I have an extensive background in electronics, as well as in the field of audio. My passion is music, and electronics. The key is getting them to work together, but thats another story. My puzzling trivia here tonight consists of two things... "sound stage" and "frequency response"

Lets start with sound stage. Ok when I first started listening to portable, or lets just say headphones.... long long time ago. I was immature about music and how it worked. Now I am well aware of how a system is supposed to sound. Or at least to my ears. But coming face to face with "headphones" i have come to realize one thing that is very important to how we perceive sound. There is no true to life sound stage with headphones. (If i am wrong please let me know because i will gladly come up with the money to pay for headphones that put the sound in front of me)

So sound stage is unimportant in headphones to me but not completely. To be honest with you on how i think a headphone should sound is simple. The singers voice is inside your head. Take th singers voice put it out in front of you say about 8 feet. In real life an actual band playing... where should the instruments be? Reduce that singers voice to 0 feet and 0 inches and basically you have no sound stage lol but thats not true. Basically as long as the instruments are separated, and each are individually easily located along a horizontal, and vertical (tricky) axis. sound stage is ok with me. To sum it up in short words... everything should be "in your head"

On to frequency response a very complicated subject (just take a look at some graphs.) In a perfect world the source should put out a flat signal... meaning a pink noise test signal that has 20hz through 20kzh on it the output should yield a 0db gain or loss at all frequencies. An amp "should" simply amplify that signal making it exactly the same only stronger. again 0db on all aspects of the frequency response. Alot of amps and sources due that... its more of a battery or power issue that causes strain on the lower spectrum than anything... example=ipod

Ok so whats the point of this thread. how should we perceive sound through headphones? I haven't figured it out yet. Im a purist in many ways, dont get me wrong i tend to listen to music that isnt intended to be heard at a purist thought of mine, its just more the technical part of me that hears a poorly recorded song that likes to hear the bad recording. It makes it all the better when you listen to a live recorded track (properly recorded at that) and just listen. Sit back and relax and say WOW. Unfortunately i have listened to a system that has done that. 2 actually. one was a car (yes a car) and one was a high end home system. I am very analytical when i first listen to a system i have never heard before, i close my eyes before the music starts to play. The ears lie less when you don't know what products your listening to. Its easy to sit in front of a live band and see the singer and drummer doing their thing, but to close your eyes and see the same thing through equipment is astounding

So the problem is portable, or personal listening. How do you accomplish a live recording in front of you? I don't think headphones are right for me because of this. Sure its easy to get "" good sound, but not really i guess

I mean for example... my primary headphones are etymotic er4p/s And yes they are well if i had to put it in words, darn good for what they are. Though i think they are a little to aggressive in the upper end of the spectrum, they do everything well. Singer is in front... the drummer is behind. Instruments that are to the left and right where they should be, no bloated bass... yada yada yada. But realistically these are the best that I can find?? i have listened to many... iem's, full cans... name it. Just no good results i have found.

Seriously when are "they" going to come out with serious personal music devices? Its not the source at fault, or the amp... those are easy things to do well.... trust me its easy to design an build an amp to do what its intended for dirt cheap. Whats the problem? headphones. The headphones produce the sound... just like speakers, except phones are on your head and speakers are in front of you.... like they should be.

Why hasn't anyone designed a headphone that can deceptively put sound way in front of you, and put out a frequency response that is true to the recording? It is 2008. Thinking back to 95 on the bus to high school, things haven't really changed that much in this field of audio. I can put speakers in a car and make them sound as if they are far far away, but put on some headphones and the sound is right back in your head.

Guess this is more of a frustrated with headphones thread than anything... don't get me wrong... im am all about portable audio.... I love being able to put on some phones and listen to music. Id just rather listen to music than listen to the things that are not right about it.

Just looking for a few people to reply on how they perceive sound through their headphones and enjoy the music, as apposed to adjusting or upgrading every chance that they get

 

[Uncle Erik]

Quote:

Originally Posted by 12v /img/forum/go_quote.gif Why hasn't anyone designed a headphone that can deceptively put sound way in front of you, and put out a frequency response that is true to the recording? It is 2008.

It happened back in the 1990s.

 

[fordgtlover]

There's a lot more space between you and your car speakers than between your headphones and your ears.

 

[fhuang]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif It happened back in the 1990s.

why didn't i learn this hubby earlier?

 

[ericj]

The truthfulness of frequency response in headphones is a very complex question with no satisfying answer.

At face value, you'd think that a completely flat response - measurably ruler flat - would be ideal. And you can get this in a headphone, but it's not the answer.

Because of the constrained space you're working in with anything short of a 'float' style frame (and the K1000 is just a float taken to extremes), a lot of resonances come into play.

You have to have a dip at about 7200hz because that's right about the neighborhood of the resonant frequency of the ear canal. not having a dip there is what is generally perceived as 'harshness' - people describe these headphones as 'fatigueing'. I've seen the effect called 'ear-burn'. The Sony MDR-V6 is an example of a headphone with this problem.

The resonances of the pocket of air between the driver itself and the meatus of the ear come into effect as well. And it doesn't stop there, either.

On top of that, you've got the fletcher-munson loudness curves. It turns out that perceived loudness for humans is variable depending on the frequency and SPL. Headphones that have a hump in the bass and a hump in the treble sound 'better' at low volume because of the fletcher-munson effect.

At this point, all of the premium headphone manufacturers have come up with general theories of response curves that address most if not all of these problems. "Diffuse Field" equalization for example is an attempt to make headphones sound like near-field monitors in an anechoic chamber. The premium beyers are allegedly DF equalized, and AKG dabbled in this method as well with the K240-DF - an excellent headphone that i recommend to anybody who has gear capable of doing justice to 600-ohm cans.

And in the end it will boil down to preference. Nothing more, nothing less. There is no solution and no answer.

 

[12v]

basically it all boils down to frequency response. Im well aware of the fact that a perfect speaker out doesnt reveal perfect in ear response... especially in a headphone. Its more of a way to tricking your ears to hearing things than anything. Take etymotics phones for example. they took what it appears to be (could have read it wrong i am kinda a.d.d.) a perfectly flat speaker measured it at a distance in ear response, and build a driver accordingly. Results are well a detailed speaker but lets face it. Upper mid and treble frequencies are overpowering to the rest of the system, and bass lacks impact. But maybe thats how a iem is supposed to sound? listen to it and you clearly see that the the bass guitar player is behind the singer, every note is hit. almost seems spot on. Play a bass test cd (what a joke they are) and they hit every note. Play a live track however.... something clearly is off. Hear the singer but where is the band and the bass drum thump. There is just something missing out of it. Grado's i have heard. Though not the top of the line just doesnt sound right. There is just something every time that i put on headphones to enjoy music.

we can talk about resonant frequencies and how the ear canal changes things and blah blah blah, just like a car and a room can have reflective services which cause dips and peaks in frequency response. The truth is there are plenty of great headphones out there. But look at the curves, headphone to headphone, they are very different from each other. Companies make products with a specific sound. whether its a boosted bass response to accommodate for lack of space for impact, or increased mid response to put the center stage in front of the rest of the band, or increased treble to make the ear perceive things in a different way, or whatever.

Truth is things change every inch that speaker moves away from your ear, how it fits on your head or in your ears. Changes with background noise, so many variables to list. But where does a reference come into play? how do you select what you think is best for you without triyng out every headphone on the market. If you know exactly what you are looking for, how is it possible to find the answer to your solution without trying everything out?

 

[12v]

I dont want to make this a long boring thread or anything, just seems to me like this is an ever going change after change looking for the right sound almost got it but want better, sounds great, but no somethings not quite right shoot me now lol.

Ok everyone has a preference on how they want to listen to the music, or how they like it to sound. But where is the reference to realistic sounding come into play. There are various differences to this, but one headphone to the next there are HUGE differences. So what gives?

 

[ClieOS]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif And in the end it will boil down to preference. Nothing more, nothing less. There is no solution and no answer.

^That really sums up this little costly hobby of ours

 

[Seidhepriest]

Those are the Fletcher-Munson curves:

Human hearing is relatively linear in sensitivity at a loudness very close to threshold of pain (house-shaking speakers at a party/club loudness actually, 100-110 dB).

HRTF (head-related transfer function) models also are different for different ears, different locations relative to sound source, and different head shapes even. An ideal headphones' HRTF matches a listener's after calibration with test sounds and equalisation.

Here's a sample HRTF graph:

Out of what Eric wrote, and the stuff noted above, a couple interesting conclusions arise...

One - ideal headphones have to change their frequency response to match perceived loudness at all frequencies. They have to EQ themselves when playing at different loudness.

About soundstage... Ironically, the problem with headphone soundstage was solved some 75+ years ago, by one of sound engineering pioneers, Alan Dower Blumlein. He devised a binaural recording technique with two microphones. He also devised a technique for adjusting two-channel soundstage to match human sensitivity curves, Blumlein Shuffle (originally it was meant for three-speaker setups). Blumlein Shuffle also specifies a crossfeed at certain frequencies (the Blumlein binaural microphone setup includes a baffle between microphones, for frequency separation at midrange, and natural acoustic crossfeed while recording), which helps listening in microphones and creates a more realistic soundstage. Originally it was meant for creating a centre channel for the three-speaker setup (two-channel "stereo" setup is a simplified version of the original multichannel setup that was adopted in 1930s) out of a binaural record.

Waves Stereoimager series of professional plugins implement Blumlein Shuffle. Those are expensive but worth the money.

Also try the Bauer Stereo-to-Binaural software, Bauer stereophonic-to-binaural DSP - that attempts to create a crossfeed for headphone listening and implements some psychoacoustic stereo imaging for headphone listening. Not as smooth and noticeable as Waves Stereoimager+ though.

Players like IPod seldom have powerful headphone amplifiers, which is why there're lots of portable battery-powered headphone amplifiers. CMoy amps are probably the best value for not as much money.

Another problem is (and this is going to risk the trolling and wrath of many CDA fanatics) CD audio. CD audio becomes progressively coarser past some 10-11 KHz. At 11025 KHz there're only four samples/cycle, with everything degenerating into noise towards 22050 Hz (at 22050 Hz there're only two samples/cycle, "top" and "bottom", so there're no different wave shapes possible). Human hearing is echoic, and takes its clues from reverberations. Good speakers (cheap professional monitor speakers made by the likes of M-Audio, Roland, as an example) will always sound livelier than headphones not just because they're in front of the listener, but also because of all the reflexions coming off from speakers and anything that sound from speakers bounces off (room walls, furniture, etc.). They will also make CD audio sound less harsh as the problem with CD audio is its lack of movement at high frequencies (phase information and wave shape are lost gradually as frequency rises) and its killing very high-frequency harmonics, which have time/space reverberation cues.

There're the higher-end digital formats, like 96/24, 96/32f, 192/32, even 192/64. The common mistake is to consider that declared audio frequency range, usually half the sampling rate (e. g. 22050 audio for CD sampling rate of 44100) is actually a frequency range suitable for music. In reality, with CD audio as an example, about the quarter (or third) of this "audio range" is suitable for reproduction of music without coarse distortions (44100 Hz sampling rate/4=11025 Hz audio).

Canalphones like E4 always have an elevated very high-frequency response, so they will usually sound a tad harsh and fatiguing, also by missing the dampening and sound diffusion done by the outer earshells they always sound somewhat too artificial and "inside-the-head". Large circumaural headphones are more comfortable and (usually) sound more realistically.

In brief, get yourself some circumaural headphones, a portable headphone amp for the digital player, try some crossfeed and stereo imaging software (and "analogue" dynamic-shaping too, see SoX in the signature, or Izotope Trash), and try valve amps and vinyl and magnetic tape (maybe open reel...).

 

[Uncle Erik]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif At this point, all of the premium headphone manufacturers have come up with general theories of response curves that address most if not all of these problems. "Diffuse Field" equalization for example is an attempt to make headphones sound like near-field monitors in an anechoic chamber. The premium beyers are allegedly DF equalized, and AKG dabbled in this method as well with the K240-DF - an excellent headphone that i recommend to anybody who has gear capable of doing justice to 600-ohm cans.

Very interesting, as all of your posts are. You just sent me off hunting down more information on the K-240DF... and ended up buying one. Am very much looking forward to hearing these. Thank you!

 

[12v]

thanks everyone for the very informative info posted. As much as i would love to own a full sized set of cans... they are just not for me. Sure i listen to music at home with my iem's infront of my computer every night but I just dont seem justifying the purchase. Im on a different approach to getting the sound that i long for. a portable one, using iem's

if actually listened to a cross fed circuit before, and got interesting results. don't remember when or where, but i just remember the sound did appear to be more in front of me, but it wasn't distant. Left and right sound stage wasn't in your ears but like right in front of them. (best way i can describe) center image was at the front of my nose. That was a long time ago... just didnt sound right to me which is why i haven't looked into it until now.

Maybe I will try that software... but i would also need and eq to use with it. A 1/3 octave eq or better. That would allow me to do all my signal processing before amplification.

So i guess my approach has just changed from speaker choice to simple (if you can call it that) software.

Any recommendations on eq software that is atleast 1/3 octave? i have usb out to my headphone amp.

Ok onward to this discussion on eq. I beleive an eq is necessary in every where imaginable. Unless the environment is perfect. Those who dont believe in eq should read this. Your headphones that you own could put out the best possible freq response... built perfectly, but if they dont fit on your ears perfectly then its not going to sound the same way intended. Everyones head and ears are different.... same pertains to room environment. $80,000 speakers don't sound any better than $200 bookshelf speakers in a reflective environment. Think about that for a minute and you will get where i am coming from.

now take a look at probably one of the best inventions in audio, the audessy eq. available for your car too through alpine's imprint technology. How does it sound? have no clue, haven't listened to it but supposedly it creates a perfectly flat freq response at the seat of the listener. Every thing else is controlled by your ears way of receiving things. So, one step closer to those two worlds... what about headphones? Guess thats not really possible because if you get a perfectly flat in ear response, it not the same as a perfectly flat before ear response. very frustrating this form of audio.

i guess ill just eq the F out of my system to get close to what i want.

 

[jcx]

Smyth Research Virtual Surround Technology

Smyth is demoing at CanJam!

see also Linkwitz
Reference earphones

and the "artifice" of imaging:
Sound Reproduction

 

[pez]

Well when you say that you want to hear where exactly each band member is, that falls into the hands of the recorder. Most bands record one instrument at a time, unless your listening to a live disc.

 

[12v]

Excellent reading material, thanks for the posts!

If more people read material like that and understood it, they would realize why they spend so much upgrading and changing things. On to the negative i have come to realize that a long time ago... which is why I dont spend huge amounts of money on equipment, because they are all flawed in a way. Yeah, some sound better than others.... ALLOT better. But after a while you always long for more after you heard what you thought was the best of the best... but it is far from realistic. Whos to judge what it should sound like when you didnt record it though?

On to the digital world. First of all... the notch filter "linkwitz" post was a good read. But however, the more and more you learn about electronics and speaker behavior, the more you learn that putting things inline with that transducer (speaker) the more you realize that its not the way to go about things. My speakers in my car arent even passively crossed over, there is no way im buying a set of headphones that are! Just my thing i guess. But look into it further you can see where using a passive crossover set of phones ex... superfi5pro's can produce more bass than the single driver etymotic er4's... you have more negative control of things in a way.

Before i go any further because i know i could get way ahead of myself... what im after is a solution to this "audio" fix that we all have, not an answer.

To the main point of what i have personally come up with, after years of not even enjoying my music because there is always a better way to hear things, this is my "" solution.

First off a perfect speaker... Impossible of course, but why cant we get close. I want a single driver, or multiple (actively crossed of course) Resistance should be minimal... there is no need for a 600 ohm headphone (the way i see thing of course

) The key to that speaker is inductance. The less inductance the better.... look up "inductor" and you will see why. The simple inductor in a speaker i Believe is what holds it up the most. We need a speaker in which inductance doesn't effect any part of the human audio range.

Active eq, (the key ingredient) even if you could get the perfect transducer there is no way you could build a headphone that could put that thing far enough away from your ears to overcome peaks and dips in the freq response controlled by your ear canal, since they are "covered up" or "eliminated" by the design of the speakers themselves. What we need is a speaker that converts its analog signal given to it true to the source. Not hard at all to do from the player or amp's point of view... the speaker is the key. Any ways, all we need is a eq that controls the signal digitally before amplification, individually (yes our ears differ, even your left from your right) When we listen to speakers so far away, or a person talking infront of us we dont notice it... but so close to the ear unevenly.... sure there are differences.

Ok so we have a headphone with a flat freq response, not in ear not outside the ear, but just a flat response... which through a sign wave shouldn't be hard to achieve, (Through a complex signal not so much right? lol). Lets get that thing eq'd but how??? Further on lets say we have a signal that was recorded at the mic at flat... convertd and amplified and played through the speaker as flat (thats ideal right) Thats the first question. The second big question is relative to human nature. How do you convince what you are hearing is not actually on your ears, but 8 or 10 or 20 feet away?

is there no solution to that, or is it the simple psychological fact that we know that we have headphones on its impossible to trick the mind that we don't.

I would love to post a results thread or what have you.... truth is i have all of the equipment... except one thing.... an in ear mic. So the big question is, why has no one come up with a speaker, that has a built in mic that can recognize freq response at the source (in ear) and has an adjustable or automatic control "eq"? Even if it wasnt a complete system, even if we had a mic we could atleast measure the freq response in ear and then apply eq to correct the response.

Simple summary of my believes.... A mic records the music. What your ears should receive is the same Identical signal the mic receives period. All other factors are fault of the speaker, and since it is so close to the ear, fault of the psychological effect that we are wearing the transducers. But it is my firm believe that a true to mic playback is the best solution to the problem. Everything else would be personal preference, or a bad recording lol. Then and only then will I know that what i am hearing is what im actually supposed to hear.

So who has the in ear mic/speaker? or audessy headphone?

 

[HiWire]

Binaural recordings.

I have a recent Zenph binaural "re-recording" of Glenn Gould's 1955 performance of the Goldberg Variations by J.S. Bach... it also comes with a regular stereo version and an SACD surround version on the same disc. Since it's a piano recording, you can easily focus on the sound.

You can try it out for yourself and see if it answers some of your questions on soundstage and frequency response.