[b0dhi]

Quote:

Hardly. Square wave is made to measure overshoot, control over time, and to some extent transient attack.

All of these things are represented by frequency response. Overshoot is represented by a high frequency resonance. "Control over time" is a vague phrase. As far as it refers to anything meaningful it refers to low-frequency response. "Transient attack" is represented by bandwidth. It does show some additional information, but a CSD or HDP graph is a much better way of seeing that additional info.

Not that I'm saying FR measures everything. Far from it. But a kitten dies every time there's a thread dissecting the square wave response as though it's some mysterious Mayan manuscript.

 

[donunus]

You know theres also another thing people don't take into account when looking at frequency response graphs... In Fact Ive never seen anyone mention it in the almost 6 years ive been here on headfi...

Frequency response is a combination of the sound coming directly from the drivers, reflecting from the inner part of the pads, reflecting from the plastic inside, etc... so even if one headphone is tailored to sound perfect on paper, it does not mean it will sound the best. The headphones drivers might have an extreme dip in one part of the sound but will come out on the graph as being flat due to some inner reflections causing a peak to compensate for the drivers dip in response.

Headrooms square wave response measurements help here because if only reflections were to cause a flat response in an area around 500hz for example then it would show on the 500hz square wave to be totally distorted since reflected energy can in no way spit out sound instantly to create a perfect square wave. This is why IEMs like the se530 is almost perfect in square wave response... You are not getting much reflected energy when the drivers are shoved directly in your ears! Now, In theory you would have to measure a square wave response in as many frequencies as possible to see where the flat response coincides with a perfect reproduction of a square wav to see if all those parts of the frequency response that measure flat are really flat because of direct energy from the drivers or if they are mostly reflections causing a raucousness in the sound. Then add to the equation that the square wave is not just distorted by reflections but also because of a drivers attack and decay capability(speed) then you get into more confusion

With speakers for example, Ive noticed that so many designs are almost ruler flat from top to bottom on paper yet the sonic flavors differ so much from brand to brand. In response to this, I did an experiment. Around 10 years ago, I was looking at the responses of some speakers at first and tried to hear the parts where the biggest deviations from measuring flat are. I heard those deviations and tried to apply EQ using an audio control equalizer to make the different speakers as flat as possible(even used an RTA later on). Once measuring similarly on an RTA, The sonic flavors(house sounds) of the different brands were still their own. I asked myself why? they were already measuring flat!!! After that I heard some magnepan mg1.6qrs and I said wow, these are nice speakers. I then saw Brian Damkroegers review on stereophile and looked at the FR graph. I said whoah, this has got te be the worst measuring audiophile speaker Ive seen on paper as far as Frequency Response goes... then it dawned on me that those so called flat speakers I RTA'd and EQd didnt really come out flat just because of the pure energy from the drivers. It was the combination of the sound of the drivers the box and the room that made them flat which now explains the house sounds not going away even after the EQing. No matter how much I EQd, I was never gonna change the way each enclosure contributed to the sound. With the Maggies, you get the box out of the way... So what you measure is pretty much purely from the drivers and the room. If the maggies measures perfect, we probably have something like the holy grail of audio in our hands but thats another story.

Hope you read through and enjoyed that rambling

 

[MrGreen]

Quote:

Originally Posted by xnor /img/forum/go_quote.gif Marketing reasons? I'd love to see those measurements. About the phase-errors: Headroom says to look at the raggedness of the wave. Do they mean that I should look for how "square" the wave is, or do they mean to look at the oscillation (ringing)? Anyway, ryumatsuba started to publish graphs that show phase shift errors a while ago. Take a look at this: DT770 and HD650 and look at ~50 Hz. HD650 clearly wins. Now let's try to do the same with the =853&graphID[]=713]headroom graph.

For some reason or other, headphones are notoriously difficult to measure with consistency.

 

[stang]

What a great, 6,666th post donunus

 

[donunus]

Thats one evil number 666 and more

Hey 6666... its a flat frequency response

whoops, now with this posted, its got more sparkle in the highs hehehe

 

[stang]

Haha, it all comes together

 

[xnor]

donunus, that's a nice story but there's hardly any room between your ears and the headphone transducer so differences between the measured FR and RTA should be minimal.
Of course, there could be some earcanal resonances in the kHz range..


Quote:

Originally Posted by MrGreen /img/forum/go_quote.gif For some reason or other, headphones are notoriously difficult to measure with consistency.

That's not what I wanted to say with my post.

 

[donunus]

xnor,
just think... the differences of sound when you use different pads... bowls, flats, comfies, beyer pads, pleather to velour, etc... reflective properties, distance, etc... they all play a major part in the measurements of headphones.

For example, with denons... using some jmoney lambskin pads might make the bass response less bloated and therefore measuring flatter but since the distance from the ears is further, The squarewave measurement will also worsen in the low frequencies. Do you see what I'm getting at? If they all meld together to measure perfectly everywhere then we will most likely get a real winner of a headphone!

In unreproduced sound like violins playing, a drill making noise or a truck passing by... It is a combination of the direct sound and the response of the natural environment that we hear while speakers add an extra distortion... Box Coloration or Earcup coloration in headphones(plus hrtf compensation, crossfeed, blah blah blah its complicated).

 

[donunus]

Oh my story about the rta was with speakers. I was using an audio control RTA to eq them.

 

[xnor]

Quote:

Originally Posted by Shike /img/forum/go_quote.gif I'd like to see said measurements, considering off headroom charts the greatest harmonic is -70dB which is less than .5% distortion.

Can't find it right now, but take a look at this:
CAL! (ah-d1001 drivers)
k240monitor
Though I don't know the SPL these tests were made at.

 

[xnor]

Quote:

Originally Posted by donunus /img/forum/go_quote.gif xnor, just think... the differences of sound when you use different pads... bowls, flats, comfies, beyer pads, pleather to velour, etc... reflective properties, distance, etc... they all play a major part in the measurements of headphones.

Why? HeadRoom doesn't mod them before measuring, right.

 

[Bradan]

Quote:

Originally Posted by donunus /img/forum/go_quote.gif You know theres also another thing people don't take into account when looking at frequency response graphs... In Fact Ive never seen anyone mention it in the almost 6 years ive been here on headfi... Frequency response is a combination of the sound coming directly from the drivers, reflecting from the inner part of the pads, reflecting from the plastic inside, etc... so even if one headphone is tailored to sound perfect on paper, it does not mean it will sound the best. The headphones drivers might have an extreme dip in one part of the sound but will come out on the graph as being flat due to some inner reflections causing a peak to compensate for the drivers dip in response. Headrooms square wave response measurements help here because if only reflections were to cause a flat response in an area around 500hz for example then it would show on the 500hz square wave to be totally distorted since reflected energy can in no way spit out sound instantly to create a perfect square wave. This is why IEMs like the se530 is almost perfect in square wave response... You are not getting much reflected energy when the drivers are shoved directly in your ears! Now, In theory you would have to measure a square wave response in as many frequencies as possible to see where the flat response coincides with a perfect reproduction of a square wav to see if all those parts of the frequency response that measure flat are really flat because of direct energy from the drivers or if they are mostly reflections causing a raucousness in the sound. Then add to the equation that the square wave is not just distorted by reflections but also because of a drivers attack and decay capability(speed) then you get into more confusion With speakers for example, Ive noticed that so many designs are almost ruler flat from top to bottom on paper yet the sonic flavors differ so much from brand to brand. In response to this, I did an experiment. Around 10 years ago, I was looking at the responses of some speakers at first and tried to hear the parts where the biggest deviations from measuring flat are. I heard those deviations and tried to apply EQ using an audio control equalizer to make the different speakers as flat as possible(even used an RTA later on). Once measuring similarly on an RTA, The sonic flavors(house sounds) of the different brands were still their own. I asked myself why? they were already measuring flat!!! After that I heard some magnepan mg1.6qrs and I said wow, these are nice speakers. I then saw Brian Damkroegers review on stereophile and looked at the FR graph. I said whoah, this has got te be the worst measuring audiophile speaker Ive seen on paper as far as Frequency Response goes... then it dawned on me that those so called flat speakers I RTA'd and EQd didnt really come out flat just because of the pure energy from the drivers. It was the combination of the sound of the drivers the box and the room that made them flat which now explains the house sounds not going away even after the EQing. No matter how much I EQd, I was never gonna change the way each enclosure contributed to the sound. With the Maggies, you get the box out of the way... So what you measure is pretty much purely from the drivers and the room. If the maggies measures perfect, we probably have something like the holy grail of audio in our hands but thats another story. Hope you read through and enjoyed that rambling

I don't really care how many posts you have, here's my ideology:

No. Flat speakers don't have a house-sound, your house has a house-sound. No they don't sound different. The enclosures are made to dampen the backwaves and prevent them from contaminating the frontwaves with out-of-phase sound. Obviously every coloration of the headphone/speaker must be compensated for in the tuning of the driver. The flatwave problem has more to do with the small size of the driver and through it's small size, it's limited excursion; not enough power or control. Open headphones have very little, if any, backwave contamination because backwaves leave the headphones. IEMs generally reproduce boxwaves because they only need to fill a 1.4cm^2 space with sound, and headphones generally have to play a lot louder for their relative size/space ratios.

 

[pila405]

God, look at the Edition8:

 

[Shike]

Quote:

Originally Posted by b0dhi /img/forum/go_quote.gif Overshoot is represented by a high frequency resonance.

Which isn't reliable on the FR graph.

Quote:

"Control over time" is a vague phrase. As far as it refers to anything meaningful it refers to low-frequency response.

Control over time. Let's say you're running an FR sweep . . . it doesn't spend a lot of time on a single frequency. By using a square wave of a single frequency you can see whether the transducer is able to keep it at a consistent volume linearly. It also gives an idea of mechanical damping and whether the driver is able to recover, if it's too loose, etc.

Quote:

It does show some additional information, but a CSD or HDP graph is a much better way of seeing that additional info.

Alright, since you apparently know what this additional information is then please tell us.

Quote:

Originally Posted by xnor /img/forum/go_quote.gif Can't find it right now, but take a look at this: CAL! (ah-d1001 drivers) k240monitor Though I don't know the SPL these tests were made at.

Looks like an issue with the measuring equipment. Similar results come out of a Stax rig

 

[donunus]

Quote:

Originally Posted by Bradan /img/forum/go_quote.gif I don't really care how many posts you have, here's my ideology: No. Flat speakers don't have a house-sound, your house has a house-sound. No they don't sound different. The enclosures are made to dampen the backwaves and prevent them from contaminating the frontwaves with out-of-phase sound. Obviously every coloration of the headphone/speaker must be compensated for in the tuning of the driver. The flatwave problem has more to do with the small size of the driver and through it's small size, it's limited excursion; not enough power or control. Open headphones have very little, if any, backwave contamination because backwaves leave the headphones. IEMs generally reproduce boxwaves because they only need to fill a 1.4cm^2 space with sound, and headphones generally have to play a lot louder for their relative size/space ratios.

Do you know for sure if all the sound going into the flat measurement is purely from the speaker cones? Does a speaker port not make sound? Dont boxes vibrate? Does a box give good transient response on their own without the drivers? If they dont then isn't the time it takes for the sound to come out of the box vibrations delayed compared to the sound directly coming from the drivers? If you don't get my point then more power to you.

Lets just add another example in the mix.... put a speaker 20 ft from you and another one 5ft away.... Use a digital eq to perfectly match the in room response of both speakers.... So now they both perfectly match each other in frequency response but have a different sound... Why may I ask is that? Its because the sound of the former has a lot more delay than the other. Most of what made it flat in response were sounds created by its environment instead of a more direct sound in the speaker 5ft away. Thats basically all I was explaining in the previous post. Simple logic. I was just explaining it in a way where it relates to everything from headphones to speakers to real live sound.

and Bradan,
Whats with the attitude about my post count? I never shoved my post count to you to give what I said more validity. I'm only sharing what Ive learned so take what you want and leave the rest to others that appreciate what I have to say.