Open back headphones

Open back headphones
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Yesterday i had a pretty mad experience so i thought i would share .
My room is pretty well treated with 80 panels and bass traps from floor to ceiling.
Part of the room has a sloped roof one side as its a loft extension and i usually are sat under that ,the slope has acoustic panels also. Well i had a move around and come more out into the middle of the room. After i had got myself set up i put on my AKG 701 phones and played a mix i had been working on, MY GOD they sounded like someone had strapped a pa to my head, I could hardly believe they were the same phones .I suddenly realised it was because i was in the middle of the room and the room was changing the sound massively. I definitely learned something yesterday .So now if i hear anyone say that mixing in phones takes the room out and no need for acoustic treatment i can say think again buddy when it comes down to open back phones.I still also think the room treatment was contributing to the sound of them phones .My next question to myself is how much it would change the translation .It was definitely an eye opener yesterday so thought i would share my findings

That’s interesting! I can’t compare yet because I wont be rebuilding my studio in this house for an other couple of months, but I have the same AKG 701 cans so I can try this with a laptop in several rdifferent ooms. I’ll let you know the outcome.

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There’s a distinct difference between closed and open headphones for sure. I have a few DT 770 pros, a 880 pro and a 1990 pro and switching from the closed version to an open one feels different. However I’ve never experienced a massive difference like the one you are describing. Given the low acoustic pressure of what’s leaking outside of the headphones (and non existing low end) it shouldn’t be that drastic.

Side question:

How freaking big is your room?..

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It was massive.The room is not even very big ,about 5 m by 6 that’s all
Those panels above my head was certainly making a big difference

I was told that open back headphone responses depend a little on the environment around you because they are open. Wasnt sure how much… guess now I know lol.
Closed back like slate vsx its not a huge issue. They sound the same nearly everywhere

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I was gobsmacked myself at the difference. And the volume and bass difference was really big.It also felt like someone had added a sub

So let me make sure I understand correctly. You are listening to a particular piece of music on your headphones in your room and when you move toward the center of your room without changing anything else than your position, the low end becomes massive?

Technically that shouldn’t happen. There is virtually no low end leaking outside a pair of headphones, especially when they are placed on a human head with the ear cushions tight around the ears. The only way you could have some low end leaking is by cranking up the headphones really loud but then your ear drums would be overwhelmed by the direct sound from the drivers and wouldn’t pick up any of the room (or most likely be blown anyway). The low end from headphones can’t interfere with the room, only the mids and highs can, but in a very small proportion.

You can verify that by yourself quite easily: in a silent room, play music on your headphones but don’t wear them, just keep them close and move around. Are you experiencing a significant change in low end? Pretty sure you aren’t. Why would this be any different when the headphones are on your ears?

Sorry for asking this but are you 100% sure you didn’t unmute your monitors while you were listening on headphones? That would cause pretty much what you described.

5x6 m is a nice size for a home studio. However, you can’t fit 80 acoustic panels in such a room (unless you pile them up lol), so I’m guessing you are actually referring to square foam panels?

It happened guaranteed just as i said,yeah the small panels, 80 sounds a lot but they don’t go far

In theory it is possible since open back headphones are pretty much “small speakers” . If you live in a really quiet area and your room has room modes around those frequencies, they can still double back and get enhanced.

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My head was only about 24 inches from the slope with the panels originally .Now its about 3 or more feet and a flat ceiling with far less panels .It was night and day

I have to disagree with your statement, even though they are small speakers they operate very differently. I’ll try to explain why by using a comparison with normal loudspeakers.

Compared to the really tiny volume of air that the headphone drivers have to move inside the ear canal, loudspeakers (even small ones) move a huge amount of air. The difference is logarithmic (sound pressure measures in dB which is a logarithmic scale) so it is way larger than the difference between the size of the loudspeaker cone and the size of the headphone driver.

To create a pressure wave, a loudspeaker cone must be large enough so that when it pushes forward, the air in front of the cone quickly builds up pressure, instead of escaping to the sides of the cone. Headphones operate in a different way: they rely on a closed tunnel. There is very little air escaping and your eardrum is basically coupled with the driver. But as soon as you take the headset off, it gets de-coupled and the efficiency in the low end drops drastically.

Just try it for yourself: set the volume as loud as you safely can while wearing the headphones then take them off of your head and move them away at an arm’s length (about 25 inches). Can you hear the low end now? No, it sounds like there is a high pass filter somewhere around 500-1k Hz. If you can’t hear the low end at all from that distance, why would a wall, which is farther away, be able to reflect it, let alone with enough energy that it is still able to make a “massive” difference once it reaches back to your head when wearing the set?

My point is, the amount of low frequencies that propagate at a distance from headphones is ridiculously tiny and can’t be the cause of what @takka360 described. I’m not saying it didn’t happen, of course it did. But I’m pretty sure that the interference of the headphones with the room is not the explanation here. I don’t know what is, though.

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Now that’s interesting, it is unusually close. I guess if the low frequencies were able to leak from the headphones they could bounce of the nearby wall and somewhat phase cancel with those that go directly into your ear, but I still think it is too far away for the low end to actually be reflected back with any significance.

I’d be curious to know what happened exactly. Are you able to reproduce the problem?

At least it’s fortunate that it works in a way that is favorable to you in your new position.

I know 100 percent it was something to do with moving away from the panels above my head and because they were so close .The acoustic treatment definitely has something to do with this and i would put money on it.

Well if it is the case then you should be able to reproduce this phenomenon without actually wearing the headphones right? The alleged interaction is between the room and the headphones, not your head. So why don’t you place the headphones in the same position, keep your head close, and move both the headphones and your head until you hear something happening?

I will experiment with that

Let us know how it goes, this is really intriguing…

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I dont have those headphones but I have seen the response from Audeze open back headphones. They are fairly loud all the way to low mids. Just barely enough for low mids to react with walls within a couple feet. 24 inches to 3 feet as op describes would fit the bill for weird responses in 400 to 650hz area approximately.

It is intriguing for sure.

I just tried it again .I sat in my old normal place and got up and walked out into the middle of the room and today i didn’t seem to notice the bass as much as before but the image got wider and not as tight sounding and seemed slightly louder, just bigger sounding .I tried it holding the phones and walked with them but couldn’t really tell that way .I’m pretty sure its the panels on the sloped roof its cant be anything else .It is a very dead spot it seems under the slope.I would take a picture but my phone camera no longer works after the screen was changed

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The response graph isn’t meaningful in this situation since it is only applicable to what is actually heard by the user wearing the headphones. There are no response graphs that show what is happening in the room, since listening to music played on headphones from a distance is not actually a usual consumer need :crazy_face:

By the way did you know that the frequency charts we see for headphones are actually compensated? Manufacturers usually don’t show the raw frequency response because it is not flat at all: the headphones are tuned to account for the physical shape of our ear, which emphasize some frequencies (most notably between 2 and 9 kHz).

Just barely enough for low mids to react with walls within a couple feet. 24 inches to 3 feet as op describes would fit the bill for weird responses in 400 to 650hz area approximately.

OP mentioned

So we’re not talking aout the same frequencies. Besides, room modes can only happen up to 200, maybe 300 Hz at most. Any higher, the distribution of the energy doesn’t allow significant build-up or null so that can’t explain what happened.

Which leaves us with an unsolved mystery! :ghost:

How thick are your panels? An absorber panel can only absorb frequencies whose wavelengths are greater than 1/4 of their thickness. Do the math, it would take a very thick panel to actually have any sort of influence over the low end (hint: a 100 Hz wavelength is more than 11 feet / 3,4 meters). This is probably not what you have, is it?

I guess it would be interesting to take measurements in your room with REW and a measurement mic (if you have one).

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I really cant be bothered anymore mate to be honest. I know what i heard i live in these headphones and had them 8 years .I know its them panels with my head real close to the sloped roof.The whole slope is covered in panels not even 24 inches from my head probably only 18 inches .it deadens them phones more 100 percent .

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