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Is burn in real or placebo? - Page 11  

post #151 of 520

@foreign: Oh I do have a sense of humor, just didn't recognize it as sarcasm. But I'd like to add anyway, that worn earpads can cause an increase in bass that is NOT desirable.

post #152 of 520
Quote:
Originally Posted by deltawave View Post

Hey guys!
I've been lurking for a while, but it seems this is the time for me to post.
I'm a professional audio engineer and system designer with a background in concert and recording audio along with experience in lighting and pro video engineering.

Now the pro audio section is quite a lot different from the HIFI world, (I'm a HIFI guy when not working), but the headphone burn-in topic has come up in discussion between some of my workmates and I in the past.
So about a year ago we had decided to test the whole burn-in topic and bought some basic Sony MDR-v6's and hooked them up to SMAART (an RTA anyalizer). The way we did this was to use two balanced Earthworks M-30 measurement mics, and a Sound Devices computer interface. We used some studio foam on each side, then stuck the mics into it at ear level, then played pink noise/white noise and recorded what we saw in SMAART. We ran them for around 20 hours between measurements and noticed a change ever so slightly over around 80 hours of burn in.

I won't go into exactly what frequencies were effected, however there was a clear change of 1-4 DB at many separate frequencies, which tells me that the drivers must have changed their response over time, along with their sensitivity at different frequencies.

I hope this helps!

Your friendly Audio dude
Any chance of posting some data?
post #153 of 520

Are you sure there wasn't just a difference in foam, clamping, positioning, etc.?  Was it tested with the drivers cooled down?  I mean, it's not exactly impossible for there to be changes, but just making sure we're interpreting the data correctly.

 

Also, care to be a bit more specific about which frequencies?  If something shifted 1-4 dB at say 500 Hz, that'd be one thing.  If it happened at 9 kHz, that's another.  Measurement consistency seems a lot higher in the midrange.

 

I'm going to guess that the same experiment wasn't run with a control that didn't have sounds being played through the headphones... or not?

post #154 of 520
The headphones stayed in one place through the duration of time we tested them. We ran them for around 20 hours at a time with pink noise, then off for a period of time.
We took our total readings after letting them set for a few hours.

If Ii remember correctly, there was a slight change (+\- 3 db) around 60hz, but the most significant change was the 700hz-1k range where the headphones lessened their output by about 4 db.

I used a balanced set of Earthworks m-30's with a SoundDevices 2 channel mic pre running 24x44.1. Just a basic SMAART setup, the headphones were being pushed by a MacBook Pro with the standard headphone out.

I didn't feel the need to use highend amps/dac's for this experiment because I was only out to see if there was a change in frequency responce.
There was a change, better or worse? I don't know.
post #155 of 520
Also, I plan on trying this test again soon, though it'll be with a pair of AKG k240 Studios.

I don't have the data from the other test (wasn't super scientific, just playing around with some gear) however when i test them again ill be sure to document it well!

It's great to see so much interest in investigating this, it'll give me something to do after work for sure!
post #156 of 520

Would there be a chance you could measure both ears, then condition one of them, then measure both again before conditioning the other ear? Might make for a more controlled test.

post #157 of 520
And calibration documents verified to protocol of all international standards within the last six months........ rolleyes.gif
Edited by Happy Camper - 5/25/13 at 10:42pm
post #158 of 520
Quote:
Originally Posted by jaddie View Post

Would there be a chance you could measure both ears, then condition one of them, then measure both again before conditioning the other ear? Might make for a more controlled test.

while patting your head and rubbing your belly. Remember though that you'll have to steer with your knees so light that cigarette before you start. Pics please.
post #159 of 520

Ok...very funny.  Judging by the reaction, I should have said "earphone" rather than just "ear". I didn't think requesting a control group was such a hilarious request, but I've been wrong before.

post #160 of 520

Both, more or less depending on the headphone being tested.  Please do not share individual experiences in the Sound Science forum biggrin.gif

post #161 of 520

No it makes a lot of sense jaddie. Put the headphone on the measurement apparatus, from here on you shouldn't touch the headphone anymore at all, measure both channels, play sound through one channel for a few hours, give it a couple of minutes of cooldown (you may also measure before cooldown if you're interested in how a heated up driver changes performance), measure both channels again, play sound through the other channel ...

 

Dunno about earphones but with a new headphone you should see differences even in the channel where no sound was playing.


Edited by xnor - 5/26/13 at 4:54am
post #162 of 520
Quote:
Originally Posted by Happy Camper View Post
...
Since the field of science is black and white, let's see a top ten list of songs.

Snarky fun so don't get your slide rule in a twist. wink.gif

 

Hocus Pocus, by Focus

88 lines about 44 women, by The Nails

Da Da Da, by Trio

Song to help you keep your job, by Ray

Basketball Jones, by Cheech and Chong

Eat it, by Weird Al Yankovic

Bohemian Rhapsody, by The Muppets

Always look on the bright side of life, by Monty Python

Detachable Penis, by King Missile

The Bad Touch, by The Bloodhound Gang

post #163 of 520
Quote:
Originally Posted by UmustBKidn View Post

Hocus Pocus, by Focus
88 lines about 44 women, by The Nails
Da Da Da, by Trio
Song to help you keep your job, by Ray
Basketball Jones, by Cheech and Chong
Eat it, by Weird Al Yankovic
Bohemian Rhapsody, by The Muppets
Always look on the bright side of life, by Monty Python
Detachable Penis, by King Missile
The Bad Touch, by The Bloodhound Gang


There is fun in science after all smily_headphones1.gif
post #164 of 520

I cannot believe that people don't hear the difference and think its placebo :(

post #165 of 520
Quote:
Originally Posted by MrTechAgent View Post

I cannot believe that people don't hear the difference and think its placebo :(

 

I cannot believe that in the 21st century people still believe their sensory organs are more accurate than measuring apparatus.

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