[bluemonkeyflyer]

Brilliant!  I look forward to hearing about your results.
 
Quote:

Hey guys,
 
I've also been doing measurements as I build my Thunderpants knockoffs. I'm taking a slightly different approach in that I want my cups to be hot swappable, so that I can have different damping schemes for mood/isolation/weight. And just to have fun with different enclosure types. So I'm attaching the baffles to a DT880 type swivel headband and using a strap for cups.
 
I highly recommend that you guys get a hold of Room EQ Wizard (freeware) and a Panasonic WM-61a mic capsule ($3) to perform measurements. You just solder the capsule to the end of some beaten up earbud cord, short the ring and tip on the plug, and you have an adequate microphone for measurements that will also fit in your ear (inside an ear plug). REW does the measurement sweep and deconvolution for you, and you get to see the impulse response etc. I'm able to get good repeatability with these in ear measurements, and each measurement only takes a few seconds. 
 
I want to get a damping scheme that is as close as possible to flat, according to the in ear mic, to use with binaural reproduction, and at least one more for diffuse field EQ. Maybe many more! My dad is a wood turning so I can order up different cup types and sizes.
 
As I get further along I'll post some pics.
 
I actually have a couple of technical questions for you guys as well. First up - what's a good PC oscilloscope? I want to check my square waves. At the moment I'm generating in REW, recording in Audacity, and looking at the waveform...but Audacity keeps crashing. So far I can't get the square wave to look totally flat at 30 Hz like the Thunderpants measurements at Inner Fidelity, but I can get a waveform similar to to measurement of LFFs pair. (Step rise and roughly linear fall to zero.) I'm wondering about the bass vent. In this case, the bass vent does not work like that of speaker system, right (constructive interference)? It's more like a pressure valve? In that case does the shape matter at all? Thunderpants have a single hole. What happens if that is replaced by a line with the same area (e.g. a thin circumference of felt)? And then the mathematical limit of a slightly porous cup?
 

 

 

[RexAeterna]

i like the whole mic idea as well. i will try that in the near future,but i have a habit tuning things by ear cause i always did that when i was younger tuning guitars and pianos by nothing but my ears so that's how i basically tuned my fostex was by ear to match my 240DF's.

 

[LFF]

Quote:

i like the whole mic idea as well. i will try that in the near future,but i have a habit tuning things by ear cause i always did that when i was younger tuning guitars and pianos by nothing but my ears so that's how i basically tuned my fostex was by ear to match my 240DF's.

Trust your ears. My Paradox was tuned by ear.

 

[rhythmdevils]

I agree.  Ears > mics

 

[Twinster]

I agree that the end result need to please my ears but I found that you need to try so many   Different tracks to get a good idea of the total frequency response of the headphone after a tweak.
 
With a measurement using a full sweep 20Hz-20Khz it's easier to find weakness and apply  a tweak/fix to it.
 
Of course the end result is judge by my own private Binaural mics 

Quote:

I agree.  Ears > mics

 
 

 

[mmayer167]

If it's worth anything to any of you, I found it really counterproductive to make a mod and judge it within 15 minutes of listening. Granted sometimes  you just know right away but if  your ears are like myn they percieve sound differently as the listening session or day goes on. I like to make a mod and if its bad enough i'll go a different route but if it's tolerable i'll give it a rest and sleep on it and re-evaluate with fresh ears the next day. (this method is for those us who dont have a stock pair or whatever to compare to)  This does slow the process down and is hard for us impatient folk but your end result will be better i bet. Also it will give you ideas and re-charge to takle a re-damp if you dont like what you hear.
 
M

 

[SanjiWatsuki]

One thing I noticed about the T50RP mods that Tyll measured was that the ones which measured better with more flat bass often took way more power to get loud, like TFF's mod or the Smeggy Thunderpants. If you're damping correctly to improve the sound quality and bass, you should have to crank the volume more because you're losing more of the sound to the cotton, the Plasticine, the Dynamat, etc, etc. In my random wanderings in this thread, I just haven't seen that little nugget of knowledge mentioned much.

 

[rhythmdevils]

Whatever works IMO as far as ears, mics, ferries, whatever helps get you there.  I think measurements are a cool new tool. 
 
I agree with you Mayer when it comes to your own mods.  I can judge someone else's headphone pretty quickly, but it's different when it's your own creation.  Another thing I have found to happen is that you often get really honed in on a certain aspect of the sound while trying fixing a specific problem, like a peak somewhere.  As often seems to happen when damping, fixing one problem creates another.  So if you fix that problem it can take a while to come out of that focus to notice that you've lost something else in the process.  I took a pair of T20v1 to a meet that I was pretty happy with after a tweak the day before, and people kept saying "the treble is nice, but where's the bass?" 
 
It had been easy for me to get excellent bass from these so I wasn't really thinking about it, I was fixated on fixing the peaky upper midrange and getting clean treble, which I finally had some success with and didn't even notice I'd lost all trace of lower bass.  But when I listened to them again with that in mind, it was pretty clear.  No bass! 
 
 

 

[RexAeterna]

One thing I noticed about the T50RP mods that Tyll measured was that the ones which measured better with more flat bass often took way more power to get loud, like TFF's mod or the Smeggy Thunderpants. If you're damping correctly to improve the sound quality and bass, you should have to crank the volume more because you're losing more of the sound to the cotton, the Plasticine, the Dynamat, etc, etc. In my random wanderings in this thread, I just haven't seen that little nugget of knowledge mentioned much.

yea,they have insane detailed bass and sub-bass to them. i find it not light at all since i'm so use to tight non-accentuated bass from my 240DF's. it just presents the bass way it should and if you want to go nuts to have it vibrate since these can handle lots of power,feed them off of speaker outputs. from experimenting though i think like most planer drivers i think these are voltage driven,not current driven cause i was using them on my ipod last night and even after hour of listening the battery was still close to full. i tried my pioneer monitor 10's on it before and that sucker would drain the battery down within 20 minutes cause they loved current. maybe these do love current as well but from quick observation i think these are actually more voltage dependent overall.

 

[micmacmo]

Quote:

If it's worth anything to any of you, I found it really counterproductive to make a mod and judge it within 15 minutes of listening. Granted sometimes  you just know right away but if  your ears are like myn they percieve sound differently as the listening session or day goes on. I like to make a mod and if its bad enough i'll go a different route but if it's tolerable i'll give it a rest and sleep on it and re-evaluate with fresh ears the next day. (this method is for those us who dont have a stock pair or whatever to compare to)  This does slow the process down and is hard for us impatient folk but your end result will be better i bet. Also it will give you ideas and re-charge to takle a re-damp if you dont like what you hear.
 
M

I couldn't agree more. Some mods just sound wrong and I discard them quickly. But for the others, I have a few musical passages that can be problematic (an annoying ring here, a boomy bass note there, a detail that often gets smeared). A good mod manages to overcome most of these. BUT, the next-morning test is really eye-opening (no pun intended). My perception changes completely (and often dishearteningly) overnight. I've even had mods that I liked but, when I tried to re-create them after further experiments, I just couldn't get them to sound as good as I remember.  
 

 

[kingoftown1]

Quote:

I couldn't agree more. Some mods just sound wrong and I discard them quickly. But for the others, I have a few musical passages that can be problematic (an annoying ring here, a boomy bass note there, a detail that often gets smeared). A good mod manages to overcome most of these. BUT, the next-morning test is really eye-opening (no pun intended). My perception changes completely (and often dishearteningly) overnight. I've even had mods that I liked but, when I tried to re-create them after further experiments, I just couldn't get them to sound as good as I remember.  
 

I'd make sure to listen to any mod you perform at various points throughout the day, since (at least in my case) hearing changes as the day progresses
 

 

[micmacmo]

Agreed. I have to achieve consensus with myself over the course of the day over what "good sound" sounds like.
 
 Ever wonder if the mods are perfect and it's just your built-in auditory instrument that's at fault? 
 
Quote:

I'd make sure to listen to any mod you perform at various points throughout the day, since (at least in my case) hearing changes as the day progresses
 

 

 

[symphonic]

Before I started modding the T50s I took some measurements and compared them to the Inner Fidelity graph. I also have Superlux 668b and Roland RH-50 on hand. My AD700s are back in Germany for now. The shapes definitely look correct. The capsule is flat to within a dB up to 10 kHz I believe, where it has a small 3 dB peak. I found that the capsule already works quite well using the plug-in power of a sound card (+5 V), but I built a little 9 V battery box so that I can have stereo binaural microphones. I'm not sure if I have image posting privileges yet, but I can supply some on-ear curves at some point.
 
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This is an interesting approach, symphonic. I was thinking of doing something similar before, but with the Roland Binaural mics (I forget the model name now). Unfortunately, I ran into the problem that they require plug-in power, which my audio interface can't provide (and the full beans 48V phantom I'm sure would fry them), so I never ended up buying them. Have you tried your measurement method with any stock headphones that someone like Tyll has already done measurements for? Then we can get some idea of how well the Panasonic capsule performs.
 


 

 
I'm essentially copying Smyth Research until I can afford to listen to/buy a Realiser. I snipped off my Walkman ear buds and soldered the mics in place (which are about .5 cm or so), and set them into ear plugs. The mic fits quite far in. I'm using the (safer and apparently more consistent) blocked ear canal approach, but would like to try 'open' as well. I then put the headphone to my ear and sweep. 
 
I have no experience as a musician or audio technician, so I don't trust my ears (yet) for tuning, and I don't want to fool myself. The mics are my training wheels. Also, I'm a physics grad student, so I'm enjoying the experimentation. I'm curious as to how measurable the differences between some configurations are. Overall, one would like to have a lightweight headphone that sounds as good as possible. I'm interested to see at what point wood thickness, baffle weight etc stop playing a significant role.
 
 
I'm hopeful that microphones can be a good tool for those of us without experienced ears - especially those of us building new cups. And it is nice to get rapid feedback about what frequencies various bits of fabric absorb.
 
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I take from your description that you take measurements with the headphone on you head and the mic inside one of the cup? That is genius. 

 That way it take your ear and seal in the equation.
 
 


 
 

 

 

[sphinxvc]

Quote:

It had been easy for me to get excellent bass from these so I wasn't really thinking about it, I was fixated on fixing the peaky upper midrange and getting clean treble, which I finally had some success with and didn't even notice I'd lost all trace of lower bass.  But when I listened to them again with that in mind, it was pretty clear.  No bass! 

Rhythmdevils, were you eventually able to fix the peaky upper midrange and get your bass back?  I'm facing the same issue with my pair.  

 

[Arleus]

Since the capsules are so cheap, I'll probably give this a go too. If I'd realised that decent capsules could be acquired for such a low price, I probably would have got on this sooner! Oh well, live and learn. Could you point me towards a schematic for the plug-in power box? I'm pretty hopeless with electronics if I'm honest.
 
Quote:

Before I started modding the T50s I took some measurements and compared them to the Inner Fidelity graph. I also have Superlux 668b and Roland RH-50 on hand. My AD700s are back in Germany for now. The shapes definitely look correct. The capsule is flat to within a dB up to 10 kHz I believe, where it has a small 3 dB peak. I found that the capsule already works quite well using the plug-in power of a sound card (+5 V), but I built a little 9 V battery box so that I can have stereo binaural microphones. I'm not sure if I have image posting privileges yet, but I can supply some on-ear curves at some point.