Feel free to ask questions. I'll do my best to answer.

Tuesday, May 28, 2013

German Maestro GMP160 part 2

So I decided to modify the housing of the GMP160.  I liked my EQ mod, but it sure would be nice to be able to use these cans for everything without a high powered EQ.  You can see the into to this here.

After about a million mods and measurements, I ended up with this:
Here's my mod vs. the Mad Dog 3.2:

But it's still not good enough!  I think that 8k region needs attenuating.  It just doesn't seem to track well with what I hear.  More work must be done.

Saturday, May 25, 2013

German Maestro GMP400

Loved these cans from the get go.  They have a fairly balance yet warm and revealing/spacious sound right out of the box and they are extremely comfortable.  When I first got the measurement rig working, fairly accurate, and repeatable, I put these up to see what was really going on.
 The frequency response is pretty uneven with 5 dB swings and one very deep notch around 1.8 kHz.  I really didn't want try to EQ this one.  It would require too many filters.  Anyway, I got fiddling with it today and changed every pad I could, turned it into the sealed version (or into a sealed version I suppose), changed the internal damping material, etc...  Eventually I was able to come up with something interesting.

Considerably smoother and consistent response!  IOW, this can now be EQed if I desire.  The best part about this is really the apparent size of the soundstage.  This is now the definition of envelopment!  The down side is an amp is mandatory, but fortunately I have one of those.  What I ended up doing is removing all the damping material out of the cup and adding 6 thin layers of 2"X2" gauze cut into circles.  I'll probably tweak it a little yet, but I am really pleased with the benefits.  Anyway, I'm sure I'll make an EQ setting for this, but the sound of it is fairly neutral now.

Friday, May 24, 2013

Beyerdynamic DT770M

This is my first measurement of these phones:

It disturbed me that the difference in the bass was so large--the left side has ample deep bass, the right side doesn't.  So I decided to do a little investigation.

First I took the headphones apart to measure the raw driver.  You can see I was unable to hold left side tight to the measurement rig b/c the wires are fastened pretty close to the housing and I have no desire to try to solder these again.
From this point forward, the red line will be the right, the left line will be in blue.  Anyway, the raw driver measurement doesn't show anything to be concerned about. Good news I thought.

Next I put the drivers in the housing without damping material just to see what would happen.
Eureka!  There's are bass problem.  So I was hoping it was just some problem with how the driver was seating in the cup.  I removed them both to add the damping material (plus an extra cotton ball), and sealed every potential air leak I could find hoping that the reseating would fix the problem.
Not exactly, but it did remove that 6kHz notch. :)

Ready to surrender for the day, I put the stock pads back on for another measurement to see how it might compare to the first measurement:

The extra cotton definitely changed the bass tuning a bit and changed the shape of the treble response.  I'm guessing the time domain would look a little better b/c of that.

Next I held them loose on the measurement rig to see what effects the seal has.
I contacted Beyerdynamic to see what they think and how to get it fixed.  Let me know if you have any suggestions.  I'm stumped.

Saturday, May 11, 2013

Jawbone Jambox

You see this little device reviewed on several sites around the web and it seems to get a lot of favorable impressions.  I had access to one for a few days and well, I had to see what this little thing could really do.  Let me just say that this is not a great sounding stereo.  It's not capable of the output anyone would reasonably want for great stereo.  That said, it's not horrible and can fit in your hand easily like a juicebox and puts out enough noise for near field listening.  It also has crosstalk cancellation in its circuitry that can be turned off and on by holding the + and - volume buttons down simultaneously for a few seconds.  That's a pretty cool feature!  The depth of field this juicebox can project is mighty provided you are fairly close to it(within a meter or so).  It unfortunately emits some electronic noise--which is a pretty common complaint it seems.  That's the biggest letdown of this device to me.

Putting it on a table, it sounds pretty weak in the low end, but certainly acceptable when on the floor.

Let's have a look at what the measurements say:
 This works out pretty well if you are reading on the floor or playing a video game.  The video games using binaural processing would be really cool.  The depth of sound field and envelopment is fun to say the least.

What if you city doesn't allow you to wear headphones while on your bicycle?  The awesome depth/envelopment made me question what this might sound like from my handlebars.  he he he....  Definitely too bright/thin, but with a little EQ, certainly acceptable if a little quiet overall:
Filters for Accudio look like this:
Filter 1:     20Hz   Gain -15dB  Bandwidth 1.47oct
Filter 2:     33Hz   Gain   -8dB  Bandwidth 1.00oct
Filter 3:     50Hz   Gain -12dB  Bandwidth 0.87oct
Filter 4: 1809Hz   Gain   -2dB  Bandwidth 0.24oct
Filter 5: 3522Hz   Gain   -4dB  Bandwidth 1.36oct

The three bass filter are there just to provide better power handling.  They really don't make any noticeable difference in the sound.

Tuesday, May 7, 2013

Beyerdynamic DT990 600 Ohm

I've always like this set of cans, but they can also sound pretty bright at times.  After measuring these several times, this is what I came up with--the smiley face sound that many people talk about with these cans.  Everyone who has worn these knows they are comfortable, spacious, and are well made.  The 600Ohm version really doesn't get loud enough of off an iPod in general though it's usable.  An amp will make it rock.  This is what my graph shows: 
Here's how the 32Ohm version measured at Goldenears.net:
Headroom measured pretty much the same thing from the 600 and 250 Ohm versions:

You can see they apply some degree of smoothing.
I'm feeling a bit more confident in my measurement rig and procedure now :)

My subjective 'flat' EQ made with Accudio:
Looks a lot like the Mad Dog settings:
And now the Beyerdynamic Custom One Pro setting:

The filter set looks like this:
filter 1:  690Hz     Gain  5dB  Bandwidth 1.02oct.
filter 2:  2737Hz   Gain  3dB  Bandwidth 0.84oct.
filter 3:  3750Hz   Gain -2dB  Bandwidth 4.06oct.
filter 4:  4525Hz   Gain  5dB  Bandwidth 0.37oct.
filter 5:  7294Hz   Gain -6dB  Bandwidth 0.51oct.
filter 6:  8977Hz   Gain -6dB  Bandwidth 0.28oct.
filter 7:  13300Hz Gain -5dB  Bandwidth 0.48oct.

Sunday, May 5, 2013

Beyerdynamic Custom One Pro

This is a popular headphone and for good reason.  It's VERSATILE!  It sounds great out of the box, but it's no fun to leave well enough alone.  This is DIY modification.  The midrange is among the best I've heard.  No annoying resonances, plenty of deep bass, excellent isolation, etc...  For recording, these are hard to beat.  Close the slider for your vocal performance, put it in 2 or 3 for a nice, neutral performance, and open'er up to see what it will sound like in a teenager's car.  It grips your head and lets you know it's there, but it's not overly abusive.

Here's what Beyerdynamic gave me after adding their velvet pads originally made for the DT770.

The third or fourth position give the smoothest performance, but not the flattest.  Hoping for tighter(faster) sounding bass, I chose to EQ the third position.  Decreasing the work your amp has to do never sounds like a bad idea to me.  So I got to electronically reduce the bass and let the physics of the alignment do the work.  Here's how it turned out for my subjectively flat setting updated 05/08/13:

This one requires more filters than my previous attempts, but the sound is worth the effort even if it's not perfect yet.
1st filter:    60Hz       -12dB    Bandwidth: 2.54
2nd filter:   141Hz        5dB    Bandwidth: 0.48
3rd filter:    250Hz        6dB    Bandwidth: 1.39
4th filter:  1000Hz        2dB    Bandwidth: 1.39
5th filter:   1340Hz      -2dB    Bandwidth: 0.43
6th filter:   2300Hz      -3dB    Bandwidth: 0.64
7th filter:   8400Hz      -9dB    Bandwidth: 0.71

Saturday, May 4, 2013

German Maestro GMP 160

My favorite portable headphone with one glaring issue:
Yes, the giant 14dB boost at just a little over 8kHz!  On about 50% of my portable music collection, it's not that annoying.  It may sound a bit bright, but not brutal.  Then there is the other 50% that is totally unlistenable.  That will not due.  These are all  day comfortable and allow me to hear the outside world while I'm walking my dog.  Nearly perfect cans for such activities. The little 100Hz bump sounds about right likely due the lack of deep bass.  It does kick drums justice. :)

Anyway, I decided to do a little REW EQ to see if I couldn't come up with something to iron out think wrinkle in an otherwise sweet set of cans.  I ended up with a filter at 8217Hz removing 14dB with a bandwidth of 0.90.  Here's what that gives your:
Now it's all day great sounding, comfortable, light, and keeps me in touch with my environment.  Perfect for its purpose.

Friday, May 3, 2013

Mad Dog Headphones

Well here's another product that I'm enthusiastic about.  My measurement rig is still pretty rough, but to my ears, This pretty much gets it right.  I can hear where some people may think it's a bit dark, but overall this is easily the best headphone I have heard.  I like the other cans I've measured, but this one provokes no fatigue at all.  Here's what I got on my modest rig:

Just for a reference, this is how Mr. Speakers has the Mad Dog vs. the Audeze LCD2:
My measurements don't look too far off.  That's encouraging.  Audeze's own graphs look similar as well.

Inner Fidelity's measurements also match:
The older version of the Mad Dog:
JUST FOUND!  The newer version of the Mad Dog measured by Inner Fidelity:

You can find those by clicking THIS.

In order to make it subjectively flat to me, I decided to do a little EQ work.  What I found using REW's EQ function and the Accudio App that I could make a 1 band parametric filter at 2685Hz and boost it 5dB with a Bandwidth of 1.29, the 'dark' sound quality was alleviated.  This is just my first attempt at this for these headphones based on my measurements as well as Mr' Speakers.  The result looks like this:

An updated version of this filter to get the treble balance better:
filter 1:  2685Hz  Gain 5dB  Bandwidth 1.29
filter 2:  5800Hz  Gain -4dB Bandwidth 0.15
filter 3:  8000Hz  Gain 7dB  Bandwidth 0.33

New response:

You'll loose 2dB more of output by doing this.  So off of your iPod it may not be a good idea.  If you have an amp, You'll probably not notice.

The best part of this kit is it doesn't sound like you have cups on your ears like so many sealed cans do.  I attribute this to extensive damping inside the cups, but I really don't know.  Whatever the cause, I like the outcome a lot.

Thursday, May 2, 2013

One Step Closer to Headphone Bliss

Last August I got all excited about headphones and wanted to find out "what makes a good headphone" by the measurements.  I found out that things aren't simple.  You can read that little into here.

My first measurement rig was fairly rudimentary.  I've managed to cobble something a bit more sophisticated together now, but it still has its issues.  None the less I got my headphones out and a couple borrowed from friend and made some measurements.

I certainly plan on doing more of these in the future after I make further improvements to the measuring rig.  Messing around with REWs "EQ" feature is enlightening combines with Accudio's EQ app.  Any multiband parametric EQ should be able to get you to bliss with your current cans if you take the measurements the way I did here.  Most enlightening...

Just to add the Mad Dog by Mr. speakers: