Chinese made units have somewhat rougher edges, but you won't tell until you touch a Euro AKG. Build quality is so-so regardless of origin.

I haven't tried to build myself a headamp for a decade. A decade of poor sound it was. Pure class A drains batteries too fast, so I need a good linear power supply asap.

Regarding smaller head fit: I had my kid hanging around my working place. Eventually he borrowed my headphones and K712 fit him perfectly. His head circumference is around 53 cm (20,5"). Plastic tube wasn't used this time. Regarding build quality: I have noticed some low end inconsistency on...

Here you go: A piece of stiff plastic/rubber tubing, cut longitudally, then clip it here: One piece holds a side well enough. You may also try padding the headband.

I tried the mod on K712. Lots of deep bass, the everything seems cleaner and bigger. Very impressive with electronic music (i.e. Infected Mushroom - Groove Attack) and metal (Ihsahn - Disassembled). Stereo effects, definition - it's all there, just bigger and more powerful. True basshead...

I tried to replicate you setting. My EQ has different bands, so the actual setting is a bit different from yours: 31 Hz: +4 dB 62 Hz: 0 dB 125 Hz: -1 dB 250 Hz: -1 dB 500 Hz: 0 dB 1 kHz: +1 dB 2kHz: -1 dB 4 kHz: +1 dB 8 kHz: -1 dB 16 kHz: +1dB The diffrence is subtle (as the settings are), but...

Theory aside: the mod makes sound bigger and cleaner. I doubt that I would be able to EQ that. Lower bass is a bit on "too much" side, but added weight is worth it. I'm currently using slightly thinner foam rings in order to avoid too much low midrange boost. Thicker rings + port mod make bass...

At least this one: Directly refers to K712. @chicolom extrapolates his experience to other *7** models and I can't see anything wrong here, since they all share a similar construction and similar (if not identical) drivers. The newer models (Annie, 712, 7XX) not only have better bass...

The question was already answered, here the discussion begins: https://www.head-fi.org/threads/the-akg-k712-pro-support-and-impressions-thread.659251/page-126#post-9878206 please note what @chicolom says. I'm starting to feel a bit tempted, since the mod only affects the lower bass region.

K712 do have a deep, tight and prominent bass right out of the box. Uncovering the port would likely turn them into a bass monster. I strongly advise to let them grow on you before attempting any modifications, just make sure that you have a decent source and amp. Please also keep in mind that...

Richard Barbieri - Planets and Persona Isn't my favourite nor is a test album, but it's a great work of art of creating sounds and a pure joy to listen on higher fidelity equipment.

If you ever feel like your K712 lacks a bit of body and smoothness you may try a simple mod: The ring was cut from a CD sleeve. It's a thin non-woven fabric. It boosts lows and mids a little bit, making high-mid peak less obvious. You certainly don't want to overdo this mod, as midrange can...

I hope it helps. The diaphragm returns to it's original shape immediately.

I have just solved the rattle issue. A coil wire seemed to touch the diaphragm suspension. I've gently pushed it down with a toothpick and now the rattle is gone.

#039371 here. Huge headband - bigger than K501 and much bigger than K612. Overall frequency response resembles me Etymotic ER6 (my long-time portable favourite). Definitely not too much bass, but you'll never miss a low note. Very crisp treble requires getting used to. Soundstage isn't perfect -...

It's OK, since system volume controls E3 amplification and doesn't affect digital audio signal coming from USB.

Here's the K612 with pads twisted off and foam removed, please note an uneven lower left edge of the diaphragm. That's the excessive glue. It's clearly a factory defect, but, since it doesn't impair listening experience any more, I don't bother. I could only clearly see diaphragm distorting...

Inner tape lining has been undone today. It turned out to be bad for headstage/imaging.

@DavidA, 50DN sewer pipe end caps can be purchased in a plumbery store. Longer air chambers (I believe the optimum is around 1") produce a resonant peak that sounds natural to a human ear.

Just found a replacement for Prestige Series housing front piece. Perfectly fits driver, cup and cushions: Requires some cutting, but allows a greater housing extension.

The mods are applicable to modern AKG's as well. They still share similar construction. The latest 6(7)12 Pro's don't need bass extension trickery, but may benefit a bit from damping and would accept lid lining gratefully.

Addressing to the famous AKG *01 2,5 kHz spike I never admitted to exist... I finally admit it. Measuring K501 rear lid inner size shows that it's tuned to produce a peak between 3 and 3,5 kHz. That averages to about 3,25 kHz, that's about 7% less than the target of 3,5 kHz I'm usually referring...

The resonant ring boosts a narrow band around (340/diameter/2) Hz (speed and sizes all metric). It won't look good at CSD plots but it will sound good to human ear. I was referring to Tyll Hertsens' target curve that's peaking sharply at 3.5 kHz. A ring with inner diameter of 49mm is a good...

@MorrisVentus I did already share my experience regarding the rattling. I do think that's a QC issue and IME it's curable by burn-in. You may do a visual check: just twist the cushions off, remove the foam disc (if there is one) and look for excessive glue on diaphragm perimeter. You may also...

I'd love to share one of the most efficient T20RPmk2 mods I've ever done. I got the idea from observing various AKG headphone internals. You probably know those funny headphones with huge headstage and lots of internal reflections: This little plastic ring brings in loads of upper mids. So...