Modded Beyerdynamic DT770 Studio (With Measurements)

Edit: Yes, that should read DT770. Dang.

I'm going to keep this brief, as I have a tendency to word vomit (which is why I don't post much).

I'm getting close to finishing the mods on my DT770 Studios, and after getting opinions from friends and semi-professionals I thought it would be helpful to get some hard, objective feedback. Since I don't have a measurement rig I emailed Tyll at Innerfidelity and he was kind enough to do the work for me as part of his headphone measurement program.

I'll limit this to the measurements, quick assessment and few short comparisons, and if anyone is interested I'll share some more stuff.

Quick word about me. I've been playing guitar for 25 years, and I used to work in a public library (and a particle accelerator facility as an archivist) so I'm kind of a nerd/goober. I like rock, jazz, classical, metal and world music. I lurk but stay quite unless I feel like I have something to share, so here goes.



Some thoughts:

Right off the bat I was a bit surprised by the dip at 6-7khz. I admit I aggressively worked to reduce sibilance but I wondering if the distortion (or ringing) showing up in those frequencies might have something to do with that. Regardless, I don't hear it as that extreme.

I do hear the bump at 5khz, which works well with electric guitars but can make female vocals and horns a bit forward at times.

I'm pleased with the relative flat response from 1khz down, considering the original DT770 frequency response and the fact that I'm just using my ears. The wiggles around 60hz-100hz might be from the pads.

I'm chalking up the couple of distortion peaks to the vibration of a few of the materials used in the mod that should be permanent but aren't yet. Variation from left to tight is a goof on my part- last time I closed up the cups I accidentally partially covered one of the ports from the inside of the cup. Oh well.

Impulse resonse is much better than stock. Done before 1 millisecond. Shape looks a bit odd though.

Happy with the 300hz square wave, for the most part. No subsequent peaks and not much ringing, not to mention left and right are pretty much identical, though I'm not happy about the slight right leaning to the leading edge, nor the subsequent blub immediately following. Rest of the wave looks good to me. 30hz could look better. Right side dips to zero and I will admit bass could be tighter and more focused but it's not muddy either, certainly cleaner than the Z1R and the P9. It is punchy and sonorous but it's softer than the LCD-3.

Well that's it for excuses. Comparisons next. This is brief? Yeah, that's why I don't post much.

 

One thing to note is that these comparisons were done after having done a couple of things to correct some of the flaws in my DT770s, mainly bass dip and the 6-7khz dip. The 3-5khz sounds a bit amoother now as well.


Focal Listen

I liked this headphone quite a bit, but with reservations. Listening to McCoy Tyner and the Latin All Stars was fantastic. Lots of air and detail, great instrument separation, good depth to soundstage and instrument timbre was pretty good, though when the flute climbed into the upper octaves the high frequencies were a bit overwhelming. DT770s have better imaging and a wider soundstage, though the Listen seems to have abit more depth. Cymbals are less splashy and have more weight on the DT770s. The Listen had a bit more sparkle, and transients were a little quicker than mine. The Listen is a bit leaner, while instruments sound fuller on the DT770. Bass is pretty good on the Focal, though not as impactful or as sonorous as the the DT770. Mine have a bit softer presentation of high frequencies, with the Listen being more energetic in the region.

The difference between these headphones becomes (almost) painfully obvious when I switch to Hum's Downward Is Heavenward I was greeted with the sound of frying bacon. The roar of distorted guitars I am used to with my headphones was less roar and more screech. It was clear that the ambience and detail I heard with McCoy Tyner was somewhat artificially boosted. I tried Smashing Pumpkins Siamese Dream, which is a bit warmer of a recording than the Hum album, but it was more of the same. There's some sibilance happening here too. With mine, sibilance isn't an issue at all. Treble is smooth, but cymbals ring and decay nicely, snare drum thwaks hard (you can hear the snares and the high hat rattle in the beginning of Cherub Rock), there is still plently of space between the instruments.

Where the DT770s stand out is timbre. Every instrument less like a recording of an instrument and more like the real thing. Everything is a bit more forward, but ambience is obvious and the soundstage is quite wide. I can listen to anything with the DT770 and enjoy the music, even dissect it a bit. I can't say the same thing for the Listen. For instrumental music, though, and for those who want more air and sparkle, the Listen is pretty good.

 

Just a couple of notes for you:

1. Please post more details on what you did to your DT770. Otherwise, it's hard for people to understand where you're coming from even when you post measurements and subjective impressions. The problem mainly is that: you are probably the only person who has access to this modded unicorn thing, and so... nobody can reproduce those measurements or impressions, and they honestly have no idea what you're talking about.

2. Please be careful while reading Tyll's graphs. They follow a very specific response curve. Your DT770 graphs look just about "right-ish" save for a bit of upper bass, or lower mid suckout and a bit of mid-upper treble tizz. Again, you gotta read his graph with a very specific "EQ curve" per se... if you would like to calibrate them toward the various measurements done here. Tyll has meant to "improve" on the compensation curve for ages, but decided against it to preserve the original database of measurements he had. TL;DR: take his graphs relative to one another, but not necessarily to anything here. Also a "straight" line on his FR graph would sound very very shrill and horrible.

3. More details on the mod itself would be nice. Impressions of the mod are welcome but I personally have learned to leave that up to the next person to perform the mod to provide. As the originator of some mods, sometimes I've been under the effect of "mah mod is godly" and so I tend to have a biased view of it.

Oh, and those are just notes, nothing negative against you, man. Please post more details on the mod itself whenever you're ready. I'm looking forward to them! Thanks for sharing things with us!

The DT770 has been one of my long-term projects as well, and I haven't gotten anywhere reasonable with them, so I'm very curious to see what anyone else has come up with.

 

Pics would be lovely too.

I've always liked Beyer comfort as much as I have disliked their sound. Very comfortable.

 

Thanks, Bill-P! I've read a lot of your work on modding- the DT770 diary, the Massdrop article, etc. You and Brent Butterworth were my go to sources for this project. The rest was some wonky lateral thinking and experimentation. I tried to apply the concept of miking speaker cabs to front damping the driver by filtering certain areas and leaving other areas less layered. The diameter and positioning of the shapes play a big part in the final result.

This is a quick and dirty reproduction of the mods represented in the above measurements. This is one of many permutations I went through.



Top Left:
Starched cotton fabric (quilting square)

Top Right:
Double Ply TP (current mod thankfully has none, good properties but subject to humidity and wrinkling)

Middle Center:
Tork Industrial Paper Wiper


Middle Right:
Craft Store Felt

Bottom Right:
Dried Out Parent's Choice Baby Wipes

Cotton fabric is closest to the ear, behind that is the TP, the Tork piece, the Baby Wipe and last the felt. This all sits on top of the ring that holds down the stock black filter, not underneath. Pac Man's mouth points up and to the front (yes, it makes a subtle difference).

On the back of the driver housing is about half a strip of Loctite Fun Tak.


When I have more time I can measure the materials if you're interested.

 

I agree. Two reasons I modded the DT770:

1. It was my first serious headphone. Got it back in 2009 but after awhile I couldn't take the treble. I always missed the bass, though. Bought this version for recording synth. I could easily pick out aliasing and distortion but the treble/upper mids were still too brutal for listening to the kind of music I like.

2. Like subtractive synthesis, I thought it would easier to take away from unwanted frequencies than to try to add more of what was already there. DT770 is a great block of wood to work with, so to speak.

My ears always pressed a bit against the driver cover in stock form. The layers of dampening actually provide a bit of pain-saving cushioning for me.

Here are some more pics, as requested.