Sennheiser HD 800 Redux

[mypasswordis]

Hang on, are you speaking from the position of a headphone designer? No, cause you're not one so shut up. None of us to the best of my knowledge are. All any of us are doing is putting off-the-shelf drivers in a new enclosure or taking off the shelf headphones and designing amps around them. We find new sounds with this effort, but nobody here has designed an actual dynamic driver*.

The headphone designers have a really hard time of it. Its a wonder they can get anything done with having to work in BOTH electrical and mechanical fields. Let the headphone designers do their own thing, their job is already hard enough.

Lack of science? You are out of your fucking mind Straight up insane insulting headphone MFRs like that. The technology in the AKG "varimotion" drivers and how AKG solved the problems they set out to solve is amazing. The ring radiators senn is pushing are a freakish show of knowledge. Beyer is too busy hyping the retarded field strengths in the T1 drivers to talk about anything else, but what kind of shade-tree engineering went into just getting those magnets & coils set up? Ooh, yea, none. They use plenty of scientific methods even when you don't like the results.

The additional effort required to design an amplifier around a headphone with unusual (based on what standards?) drive requirements is a joke.

There are tons of amp designers on this board. Ask really quick how hard it is to make a headphone amp with 120ohms output impedance. Don't let them weasel their way out with the bitch response of "why would you want to" just ask how hard is it? The effort is nominal.

Sorry.

*Apologies to anyone who has actually designed a dynamic driver. If you think your job is easy enough to let amp designers tell you what to do I have a few things I could add.

Do your research and learn some spelling and grammar before your next inane tirade, it'll help you seem less idiotic.

[grawk]

the difference is that ari ISN'T an idiot.

[Dusty Chalk]

Neither is Justin, actually. I do think Ari's tirade was a bit over-the-top based on one sentence. I mean, telling him to shut up just because he expressed an opinion? And not even the one he was arguing with -- Justin said "more science and less voodoo" not implying that there isn't any science or that it's all voodoo, which is what Ari seemed to take exception with.

[luvdunhill]

Ari and Justin:

Please read and comment on this thread.

http://www.diyaudio.com/forums/showthread.php?t=212953

[nattonrice]

I love that thread.

It's a shame that CW isn't around anymore, for memory he had easy access to the same washi that Feastrex use.

Edited August 4, 2012 by nattonrice

[complin]

I think the thing with higher output impedance amps you'll get more interaction with the headphones and you'll find "magic" combinations from time to time. But it's a hit or miss kind of thing, and for makers who want a significant number of sales, making amps with hit and miss results is a dangerous model.

If (when, hopefully) headphone jacks commonly have very low output impedances, the fucking Germans will be able to give up this stupid 120 Ohm impedance that requires them to fuck with their designs, and can build headphones under the assumption that their going to get electrical damping.

I betcha Beyer headphones generally suck almost entirely because of this assumed 120 Ohm output and their acoustic damping schemes in response.

/rant

From Jan Meier's web site

impedance optimisation

The headphone jackets on power amplifiers and receivers are very often directly connected to the loudspeaker outputs. To prevent damage to the headphones and to the amplifier, resistors are placed in between. These resistors generally have values between 200 and 600 Ohm.

On the other hand, radio's and CD-players have headphone jackets that are driven by an opamp and have much lower impedance values (< 50 Ohm) between opamp and jacket.

The resulting output resistance Ro of a headphone jacket has a major impact on the sound. Not only does it reduce the voltage seen by the headphone, it also changes the frequency characteristics of the sound.

The impedance of the headphone is frequency dependent, Zphone(f), and a sinus signal of frequency f will be attenuated by the output impedance by a factor:

Zphone(f) / (Zphone(f) + Ro)| < 1

Generally Zphone(f) has a maximum at the lower frequencies and therefore the attenuation of the lower frequencies is less than that of the higher frequencies. The figure shows the attenuation at various frequencies for the Sennheiser HD600 and the Beyerdynamic DT931 at output impedances of 150 and 470 Ohm. It clearly shows that the lower frequencies are less attenuated than the higher frequencies.

With most headphones, increasing the output impedance makes the headphone sound darker and more muddy (the amplifier loosens his grip/control on the movement of the driver). However, some headphones (like the Beyerdynamic DT931) definitely sound better at 120 Ohm (which is an international audio standard).

If your headphone sounds sharp and aggressive, you might consider increasing the effective output impedance of your headphone jacket. The simplest method is to place an adapter between headphone jack and headphone as shown in the figure. The adapter has a resistor placed in series with each audio-channel of the headphone. The effective output impedance is the sum of the output impedance of the jacket and the value of the resistor

(Ro + Ra).

Note: The value of the resistor should not be higher than 3 till 4 times the impedance of the headphone drivers. Further increases do hardly effect sound.

If your headphone sounds dark and muddy and is driven by an amplifier or receiver, you might try to decrease the effective output impedance. This also can be done by an adapter, but this time the resistors (with value Ra) are placed in parallel with the audio-channels of the headphone. The effective output impedance of the combination of headphone jacket and adapter becomes (without proof)

Ro * Ra / (Ro + Ra).

The value of the resistor should be 0.1 .. 1 times the impedance of the headphone drivers to have a noticable effect. However, be aware that with very low values of Ra your amplifier has to deliver a much higher current signal to obtain the same sound pressure. This might have some adverse effects on sound quality by itself. Also be aware that the resistors should be able to dissipate enough heat!

[complin]

I think the thing with higher output impedance amps you'll get more interaction with the headphones and you'll find "magic" combinations from time to time. But it's a hit or miss kind of thing, and for makers who want a significant number of sales, making amps with hit and miss results is a dangerous model.

If (when, hopefully) headphone jacks commonly have very low output impedances, the fucking Germans will be able to give up this stupid 120 Ohm impedance that requires them to fuck with their designs, and can build headphones under the assumption that their going to get electrical damping.

I betcha Beyer headphones generally suck almost entirely because of this assumed 120 Ohm output and their acoustic damping schemes in response.

/rant

I think this was an international standard agreed among audio manufacturers, so perhaps the Germans aren't to blame after all.

It was agreed in 1966 by ANSI - IEC International Electrotechnical Commission standards. It is standard IEC 61938 Ed. 1.0 b:1996, Audio, video and audiovisual systems - Interconnections and matching values - Preferred matching values of analogue signals

http://www.amazon.com/IEC-61938-Ed-1-0-Interconnections/dp/B000XYSAV4

I believe there was a similar standard for some while around headphones used in recording and broadcasting called the 600(omega) Standard or 600 ohms, which is why many of the professional headphones had this nominal impedance.

When you actually look back through this issue I think probably prevailing headphone impedance has been driven to a large extent by the devices driving the headphones. Crystal set, tube amplifier, transistor amplifier, battery powered devices. Each of these have probably dictated what would be the most suitable prevailing standard. Particularly now we have so many battery powered devices 32 ohm is more the norm to conserve battery power and very small levels audio power.

[RudeWolf]

Aren't you mixing up efficiency with impedance? I was thinking that 32Ohm and less headphones are getting popular because of the fact that most built-in amps have a hard time supplying voltage.

[nikongod]

Sorry I don't write so well. I never have, its been a problem pretty much forever. I suffer from dysgraphia and generally write, read, and edit posts a few times so you guys have a hope of reading them. Sometimes I re-read what I wrote and just say "hunh". Sorry for missing a word.

Ari and Justin:

Please read and comment on this thread.

http://www.diyaudio....ad.php?t=212953

FUUUU that thread is insane in the best way. I understood almost nothing!

Posts 19&20 were great. It looks like dude knows a LOT about magnets, but is going to get KILLED when designing the cones. He should team up with someone who makes awesome cones but uses whatever magnets he can get his hands on.....

I believe there was a similar standard for some while around headphones used in recording and broadcasting called the 600(omega) Standard or 600 ohms, which is why many of the professional headphones had this nominal impedance.

Professional gear is ALL rated to drive 600ohms or lower.

This means that you can plug a set of 600ohm headphones into a spare output on almost any studio mixing console. Since pretty much every studio console ever will put out at least 2v you should get enough SPL with most headphones to satisfy even the head-SPL contest holders on head-fi.

You could plug a set of 2Kohm headphones in for sure, but they may not go quite loud enough to draw blood.

32ohms is risky - not all consoles will drive 32ohms.

The same 600ohm headphones are not likely to hiss when you plug them into that shitty headphone output (a 120ohm resistor tapped off of the speaker amp) on your home stereo. The dedicated headphone amp is a relatively new thing to see in our micro-niche of audio.

Why a 120 ohm output? A long long time ago everything on earth used tubes. The majority tube consoles have output transformers.

Since studio gear must be able to drive 600ohm loads we usually have an XXXX:600ohm output transformer.

Whats the output impedance of that setup? I'l give you a hint... about 120ohms. Maybe 200ohms. VERY rarely less.

Edited August 7, 2012 by nikongod

[bellhead]

Sold my early 9xx pair (too bright, no matter what cable), then bought new 133xx pair, and they are much less bright.

They sound a lot better with tubes, supplying some bloom in the mids and highs and adding some humanity to the sound.

So when LCD3s or other phones pump out some midrange glare on some old crappy CDs, the Senns just hit the spot and squash the annoying peaks (like in vocals).

Wish the image size could be a little bigger sometimes. I like the non-lumpy bass a lot.

[wink]

At the cancon2 meet in Sydney Aus, on Saturday, most who tried my Anax modded HD800 liked them better than the standard.

The real surprise was that of all my dynamic/ortho phones, the consensus was that the best liked were the two AKG K1000's.

http://www.head-fi.org/t/623403/can-con-2-sydney-2012-meet-impressions

[Spychedelic Whale]

In case you miss it: http://gizmodo.com/5949316/ask-one-of-the-worlds-top-headphone-engineers-whatever-you-want

[Tari]

Way to sidestep any question of real import and turn the answers you do give into a chance to market all your new products and be coy about upcoming ones.

[spritzer]

Glad you guys could see how Sennheiser operate. They won't tell you anything without a NDA....

[guzziguy]

... and they'll try hard to steal your headphone stands, too!

[dsavitsk]

I finally bought some HD800s. I don't buy many headphones so this was a big deal. I was talking to someone today, and he asked if the whole cup was the speaker. I then realized that the whole outer shell is supposed to look like a speaker cone. Maybe everyone else knew this, but I had never noticed. They still sound good, but they went from ugly to lame.

 

 

[spritzer]

Well they had to angle the drivers somehow.  I do wonder if they would achieved a better balance by pushing the drivers further away from the ears.  I just did this with a set of HE60's and the effect is far from subtle.  A lot less bright... 

[recstar24]

Whoa nice job Doug. It's a great can, the things it can do and show you should be very helpful in all of your circuit building.

[shellylh]

Nice Doug!

[Tyll Hertsens]

Ha e you done the mod, Doug?

 

Do eet!

[wink]

  I just did this with a set of HE60's and the effect is far from subtle.  A lot less bright... 

 

Certainly needs that.

How would thicker earpads go?

[spritzer]

Certainly needs that.

How would thicker earpads go?

 

Yes but I went the other way and recessed the drivers inside the cups.  It helped that I used HD600 parts for this... 

[wink]

Solves the problem of a wider headband, I guess.

[spritzer]

I can't spare any room there... 

 

The end result is a truly lovely headphone though.  Closer to the HD6x0's in balance but with that super quick response and lean bass of the HE60.  Doesn't hurt that it was practically free, only paid for the cable and new earpads.  Rest were either pulled parts from repairs that I reconditioned or parts given to me. 

[crappyjones123]

I'm probably going to have to give up my speakers from the fall onwards at least until I have an apartment by myself.

I love the 650s. As of right now, outside the house listening is through the trusty jh 16s and inside the house I always use speakers. Would there be a significant upgrade to go from the 650 to the 800 or am I better off just keeping the 650s? I predict a very sedentary and quiet lifestyle come up so headphones will be used again.