solderdude
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Post by solderdude on Apr 1, 2014 5:04:20 GMT
When changing the 56 for 68 you will only attenuate the peak a few dB more. When changing the capacitances + inductors you widen the frequency band in which it filters and thus you attenuate the peak + some of its side bands a bit more as well lowering the overall treble amount.
You could experiment with the 68 Ohm first (or even make it 82 Ohm) and see if it brings the desired result.
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Post by hifidez on Apr 22, 2014 8:25:20 GMT
I am still using my 681s regularly and I am still happy with the stock sound balance. Yep it's got a loudness curve built in but not over the top imo. I reckon they dont sound as poor as they could/should because of the dip circa 3kHz; a Linkwitz dip? This leaves the top end a bit sparkly but without any harshness.
Over in RG forum I did critiscise the 681s for their very obvious headband resonance; no-one else thought this important though. However, there is an in depth study of headband resonances in the latest Hi-Fi News. I feel vindicated! PM me, anyone, if you want 'more information' on this article.
Regards,
Derek
ps... looking at Solderdude's graph again I see the dip is 4kHz but it'll still have an effect? I miss-counted the (somewhat fuzzy) gridlines.
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Rabbit
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Post by Rabbit on Apr 22, 2014 15:45:02 GMT
Hi Derek,
Is the 'resonance' the frequency that the headband resonates at? I mentioned this in connection with the AKG550 way back.
I snap my teeth together while wearing them and the frequency reveals itself through the bones in your skull. I've been aware of that with the K550 for some time, but I don't think anyone really took me too seriously so I never mentioned it again!!
I'll try my teeth trick with the Superlux.
I'll have to get the magazine and take a look now!! Thanks.
Got it!! I downloaded it.
That's a really interesting article, Derek, thanks for that. It is something that I have felt has been ignored with headphones too. Just crunch your teeth together while wearing them and you will hear a resonance with some headphones.
When I first heard it on the K550, I felt that it was actually quite strong and could hear a 'pitch' conducted through the bones in my head. I felt that if that pitch was produced by the cups, then it would be boosted by the natural ringing of the headband.
It makes sense to completely isolate each cup if possible, just as we do with speakers. After all, as he says, we wouldn't even consider putting a bar between two speakers in order to link them together!! (Although speakers produce a lot more volume so perhaps resonances are more easily obtained!!)
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Post by hifidez on Apr 23, 2014 6:59:31 GMT
Yes Ian, the metal hoops themselves have an obvious note. They go 'b o n g' when you pluck them.. I need to measure the frequency! Wrt the hifi news measurements I wonder if there is the possibility of using headphones as their own mics to record and subsequently analyse the noise generated when a headband is tapped?
I've used 'phones as mics to experiment with binaural recording. Didnt early Sennheisers use mic capsules?
Derek
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solderdude
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Post by solderdude on Apr 23, 2014 7:14:12 GMT
A headphone driver can be used as a (crappy) mic. Simply plug it into the mic input of your sound card and make a recording. Audacity (or other programs) can then easily show the spectrum of that recording/file by analyzing it.
You can even analyse microphony of cables this way.
I could do a test when I have some time for it. One can even determine how much microphony or 'zing' there is a absolute dB values if a (calibrated) test rig is used.
Might be a nice addition to normal specs (somewhat similar to the isolation measurements Tyll provides)....
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Post by goldenboy on Oct 20, 2015 1:08:33 GMT
I'm posting back to report that I have ended up getting the HD681F recently instead of the original HD681 added with velour pads. I have owned the bassy HD681EVO but eventually sold it after playing with the filter mod that is why i chose the HD681F instead for the lesser bass variant.
I'm liking the bass of these HP's and and feels like more natural or acceptable to my ears. The only issue I'm having is the more pronounced 2kHz peak? Which sounded like the voice is shouting out to me in some music. lol. I believe The MKIII filter guide only affects the sibilance 3-9kHz region.
I need to know if there was a filter that was tried and tested that will affect from 2-9kHz? Also, I'm wondering why the damper sticker was placed in opposite direction of each ear cups?
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solderdude
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Post by solderdude on Oct 20, 2015 8:22:52 GMT
The distortion plot of the HD681 (modified and not F type) shows there is no resonance or peak around 2kHz. There is distortion around 4.5kHz and (still) some massive HF energy around 14kHz. Distortion in the bass (especially 3rd harmonics) is a bit high but not for its price... The stock HD681 (without filter and stock pads) does show a rather large peak. Unfortunately that is not easy to filter out passively as well as 2 filters close to each other (when made passive) will interact too much. One could make the filter wider so the 14kHz as well as the 3kHz is lowered a bit more though but requires a lot higher inductance values. The 2.5kHz emphasis gives this headphone it's 'forward' and 'clear' sound signature. Below the stock HD681 vs modified (low+treble filtered + K240 velours pads) You can see the filter + pads have lowered the 2.5kHz peak somewhat. The plateau around that spot is still there but only seems to be there because of the 500Hz and 4kHz dips. You can move the filter a bit more towards lower frequencies by changing the filter values. replace L3-L4 with 1mH (was 470uH)
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Post by goldenboy on Oct 20, 2015 17:36:47 GMT
Thanks for the response and for the detailed explanation SD! I really appreciate it. I'll tinker my HP a little bit this weekend and add some filters to feel the improvements in the high frequencies.
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Post by ihack13 on Dec 19, 2016 12:18:33 GMT
Hi, after following a lot of links from different sites and forums around the world, I found solderdude on rock grotto and finally landed here . I do have a Presonus HD7 and as far as I know it is the same as a Superlux, apart from the headband and colors. I do not know however which version of the 681 it is. B or F or simply 681. I compared this Headphone to my Sennheiser HD 212 Pro and what I realized was, that the bass was somehow there but it didnt kick in like the sennheiser did. I am not sure how to describe it. It just bangs on the spot on the Sennheiser and the HD7 is somehow strong too but its not on the spot. Flat or shallow is maybe not the precise word here either. But whatever.. But when you listen to something like writings on the wall or an Adele song, the HD7 is soooooo clear . What the actual hell?!. The difference is crazy. However I noticed that after some time it began to hurt. The overall comfort was a bit meh... Headband was pressing to firm from top I think, my skin got all sweaty because of the Pads and I think I listened too much Adele like stuff to test the highs and mids and got a headache from that. My first thought was to give these headphones to my brother and get myself the HD668B which were praised because of their bass in some other forums and were a step up to the 681 as some mentioned. But reading how solderdude returned his 668B in favor of the 681 I gave up on this idea, because I think you are the king solderdude So my question is 1 - do you know which Superluxes I have or how to identify them? 2- which filter on the revisited Superlux pdf to choose? You mentioned page 9 I think if I want to keep the bass? 3- My knowledge in electronics is just basic but I do some pretty good soldering on PCBs. Can I go with smaller resistors and parts instead of the chunky ones? I have an adjustable soldering Iron with small tip (Aoyue 936 int) And yeah. I will replace the pads, with the 8 buck ones from thomann. I might first try the mod though. So maybe I will buy another pair for my bro and order two pairs of pads alltogether. note: I dont have crazy Audio equipment and amplifiers. I use the headphone on Phone, Ipad and Macbook.
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solderdude
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Post by solderdude on Dec 19, 2016 12:41:39 GMT
The HD7 is indeed manufactured bu Superlux. It is possibly closest to the B version (Balanced) and has less subbass than the non letter version. IMO the stock HD681 has a bit too much bass.
The HD668B has less of that treble peak and in amount of bass is similar-ish to the HD681B. It is also more boring sounding. Great for monitoring, less great for hi-fi listening.
When you are planning to buy new headphones and want good bass and no sibilant treble you should really consider the HD662-EVO. It is better sounding than the HD681 versions.
Superlux are going to launch a new version of the HD668B in a while. Don't know when yet... Superlux is not really forthcoming with time tables.
The HD662-EVO is great directly out of i-stuff.
Also comes with far less sweaty velours pads and very easy to do small non-intrusive modifications make it even better.
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Post by ihack13 on Dec 19, 2016 13:56:38 GMT
Unlike the Superlux according to this file www.rock-grotto.co.uk/HD681.pdfMine were flat on the side. I had to peel off the Stickers and underneath it there are 3 screws. Seems different? imgur.com/a/HryMJPS: I need a break. I am laughing off my arse right now. I just discovered your toilet paper hack for the Evos Cant stop laughing.
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solderdude
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Post by solderdude on Dec 19, 2016 15:57:09 GMT
They aren't the same headphones. Just like the Samson SR850 they were made in the Superlux factories. Even the drivers do not have to be the same ones. I haven't seen physical differences in the HD681, HD681F and HD681B versions which would make them sound different. Perhaps (maybe just talking out of my ...) differences between the types are caused by coarse selections being made in the production process due to a large spread ? Don't know.. Have heard a bass shy HD681 gaining bass levels within minutes but never reaching the same level as others. This was before I measured them so have no proof. The toiletpaper thing is a well known trick in the PA and studio business. It is applied by a lot of modders. One of several cheap 'tools' one has available to tame highs in SOME cases. Doesn't always work in the same way, nor does felt, foam, coffeefilter paper, paper towels etc. Very driver/headphone dependent. diyaudioheaven.wordpress.com/headphones/taming-the-treble/
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Post by ihack13 on Dec 19, 2016 16:47:20 GMT
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solderdude
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Post by solderdude on Dec 19, 2016 22:02:06 GMT
When you modify it, it will only take the treble 'etch' off, won't increase the bass.
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Post by ihack13 on Dec 19, 2016 22:13:51 GMT
When you modify it, it will only take the treble 'etch' off, won't increase the bass. solderdude. At this point I have no idea. I plugged in the headphones and listened to some tracks again... The HD7 does have bass. Sometimes it feels like it even has more than the Sennheisers.... Also thanks to some bass tests I noticed that I get some buzzing on the left from my sennheisers... Seems they are broken Tomorrow I will do some amateur electronical sketches to try to make an external filter with a switch for all the different settings that you wrote down. Hopefully I can get the parts on Wednesday or Thursday and begin soldering. I also noticed that my HD7 dont look like the ones on the photos when I google it. The HD7 pictures on the internet look exactly like the red Superlux. They have rings. The ones that you and some others replaced with some aluminum rings. Mine simply has a sticker with a blue border. I guess I will just mod and see. By now I think these HD7 are normal 681s . When I listen to Sam Smith - Writings on the wall, and he pronounces S , its almost a horrible sound. I guess these are the peaks that you are talking about. Sorry for being a pain in the ass. I will see what I can do tomorrow.
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