Beyer T1 modification attempts + measurements

Discussion in 'Modifications and Tweaks' started by mawk, Aug 6, 2017.

  1. mawk

    mawk Acquaintance

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    I've had a T1.1 here for a few months now and spent far too much time playing with bits of foam trying to change the sound (read: fix the ridiculous treble peak). Ultimately I wasn't able to get these to where I wanted them, but before I sell them off I thought I would share a few measurements and thoughts just in case someone finds this useful down the track...

    I make no claims as to the accuracy of my measurement rig, but I get pretty consistent results so I make use of it for mod comparisons.

    Stock measurement:

    [​IMG]

    The first thing I tried was the EDT770 pads in an attempt to increase the bass response. I remember a while back someone was selling T1s with these pads and said they preferred it over stock.

    [​IMG]

    Yeah, no. These don't sound as crazy as they measure but the v-shape and the mid suckout is still pretty horrible. Just no. If I can provide any sort of service with this thread, it will hopefully be to stop some poor sap putting 770 pads on their T1. Especially if they have to pay through the nose for brand new ones from overseas, like I did.

    Next I experimented with material in front of the driver/baffle. This isn't particularly easy due to the angled driver, but all in all it wasn't too bad. Unfortunately despite trying every material I could lay my hands on I couldn't get them behave. Shelf liner fucked up the treble, thick foam reduced the measured treble response nicely but still sounded fucked to me. The only thing I found to have any positive (subjective) effect was putting on the front of the baffle (not on top of the driver itself):

    [​IMG]

    The only thing I can think of is that the slightly increased midrange response somehow forgave the treble peaks a little. Anyway, I liked it.

    The final attempts involved stuff behind the driver. Beyer has put NO damping back here and for some reason decided that it was a good idea to stick a thick plastic ring right behind the driver for everything to bounce off. If you listen to some of Tyll's talks about headphone measurements at shows he mentions the treble response of the T1 and postulates that the peaks and troughs could be the result of comb filter effects from sound bleeding back into the ear chamber from the back of the driver. So my theory was that rear damping would help this problem (ignore the rough measurement, it was raining pretty hard when I took it):

    [​IMG]

    This is with a single ball of cotton teased out in the chamber behind the driver. Lower bass response (as expected with rear damping) but the treble looks a bit smoother. I tried more cotton and other materials but it reduced the bass too much without affecting the treble. I also tried placing felt over the plastic ring (as suggested on some old HF thread) but it didn't do anything. I think that this type of mod has the most potential, and if I had more patience I'd like to play with more rear damping schemes. However the T1 is not the easiest thing to disassemble and to be honest I'd rather listen to my HD650 than fool around with this any more.

    If I ever have another go at this I'll post an update, but for now I'm done. For the record, I think these are great headphones that just have fatally flawed treble response. The soundstage and imaging are superb. Bass texture too. I would love to see what someone competent (paging @Bill-P) could do with these, I really do think they could be amazing if modded right.
     
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  2. Melvillian

    Melvillian Friend

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    I bought a used T1 gen 1 for gaming because of their amazing staging and accuracy, but found them very shrill to the point that I was concerned about damaging my hearing. I decided to put some cotton behind the driver and it helped somewhat but it also took a lot of the air out. Then I decided to line the plastic inside the cup with some self adhesive felt. This helped tame the treble a little bit but had some weird effects with the bass. Not sure if it's distortion or some weird resonance going on. I don't have a measuring rig so I can't really tell. I've basically stopped using it. I'm also interested to see if any of the experienced modders can fix this headphone.

    Edit* I still have the headphone and find it easy to disassemble. If anyone has any suggestions I can give it a try and provide subjective impressions of the results. Not sure if anyone is interested at this point though. This headphone has been around a long time.
     
    Last edited: Aug 6, 2017
  3. Elnrik

    Elnrik Super Friendly

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    I'm convinced that if Beyerdynamic came out with a model that didn't have the Beyer middle finger spike in the treble, they're gonna sell a crap ton of them. Unfortunately, they seem to be a bunch of stubborn Germans, and refuse to do this.

    Thanks for the post. Efforts appreciated.
     
  4. spoony

    spoony Spooky

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    I successfully modded a pair of DT990 with a pair of leftover HPAEC840 pleather pads (no measurements or pictures handy, sorry). At first they imparted a 20+ dB bass boost, then I got to work and after a few experiments had to smother the driver with damping to reduce the driver excursion; I used a pair of cosmetic polyurethane pads (like these) directly against the back of the driver, this resulted in a ~5 dB gradual bass rise from 300 Hz downwards which suited my tastes just fine. The treble spike got a lot lower in amplitude (+3 dB over 1 KHz), but I still applied some 1 mm thick stiff felt and 1 'ply' of kleenex tissue. Imaging and staging wasn't too obviously affected, distortion in the bass and mids went down an order of magnitude, and I didn't feel a loss of dynamics with the new damping scheme. Efficiency went down as well. It's doable if you put the effort in.
     
  5. Klasse

    Klasse Friend

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    What's the s/n?

    It would be interesting if you can share (silver screen) HD650's measurements of your rig to have as a reference.
    (knowing HD650 is typically a very consistent headphone)
     
  6. mawk

    mawk Acquaintance

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    To clarify, I was using the velour 770 pads (see here) rather than the pleather. I had a DT990 back in the day as well, and I actually found it to respond better to mods than the T1. I don't have any measurements though.

    S/N 17XXX. Will take a 650 measurement when I next have some quiet time in the house, hopefully in the next few days...
     
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  7. Bill-P

    Bill-P Level 42 Mad Wizard

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    Yeah, I admittedly have tried to mod Beyer headphones before. But one problem I realized was that Beyer had insane sample variation between their headphones. It was practically impossible to have a one-mod-fit-all solution for them. Different headphones (even within the same model, same revision, same serial number range, etc...) need different mods. And most of it has to be done with regular listening. Measurements don't actually show just how bad the treble actually can be.

    In fact, Beyer was the headphone brand that started me on the path to look at spectrograms instead of just FR and CSD. The other 2 obviously weren't enough to show just how bad the treble really is on these things.

    And that aside, the other problem is that you're comparing them to HD650. Nothing does treble quite like the HD650 IMO. Not even the HD580/600. I just don't like how bass is so elevated in the HD650, but they really do treble very well. I don't think you can ever get any other headphone to sound like HD650's treble, mod or not.
     
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  8. Melvillian

    Melvillian Friend

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    I was going to suggest sending you or one of the other trusted and experienced modders a T1 to see what you guys could come up with, but I guess that would be a waste of time.

    It took me a long time to really appreciate the treble of the HD650. The bass has started to bother me more than before though and I'm thinking about trying the KISS mod to reduce it. Everyone seems to love your 580. Would love to hear it one day.
     
  9. mawk

    mawk Acquaintance

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    Cobbled together the v0.2 measurement rig again and took an HD650M measurement for comparison (green line, matched to 1K)

    [​IMG]

    @Bill-P You're right, but I'm trying not to compare the T1's treble to the 650. I know it's never going to have that smoothness. I actually think I could live with the funny sounding cymbals etc that the T1 throws out if I could find a way of reliably reducing the overall treble level without messing up the sound...
     
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  10. 7seven

    7seven Rando

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    EDIT: Removing the screen is not good, it actually did reduce the roughness of treble slightly but sounds like shit overall. luckily it peeled off easily without damage so they can be stuck back on.
    The screen is very restrictive of airflow and must play a big part in damping, underneath there was another layer of finer plastic screening over the centre of the driver.


    This is great a headphone, with my set (late 17k sn) treble is on the edge of being an issue but not quite. The treble is sharp but very clean, I would like improved clarity and smoothness in treble but without reducing treble or negatively affecting other areas of the sound, I think that should be possible with mods but based on what I read damping inside the cups is not the solution.

    There is one obvious thing that could be changed and thats the driver screen and cage. any fabric, foam, plastic etc. impeding the soundwaves path from driver to your ear usually doesnt help SQ, esp for treble, its there to protect from dust and damage.

    I have plenty of positive experiences with this kind of mod but of course all HPs are different and this is irreversible.
    If removing the fine plastic screen yields good results I may try removing some of the plastic from the centre of the cage.

    Im not usually concerned with cables but I think the high frequencies are impacted the most so for T1 it could help

    edit: annoyingly Beyer didnt just choose to use torx screws but also the specialized T5.5 size which is hard to find a tool for.
     
    Last edited: Nov 5, 2018
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