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Audeze LCD-4

Discussion in 'High-end Audio Forum' started by matias, Sep 28, 2015.
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  1. jodgey4
    The site is updated to 200ohms. Sensitivity is now 100dB/mW.
     
  2. MacedonianHero Contributor
     
     
    Impedance does not tell you how easy/difficult a pair of headphones will be to drive. Just pick up a pair of HE-6s (50ohms or so). It's the efficiency (sensitivity) rating that is more indicative. Plus, orthos are purely a resistive load...so much easier to drive (as damping factor isn't much of a factor).
     
  3. jodgey4
    "if everything else is kept equal.", (i.e. sensitivity) then @Articnoise is correct. It'll take more voltage to drive the cans to the same level. Power = V^2/R. Doubling R means (V^2) has to double as well to get the same amount of power. Depending on how Audeze made the changes, it could be very likely that the impedance increased the sensitivity (more circuit traces in face of the 1.5T magnets)... it says 100dB/mW now, anybody remember what it was with the 100hom version?
     
  4. MacedonianHero Contributor
     
    I just said that one shouldn't be overly concerned with the impedance of headphones WITHOUT considering the sensitivity (which is a bigger factor). As I mentioned, look at the HE-6s; they come in at 50 ohms...but are MUCH harder to drive than say a 600 ohm T1!!!
     
    Plus look at the impedance vs. fr graphs for orthos...they are purely a resistive load (also easier to drive properly due to not being dependent on damping factor).
     
  5. jodgey4
    Being a purely resisitive load or not doesn't really mean too much for power consumption, which was the conversation being had.
     
    And I think sensitivity has already been discussed. I'm not disagreeing with you there. I think we're talking past each other at this point [​IMG] haha.
     
  6. MacedonianHero Contributor
     
    I think we are a bit...but I often see folks talking about impedance and thinking that's a big player on "ease of drive", when sensitivity is more of a factor (just as the Hifiman HE-6s are only 50 ohms but really need a speaker amp to sound their best; while both the HD800 at 300 ohms or T1 at 600 ohms are MUCH easier to drive). 
     
    The resistive load is more for driving them well...I suggest you read Tyll's excellent article on damping factor here:
     
    http://www.innerfidelity.com/content/comparison-beyerdynamic-dt-880-32-ohm-dt-880-250-ohm-and-dt-880-600-ohm-headphones#Cvxyzh8u6fYguDgG.97
     
    Being purely resistive means that orthos are mostly immune to this...so technically they are easier to drive as you don't need to worry much about the output impedance of your amp to "dial in" your damping factor. With orthos, it's basically plug and play (and make sure the power is there).
     
  7. Articnoise
     

    I don’t need to pick up a HE6 I already have one.

     

    An amps output power is depending on Impedance load, no way around it. The efficiency of a headphone or speakers is another variable. Both will affect the amount of headroom. The example below is for Master 9. Other amps, with a few exactions, have the same characteristics. This is also true for speaker amps - more power on tap at 4 than on 8 Ohms and so on.

     

    Headphone amp Output Power

     (Balanced, Pure Class A )      

    40 ohm:   9000MW

    100 ohm: 3800MW

    300 ohm: 1250MW

    600 ohm:   630MW

     

    Headphone amp Output Power

     (Single-ended, Pure Class A )                           

    40 ohm:   2500MW

    100 ohm: 1050MW

    300 ohm: 350MW

    600 ohm:   175MW

     

    http://www.audio-gd.com/Master/Master-9/Master-9EN_Specs.htm

     
  8. MacedonianHero Contributor
     
    But when you take the sensitivity into account at 100dB/mW that power is more than plenty. [​IMG] Thus my point.
     
    Here is a great tool...just punch in 200 ohms and 100db/mW and see the comparison of the power you need in comparison to 100 ohms. Your amp won't break a sweat with either 100 or 200 ohms because the efficiency is quite good. 
     
    http://www.digizoid.com/headphones-power.html
    or
    http://www.head-fi.org/a/headphone-power-calculator-spreadsheet
     
    Fun with numbers:
     
    Headphone Impedance      Desired SPL                 Power Needed (mW)
    100 ohms                         110dB SPL                  10
    200 ohms                         110dB SPL                  9.94
     
  9. RCBinTN
    Thanks.  I am learning all the time.  And, this discussion is very helpful to the new folks trying to match an amp to HP's.  Just IMO.
     
  10. MacedonianHero Contributor
     
    No worries. Just one more thing to consider is the traditional damping factors isn't as much an issue with orthos is that they are purely a resistive load (per a typical FR response vs impedance). Tyll did an excellent write up here discussing what damping factor is and how to select a proper amplifier:
     
    http://www.innerfidelity.com/content/comparison-beyerdynamic-dt-880-32-ohm-dt-880-250-ohm-and-dt-880-600-ohm-headphones#Wg1QiLg2qMKYcqao.97
     
    But as mentioned, orthos are more or less not affected by this, so those of you with OTL tube amps and higher output impedances need not worry when pairing them with typically low Z orthos. But with the new 200 ohm LCD-4s, it's not an issue anyway.
     
  11. mlxx
     
    I think you missed the point Articnoise was making...
     
    Given the same sensitivity, the power required for any two headphones is the same, you don't need a calculator to work that out. What is important as Articnoise explained, is how the amplifier will perform at a specific impedance. What you should look at is your amplifier specs. For example, you have a Hugo TT, check the amplifier requirements for 100Ohms and 200Ohms, I think you may find you have probably lost a significant amount of your headroom for the updated LCD4 and the TT might be sweating a bit now (your GSX won't care). Even though the power requirements may stay the same, if the impedance changes then the voltage and current requirements will change, the new LCD4 needs more voltage now, affecting the amplifier. This doubling of the impedance from 100 to 200 is not a small tweak, it may make some amplifiers borderline now, especially voltage limited battery powered ones.
     
    Regarding the LCD4 changes.. anyone know exactly what has changed (other than guessing)? Any existing owners taking up the free upgrade offer? Probably need some impressions again, I guess all the impressions thus far are out the window now. I will have to test these again.
     
    So @Audeze.. last time with the LCD3 secret fazor changes, you said in future you were going to keep us informed of any changes so customers knew what they were buying. Is this still the case or have we gone back to the dark ages again, having to speculate why the numbers keep changing on the specs?
     
    Articnoise likes this.
  12. MacedonianHero Contributor
    I think you missed my point. Given my fun with numbers comment, why should we be worried over 0.06mW? Any amp from my TT to my GS-X Mk2 will barely notice.

    0.06mW will not affect "headroom". As I mentioned, impedance is not as big a factor as sensitivity, which hasn't changed.
     
  13. jodgey4
    The amount of power needed should be the *exact* same to reach 110/120dB peaks at the same sensitivity. The 200 ohms means it'll take more voltage, and less current. Also, Audeze recommends much more than 10mW, which means many amps will indeed fall out of their recommendation. Your information is incorrect, and misleading by leaving out the whole story. Not to mention, the are many ways to measure sensitivity, and choose desired peak levels.
     
  14. MacedonianHero Contributor
     
    Did you not notice that my comments number was at 110dB? Please go ahead and run the numbers...you end up with a 0.06mW difference. You can argue with a lot of things....math isn't one of them. Do you have any experience with the 600 ohm beyerdynamic headphones? Years ago, I was quite worried about "powering them correctly", but thanks to their higher efficiency, powering them wasn't much of an issue. The thing about them wasn't so much the power, but damping factor.
     
    With regards to your "more voltage" comment, to hit a 110dB peak, you will need 1V RMS for 100 ohms and 1.41V RMS for 200 ohms. I have always agreed that it won't be the same, but 0.41V RMS shouldn't matter to any amplifier worth its salt. Again, that's just the numbers...
     
    Don't get me wrong, I'm not saying you should use an under-powered portable amp for the LCD-4s. I'm assuming that most would be using a proper desktop amplifier that can keep up with a $4000 pair of headphones...and because of that, the 100 to 200 ohm change won't make much of a difference whatsoever to your amp. I have zero reservations about either my Hugo TT or GS-X Mk2 powering them. Both don't even break a sweat with my 600 ohm T1s, so a 200 ohm LCD-4 is no cause for concern for less headroom. 
     
  15. prismstorm
    Last week I was at my distributor demo-ing the LCD-4 and the product manger quoted that he had just been at a conference call with Audeze in the morning about how the diaphragm of the LCD-4 has been 'changed and improved', albeit with no details how, and that if I pre-order a pair right then it would be with the new film. He didn't mention anything about it being 200 ohms back then, and I was driving their demo (with 100 ohm) to pretty satisfactory level with my Mojo, and also with their Deckard and Hugo TT. 
     
    @Audeze I think it would be more comforting to potential customers if these sort of changes were publicly announced and people didn't have to find out through a random, spontaneous banter with a distributor product manager. I really wonder why such things were silently changed on the website but no official word on what has been changed. If this change is indeed a good thing and an upgrade wouldn't it be beneficial to the company to make it known? Keeping quiet about these things don't exactly instill confidence on potential customers still on the fence about it ...
     
    I am extremely noob at headphones so can somebody enlighten me to exactly what this 200 ohms change entail? That my Mojo can no longer drive the new revised LCD-4 to any adequacy and I will need to purchase a powerful desktop amp to even think of owning the cans? I have heard higher impedances play 'more well' with powerful amplifiers than really low impedances like the 20 ohms from the X so for non-mobile use it's supposed to be better.
     
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