[obsidyen]

  would you guys buy TH900 over the T1 Gen 2 or HD800S?

I would, definitely. While TH900 is a bit tizzy for me, it's still superior for EDM/pop  than the other two headphones. If I listened to more classical and jazz, I'd go with HD800S.

 

[tomatoshoe]

  would you guys buy TH900 over the T1 Gen 2 or HD800S?

 
It all depends on your musical preference. What do you listen to?
 
I have the TH900, and just returned the HD800S. The reason is because I always ended up enjoying the music more on the TH900. (I listen to mostly EDM, hip-hop, rap, pop, rock/ mostly bass intensive music)
 
However, the HD800S are still very good headphones. Very transparent and true to the song. Bass is just enough and sound overall has a slight musicality to it. If I didn't have the TH900 and only had the HD800S, I'd still be fairly happy. The TH900's feel more intimate to me. The soundstage for the HD800S isn't to my liking as it's fairly large and not as intimate.

 

[svmusa]

If any one interested, I have put my brand new TH900 MK2 on classifieds. They don't have the isolation I need other than that they are great phones and scales very well.
 
http://www.head-fi.org/t/810457/brand-new-barely-used-fostex-th-900-mk2-for-sale

 

[sgtstinker]

  If any one interested, I have put my brand new TH900 MK2 on classifieds. They don't have the isolation I need other than that they are great phones and scales very well.
 
http://www.head-fi.org/t/810457/brand-new-barely-used-fostex-th-900-mk2-for-sale

Great deal, almost tempted to jump on it myself. But I wonder if you replaced the pads with something like the MrSpeakers Alpha pads if that would fix your isolation issue?

 

[JamesKH]

One of the most beautiful headphones i've ever seen.  I have a pair myself.  

 

[DavidA]

  Great deal, almost tempted to jump on it myself. But I wonder if you replaced the pads with something like the MrSpeakers Alpha pads if that would fix your isolation issue?

Changing pads will not fix isolation issue since the leak is from the gap between the cup and frame.

 

[sgtstinker]

  Changing pads will not fix isolation issue since the leak is from the gap between the cup and frame.

Yeah I guess that is true. I just remember reading on another thread that the Alpha pads make the TH900 seal and isolate better. Although with the gap I'm not sure it'd do anything to affect the leakage. 

 

[DavidA]

  Yeah I guess that is true. I just remember reading on another thread that the Alpha pads make the TH900 seal and isolate better. Although with the gap I'm not sure it'd do anything to affect the leakage. 

I think the reason the TH-900/600/X00 sound so good is due to the gap. its what gives them a cross between open and closed headphones.  The seal between the ear pad and your head affect the bass the mostly, mids and highs are not affected much by the seal.
If I compare what external noise I can hear between the TH-600 and HE-560, the TH-600 lets in about 70% of the external noise while the HE-560 lets in 90%.

 

[Jiexi]

I keep reading about how much the sound leaking is a problem for people looking for a pair of closed headphones. If something like the LCD-3 was a 10 on sound leakage, and the LCD-XC was a 1, how would you guys rate the sound isolation of the TH900? 

 

[Aiyah]

8

 

[Jiexi]

8

Alright, so they're basically open back headphones. I was really hoping that number would be closer to 5. Thanks for the info.

 

[sarora]

  Alright, so they're basically open back headphones. I was really hoping that number would be closer to 5. Thanks for the info.

Sort of, yes. They are extremely hybrid - which gives them a good benefit in the sense that you get the wide soundstage that you get from open headphones with some isolation.
 
For technical stats - the measurements for broadband isolation from reference (100Hz - 10kHz, 0 dB reference) provided by Innerfidelity (http://www.innerfidelity.com/headphone-measurements) for the LCD-XC (closed), LCD-4/LCD-3 (open), and TH900 stock are -13 dBr (LCD-XC), -7 dBr (TH900 stock), and -2 dBr (LCD-4 and LCD-3 as well), so yes, the TH900 stock doesn't have the best isolation alone for a closed headphone: 7 dB of measured isolation on the broadband frequency range without modifications. 
 
Some modifications that improve the isolation:
 

1. As mentioned, thicker pads - I use the Lawton Angle Pads which are thicker but the MrSpeakers Alpha Pads are the thickest. I have these as well, but I prefer the angle pads because they fit better.
2. Dampening - adding some dampening around the drivers helps absorb and improve isolation and soundstage. The Lawton Mod (http://lawtonaudio.com/fostextune-up.html) is like $45 DIY, which is easy but effective and I recommend this since it isn't very expensive or hard to do.
3. Larger enclosure - I use custom wooden cups instead of the thin wooden cups that the TH900 comes with. They're about 2-2.5x the depth and volume from the stock wooden chambers and make a big difference. As with loudspeakers and their enclosures, the size and thickness of the enclosure makes a huge impact for isolation and changes the soundstage.

 
With these three modifications vs. stock, the TH900's are much more closed with regards to isolation. However, wooden cups can be expensive, so it depends on how much one wishes to play around with the headphones, etc.

 

[Jiexi]

 
Sort of, yes. They are extremely hybrid - which gives them a good benefit in the sense that you get the wide soundstage that you get from open headphones with some isolation.
 
For technical stats - the measurements for broadband isolation from reference (100Hz - 10kHz, 0 dB reference) provided by Innerfidelity (http://www.innerfidelity.com/headphone-measurements) for the LCD-XC (closed), LCD-4/LCD-3 (open), and TH900 stock are -13 dBr (LCD-XC), -7 dBr (TH900 stock), and -2 dBr (LCD-4 and LCD-3 as well), so yes, the TH900 stock doesn't have the best isolation alone for a closed headphone: 7 dB of measured isolation on the broadband frequency range without modifications. 
 
Some modifications that improve the isolation:
 

1. As mentioned, thicker pads - I use the Lawton Angle Pads which are thicker but the MrSpeakers Alpha Pads are the thickest. I have these as well, but I prefer the angle pads because they fit better.
2. Dampening - adding some dampening around the drivers helps absorb and improve isolation and soundstage. The Lawton Mod (http://lawtonaudio.com/fostextune-up.html) is like $45 DIY, which is easy but effective and I recommend this since it isn't very expensive or hard to do.
3. Larger enclosure - I use custom wooden cups instead of the thin wooden cups that the TH900 comes with. They're about 2-2.5x the depth and volume from the stock wooden chambers and make a big difference. As with loudspeakers and their enclosures, the size and thickness of the enclosure makes a huge impact for isolation and changes the soundstage.

 
With these three modifications vs. stock, the TH900's are much more closed with regards to isolation. However, wooden cups can be expensive, so it depends on how much one wishes to play around with the headphones, etc.

How much would you say these mods bring the sound isolation closer to the LCD-XCs?

 

[muski]

Thanks, sarora, for your informative post. Really great.
 
Cheers,
muski

 

[sarora]

  How much would you say these mods bring the sound isolation closer to the LCD-XCs?

I have never heard the LCD-XC, only the LCD-2, LCD-3 (both open) and EL-8C from Audeze so I can only comment with data.
 
From stock TH900 to the mods I described, a big difference. This is to be expected though. The TH900 is a dynamic headphone, just your "standard" 50mm moving coil dynamic, so no large planar magnetic diaphragm with waveguides and larger surface areas. The TH900, however, is a pretty powerful dynamic headphone with a 1.5 tesla rated driver and can handle quite a bit of power, which make them really bass heavy and hard hitting.
 
It's essentially like a mini loudspeaker (more akin to a mini subwoofer) at this point, as speakers are almost always dynamic. So the mods - thicker pads which attempt to create a tighter seal and more closed area between your ear and the driver to mitigate the leakage -- that's one part, however, the other two mods I mentioned: dampening which works like/is literally acoustic foam that absorbs some of the resonant waves from the back of the driver as that's where a lot of the leakage happens (behind the driver - towards the casing), and enclosure which is quite important as it would be on a loudspeaker; larger enclosure means that the wood can "absorb" a lot of the sound as it is essentially a closed seal (the one I use is about 2.5x the volume of the stock with much thicker wood, and of course dampening on the wood with acoustic foam instead of the stock cotton -- result is much more "room" and resistance for leakage vs. small/thin enclosure). 
 
It's all wood based for the enclosure and the TH900, as mentioned, are very similar to a mini loudspeaker, so you can use the same basic strategies you would use when designing/modifying a traditional speaker for improving isolation on the TH900's.
 
Basically, the stock doesn't have enough of a enclosure (size, thickness) nor is it damped well (just some cotton by default) and then there's the pads which help to complete the front seal, though the enclosure & dampening makes a much bigger difference.
 
(Also, speakers are obviously "open" by default so you often hear people saying that open headphones are more like the sound of loudspeakers, which is generally true, since speakers don't have pads to create any type of seal. However, speakers are designed with enclosures of particular shape and size and materials, often some form of dampening inside the enclosure as well, to mitigate the soundwaves and various resonances generated as the driver moves back and forth)