70mm drivers, fully open design, premium materials, and simply the best comfort of any headphone at any price. The MA900 has many things going for it. The sound signature is a little laid back, but ever polite. One would think that a 70mm driver could provide a hearty slam. This isn't the case -- sub-bass is almost nonexistent, and midbass is inferior to that of a Grado. Decay is slow on the MA900, so the midbass isn't super-crisp. Treble, on the other hand, is quite smooth on this headphone. It's not a bright headphone, so even the shrillest of instruments, such the piccolo, won't pierce your ears.
 
The big problem, however, is the midrange. It's clouded. At $350 (imported from USA to Canada in June 2012 -- Sony Store only carries up to MA500) I wanted a headphone that was crystal-clear. Unfortunately, I think the thick fabric covering the driver has ended up muffling the headphone a little. Soundstage width is a little congested unless the MA900 is worn in reverse. But in reverse, bass extension and impact are reduced even further.
 
I suspect the frequency response is tuned to more of a studio monitor headphone than a musical headphone. Unfortunately, it means the MA900 is miserable-sounding at a low listening volume, as the bass is too neutral to provide any spark to the music. Ultimately, while the MA900 is a good headphone if you blast your music, I like to normally listen at <75dB SPL. For that, my Grado vented SR225i (2 large holes, 8 small) bettered it in most aspects, as its frequency response better follows the equal-loudness curves. I ended up returning my MA900.
 
There's a good reason why the street price has dropped from $300 to $200, and that Sony Canada only carries the lesser models (MA100/300/500) in stock. It just isn't very good. The lesser models are even worse, however, so I don't know what Sony's thinking.
 

Having owned the $100 NuForce uDAC1 for over two years, I felt it was about time to upgrade. It had been acceptable, but I could still notice a bit of a veil in the midrange. The itch was also caused by going to a Head-Fi meet. When I plugged the uDAC1 into some high-end amplifiers, I realized how limiting it actually was. What does the HDP get you? Not much.
 
I had a good review on the HDP before, but I can no longer recommend it. The HDP, being a $500 product, has worse gain than their $100 uDAC1. It can barely amplify a Grado. I have posted on Head-Fi about this and NuForce has assured me that this is normal. That is complete bee-ess. My first unit had hissing when turned on. This second unit, sent directly from NuForce after I paid an extra $100 service fee, still has hissing beyond 3 o-clock, and the gain is worse than the first unit!
 
Please see http://www.youtube.com/watch?v=SMkj-5L0w74 for video proof.
 
 

Got this for a friend off the FS forum, but decided to use it myself for a few days. This was supposed to be the uDAC killer? Really?
 
My unit (first edition) is presented well and looks to be built all right, though there have already been three revisions and reports of numerous problems with the jack on the forums. So it gets 3 stars there from me.
 
Clarity is the main issue for the Fiio E10. The upper bass is boosted a little, and the mids around 2500hz are recessed a little. This is enough to create a veil on most of my non-bright headphones. It does tame a Grado very well, however, and the E10 is a nice match for it. It sounds okay until you hear the competition in the same price range.
 
My HP Touchpad (Beats Audio processing disabled) and NuForce uDAC1 actually sound better than it. This comes as a surprise, since there's at least multiple reviews that state the E10 sounds better than a NuForce uDAC2. Not to my ears, it doesn't. The uDAC1 has significantly more bass impact, percussion impact, soundstage, and airiness. As for the HP Touchpad, it actually has a superior Wolfson DAC compared to the iPad, and it really does give the uDAC1 a run for its money. The HP Touchpad has the best clarity and overall sound quality of the three. It's too bad I can't use it as a dedicated DAC.
 
(Upon research, the HP Touchpad uses the newer Wolfson WM8958, while the Fiio E10 uses the older WM8740. This may explain the reasoning behind the HP Touchpad's superior sound; it just has a better chip.)
 
The bass boost is a nice idea, until you realize it boosts the 200hz-500hz range. This is way too much, as most headphones are close to neutral there. Most of the bass help is needed below 100hz. Had the bass boost only affected frequencies below 100hz, it would've been suitable. However, as it stands, it turns the sound into mudville. Sadly, and I hate to admit this, but the Beats Audio processing on the HP Touchpad boosts the bass in a more subtle and ideal way. Guess the Beats brand does something right.
 
So pair it up with your favorite bright headphone, like a Grado. But if you try pairing this up with a less-bright headphone like a Sennheiser, you might be getting a sound that's just too dark. This isn't much better than integrated sound on your computer, to be quite honest, though it'll boost the volume to levels that integrated sound cannot.
 
I am astounded as to why this product gets so much praise, but I guess the dark signature just isn't for me. All that negative publicity surrounding the nuForce uDAC really hurt its standing, but I must have been lucky with my uDAC1, since I really do believe it sounds better than the E10. The Headfonia review (http://www.headfonia.com/the-latest-must-have-the-fiio-e10-usb-dacamp/) hinted at the worse soundstage and airiness in its review, but still recommended it over the uDAC2. However, I believe these issues are too significant for the people who prefer a brighter sound signature.
 
One last thing. The E10 doesn't have the channel imbalance issue that the uDAC1 and uDAC2 have at ultra-low volumes.
 
(Tested with: Sennheiser HD595, Grado SR225i, Sennheiser CX980, Koss KSC35, Audio-Technica M50)

This is a timeless classic, although lately it's been outclassed by others at the same price point. But the main advantage is that the PortaPros are readily available at a local shop for less than the MSRP. However, if the price is too good to be true, it probably is! Be aware that there are counterfeits being sold: http://loveray.blogspot.com/2010/12/how-to-identify-fake-koss-porta-pro.html
 
As for the sound, expect an above-average amount of loose bass, which smears the other frequencies a bit. Of the KSC35, the KSC75, and the PortaPro, the PortaPro has the most bass because of how the driver is clamped to your ear. This extra bass works when listening to music outside, but in a home environment, a dedicated home headphone is a better match.
 
The ComfortZone setting is a nice idea, but most people will probably prefer the lightest setting. As a result, it's nothing more than a gimmick. The headband may also snag some hair, so watch out for that. Lastly, the carrying bag barely fits the PortaPro when it's folded, so it's a bit of a hassle to pack it up.
 
Of course, there's always Koss' lifetime warranty, so they can be abused pretty heavily.
 
The PortaPros are a good value for the price, but if you want better audio quality and portability, and are willing to pay extra, take a look at the Koss KSC35.

Paid $52 CAD (incl. shipping) at koss.com.
 
Looking to buy the PortaPro but are willing to pay extra for something special? The KSC35 not only has the PortaPro drivers, but trumps them in virtually every way. It's lighter, the bass is less overpowering because the pads don't clamp down on your ears, and it actually fits in its carrying bag quickly, whereas the PortaPro needs a bit of shoving in. You are literally paying a premium for two hard plastic earclips, but it's these earclips that set the KSC35 apart from the PortaPro and the KSC35's less expensive relative, the KSC75.
 
One weakness is that the earclips are fragile. Mishandling may cause them to break off the driver and ruin the plastic nudge on the driver. If this happens, you cannot use the lifetime warranty, as Koss will replace your KSC35 with the cheaper and inferior KSC75. Instead, purchase a PortaPro, then switch the headband with the earclips. Always store these headphones in the carrying bag when not in use.
 
Comfort is acceptable, as the hard plastic earclips are more secure than the rubber ones of the KSC75, but you may experience slight soreness as the plastic pinches your ears.
 
Back in the early 2000s, this was Head-Fi's value headphone of choice. Then it was suddenly discontinued in favor of the short-lived KSC50, which was heavier, didn't secure to the ear as well, and sounded worse because of its enclosure. During this time, people paid up to $100 for this headphone on eBay. Now it's available again, but only on koss.com at a price that's significantly higher than a PortaPro at retail. So while it doesn't hold much value compared to the KSC75 and PortaPro, it is the Koss portable of choice for those who are willing to shell out extra.

Paid $30 CAD at ncix.com.
 
This is a 6-year old model that has been made obsolete by the MDR-XB series, but it's still produced for the value segment. Or maybe they were overproduced and stock needs to go.
 
Anyway, these headphones aren't good. There's a distinct hollowness in the sound, and it feels very flimsy, though this flimsiness does make the headphone rather light on the head. The music/movie switch is useless.
 
Don't get these. If you want Sony, look at the MDR-XB series and spend the extra cash. The MDR-XB500 and MDR-XB700 have received good praise.

 
 
 
Paid MSRP at baybloorradio.com, which has a high markup. Picked these over the SR325is because they were significantly lighter. Reviewed with a Nuforce uDac.
 
Audio: What can be said about the Grado house sound? It's a love-or-hate intimate style. Electric and acoustic guitars simply rock on this headphone, as do instrumental pieces with few key instruments. However, the bass is rather anemic at stock.
 
Design: Being lightweight is good. However, free rotation of the cups is an issue, and there is crimping on the cable near the Y splitter. The left side gave out after 2.5 years due to this crimping, but the fine folks at Ring Audio (http://www.ringaudio.com) repaired it nicely.
 
Comfort: I find them quite comfortable, but I have small ears. They are amazingly light at 200g, and if you wash the bowl pads to soften them up, they become even more comfortable. People like to complain about the vicegrip clamp out of the box, but it's easy to bend the headband to your desired clamping level.
 
Recommended buy if you are aware of the bass deficiency and can work around it.
 
EDIT (Aug 2011): The bass (and as a result, audio quality) can be improved greatly by using the vent mod. This is preferred over taping the bowl pads since it won't muffle the midrange. By venting 7 small pinpricks on the felt around the driver, the bass of the SR225i increases to the point where it's slightly less powerful than that of the HF2. Of course, if you prefer even more bass, you may vent all 10 holes and make all the holes larger. The star ratings for audio quality and overall reflect the sound with the vent mod; -1 star at stock.
 
EDIT (Feb 2012): Decided to vent all 10 holes, then enlarge two of the pinprick holes all the way. Wow! Now they sound almost as good as an RS1i, and so sound quality and overall rating are now 5 stars!