Pros - Comfort, Improvement with Amplification, Cost
Cons - Brightness without Amplification, Availability
Philips SBC HP910 Headphone
The head-fi ratings are based on the amplified sound.
Let me mention that the frequency response range is from 5 Hz up to 32k Hz meaning the bass is much more extended than one may initially expect.
Straight out of the box you notice that care and thought went into the design and functionality of the headphone. The box is well organized and the headphones come with a 1/8 to 1/4 inch adapter. The earcups are soft blue felt and the headband auto-sizes to your noggin. They fit tremendously well and are never too tight. The earcups are large enough for very large ears and nicely sized for someone with small ears. When you wear them you hardly feel them on your ears or on your head. The headphones themselves feel a tad on the cheap side in that they are so light. The plastic feels hollow but so far they have lived up to the test of time. I really enjoy their fit and moderate detail. I have had these over a year now and really enjoy them. Here is why.
Provided are two reviews. The first of which is what the headphones sound like unamped and the second is what they sound like amped via Grace Design m903.
Unamped all of the frequencies are adequately represented. The bass is rolled off, the mids shine true, and the highs bright.
Amped the frequencies level out tremendously. The bass is deep and impactful. It reminds me of a pair of SR-80's I had with over 500 hours on them. The bass is just a joyous addition to your listening experience.
Unamped the soundstage is a bit low and one dimensional. It will bore you.
Amped the soundstage greatly opens up and the depth of the sound field becomes deep, rich, and full of life. To really let them shine listen to Buddy Miller & Julie Miller - [Written In Chalk CD1 #05] Long Time. This will show you how wide the soundstage can be.
This is not a movie or video game headphone. With these two types of media the headphones seem to crackle a bit. It was subtle, but there. I was unimpressed by the ease of distortion found in these cans from these two sources. With music on the other hand I had no problems. Even listening to The Dead Weather - [Sea Of Cowards CD1 #10] Jawbreaker did not distort.
Impedance is a tricky thing. It is not only the resistive component of the headphone, but a combination of other factors as well. Sensitivity, impedance, and the performance of the headphone frequency response curve as a function of impedance play a huge roll in the headphones reaction to amplification. When I went from the output of my computer's audio headphone output I was somewhat displeased with the HP910's frequency response. Once I amped them up a bit with my m903 the sound was just short of life changing. The bass grew in magnitude a hundred fold. The highs were mellow but nice. The mids were right between which is where they should be.
I recommend trying Grado's SR-80i and Audio Technica's ATH-M50 if you are looking to use these unamped. If you plan on running the HP910 through a nice amp then by all means take a purchase a pair. I can almost guarantee no disappointments. Sure they are not going to rumble your head senseless with overwhelming bass. The bass will still surprise you especially in combination with the other aspects of the audio response.