Gear note: For this review I used an Audioengine D1 DAC/Amp connected to a PC using Foobar2000 to play FLAC-format music tracks, and also an iStreamer DAC connected to an iPhone4s and pre-assembled Objective2 by JDS headphone amp to play 320k CBR MP3 conversions of my FLAC tracks. The FLAC tracks range from 44 to 96 khz depending on their source. I also used the iPhone4 and iPod Touch without an additional amp to make sure the P3 could play at a reasonable volume level with those devices, and that the bass, mids and treble had the same approximate balance as heard with the desktop/laptop computers.
The bottom line: The B&W P3 sounds much better than the B&W P5 when played with Apple i-devices using the best EQ setting for each headphone. When played with a desktop or laptop computer using Foobar2000 or similar software, the P5 may be EQ'd to approximate or better the sound of the EQ'd P3, but I didn't try to find an ideal EQ setting for the P5 with desktop or laptop computers, as explained below.
The details: Using the iPhone4, iPod Touch or iPad, the Treble Booster EQ setting was necessary to bring the P3's treble nearer to the level found in typical hi-fi headphones such as the Sennheiser 600/650/800, Shure 940/1440/1840, Audio-Technica M50, various Beyerdynamics, AKG's etc. The EQ'd P3's treble is nearly as strong as those other headphones, but not strong enough to make sibilants or other high frequency irritations a problem. Without the treble boost the P3 would not have a typical high fidelity sound, in which case I would have to pass on the review. This review then is based entirely on that EQ'd sound.
The B&W P5 by default sounds somewhat hollow and weaker than the P3 in the bass and treble, but I was not able to find an EQ setting for Apple i-devices that improved the P5's sound without making it worse in other ways. Either I got lucky with the P3 or B&W planned the sound the way they did on purpose. Whatever the case, I think they made an excellent decision. There was no reason to look for an EQ setting for the P5 with laptop or desktop computers, since I assume such a thing could be done easily enough with the more flexible settings the computer software provides, and further comparisons with the P3 were not needed.
The P3's mids are very good, and whether anyone would perceive them as slightly forward or recessed will depend on the recording, since the only variance I found from ideal is a mild emphasis centered around 200-250 hz, making it slightly dark sounding. The bass is not as strong as the ATH M50, but the M50 sound is slightly emphasized in the upper bass and moreso in the lower bass. While I like the M50's bass better than the so-called neutral bass of the Sennheiser HD800 for example, the P3's bass is much closer to the neutral variety, but it's not shy in any sense of the term - it goes all the way down without rolling off. Based on use with the headphone amp and using the iPhone sans amp, the P3's efficiency is about average for this type of headphone. Testing with a new iPod Nano and average-volume tracks that are not as loud as what Amazon or iTunes typically sells, I can still get good volume with the P3.
I don't know how many reviewers rate the overall sound quality of their headphones according to their price, but it's reasonable to assume that some of them do. I don't exactly do that, but I would like to point out that the lower the price of a hi-fi headphone the less likely that the drivers will be precisely matched, or that all of the samples of that headphone model will sound alike with very small variances. In the case of the P3, looking very close at the build quality and finish, it looks good enough to suggest that the drivers and other internals are probably spec'd very closely as well. With approximately 25 hours of play time so far, I don't hear any major changes in the sound.
The B&W P3 is a supraaural (on ear) closed-back headphone. The cable is double-sided and detachable, disconnecting inside the earcups. The stereo miniplug has the Apple i-device configuration, and where my Objective2 amp doesn't make a secure connection with some of those, the P3's cable works perfectly. The cord is 1.9 mm thick, and while I would normally question the durability of such a thin cable, I haven't heard any reports of the B&W P5's equally-thin cable breaking for people that have owned the P5. There is no 6.5 mm (1/4 inch) adapter plug supplied with the P3.
Construction of the P3 is a combination of metal and plastic. There are no click-stop adjustments on the headband, so the fit is accomplished by pulling the earcups down on the sliders until they're centered over your ear canals. The clamping force is pretty strong for such a small headphone, but I don't experience any short- or long-term discomfort with it, probably due to the light weight and soft earpad fabric. The inner headband padding does not have any flexibility to speak of, i.e. it's pretty stiff, but since the headphone is very light you can pull the earcups down just enough for them to bear nearly all of the 130-gram weight, and that way the headband will act merely as a stabilizer and not press strongly on the top of your head.
The B&W P3 is slightly smaller than the B&W P5, but they are equally portable - i.e. you can pull the earcups all the way down and wear them around your neck all day when not in use. The earcups do not rotate horizontally and thus cannot fold flat, nor is there any adjustment for ears that are not parallel to each other, i.e. ears that face slightly more forward or toward the back. It does appear that the two thin metal stems that support each earcup can be bent, and if done very carefully I'm guessing that would enable a better fit of earcups to ears, which is important to get the proper sound. If not aligned over the ear canals, treble will suffer, and if the earcups are at an angle to the ears because they don't rotate to fit non-parallel ears, bass will be reduced.
Walking around with the headphone on, it didn't have any tendency to shift on my head, but leaning forward or making other moves will cause it to shift unless your hair blocks it from moving. The B&W P3 comes with a hard plastic carry case which offers good protection from moderate impacts like you would get in airline luggage etc. The P3's isolation is less than the P5 - high frequencies are attenuated well, but mids are suppressed less than 8 db from what I can tell. There isn't much leakage so use in a corporate cubicle would be OK at average playback volume, but if used next to a person who is trying to sleep, the volume would have to be kept to a more moderate level.
Now that I've covered the basics and the sound, it's time to describe how the P3 sounds with a variety of music that's available on CD's or as high-quality downloads from Internet music stores. I've used the following examples in other reviews, so these will serve as good test tracks for this review and the results can also be compared to the results noted in the other reviews.
Bauhaus - Bela Lugosi's Dead (~1980): Strong midrange sound effects - this is a good worst-case test for resonant-type sounds in the most sensitive midrange area. Handled very well by the P3.
Beethoven Symphony 9, Solti/CSO (1972): Good overall sound although the P3 reproduces the triangles, bells and other high-frequency instruments with less detail than my other more expensive headphones. Of special note for this headphone are the bass impacts beginning around 10:30 of the fourth movement.
Blues Project - Caress Me Baby (1966): Rarely mentioned, but one of the greatest white blues recordings ever. The loud piercing guitar sound at 0:41 into the track is a good test for distortion or other problems. Handled very well here.
Boz Scaggs - Lowdown (1976): Good sound quality - this is a great test for any nasality in the midrange. Handled well by the P3.
Buffalo Springfield - Kind Woman (~1968): A Richie Furay song entirely, rarely mentioned, but one of the best sounding rock ballads ever. This will sound good on most headphones, and it's very good with the P3.
Cat Stevens - Morning Has Broken (early 70's): A near-perfect test for overall sound - this track will separate the best sounding headphones from the lesser quality types. Nothing specific, except that almost any deviation from perfect reproduction will stand out with this track. Sounds good with the P3.
Catherine Wheel - Black Metallic (~1991): Goth with industrial overtones - I like this since it's a great music composition and the sound effects are smoothly integrated into the mix. This may sound distorted or mushy with some headphones, but the P3 renders the deliberate instrumental distortions clearly.
Def Leppard - Bringin' On The Heartbreak (1981): MTV goth/pop/metal at its best - good ambience and high energy - the better headphones will separate the details and make for a good experience. Lesser quality and the details tend to mush together. Sounds good with the P3.
J.S. Bach - E. Power Biggs Plays Bach in the Thomaskirche (~1970): Recorded on a tracker organ in East Germany, the tracks on this recording have the authentic baroque sound that Bach composed for, albeit the bellows are operated by motor today. The P3 plays the tones seamlessly through the upper limits of the organ, which cover nearly the full range of human hearing. Of special note are the pedal notes - tracker organs have low-pressure pipes and don't typically produce the kind of impact around 20-35 hz that modern organs do. A headphone that's lacking even a little in the low bass will sound especially bass-shy with this type of organ, but the P3 delivers the full experience of this music.
Jamming With Edward - It Hurts Me Too (1969): Intended originally as a test to fill studio down time and set recording levels etc., this was released a few years later for hardcore Rolling Stones fans. Although not as good technically in every aspect as the Chess studio recordings of 1964, and in spite of the non-serious vocals by Mick Jagger, this rates very high on my list of white blues recordings, and sounds pretty good with the P3.
Jimmy Smith - Basin Street Blues (early 60's): This track has some loud crescendos of brass and other instruments that don't sound clean and musical on some headphones. The P3 provides good reproduction. Listen particularly to the second crescendo at 15 seconds in, for maximum detail effect.
Ladytron - Destroy Everything You Touch (~2009): Featured in The September Issue, this song has heavy overdub and will sound a bit muddy on some headphones. Sounds OK with the P3.
Milt Jackson/Wes Montgomery - Delilah (Take 3) (1962): The vibraphone is heavily dependent on harmonics to sound right, and the P3 plays it well.
Pink Floyd/Dark Side of the Moon - Speak To Me (1973): Strong deep bass impacts will be heard and felt here.
Rolling Stones - Stray Cat Blues (1968): Dirty, gritty blues that very few white artists could match. On some headphones the vocals and guitar lack the edge and fall more-or-less flat. If you're a really good person, playing this song will probably make you feel nervous and uneasy.
Tony Bennett - I Left My Heart In San Francisco (1962): Frank Sinatra's favorite singer. Highest recommendation. With some of the best headphones, the sibilants on this recording are very strong, but they're not an issue with the P3.