Harman/Kardon Soho Stereo Headphone Review

Discussion in 'Headphone Reviews' started by dalethorn, Dec 28, 2013.

  1. dalethorn

    dalethorn Obsessive Auditor

    Jul 3, 2011
    Charleston South Carolina
    Youtube review: Harman/Kardon Soho Stereo Headphone Review by Dale - YouTube


    Sources: iPhone5, iPhone5 with FiiO E07k using LOD, iPhone5 with Decware Zen Head amp, various computers using the Microstreamer and Audioengine D3 DAC/amps.

    Summing up the Harman/Kardon Soho sound based on a long listen plus direct comparisons to the Beyerdynamic T51p, B&W P7, B&O H6, Shure SRH1540, and a few others, the bass is excellent when heard on its own or compared to headphones that don't have an emphasized bass. But compared to the P7, Srh1540, and to a lesser extent the H6, the Soho's lower bass has a lighter impact, although the bass overall seems to have an ideal warmth and strength - very similar to the T51p. I realize now that these impressions are heavily biased by what a person is most accustomed to, so my descriptions and comparisons should help to show where the Soho fits into the overall bass hierarchy. The Soho midrange is clear, neutral to very slightly dark - again an ideal signature for my listening.

    The Soho treble is clear and clean and well-balanced, and given that this sound is much better than what I imagined for a headphone in this price range, I ran some tone sweeps and discrete tones from different vendors to try to discover where any major deviations from accuracy occurred, since I couldn't imagine it testing as good as it sounds. The bass is smooth and flat down to 45 hz or less, with an estimated 4-5 db rolloff below that. The midrange tones didn't show any significant peaks or dips, and given my impression of an ideal midrange, I'd say it's about as flat of a frequency response as headphones get. Treble response is smooth up to 3.5 khz where there's a mild emphasis - possibly 3 db, followed by a small dip of 3-4 db around 5 khz. Above that it sounds like there's a moderate emphasis around 8 khz, increasing a bit to 4-5 db at 9 khz, followed by a dip of perhaps 3 db at 10 khz. Above 10 khz it's smooth and not remarkable, except to say that there's a decent amount of 'air' for hi-fi listening.

    Since a good soundstage depends on having a full treble, the Soho's soundstage is better than most small headphones since most of those have a recessed treble. But I don't think anyone is going to expect the Soho to perform miracles in that regard. In any case, soundstage in most headphones varies far less in my tests than the various music tracks do, so the better your recordings the better the Soho will sound, and it sounds excellent with my high-res downloads. Using a good headphone amp or DAC/amp with the Soho makes a big improvement in sound quality as well as soundstage (see below), since the Soho was built for high-quality listening.

    Reiterating the most sensitive aspect of the Soho's sound from the most common user viewpoints - the bass does not have any weakness when the Soho is played exclusively for a long enough time for the user to shed their biases based on their familiarity with the more common bass-heavy headphones. People who are gaming and require a heavier impact, or people who use the headphone on public transport where the background sound contains a lot of low frequencies - these users usually prefer a larger headphone which can produce the boosted bass frequencies more cleanly than a small headphone, since the small headphone is typically being stressed beyond its design limits by the use of bass booster controls and EQ settings. Like most quality headphones, the Soho sound improves noticeably with DACs and headphone amps as compared to driving the headphone with just a low-cost portable music player or cellphone etc.

    To appreciate the difference a good DAC and/or amp can make, play music using the DAC/amp first, then switch to the cellphone or music player and hear the difference. That difference is usually subtle and difficult to appreciate the other way around: if you listen with the cellphone first and then switch to the DAC/amp. I think that's because it's easier to hear what detail is lost in the former example instead of what's gained in the latter example, unless what's gained is dramatic as might be heard with some of the more expensive DACs and amps. Soho isolation is low - less than 10 db at high frequencies and even less lower down. Leakage is low - if used in a very quiet office in a cubicle next to other cubicles, persons in the adjoining cubicles won't likely hear disturbing sounds unless the Soho is played very loudly. There's no significant difference in bass response when wearing the Soho with eyeglasses on, since the small-ish earcups sit entirely on the ear.

    The Soho's physical design is nothing less than amazing. Removing it from the box, it looked very small folded up, but felt very dense as most high-quality electronics items tend to be. In spite of that density, the actual weight is light because of the small size, albeit purely plastic headphones are lighter. There's enough clamping force to keep the Soho on your ears if you don't make rapid head movements or bend over very far, and that moderate clamping force is necessary due to the smooth spongy earpads that sit on your ears. Getting those earpads centered on your ear canals is important in getting the full complement of treble frequencies. The headband has little padding, but the light weight makes additional padding unnecessary. However, for anyone bothered by even a slight headband pressure, I recommend pulling the earcups down an extra 1/8 to 1/4 inch to transfer more of the weight from the headband to the earcups. The construction is all metal except for a leather-like covering on the earcups.

    The Soho is ideal for portable use since the earcups can be pulled all the way down and folded flat, and the headphone worn around the neck all day with no problems, since the earcups don't get anywhere near the chin where they would potentially bother the user. Two double-entry detachable cables are supplied with the Soho - both about 4 feet long. Apparently there are 2 Soho versions - one with an Apple-type cable plus a generic cable, and one with cables for non-Apple phones or music players. My Soho is the Apple-compatible type where the non-generic cable has controls for start-stop, volume up and down, and mic. The hard clamshell carrycase supplied with the Soho is a very nice touch, and very useful - small enough to fit into airline carry-on bags or student backpacks without taking up much space in those bags.

    The music tracks below have been listed in several prior reviews, and are a random sample selected from the 400 most recent tracks I've acquired. Since these tracks cover a wide range of genres, and were selected when I was using several different headphones, there won't be a bias toward the Soho headphone with this music. My suggestion is instead of reading each comment below as an absolute unto itself, you could compare these notes to the prior reviews and other reviews as they get posted, and see how the Soho compares with each individual track.
    Last edited: Dec 28, 2013
  2. dalethorn

    dalethorn Obsessive Auditor

    Jul 3, 2011
    Charleston South Carolina
    H/K Soho review part 2 - music samples

    Ana Victoria - Roxanne (Pop Vocal): Spacious sound, good bass tone and impact, and the vocal sounds very natural. Excellent reproduction by the Soho.

    Ben Goldberg - Root and Branch (Jazz): Realistic you-are-there sound with great instrumental reproduction. The Soho plays this extremely well.

    Benedictines Of Mary - O Come Emmanuel (Medieval/Female Choral/Acapella): Very spacious sound and natural reverb for a large recording venue (cathedral). The Soho makes the voices come alive.

    Black Sabbath - Iron Man (Classic Rock): Excellent instrumental detail - the vocal sounds very natural. As with most classic rock tracks, there is very little or no deep bass. The Soho plays this music very smoothly, and the lack of deep bass doesn't unbalance the treble.

    Candy Dulfer - Lily Was Here (Jazz): Narrow soundstage, but excellent detailed instrumental tone. The Soho gives this a reasonable sense of space, but in spite of being a modern recording, the net effect is only slightly better than enhanced mono.

    Cantus - Danny Boy (Traditional/Male Choral/Acapella): The Soho plays the voices with enough low end warmth and weight to sound very natural.

    Chris Isaak - Wicked Game (Pop/Rock): The Soho plays this high treble energy recording with perfection - the voice and instruments are highly detailed but very smooth.

    Daft Punk - Lose Yourself to Dance (Electronic/Disco): Less than hi-fi quality recording, but the voices are very good. There's a decent amount of bass impact, but the bass doesn't have much detail.

    David Hazeltine - Fur Elise (Jazz): A very high-quality recording from HDTracks. The Soho reproduces the instruments perfectly with a you-are-there ambiance. The wire-brush-on-cymbal harmonics are very extended and detailed.

    David Lynch-Lykke Li - I'm Waiting Here (Soundtrack/Vocal): Dark, moody song - Lykke's voice is very detailed, the bass impacts are good, but most of the instrumentation is soft and kept in the background. The Soho plays this music very well given the sonic limitations.

    Dream Theater - Take The Time (Metal): The sound quality here is limited, but the Soho is smooth enough to bring out the details in this very busy music without verging on harshness.

    Genesis - Follow You Follow Me (Pop/Rock):The Soho plays this old and less-than-ideal recording well enough to be very enjoyable, but the soundstage is fairly narrow.

    Giant Drag - Wicked Game (Pop/Rock): Annie Hardy's version of the Chris Isaak hit has a lot of energy, but the quality is limited - still the Soho pulls out enough detail to be a pleasant listen.

    Grieg (Beecham-Royal Philharmonic) - Peer Gynt-Solveig's Lullaby (Classical): This very old (late 1950's) stereo recording must have been made on the most expensive gear in the world, since the overall sound quality and especially Ilse Hollweg's amazing voice are as close to "being there" as I've heard with some of the better classical recordings made since the year 2000. The Soho makes this an outstanding listen.

    Hubert Kah - The Picture (New Wave): This track has great bass detail and weight at the same time, which I find unusual for this type of 1980's pop music. The Soho plays this music very well.

    Hugo Audiophile - 15-16 (Electronic): I'm not sure what the 15-16 stands for - perhaps track numbers from a CD album. The strong deep-bass tones that start around 33-34 seconds into the track reproduce with moderate impact with the Soho. This is a great recording for evaluating whether a headphone's bass will be sufficient for most environments, since for many headphones that have a weaker bass, the deep bass gets absorbed and mostly lost when the environment contains a lot of low-frequency energy.

    Korn - Another Brick In the Wall (Rock): Aggressive rock that's very satisfying for hard-rock fans. The Soho plays this perfectly, which is to say, with proper edginess and bass impact, yet without unintended sonic harshness.

    Kunika Kato - Fur Alina (Vibraphone): A very unusual instrumental - the tone quality is unlike anything I've heard before. Recording close-up is part of the magic here, but the Soho does the rest in reproducing the full harmonics of this amazing instrument.

    Michael Buble - Nice 'n Easy (Easy Listening/Jazz): This is the only track I bought by Michael Buble, but it's a great recording and vocal performance. The sound of the backing band here is rendered extremely well by the Soho, and the voice isn't pumped up for Loudness Wars thankfully.

    Michael Tilson Thomas - Rhapsody In Blue (20th Century Classic): Great sound and soundstage, and terrific piano playing and tone, brought to life by the Soho. There are some very deep bass impacts starting around 38 seconds into the 17:24 length track, and the weight of those impacts is just discernable with the Soho.

    Muse - Madness (Rock): The bass in this track has good impact and detail with the Soho, and although the voice is somewhat forward, it doesn't interfere with my appreciation of the bass line here.

    Phaeleh - Afterglow (feat. Soundmouse) (Electronic/Vocal): The instrumental sounds that begin this track are played very nicely by the Soho, but the voice tends to overwhelm those background sounds - until the heavy bass impacts kick in. If there is any doubt about whether the Soho will play heavy impactful bass with good detail (if such sounds are really in the recording), this track is the proof. If you were to begin your Soho listening with this track, you might think you were listening to a headphone that has a very boosted but tight and detailed bass. Simply amazing.

    Richard Strauss (Mester-Pasadena) - Also Sprach Zarathustra (opening) (Classical): The granddaddy of bass is in the opening 1:50 of this recording, and I've heard it only once on a large and expensive loudspeaker system in Cleveland. For most people, that experience would be indistinguishable from being in a fairly strong earthquake. The Soho reproduces the very deep bass on this track, but the feel of thunder that you'd get with some of the larger bass-emphasized headphones is more subtle with the Soho. The tympani have good impact on this track.

    Sargis Aslamazian - The Sky is Cloudy (Classical/Armenian): The National Chamber Orchestra of Armenia has a great classical program, and the Soho plays this music with good separation, tone, and big-orchestra precision.

    Satri-Tomoko Sonoda - All The Things You Are (Jazz): This track came from Bakoon Products, who make high-quality audio amplifiers. There's a lot of upright bass plucking in this track, and the Soho plays it well, although it's recorded pretty close-up and may sound somewhat boomy at times.

    Tommy Smith - Johnny Come Lately (Jazz): Small-combo jazz - sax, piano and drums. The sound is fairly close-up but well-recorded, and sounds very nice with the Soho, although the wire-brush-on-cymbal harmonics are not as extended as on the David Hazeltine track above.

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