The Harman Kardon CL (Classic) is a light weight closed back on-ear headphone that was introduced in 2012. Since then, much has been written on this new headphone entry from Harman Kardon. From most reviews I've read there seems to be general agreement on the overall tonal characteristic of the CL. To summarize, the CL has an overall warm balance and a somewhat muted sound, due primarily to a mid-bass emphasis and rolled off top end - all of which, at least for the most part, mirrors my impressions of the CL. I would add, what I also find missing is detail and air which results in a reduced sense of space. With the CL you have a smaller, more intimate soundstage with less separation between instruments.
Not wishing to repeat what seems to be general agreement on the tonality of the CL, I'll dispense with the typically treble, midrange, bass blow by blow headphone description of the CL. Instead, in this review, I'll focus primarily on those aspects of the CL (both good and bad) that stand out for me which are bass, comfort, and placement. Then I conclude with a general recommendation for those considering the CL.
Equipment
The source used in this review was a Windows based PC running J.River Media Center v19 playing FLAC files with resolutions ranging from 16/44 to 24/192. The primary DAC/Amp used to drive the headphones was a Light Harmonic GeekOut 450 that I purchased recently at the California Audio Show in August. A Benchmark Media DAC1 PRE was also used briefly, but once the GeekOut proved up to the task I stayed with the Geekout. The GeekOut 450 had more than enough power to drive the two headphones used in this review, and the dual headphone jacks on the GeekOut allowed two headphones to be simultaneously connected to the source for quick comparisons.
Bass
A little background on my tastes. I value good bass in a system. That is to say, I value bass that is solid, accurate, articulate, and that extends to 20 Hz, which is why I've augmented both my desktop and home theater systems with subwoofers. Systems without a solid bass foundation to me are uninvolving and frankly, a bit boring.
So by that measure does the CL satisfy this need? No, unfortunately it doesn't. What I found is the CL does have a healthy mid-bass bump in the 40-80 Hz region. Some will find this to be too much of a good thing on some recordings. But then again, on other recordings, this bass emphasis adds just the right amount of weight to make the CL fun to listen to. When the music calls for it, the CL can also reach down and rumble in the 20-30 Hz sub-bass region which is quite impressive. For an example, try the Heartbeat track on the Head-Fi and HDtracks presents Open Your Ears, or for some real fun listen to the drop (centered around 45Hz) at 1:08 seconds into the Datsik: Murder Style Original Mix track on the Speak No Evil EP and then again on the same track starting at 1:43. It's sounds a bit woolly, but it still is impressive for this on-ear headphone.
Comparing the bass to another on-ear I own, the V-Moda XS, the bass of the XS is more accurate from the standpoint of being flatter, and tighter than the CL. But I like the fact that with the CL's enhanced bass, I'm able to listen at lower volume levels and can still enjoy the visceral impact of bass when it's present on a recording.
Comfort
Fit was an issue for me. Specifically, I found the standard headband clamping force to be heavy, too heavy to be comfortable for more than 1 or 2 hours. This is not a headphone I can wear all day without periodic recovery breaks from the pad pressure; although, for me, I can say the same about the V-Mode XS. The clamping force does however provide a good on-ear seal that blocks out some amount of exterior sound. Later I found that switching to the large headband provides a much more comfortable experience because of a lighter clamping force (more on this below). As final note on on-ear comfort, the CL rectangular pads were noticeably softer, distributed pressures over a wider area, were more comfortable, and provided a slightly better seal than the XS.
Placement
What I discovered with the CL is "placement matters". On a recommendation from fellow Head-Fi'er MrNaturalAZ (thank you), I began to experiment with positioning the ear pads. Once I realized I needed to position the ear pads lower to improve the treble response, I found the normal range of adjustment of the standard small headband limited my ability to position the ear pads properly. I promptly switched to the second "large" headband which provided a twofold benefit. First, it allowed me lower the ear pads to an optimum position, and second, the large headband seems to have less clamping pressure. With the large band, I'm now able to wear the CL for a longer period of time before experiencing any discomfort.
Note: Anticipating the need for a wider range of adjustment, Harman Kardon conveniently provides two headbands with the CL - the standard "small" band and a second "large" band. The underside of each band is marked with an "S" or "L" to differentiate between the two bands.
Takeaway: The most comfortable position may not provide the best frequency response, and treble performance can be improved with proper ear pad placement.
Conclusion
I mentioned at the outset that the tonal balance of the CL favors the mid-bass region and the highs are recessed. When combined, the balance of these two regions leaves a midrange that sounds very warm; Some may feel excessively so, even to the point of sounding muted. However, the upside of this tonal imbalance is I can listen to the CL for many hours without fatigue. I found the CL to be a very forgiving headphone with music I previously found to be harsh. Yes, the CL clearly has a colored sound signature and when listening you may find yourself increasing the volume level to extract a bit more detail. But, if the balance is to your liking you might find the CL to be a very listenable headphone that can be had for a very attractive street price ($60-$80). However, I'd like to again emphasize most of my time with the CL was spent listen to FLAC files from a PC feeding a GeekOut 450; although some time was also spent listening to streamed music via Pandora, which through the PC I found acceptable. I feel this bares repeating because the CL connected directly to an iOS device with less than optimum amplification and low resolution music will likely result in a slightly darker less detailed sound.
That being said, if your budget is targeting headphones at $200 or less, at its current street price, the CL should definitely be on your short list of headphones to audition. Why? Because in addition to being reasonably priced, the Harman Kardon CL more importantly, passed my goose bump test. By that I mean, with the CL, I can close my eyes, listen to a performance, and be transported to a place that is emotionally engaging. One example of this would be Adele's performance, on the Live at the Royal Albert Hall recording, where she closed the evening with her hit Rolling in the Deep. The power of Adele's voice combined with the energy of the crowd made for a most memorable event, and the CL, even with all its faults, is still able to convey the sense of excitement that filled the hall. I only wish I could have been there to experience Adele's performance first hand. In summary, the Harman Kardon CL is a very affordable option that provides just enough soul to make the second hand listening experience pleasantly enjoyable.
Equipment
Harman Kardon CL (now modded - see Addendum)
V-MODA XS
AMD based PC
Light Harmonic GeekOut 450 (v1.5 firmware)
Benchmark Media DAC1 PRE (discontinued)
Software
Windows 7 Professional
J.River Media Center v19 (FLAC player)
Music
Adele: Live at the Royal Albert Hall (XL Recordings)
Igor Stravinsky, The Firebird - Finale: Tutti! Orchestral Sampler (Reference Recordings)
Various Artists: Head-Fi and HDtracks presents Open Your Ears (David Chesky & Head-Fi)
Various Artists: Speak No Evil EP (Datsik: Murder Style Original Mix)
Addendum (11/2014)
Ear Pad Barrier Mod
As I was about to complete this review, I was researching the competing P3 model from Bowers & Wilkins. I watched, with great interest, Tyll Hertsens's review of the P3 because the Harman Kardon CL pads are very similar to those found on the P3. In closing his review, Tyll remarked he believed the muted high frequency response of the P3 may be caused by the ear pad foam absorbing too much high frequency energy.
Since I also felt the CL high-end was recessed and the pads were similar in construction to the P3 pads, I wanted to test Tyll's theory and create a barrier to reduce the amount of absorption from the foam. For simplicity, I decided to fashion a ring to partially isolate the foam. I experimented with few different materials (eg. masking tape and duct tape), but finally settled on a thin velcro like cable management material for the ring. You may wish to experiment with other materials to tailor the sound to your liking. To create the barrier rings, cut two small strips of the material (each approx. 4 3/4" x 1/4") then form each strip into a ring slightly larger than the circular opening of the pad. To install the rings, remove both ear pads (which are magnetically attached), insert one ring into each ear pad, then replace the ear pads. Because the material I choose is somewhat stiff, I found it necessary to reduce the thickness of the ring until I was able to achieve a comfortable ear pad seal. You may need to slightly adjust the thickness of the ring up or down a bit to meet your needs. The actual modification is shown in the pictures below. With the installation of this simple mod, there was an immediately noticeable impact on the sound signature.
Barrier Ring:
Before (without the ring):
After (with the ring):
The modded CL still has a warm balance, but vocals are less veiled, and now there's additional detail and high end sparkle that was lacking before the mod. One additional benefit of this mod is I no longer need to re-position the ear pads for optimal sound. With the mod, the most comfortable position also provides acceptable sound. This mod doesn't cure all ills, but I found it to be an improvement over the stock pads. This is a simple mod that anyone can perform that may (or may not) be to your liking. The good thing about the mod is it's completely reversible. I suggest all CL owners looking to extract a little more detail from their CLs, at least give the mod a try.
Not wishing to repeat what seems to be general agreement on the tonality of the CL, I'll dispense with the typically treble, midrange, bass blow by blow headphone description of the CL. Instead, in this review, I'll focus primarily on those aspects of the CL (both good and bad) that stand out for me which are bass, comfort, and placement. Then I conclude with a general recommendation for those considering the CL.
Equipment
The source used in this review was a Windows based PC running J.River Media Center v19 playing FLAC files with resolutions ranging from 16/44 to 24/192. The primary DAC/Amp used to drive the headphones was a Light Harmonic GeekOut 450 that I purchased recently at the California Audio Show in August. A Benchmark Media DAC1 PRE was also used briefly, but once the GeekOut proved up to the task I stayed with the Geekout. The GeekOut 450 had more than enough power to drive the two headphones used in this review, and the dual headphone jacks on the GeekOut allowed two headphones to be simultaneously connected to the source for quick comparisons.
Bass
A little background on my tastes. I value good bass in a system. That is to say, I value bass that is solid, accurate, articulate, and that extends to 20 Hz, which is why I've augmented both my desktop and home theater systems with subwoofers. Systems without a solid bass foundation to me are uninvolving and frankly, a bit boring.
So by that measure does the CL satisfy this need? No, unfortunately it doesn't. What I found is the CL does have a healthy mid-bass bump in the 40-80 Hz region. Some will find this to be too much of a good thing on some recordings. But then again, on other recordings, this bass emphasis adds just the right amount of weight to make the CL fun to listen to. When the music calls for it, the CL can also reach down and rumble in the 20-30 Hz sub-bass region which is quite impressive. For an example, try the Heartbeat track on the Head-Fi and HDtracks presents Open Your Ears, or for some real fun listen to the drop (centered around 45Hz) at 1:08 seconds into the Datsik: Murder Style Original Mix track on the Speak No Evil EP and then again on the same track starting at 1:43. It's sounds a bit woolly, but it still is impressive for this on-ear headphone.
Comparing the bass to another on-ear I own, the V-Moda XS, the bass of the XS is more accurate from the standpoint of being flatter, and tighter than the CL. But I like the fact that with the CL's enhanced bass, I'm able to listen at lower volume levels and can still enjoy the visceral impact of bass when it's present on a recording.
Comfort
Fit was an issue for me. Specifically, I found the standard headband clamping force to be heavy, too heavy to be comfortable for more than 1 or 2 hours. This is not a headphone I can wear all day without periodic recovery breaks from the pad pressure; although, for me, I can say the same about the V-Mode XS. The clamping force does however provide a good on-ear seal that blocks out some amount of exterior sound. Later I found that switching to the large headband provides a much more comfortable experience because of a lighter clamping force (more on this below). As final note on on-ear comfort, the CL rectangular pads were noticeably softer, distributed pressures over a wider area, were more comfortable, and provided a slightly better seal than the XS.
Placement
What I discovered with the CL is "placement matters". On a recommendation from fellow Head-Fi'er MrNaturalAZ (thank you), I began to experiment with positioning the ear pads. Once I realized I needed to position the ear pads lower to improve the treble response, I found the normal range of adjustment of the standard small headband limited my ability to position the ear pads properly. I promptly switched to the second "large" headband which provided a twofold benefit. First, it allowed me lower the ear pads to an optimum position, and second, the large headband seems to have less clamping pressure. With the large band, I'm now able to wear the CL for a longer period of time before experiencing any discomfort.
Note: Anticipating the need for a wider range of adjustment, Harman Kardon conveniently provides two headbands with the CL - the standard "small" band and a second "large" band. The underside of each band is marked with an "S" or "L" to differentiate between the two bands.
Takeaway: The most comfortable position may not provide the best frequency response, and treble performance can be improved with proper ear pad placement.
Conclusion
I mentioned at the outset that the tonal balance of the CL favors the mid-bass region and the highs are recessed. When combined, the balance of these two regions leaves a midrange that sounds very warm; Some may feel excessively so, even to the point of sounding muted. However, the upside of this tonal imbalance is I can listen to the CL for many hours without fatigue. I found the CL to be a very forgiving headphone with music I previously found to be harsh. Yes, the CL clearly has a colored sound signature and when listening you may find yourself increasing the volume level to extract a bit more detail. But, if the balance is to your liking you might find the CL to be a very listenable headphone that can be had for a very attractive street price ($60-$80). However, I'd like to again emphasize most of my time with the CL was spent listen to FLAC files from a PC feeding a GeekOut 450; although some time was also spent listening to streamed music via Pandora, which through the PC I found acceptable. I feel this bares repeating because the CL connected directly to an iOS device with less than optimum amplification and low resolution music will likely result in a slightly darker less detailed sound.
That being said, if your budget is targeting headphones at $200 or less, at its current street price, the CL should definitely be on your short list of headphones to audition. Why? Because in addition to being reasonably priced, the Harman Kardon CL more importantly, passed my goose bump test. By that I mean, with the CL, I can close my eyes, listen to a performance, and be transported to a place that is emotionally engaging. One example of this would be Adele's performance, on the Live at the Royal Albert Hall recording, where she closed the evening with her hit Rolling in the Deep. The power of Adele's voice combined with the energy of the crowd made for a most memorable event, and the CL, even with all its faults, is still able to convey the sense of excitement that filled the hall. I only wish I could have been there to experience Adele's performance first hand. In summary, the Harman Kardon CL is a very affordable option that provides just enough soul to make the second hand listening experience pleasantly enjoyable.
Equipment
Harman Kardon CL (now modded - see Addendum)
V-MODA XS
AMD based PC
Light Harmonic GeekOut 450 (v1.5 firmware)
Benchmark Media DAC1 PRE (discontinued)
Software
Windows 7 Professional
J.River Media Center v19 (FLAC player)
Music
Adele: Live at the Royal Albert Hall (XL Recordings)
Igor Stravinsky, The Firebird - Finale: Tutti! Orchestral Sampler (Reference Recordings)
Various Artists: Head-Fi and HDtracks presents Open Your Ears (David Chesky & Head-Fi)
Various Artists: Speak No Evil EP (Datsik: Murder Style Original Mix)
Addendum (11/2014)
Ear Pad Barrier Mod
As I was about to complete this review, I was researching the competing P3 model from Bowers & Wilkins. I watched, with great interest, Tyll Hertsens's review of the P3 because the Harman Kardon CL pads are very similar to those found on the P3. In closing his review, Tyll remarked he believed the muted high frequency response of the P3 may be caused by the ear pad foam absorbing too much high frequency energy.
Since I also felt the CL high-end was recessed and the pads were similar in construction to the P3 pads, I wanted to test Tyll's theory and create a barrier to reduce the amount of absorption from the foam. For simplicity, I decided to fashion a ring to partially isolate the foam. I experimented with few different materials (eg. masking tape and duct tape), but finally settled on a thin velcro like cable management material for the ring. You may wish to experiment with other materials to tailor the sound to your liking. To create the barrier rings, cut two small strips of the material (each approx. 4 3/4" x 1/4") then form each strip into a ring slightly larger than the circular opening of the pad. To install the rings, remove both ear pads (which are magnetically attached), insert one ring into each ear pad, then replace the ear pads. Because the material I choose is somewhat stiff, I found it necessary to reduce the thickness of the ring until I was able to achieve a comfortable ear pad seal. You may need to slightly adjust the thickness of the ring up or down a bit to meet your needs. The actual modification is shown in the pictures below. With the installation of this simple mod, there was an immediately noticeable impact on the sound signature.
Barrier Ring:
Before (without the ring):
After (with the ring):
The modded CL still has a warm balance, but vocals are less veiled, and now there's additional detail and high end sparkle that was lacking before the mod. One additional benefit of this mod is I no longer need to re-position the ear pads for optimal sound. With the mod, the most comfortable position also provides acceptable sound. This mod doesn't cure all ills, but I found it to be an improvement over the stock pads. This is a simple mod that anyone can perform that may (or may not) be to your liking. The good thing about the mod is it's completely reversible. I suggest all CL owners looking to extract a little more detail from their CLs, at least give the mod a try.
) without being lossy and/or boosted the SH!$ out of it (I'm looking at you beats ¬_¬). The Recessed mid, however, CAN totally affect a whole spectrum of music, especially the kind of music that has a lot of low end (something among 80-240HZ), wich unfortunaly for me, was the favorite sprectrum for the 80's Metalheads to crank up to eleven, making the guitars sound really bassy and sometimes dull and lossy. The sightly boosted and crispy highs of the CLs could be either Awesome or disgusting, that's really a personal preference, some people might is "Nasal" and "Too Edgy", but I consider it Snappy and crispy with a unique character; it also favors A LOT Female singers and more modern guitar tones 
