This is a very linear sounding headphone, one with equal parts bass, mids and treble without any of the three primaries fighting for attention. As my ears pick it up, the midrange has some bloom effect occurring, which means the vocals and midrange experience in general is a bit more forward sounding than the rest of the spectrum. The BT540i is also moderately bright on the upper midrange and onward into the higher end, quite a different experience swapping between this Koss and the still on pre-order Sony XB950BT which I have here to compare to.
The low end of the headphone lacks conviction, but is plenty clear for a Bluetooth headphone, safe to say bass heads will not enjoy it and should avoid it if powerful and yummy bass is your thing. Those who want a more balanced sound signature without much bass bleed into the midrange should be right as rain here with the Koss BT540i. From a clarity standpoint, I have some reservations about how well the headphone responds to bass boosting, as well as some concerns about how it responds to bass heavy tracks…which isn’t well. There is audible struggle occurring everywhere on the low end when interacting with bassy track cues. This problem plagued the headphone in both the BT connection as well as a wired connection, even via my $2000 Red Wine AK120B and $650 RSA SR71B portable rig. Even with the best rig out there, or at least one of the best portable rigs via a wired connection, the BT540i failed to impress me with regard to control, sounding muddier and warped as I cranked up the bass a bit.
I wouldn’t take that as a terrible fact, this headphone is branded as a “Crisp” sounding headphone, and this statement made by Koss is indeed reflective of the sound type the headphone offers the listener. The bass experience lacks that broad, expansively rumbling sound that I yearn for. Instead, the BT540i offers a focused tone on the low end that doesn’t extend deeply, but does offer a less exaggerated low end experience suitable for rock, pop and jazz. R&B, Rap and Dubstep lovers should be looking elsewhere, as this headphone might have a bit too much slam effect, as well as a lacking sense of physical quantity of bass that I personally would find unsuitable for these genres. This headphone is snappy on the low end.
I feel like the bass coloration leans towards one of total neutrality, hardly any detectable warmth to the experience. I’ve used many tracks to test quality in this review, I rarely talk about Rap, not really a big fan of the genre in general but I admit there are a few great tracks out there that I enjoy.
Twista – Emotions
While not particularly fantastic in terms of staging quality, the low end experiences generally have a broader and more analog bass type in this genre, so I’ve selected a track that I know increases in warmth and coloration depending on the headphone and the source pairing. My Denon D7000 and Burson Conductor 1793 is vividly colored on the low end through this track, yet is totally barren of warmth and coloration via the wired connection with this BT540i. This can be a great thing for people who prefer a more neutral experience, something more monitor and tonally focused on the low end. I feel the Koss BT540 to lack enough physical quantity to merit calling it a moderately bassy headphone, more of top end of the bass light tier to my ears. The sound quality on the low end is not dependent on BT or a wired connection, as it seems the BT enabled devices of late are more than capable enough to max out the potential clarity aspect the headphone can push. There really wasn’t much of a difference on the clarity front on the $20 BT AZiO dongle vs the $2600 portable rig.
Soundstage, Midrange and Treble
No doubt in my mind that this BT540i offers a very forward, engaging experience when it comes to the midrange and vocal experiences in general. Big band, Jazz and classic rock/pop are where this headphone will shine most. With regard to clarity and dimensionality, the Koss falls short again and doesn’t do much for me. Despite forward sound being my preferred setup and style, I’ve found the BT540i overly flat and dull in staging qualities to merit actual continued usage beyond the review process. I am a sound stage lover and I demand excellent staging properties, of which this headphone hasn’t quite satiated or impressed me with. There is hardly any depth at all to the staging quality this headphone offers, either wired or BT enabled. It really doesn’t seem to matter which route you take, the experience sounds virtually the same in a physical sense. I don’t want to directly compare to the Sony XB950BT, but I can’t shake the feeling that my ears want that on my head right now and not this Koss just so I can hear good sound staging properties in a BT enabled headphone. Relatively poor separation combined with a thin sound signature overall equates to a sound type that I am just not at all fond of. Koss can do better on this front, maybe with some angled drivers or pads.
Something needs to be done on the staging front, it fails to achieve audiophile status, but will compare to the likes of your pick of the non-audiophile branded $199 and under headphones. I would rank the stage depth as the biggest problem. I am willing to deal with the lack of stage width and height and separation but not stage depth this flat sounding, at least by comparison to that new Sony XB950BT, which trumps this Koss BT540i by a moderate degree.
Slow vocal tracks are where my ears feel happiest with this headphone, good old Seth McFarlane, Michael Bubble’ and similar artists with a lively and up front recording style pair nicely with his BT540i. I am not sure if I am asking too much of this headphone at this price point, but I really feel that the midrange is ruined by the lacking stage depth. There aren’t enough dimensions to enjoy in the recording, to get lost in the emotional ties to the artist or the song is something I regard as absolutely vital, yet I cannot achieve that in the BT540i. I am not knocking the headphone, this is still one of the clearest Bluetooth headphones I’ve ever heard, but from an audiophiles standpoint there are a lot of other $199 headphones that are not Bluetooth enabled that sound better. The midrange is plenty clear; in fact again as mentioned previously, for a BT headphone the raw clarity is good. For a standard wired headphone at $199, not really. This fact applies to all areas of listening, all sound qualities.
Treble seems like the strong point of the Koss BT540i, yet it is still too hissy and sibilant for snobs like me. This is a shouty headphone, one that feels like it is blaring on tracks like Pharrell Williams – Happy, something with a lot of hand claps and prominent vocals. The sound signature of the headphone works against the solid treble experience and quality, which is good for a $199 headphone, but not good once the pace picks up. The entire top end gets smeared and loses detail, the faster the track, the worse this sounds. I do feel Koss tuned the top end very nicely, I really enjoy the overall brightness and bite, not too much, not lacking, just right for me and I can certainly say that I would like to clone the treble experience into another BT headphone I have here and that is awaiting its own review.