Synergistic Research HT Carbon – It’s Magic. Or not.

I think it’s safe to say the HOT and HT Carbon are highly controversial but even Tyll from Innerfidelity  – someone I respect – dropped by at Synergistic’s booth at T.H.E Show Newport to check out the HT Carbon. I found it amusing when the SR rep said: ”It has a cleansing effect and I’ll leave it at that”. Check out Tyll’s full video here:

I’m fairly skeptic when it comes to this kind of “cleansing” products but in my opinion you always have to listen to something first before simply stating it works or doesn’t work. I did just that with the AudioQuest JitterBug in example and I could only conclude the JB simply doesn’t do any magic for me in my main system. The JitterBug goes for only $49 though, the HT Carbon has a $349 price tag if I’m not mistaking and that’s a whole different story. The “listen first” advice does not go for any of the products sold on Coconut-Audio though but do go there if you need a good laugh.

Back to Business

Last December I finally ordered the Sennheiser HD800 – yes the old one – and together with the Hifiman HE-1000 it are the headphones I listen most to in my free time. At more or less the same time a friend of mine asked if I was interested in burning in a brand new Leben CS300F for him. Before he finished his sentence the Leben was in the backseat of my car already. Doors locked.

Using the Headphone Transducer in combination with new gear you don’t know very well yet doesn’t seem like a good idea to me and so I on top of the Leben used the Violectric V850 + V281 for testing the HT Carbon. You won’t hear me say the HT Carbon makes your headphones sound better, but they certainly sound different.

When I posted a picture of the HT Carbon on our social media, the first thing someone told me was to break it open. I won’t be doing that but I wouldn’t be surprised if there again is sand, glue and a bunch of resistors/filters in there. I’m sure someone will crack one open soon. Is it important what is inside the HT Carbon? Yes. Of course we don’t want them to be selling something “empty” or filled with sand and magic crystals but then again if it has an impact on the sound, an impact you like…? Some will probably say Synergistic Research is selling snake oil here based on what happened with the HOT but I’m also convinced others can’t imagine their setup without the HT anymore. The first thing I noticed with the HT connected to the HD800 was how it gave a feeling of added “air” as its sound got more spacious in a Nighthawk kind of way. There also is a bigger focus on the vocals and somehow the HT Carbon seems to put vocals more to the front. I do get the impression of bass being elevated somewhat while the midrange is a little more in the back (less body)and is smoother to listen to. Smoother, to me, means losing some detail and layering in this case but the HD800 do is easier to listen to. Not that I find the HD800 a fatiguing headphone. What I am missing most when using the HT Carbon is “emotion” because of the difference in layering and the micro detail that seems to get filtered out to get the blacker background. Treble, to me, also seems less extended. I wouldn’t call it a cleaner sound. I have to say I don’t really like the HT Carbon’s effect on the HD800 and the Hifiman HE-1000. Your ears do get used to the HT Carbon effect rather quickly though and I have to admit it does give the impression to improve some very bad recorded albums in my collection.

So yeah, in the end I’m not sure I like what the HT Carbon is doing to my sound. While I’m sure some will find it fantastic, I personally am more inclined to say it doesn’t improve my listening experience. Trying the HT Carbon in my system was fun but I can’t really say I found it to “clean up” the sound.

What do you think of these kinds of audio tweaks? Do you believe in them? What is your experience with them? Have you found any that really work? And, how much would you pay for them? Do try to stay civilized though.

I look forward to reading real reviews on this gadget in the coming weeks and months and I’ll for sure be tracking any new threads that might pop up on Head-Fi or SBAF. Fun guaranteed.

Please Disqus below. (pun intended)

2.6/5 - (16 votes)
Facebooktwitterredditpinterestlinkedin

Lieven is living in Europe and he's the leader of the gang. He's running Headfonia as a side project next to his full time day job in Digital Marketing & Consultancy. He's a big fan of tube amps and custom inear monitors and has published hundreds of product reviews over the years.

15 Comments

  • Reply January 28, 2016

    spudgered

    I had the original version of this device and it actually made my headphones sound worse! It added a muddy smear to the music which attenuated frequency extremes and was very unpleasant to listen to. I took the HOT to a mini-meet and 90% of listeners thought it was detrimental to their headphone listening. Unsurprisingly a tube packed with sand and a wire with a bit of tin foil in it ain’t conducive to aural pleasure nor your wallet! AVOID AS THIS IS PURE SNAKE OIL.

  • Reply January 28, 2016

    dalethorn

    Another good look at an odd product – thanks. Seems obvious from your review that it is a filter and so some data is removed by the filtering. Probably not good. I remember when I began my adventure with some bright headphones, among which was the Shure 1440. My simple mods for filtering highs involved stuffing the earcups. What I learned was that the material used for that purpose makes all the difference, i.e. you’re likely to get best results by using what Beyer, Sennheiser, and other mfrs. use. At $350, this HT filter should be using the best materials known to hi-fi science.

    • Reply January 28, 2016

      Headfonia_L.

      Thanks Dale! It’s a “special” unit, that’s for sure. But like with everything, I’m sure some people will like what it does. That being said, I’d be more inclined to say those who do aren’t listening to the right headphone for their taste. Like maybe a T90 in combination of someone who likes thick dark mids and hates treble.

      • Reply January 28, 2016

        dalethorn

        Yeah – if headphone A sounds a bit ragged and the filter makes it seem smoother, happy customer. For awhile at least.

    • Reply February 1, 2016

      ohm image

      Dale’s famous Shure 1440. Oh, we remember that!

      • Reply February 1, 2016

        dalethorn

        That’s actually a decent headphone. Bright, but addressable with the acoustic pads. Decent bass (unlike the Shure 1840). Now at bargain prices.

        • Reply February 1, 2016

          ohm image

          I believe you. I’ve not picked one up specifically for comfort reasons. That said, I am getting a Myst IzoPhones, which is about as clampy as they get.

          • Reply February 1, 2016

            dalethorn

            If you’re willing to pay shipping, I’ll send you my Flare Audio R1 at no cost. Then you will experience something akin to the Iron Maiden (and not the music group of that name).

  • Reply January 28, 2016

    SquidCap

    Measure it ffs. If a person review gear, he maybe should invest in the tools he needs to make any kind of valid testing. No need to fucking guess, second hand oscilloscope, one 80 buck ADC and a UMIK should at least be in the inventory. Amateurs..

    In this case, i’ll bet we find: lopass/high-shelf, -2dB starting from 12k, presence peak between 3k-8k around 3dB. Then you measure it with multimeter and reverse engineer the filter.. It is not rocket science.

    • Reply January 28, 2016

      Headfonia_L.

      Dear Sir, be open minded, not everything is about measurements. I’ll take my ears anytime over numbers. Not saying numbers aren’t important but if it sounds good, I really don’t give a heck about measurements.

      • Reply January 28, 2016

        dalethorn

        Our problem is that measurements are good tools for manufacturing and quality control, but they don’t model the listening experience very well. Someday maybe there will be a breakthrough.

  • Reply January 28, 2016

    Joseph Quattrochi

    Props to you for giving this product an honest try. As an aside, I can’t help but notice a sentence that stands out to me as..a bit strange.

    “The first thing I noticed with the HT connected to the HD800 was how it gave a feeling of added “air” as its sound got more spacious in a Nighthawk kind of way.”

    In what universe does adding more air and spaciousness to the HD800 make it more similar the Audioquest Nighthawk?

    • Reply January 28, 2016

      Headfonia_L.

      it means: in an artificial, unnatural and blooming way 🙂

  • Reply December 27, 2017

    Larry

    Thank you for your honest review. This confirmed my suspicion that as an active device, it may make less musically accurate and revealing headphones sound better — a Band-Aid of sorts. But with higher-end gear, I prefer more passive tweaks (i.e. Synergistic’s HFT devices for room acoustics).

    Speaking of passive devices, has anyone at Headfonia reviewed the Bybee QSE? I’ve heard them in high-end home audio systems and they’re magical — the vocals and instruments become more 3-dimensional, I feel a deeper emotional connection to the music, and the soundstage is enhanced. I’m planning on buying a Woo Audio Eclipse along with a couple QSEs to improve the sound even further.

    • Reply December 27, 2017

      dale thorn

      For me, a $350 tweak has to be pretty much non-controversial. Controversy is OK for a $50 tweak, maybe even $100 if it has great promise, but for $350 as a mere tweak, it had better be an unambiguous improvement.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.