Dec 14, 2018254 views

Focal CSD Measurements

Focal gets a lot of hype in online headphone discussion forums these days. For those unfamiliar, Focal utilize a novel 'inverted dome' diaphragm for their drivers. . . one of the known issues for this is that they hard clip at higher volumes, but this is not often an issue for reasonable listening levels. I am curious if there are other unspoken limitations, given the apparent novelty of this driver approach. Despite a humiliating fiasco for Utopia manufacturing precision (https://www.innerfidelity.com/content/focal-utopia-update), Tyll had an enduring fascination with the brand. I personally think this informs a lot of the current enthusiasm. I have recently been looking at spectral decay plots, something that unfortunately Tyll could not produce on his otherwise legendary test rig. It appears to me that the inverted domes could have a similar persistent issue with spectral band ringing in the upper mids: Focal clear CSD (https://www.soundstagenetwork.com/index.php?option=com_content&view=article&id=1823:focal-clear-headphones&catid=263&Itemid=203)
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Their Elegia measurement shows some resonance around 3.5K as well, but it appears relatively better damped than for the clear (https://www.soundstagenetwork.com/index.php?option=com_content&view=article&id=1965:focal-elegia-headphones&catid=263&Itemid=203):
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I had a fresh look at the very fine folks at SBAF measurements of the clear specifically (https://www.superbestaudiofriends.org/index.php?threads/focal-clear-measurements.5529/)
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Despite the lower spectral res of this CSD, we see similar resonant peaks in the upper mids. . . In a hobby where folks claim to differentiate between amps/DACs at >120 dB SNR, it seems a bit telling that relatively pronounced -20 dB ringing has gone without objection on these 'end game' cans. . . Thoughts? Is this another fundamental (if relatively unobjectionable, given the resonance window) shortcoming of the 'inverted dome'?
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Anarghya Jantali, Volly, and 5 others
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kjling
oops... was meant to be a sub-reply to my note below...
kjling
Gorgeous!
IMHO, measurements, specs are all well & good... but ultimately, this hobby is so subjective that no amount of charts will inform us of what we like to hear on the day. E.g. i do like the benchmark HD6xx especially on a tube amp (which will always measure worse than SS amps) but I love my Elex and LOVE the Utopia. Yet I also enjoy the Audioquest NightOwl Carbon, a super laidback warm headphone and my LCD2C. A modded Hifiman HE-560 (ZMF auteur suede non perforated pads) is heavenly, and my current muse is the Hifiman Arya. I also have a ZMF Verite Ltd on the way. My likes are super diverse, i might even be accused of being easy to please. Yet I am not impressed at all by the HD58x, K7xx (only good for gaming due to extra wide soundstage), which others will sing high praises for. My 1 cent - YMMV, just try if possible before u buy, and go with what u like to hear. Don't let anyone tell you otherwise.
WOW! Louder sound takes longer to drop below 55db than quieter sound, this is real mystery why its like that, we should hire Sherlock Holmes or Columbo to investigate this phenomena.
Neubrineo
Resonance has a pronounced effect on decay rate regardless of the initial or final value, it's fundamental to its nature. So, no, when its part of a resonance like this quieter sounds might take longer, despite being from a lower initial value. This is ringing (resonance), possibly as a predecessor to well known hard clipping, neither of which you seem to understand based on your cute quip here, Columbo.
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I haven't noticed any 'ring' in my Elex but I have gotten them to clip on some audio tracks. I thought I broke them, at first and was going to return/exchange them. Then, upon research, I found that this was 'common'. I love the Elex and listen to them every day. I just wish the clipping wasn't a thing.
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Time to give your ears a break haha! Hopefully they'll be able to appreciate lower level listening after that :p
phoenixsong
As the immortal Ricky Bobby once said....
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Out of curiosity, do you have much experience listening with Focal headphones? As a pretty solid fan, I can tell you that ringing is not as prevalent as you may think and it's more akin to the tonality of other metal treated drivers. So if you're used to that sort of tonality, you know what to expect here. Some people are turned off by it but I've been listening to these types of drivers for years so for me it's the norm. The over excursion issues is hard mechanical clipping. Focal has been pretty outspoken about this, the why, etc. AFAIK, the Clear and Elegia are the only models that don't exhibit this. The Elex may be the worst offender followed by the Elear. And trust, I have to really give the Elex some power to push them to that point. I only really notice on songs with a heavily distorted low-end when the volume is turned way up. Personally, I don't think it's an issue in the real world. Especially with the Clear. They live up to their namesake for a good reason.
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I have. Some WA7's and the iTube2, actually. I still prefer them out of an SS amp. I actually really enjoy the bass in the Focal's as it is. The bass lacks quantity but that's not a bad thing. It's of such good quality I don't mind and it extends quite far. I have the Atlas or X00 Ebony's when I'm in a basshead mood :)
jaydunndiddit
neither the WA7 nor the iTube2 uses the Tung Sol 5998.. take my word for it, and look out for a chance to try it on an amp that runs it one day :) Or sth like the Glenn OTL with 6x 6BX7/6BL7 or 2x 6336 power tubes.
I would also think that the type of metal they use could be a culprit. The Elear, Clear and Elegia use the same Alminum / Magnesium metal drivers. The Utopia however uses Beryllium. Personally I've never been a fan of aluminum in drivers. I do own the Elear though, and I do hear that peak in a few types of music.
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I doubt the transducer precision would compare, but there are a lot of quite nice audio analyzer apps for Android / iOS that can use your phone mic. I use 'Sound Analyzer App' for Android, I like that it also gives you a spectral breakdown. I would think it would tend to overestimate the SPL per channel, since it's hard to isolate the cross channel speaker from the phone mic. . . still quite useful to level match for A/B (and don't kid yourself, any listening comparison without level match should be treated as very suspect)
This is a good point, and I think something we should generally keep in mind when comparing THD specs at 90+ dB! The particularly dramatic Soundstagenetwork Focal measurements are at 94dB, maybe no surprise then that there is some 'rattle' showing at relatively low (and narrow) levels, not even hard clipping per say.
Great work!