Audeze LCD-XC (2021) Analysis and Measurements

Background

Back in the time when I purchased LCD-X 2021 (henceforth abbreviated as X; similarly LCD-XC 2021 will be shortened to XC in my posts) early this year, I was hesitating between X and XC until the final moment to hit the order submit button. My assumption was X could be better in tonality (I favor open-back LCD tonality) but XC might be more practical for office uses. The pandemic and work-at-home situations seem to prolong, thus I went for X in the end.

Months later, I came across RD’s findings on XC’s characters over previous Audeze products. A few of them might be persistent with Audeze’s closed-back LCDs, but I feel like there’s some voicing changes in XC, which made me jump into the loaner tour lately. I know the likelihood to purchase XC for myself is extremely low for now because of their weights, but I want to find out XC’s voicing and technical capabilities myself.

 

Subjective Evaluation

Most of the subjective evaluation below was done via Soekris DAC 2541 as a dac-amp with its builtin amp and 4-pin XLR out.

What I Like

• During my time, I couldn’t hear the cup resonance nor too much closedness. For closed-back headphones, this is one of a few crucial decision criteria for me and Audeze easily nailed it. XC actually behaves more like open-back headphones in presentation.
• As usual in Audezes, XC is very responsive to equalizers. The stock tonality of XC was sometimes a little edgier and sharper on the lower treble than I prefer, but it was tunable with almost minimal effort (no hassle, only few filter settings, etc).
• I appreciate XC’s deep, tight and fast bass. 2021’s less airtight and shallower pads seemed to give a tiny disadvantage in linearity of the lowest frequency, but that was addressed very well in XC if not completely resolved. Frankly XC’s bass was definitely on the impressive side even within the Audeze spectrum.

What I Don’t Like

• In both stock and equalized configuration, front-to-back staging is not a strong suit. Testing with the Abyss test tracks, I found it difficult in distinguishing mic at 6ft from the sound source form at 9ft. It’s not a disaster (only very few HPs can do this to my liking) but XC’s relatively good lateral staging might make it worse to some extent. I was also underwhelmed in the imaging direction test -- hard to discern 0 and 45 degrees to my ears.
• XC weighed 710g on my scale and that’s heavy on the head. Kinda expected. Not very surprising.
• While carbon cups look very sleek to my eyes, Audeze should have chosen better fonts for their logo on the cup. Or taking out all alphabetical letters might have been a much better idea.

Comparison

• If I recall correctly, X and XC sound similar rather than different except for tonal balance. However, I wasn’t too bothered by virtual stages when I had LCD-X unlike this time around (no matter whether XC was equalized or not). I believe this perceived discrepancy partly comes from different amplification as I used much better amps for X.
• On the other hand, XC can reproduce better bass in the lowest register where X was a little shy to my taste.
• Both my modded HD6XX and the loaner XC had difficulty in handling microdetails, but in different ways. By comparison, XC seems to filter out small details and make a cleaner and clearer presentation while 6XX out-resolves but fails to articulate.
• I hear slightly more technical cues with XC compared to the two Fostex vintage orthos in the house (T30, RP18), but the margin is slim at best. While XC also excels over Yamaha HP-1 in many criteria, it’s worth noting Yamaha was better at separating and placing multiple layers.

 

Measurements

All the measurements below were done via MiniDSP EARS and the same Soekris 2541 was used as a dac-amp. Mainly calibrated at 95db spl@300hz otherwise specified. You may also be interested in Marv’s measurements. But, as usual, be ready to pay enough caution in every cause of discrepancy when cross-comparing things.

1. Frequency Response



2. THDs at 95, 100, and 105 dbSPL@300hz



3. Breakdowns by Harmonics Order



4. CSD Waterfall

 

Thoughts on Measurements

My comments below.

• Bass FR discrepancy is probably due to the seal. My perception is closer to the left channel curve for both ears.
• Overall FR seems very linear except for the gradual peak around 2.5khz with zero hint of troubles in CSD plot. Small and narrow peak at 8.5khz is audible but not in an annoying way by any means.
• THD rises by roughly 5db as fundamental increases by 5db. Looking at the second and third orders separately for those levels, it seems that the marginal THD was mostly explained by the D2 incrementals (additional plots below).
• Individual harmonics at 95db illustrate XC’s superb control on higher order harmonics for 200hz upward.
• CSDs at 95db look very clean and linear in time for closed-back headphones. Seems very well behaving across the entire spectrum.

Here are D2 and D3 curves for the left channel.

 

Additional Measurements

Below are FR and CSD plots WITH equalizer settings I settled down. Focus on clean downward shifts from the stock curves.

 

@Vtory Your LCD-X distortion and CSD measurements are cleaner than LCD-XC. Assuming all else is the same we assume then the extra noise is due to closed cup resonance and/or reverb? What do you make of it @rhythmdevils ? since I think it was hypothesized that the drivers would be more damped due to the closed cups. And as we saw with your HE-6se damping mods, damping does reduce CSDs. Does this LCD-XC demonstrate how closed or any strongly reflective surface (even semi-porous damping material like micropore tape) is bad for sound? Would stuffing the cups with some absorbent material help?

 

It’s just cup resonance and not getting the tuning right with the LCD-X driver in a closed back cup. I’d do lots of mods to try to improve them

 

I'd say both are clean in measurements when viewed on the courtesy of apple-to-apple. Not very comfortable to discern the difference objectively (delta rather attributable to run to run variation imho). Also my speculation is RD's X isn't fully closed-back (acoustic impedance would be somewhere between open and semi-open I guess) and he put more thoughts in vents and air flows. So perhaps very likely to sidestep closed cups limitations shown here.