Cartridge Performance vs Humidity

For years we’ve seen audiophile die-hards going to great lengths positioning light bulbs near their cartridges etc. to achieve optimal temperature conditions. Sadly there’s more to this than meets the eye (or ear) and those who think they’ve nailed it merely by tweaking temperature/VTF/warm-up time to compensate for seasonal changes may be a little shocked by what comes next.

I suppose the real experts are the many folk who live in low humidity regions who will often tell you that they have, with difficulty, settled for 40% RH, which appears quite good given that, locally, their RH could be in single figures for much of the year(!)

 Since my currently installed cart is a Lyra Delos, I’ll set the scene with Jonathan Carr’s take on the subject –

”The fundamental cause is that cartridge suspensions (particularly the elastomer dampers) change in mechanical characteristics as a function of operating temperature, and these characteristics also change with humidity. The temperature dependency is why you will see references to "temperature-stable" suspension and damping systems in cartridge literature from Denon, Highphonic and others.

The 11th figure on the following page compares the temperature dependency of Denon's DL-1000A with other cartridges (presumably also Denon-made).

https://www.denon.jp/jp/museum/products/dl1000a.html

Although "temperature-stable" suspensions are less temperature dependent than other suspensions, they are not completely temperature independent. Some effect of temperature on cartridge performance still remains (and you can see this in the same Denon figure).

In my own experience, silicon rubber does combine acceptable damping performance with temperature stability, but it tends to not sound very good, so you probably won't find many cartridge designers using it.

The manufacturer of your cartridge may specify a preferred operating temperature and relative humidity. Chances are that you will be able to reduce the warm-up time and get better sound overall if you heed those recommendations.

FWIW, the frequency response of phono cartridges also changes depending on the LP groove radius - the deeper the cartridge goes in towards the label area, the more the top frequencies will be attenuated (by enough to be clearly measurable).”

 Ok, so how does this pan out in real life when humidity is the only variable?

Earlier in the year I’d made needledrops where “t” in every case was 22C and humidity was 43-44%.

Recently, using settings as identical as possible (which included warm-up time) I re-recorded one side of an album at 64% humidity and A-B compared on the HDD.

The differences surprised me. I would characterise it as being similar to a substantial VTA/SRA change. Higher humidity is equivalent to “negative” VTA (i.e. “tail down” tonearm attitude). Lower humidity sounds distinctly brighter and seemingly more resolved at HF. It wasn’t quite as black & white as VTA, though. High humidity could be said to be smoother and slightly more seamless and coherent sounding but go too far and HF “resolution” and prominence seems to suffer. However, the lower registers had a pleasing “bloom” and greater solidity in the presence region (once again, perhaps a little TOO pleasing if you overcook it).

Noise levels turned out to be equivalent either way. If non-existent at low humidity then noise is still non-existent at high humidity. If there was actual damage already on the vinyl at a given location, then a click will still be a click at either extreme.

Not that either extreme made for unpleasant listening and I wouldn’t describe either condition as a “deal-breaker”. I could further sum up by saying that with the low H condition I found myself focussing a great deal on the wealth of individual instrumental detail, whilst with high H I was able to sit back and enjoy the overall performance of the music without being analytical.
There is no suggestion either that there is an absence of bass and lower midrange from the low H condition but there is a greater emphasis (and corresponding treble de-emphasis) from the high H version. There was a slightly greater sense of continuity or continuousness associated with higher H.

It is very much a case of paying your money and taking your choice. The most sensible option is to go for a setting half-way between these 2 extremes (as recommended by the designers).

These differences are probably things we are subconsciously aware of during the summer-winter transitions but we either just accept them or use the time honoured method of adjusting VTF by a few hundredths of a gram (or less depending on the severity).

In the final analysis I think Jonathan Carr called it just right. I would estimate that 55% is a target you should aim for (certainly with Lyra) if you want the best balanced results or are archiving your vinyl onto digital memory. I know Syntax owns a number of carts claimed to be immune to the effects of humidity. Hopefully, if he's done any environmental tests, he may be able to enlighten us as to whether they're telling the truth or not? ;^) :)

It’s possible one could also try to compensate for low/high humidity by cranking the VTA but it may not fix everything (and of course line-contact styli might end up slightly less than orthogonal by doing so). This could be seen as a way of re-balancing things due to the fact that suspension humidity/temp changes may well have a direct effect on SRA anyway? Subtle VTF compensation (which I’ve tried over the last few decades) undoubtedly has a similar effect but I suspect won’t completely solve the problem either.

I don’t have a massive humidity problem in my region as it’s generally in the range 40-70% but I don’t consider either of those extreme values acceptable. My inclination would be to try to achieve a more optimal setting somewhere within the +/-5% range. In recent years I did try dehumidifiers in summer but they are grindingly slow and the big, chemical, fan-driven ones smell terrible! I found it was actually easier to throw the windows open before a session, not to mention 10 times faster, than using a dehumidifier (assuming H was indeed lower outside – which I measured first). ;^)

It does turn analogue reproduction into even more of an exact science. Makes me wonder how I ever survived years ago… ;^)