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… ;^)
