As you may remember Steve, from earlier postings, I don’t have sealed box or coils to heat up - I have big flappy sheets of plastic film (eletrostatic QUAD ESL-57) - does that make a material difference (no pun intended) ?
Peter.
Interesting Bill…
One thing I note is that your raw LP analysis curve exhibits the same bell-shaped peak at the very LF end as mine does, although mine is at a very slightly higher frequency (the one I captured for YT that was from a vinyl T recording aso exhibted the same cery LF bell-shaped peak).
Do I read correctly from your post that this is TT rumble? If so, do all TTs exhibit such rumble?
You say that you see no reason not to remove this LF stuff - but does that affect the listening experience in any way?
Here I’m thinking about previous audiophile discussions I have read in the past where they insist that the ulta-high HF signals on SACD, although inaudible to the human ear, nevertheless add to and improve the listening experience.
One of the key learnings I have taken away from this is that our oft-repeated advice that the ears are the best tool to use for assessing the sound is maybe not the whole story. There seem to be situations, for inaudible frequency ranges, where other analysis tools are needed…
Peter
But that then leaves us with the question: does the presence of sound at frequencies that are inaudible to the human ear have an impact on other sounds at frequencies that are audible to the human ear? Or putting it differently: if we remove these inaudible sounds do we also change the sounds that remain audible? 
Answering my own question: I have reported above, that applying a little bass roll-off (is that the correct term?) via my customized Equalizer filter gives me a better bass sound; by which I mean that it sounds “better” to my ears when playing back through the desktop PC’s sound-card driving my Bose Companion 2 PC speakers. Let’s remember, that in this digital age, sound is analogue; our ears are analogue devices; our hearing experience is unique to each of us and our assessment of it is entirely subjective. I firmly believe that the bottom line should always be: “Am I happy with the result?” However, there is no harm in asking: “Can I improve… ?” - which is where I came in. 
regards,
Peter
I should have said that I assume it is TT rumble. I see it on every capture so I assume it is an artifact of the TT, not the vinyl.
The standard RIAA curve continues with its bass boost all the way to DC. Some pre-amps use a modified RIAA curve that inserts a bass roll-off around 20 Hz which effectively flattens the RIAA curve below 20 Hz or so.
The HPF will introduce phase changes above it’s cut-off frequency. My experience is that these are inaudible.
Assuming the power amp will pass sub-sonic frequencies (and mine says it will), I don’t want my speakers to try to reproduce them.
– Bill
Doubly well spotted Steve 
I’ve just captured today’s webstream from the same Dublin netcast, with the same SoundMax soundcard:
- before any DC removal - I get the same rise below 5 Hz,
- after DC-offset removal - the LF stuff is nicely tamed.
I’m really impressed with your diagnostic capability. 
Peter.
I qoute from the Quad ESL Unofficial Page & Info Center:
“If you use a larger amplifier or try to overdrive the speakers, you risk arcing. Arcing occurs when the potential across the stator panels is sufficient to ionize the air and spark across the gap and through the membrane. Arcing will ruin the panels, if it occurs enough times or is severe.”
It depends on if your power amplifier has muscle enough to overdrive the speakers.
–
Ragnar - Fellow owner of big flappy sheets in the form of Apogee Calipers (magnetostats)
Hi Ragnar,
when I took my ESL’s back to the QUAD factory (when it was still owned by QUAD) for a service they told me they had had to replace no panels as there was no sign of arcing. That was good news as I had bought them secondhand and given them pretty extensive use myself both on classical and rock.
They are driven by a QUAD 33 control unit and QUAD 303 power amp - so I gues that the 303 is quite capable of overdriving the flappy-bits - but I never push them that hard (I’ve gone off loudeness as I’ve got older … )
Peter
it’s been a few months, but this thread comes close to a quesiton i’m pursuing, re: the best phono cartridge for my LP importing.
[Background details: this is from a Stanton turntable with digital SPDIF out, coming through an M-audio firewire 410 box. the source is ~ 2 minutes of solo classical guitar. i’ve also applied the ~hi-pass equalization filter recommended by Steve, above, in both cases.]
below are the (log frequency analysis) plots for an AudioTechnica cartridge and a Stanton cartridge. the Stanton is noticably (about 7 db) louder than the AT. i’m curious about the differences in these response curves. Eg, the Stanton has a mode ~ 15 Hz entirely below anything produced by the AT?!
should i care?! are there general characteristics of “good” response curves? have any others evaluated cartridges this way?
Which sounds better?
ah. my opinion is confounded by hearing the Stanton with a different pair of speakers than i was used to with the AT cartridge, and now also by applying your equalization filter. (the last time i was on this quest for perfect sound, i was a teenager buying my first stereo. i thought i’d learned my lesson, but i’m afraid Audacity has made me a monster again!)
but this all just made me curious. i saw here that waxcylinder
was apparently able to do much better, and i was wondering if anyone was doing component profiling tests, ala the streaming alternatives he mentions.
The best cart I ever had was the Shure V15-III - It was a good match for my SME arm and my QUAD 33 control unit had a special input card for that cart (Peter Walker of QUAD also thought it was the best cart at that time - but that was many years ago now).
When I last had to change the stylus on the V15 it was so eyewateringly expensive that the specialist dealer sold me a more modern Shure instead. Still excellent but I miss not only the sound but the classic looks of the V15 (I do still have it with its worn-out stylus).
Always critically importantant, no matter what cart you use, is to set it up properly and precisely - that pays dividends IMHO.
WC