Phono Stage upgrade to complement Dohmann Helix One Mk 2

@lewm

because of the quality components of the pre- and amp, I am leaning towards an capacitor HPF, as opposed to running it through the sub, which just has a standard 6db per octave HPF, which would just be a standard, probably low-grade capacitor, correct?  A silver Duelund CAST capacitor in line with the two components, and then a separate line to the subs: it seems that Martin Logan subs might fit in the system better, since they also make ESL, and are more designed for a two channel system.  It seems that the Velodyne is for multi-channel home theatre use.

@drbond , you will hate any analog high pass filter. To operate a subwoofer correctly all filters have to be digital. The highest quality units now use 64 bit floating point processors and have none of the issues older units had like the volume control problem. Conversions in and out of 24/192 are invisible. 

@lewm correct. IMHO the Velodyns are mid Fi. The Balanced Force MLs are superior in every way The Magicos Q series, also balanced force, are the best on the market because of their extremely stiff, heavy enclosures. Because the electronics in all subwoofers are sort of second rate I prefer passive ones. You can only get these in kit form or build them yourself. Otherwise you can just bypass the electronics. This is mandatory for the filter section. Some class D amps are tolerable for subwoofer duty but the best bass I have heard comes from A, AB amplifiers with vanishingly low output impedances. The JC 1 is a killer subwoofer amp. These produce way too much heat to put in an enclosure. Only Class D amps are efficient enough for that.

@mijostyn

Understanding that digital LPF is better for sub woofers, can a high grade analog capacitor (e.g. silver Duelund CAST) be used for the HPF to the ESL with good results?  What’s the main disadvantage to using an analog HPF via an in line capacitor and a digital LPF to a subwoofer?

What are the higher end passive sub woofers on the market? (I do have an extra couple of amplifiers (class A and AB) sitting around).

I only chose Velodyne as an example of a good company that’s been making and selling subwoofers for at least 30 years. I am aware that for very big bucks Magico and others also make subwoofers. I’ve never heard them and the question was how to incorporate a subwoofer with minimum effort not what’s the best subwoofer. I don’t live in your world of absolute certainty and perfection but you’re entitled to your opinion. However it would be nice if you acknowledged that you’re stating an opinion or in this case a set of various opinions.

drbond , you will hate any analog high pass filter.

^That^ is a bold statement.

And how do we reconcile the fact that most speakers have a crossover in them, and those are analogue?
(Or are we throwing that out because the ESLs may not?)

While I generally appreciate digital, when one has a nice analogue system, there is an allure in keeping the front end free of digital.

To operate a subwoofer correctly all filters have to be digital. The highest quality units now use 64 bit floating point processors and have none of the issues older units had like the volume control problem. Conversions in and out of 24/192 are invisible

The idea that a sample rate and bit depth used for recording bats and other high frequencies is “required”, starts to fly in the face of logic.
Couple that with people tolerating many % of distortion in the lowest registers makes that paragraph a bit absurd.

I like digital as much as the next fellow, but one could just about do the math with a slide rule or abacus and keep up, and the idea of 64-bit math for the signal that has the highest amplitude in the spectrum means with probably could do it with 8-bits and 500 samples/second.

But if you are saying that the HPF for the main speakers should be 24bit/192k or something like that, then I have no argument. One pretty much needs that to keep the HP stuff that is going to the main speakers sounding good at 20kHz and beyond.
 

… can a high grade analog capacitor (e.g. silver Duelund CAST) be used for the HPF to the ESL with good results? 

Of a battery biased HPF.
Is your connection from preamp to amp RCA or balanced?
(I am guessing XLR if you ran Atmasphere amps at some point.)

I cannot figure out a way to post a photo of the inside of my Vandy M5-HP (high pass filters), and I have the older RCAs as well. The XLR ones have a row of dip switches for matching to the amp’s input impedance, which then makes the knee of the curve exactly at 100Hz.

I am not overly “bowled over” with the battery biasing cables, but perhaps there is something to it. And the cotton and silk covered cables do not have the dielectric polarising issues… and people rave about them… so maybe it makes a difference.

What are the higher end passive sub woofers on the market? (I do have an extra couple of amplifiers (class A and AB) sitting around).

The powered subs are more of a system, and there is an allure to having a sub that either comes on when the rest of the system does, or has some efficient amp that can be left on.

Other than power outages, mine was on for 20 years in the old house.
I rarely even thought about it… it just sat in the corner.

While I am intending on some DIY jobs for the new house, a lot of that is for Feng Shui and WAF… and there not a lot of choice in my location nor places to find them in the wild or in shops. In FLA they should be “springing up” somewhere.