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In Reply to: RE: DIY Detail Magnifier posted by Awe-d-o-file on April 10, 2015 at 09:33:48
To those who are arguing about mechanism in the posts below this one, here is what my favorite guru, Al Sekela, wrote in 2010:
"These are meant to be installed across the input terminals of speakers. They consist of a resistor in series with a capacitor, where both have been selected by Lloyd Walker to give the best sonic results.
The capacitor blocks audio frequencies from the resistor, but allows ultrasonic and radio frequencies to get through. Since most speakers have a lot of parasitic inductance, they appear to be open-circuits to high frequencies on the speaker cables. The resistor dissipates energy in these high frequency disturbances, which are simply noise as far as the audio system is concerned.
The trouble this kind of noise causes comes from intermodulation with the audio signal. RF noise on the speaker cables gets into the amp by way of the feedback network or parasitic capacitances, and can create spurious audio-band tones when it intermodulates with the signal.
By dissipating the noise in a resistor, there is less of it to cause trouble in the amp.
Similar problems can be caused by RF noise on the AC line. There are R-C filters available to damp such noise, but one must be careful and use only capacitors designed for continuous exposure to the AC line.
As in all audio applications, different types of resistors and capacitors have different sonic signatures. The ones chosen by Walker may or may not be your favorites for speaker cables."
There is only one point that Al did not deal with in this post, so far as I know. It would seem to me that you need to use a capacitor that is still acting as a capacitor at RF frequencies. Many/most of the best sounding audio capacitors have reached and past their resonance points at higher RF frequencies and would be inductive at the extremes. Since the capacitor is sonically invisible in this application, and given that requirement, it might be worthwhile to use a ceramic or maybe a silver mica. The latter type sounds good AND remains a capacitor at RF, I think.
Follow Ups:
"Since the capacitor is sonically invisible in this application"
I can' t follow you in that way: for an equal value the "quality" of the cap is clearly audible! I've tested a few and each time difference was huge.
Stein music use in its top level one use oil capacitor. For me the result is 50% value and 50% quality caps.
Aupiho,
A curious characteristic of the Stein Music Speaker Matches Plus is not simply that their noise reduction is striking and heard completely within a couple of days of installation but that the benefit then continues afterwards whether or not they remain installed. I checked this for a month or two after the $550 purchase and then delightedly sold the pair. The dealer of thirty years experience subsequently admitted to having exactly the same experience later himself.
DG
What you says is something I'm telling myself for zobel networks too ... Often for the firsts days after, a tweak change is huge but after a while when you remove it the difference become more thin...Even if a difference still there the gap between with and without is not so big than before...
What is interesting with a tweak like stein speaker match plus is that the improvement is really huge and that you can't go back without particulary if you have fullrange drivers like me!
My idea is that some tweaks acts like a burn-in improvement: just like if the tweak was giving the abit to you system to work with full potential and that in the same time the system is changing inside to respond to this full potential and better its potential itself... On a loudspeaker the idea is that the stein zobel helps the speaker to move in a way he didn't go before....a kind of second burn in wich helps the driver to have far better performance...
Just an idea...not a proof but...
Edits: 04/16/15
What speakers do you use? I tried to find out something about these on the internet, but all I could find was one blurb that mentioned the dreaded Quantum Effect. I think more likely they are RC networks, like the HDLs but perhaps using different values of R and C. If that's correct, then one would not expect the effect to linger after removing the device from the speakers. So, maybe I am not correct.Or, maybe they are true Zobel networks, designed to improve amplifier/speaker matching. That might be consistent with other claims I saw that they reduce or eliminate "back EMF".
Edits: 04/16/15
Of course it's impossible to argue against your subjective impression that the capacitor makes a "huge" difference, but it seems to me that the impedance of a .01uF capacitor (used in the Walker HDL and also recommended by Al) is very very high until you get into the RF range, which speaks to the intended purpose of the device. Therefore, essentially no signal voltage passes through the capacitor, which is why I say the cap is sonically "invisible". Indeed, on my home-made HDLs, I cannot hear any difference among different capacitors on my speakers.
However, I think I saw elsewhere that you use something like 0.2uF or 0.3uF. I suppose at that high-ish value of capacitance, the low pass frequency comes much closer to the upper limit of audio frequencies, so there might be some audible effect in the treble. I almost want to say that if you can "hear" the capacitor, it's value is by definition too high, if the goal is the same as that of the HDLs and similar devices. But whatever floats your boat is fine with me.
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