My active crossovers I built sounded sort of thin to me, really good on some things, not so much on others. I removed the 10 pf ceramic bandwidth limiting capacitors in the feedback path, and problem is gone. I had thought that their frequency of operation was so far outside of audio band that I was safe from their supposed problems. Luckily no oscillation, as I don't have room to install mica capacitors.
In retrospect, if I really need bandwidth limiting caps, I maybe should have chosen smaller resistor values to obtain larger capacitor values (and have more choice in quality capacitors).
By the way, In my opinion, I think modern rock/metal is the best way to find problems with speakers, my overpriced retail speakers and bad crossover all sounded great with acoustic material.
In retrospect, if I really need bandwidth limiting caps, I maybe should have chosen smaller resistor values to obtain larger capacitor values (and have more choice in quality capacitors).
By the way, In my opinion, I think modern rock/metal is the best way to find problems with speakers, my overpriced retail speakers and bad crossover all sounded great with acoustic material.
not all ceramic is bad, np0 or c0g are generally better than mica and approach film quality on measurable distortion and dielectric adsorption, with higher feedback R many op amps require some feedback C to cancel destabilizing parasitic C at their inputs, often only a few pF is required - don't even think about using hi K ceramics like Z5U in signal apps
generally harmonically "simple" music with single voice, few instruments gives best sound with distorting systems - challenging music is well recorded (without the compression common in Rock and other pop formats) and harmonically complex - classical orchestral music with real dynamic range is the hardest to get right
Rock/Metal usually relies on distortion in tube instrument amps as a part of the musical "voice" and may have further compression used to keep average levels high - its very hard to judge when such pre-distorted source is getting a little more added by your system - but the high average levels will certainly test your excursion limits and amp clipping levels
generally harmonically "simple" music with single voice, few instruments gives best sound with distorting systems - challenging music is well recorded (without the compression common in Rock and other pop formats) and harmonically complex - classical orchestral music with real dynamic range is the hardest to get right
Rock/Metal usually relies on distortion in tube instrument amps as a part of the musical "voice" and may have further compression used to keep average levels high - its very hard to judge when such pre-distorted source is getting a little more added by your system - but the high average levels will certainly test your excursion limits and amp clipping levels
Hi,
If you have a choice here, go for extended foil polystyrenes as their end caps are attached to a greater area of the foil, and (generally) will sound better, too.
FSC-EX versions are extended foils, but you may not get them in the lowish values you are after. The FSCs mentioned above aren't very far behind them, though, in the sound-stakes.
Sonically, these extended-foils are one of the finest caps for small values, with only (non-magnetic leaded, which are rather rare) silver micas being close. So long as their slightly higher inductance (due to their rolled-up construction) isn't significant, and for most audio situations it won't be, I would choose these polystyrenes over all other caps, for relatively low pF values like compensation caps etc.
It was the accidental discovery of the obvious differences in sound between polystyrenes and ceramics (in a MC head amp) some 30+ years ago, which started me out on 'the road to ruin' of listening to all passive components in my entire system, and choosing accordingly!
Regards,
If you have a choice here, go for extended foil polystyrenes as their end caps are attached to a greater area of the foil, and (generally) will sound better, too.
FSC-EX versions are extended foils, but you may not get them in the lowish values you are after. The FSCs mentioned above aren't very far behind them, though, in the sound-stakes.
Sonically, these extended-foils are one of the finest caps for small values, with only (non-magnetic leaded, which are rather rare) silver micas being close. So long as their slightly higher inductance (due to their rolled-up construction) isn't significant, and for most audio situations it won't be, I would choose these polystyrenes over all other caps, for relatively low pF values like compensation caps etc.
It was the accidental discovery of the obvious differences in sound between polystyrenes and ceramics (in a MC head amp) some 30+ years ago, which started me out on 'the road to ruin' of listening to all passive components in my entire system, and choosing accordingly!
Regards,
It may be interesting (and simple) to substitute micas and/or polystyrene of the same value and compare what you hear. If they sound different from the cermics but the same as what you hear with the ceramics out, then the issue is the composition of the cap. If they return the sound to what it was before simply removing the ceramics, then it is a matter of the circuit behavior independant of the type of cap.
A simple experiment and one that will get you closer to the root of the matter. And by the way, I have not the slightest expectation about the results one way or the other -- either outcome sounds within the realm of plausibility to me.
A simple experiment and one that will get you closer to the root of the matter. And by the way, I have not the slightest expectation about the results one way or the other -- either outcome sounds within the realm of plausibility to me.
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