So admittedly I know very little, have few tools and would like some basic help with understanding and improving this particular crossover.
It's for a ported 3-way with two 8ohm 6,5" bass woofers in parallel, a 4ohm 4" or 5" aluminium midrange and a 4 ohm 1" soft-dome tweeter. It's from a reputable, well-known speaker manufacturer.
I just upgraded all caps to mostly ClarityCap CSA, the 100uf, 33uf and 22uf were NPEs before so the ESR ratio changed there - maybe there's a bit too much high-mid to treble output. Or it was just congested before? Then again, I trust this speaker was originally voiced to NOT be congested.
The coils would be next - here's what I would want to do if I had money:
A Jantzen C-coil for the bass, copper foils for the rest. That would be about 400 euros. Where would you see no need for a foil coil here? I made the hypothetical shopping list keeping in mind the coil resistances so that the ratio of resistance decrease from the originals would be approximately proportional, which adds some expense, considering the C-coil is down to 0,07ohms.
Do you see that I should maybe try any bypass capacitor "magic" here, in what value? Anything I should attempt especially to lessen/avoid fatigue?
I don't mind that I need to learn to design a new speaker essentially now that I changed anything, that's pretty much ideal but I need some tips.
I don't fully understand this design as it is, either. What order is the midrange circuit? Is it a 3rd order with a correction filter, or a 4th order? There is no resistor in line with the 22uf and 0,018mH so is it then not a notch filter?
I understand that I'm asking too much to analyze this without knowing more but I just need something thrown to me, until I can afford a DATS, and so forth.
Anything.
It's for a ported 3-way with two 8ohm 6,5" bass woofers in parallel, a 4ohm 4" or 5" aluminium midrange and a 4 ohm 1" soft-dome tweeter. It's from a reputable, well-known speaker manufacturer.
I just upgraded all caps to mostly ClarityCap CSA, the 100uf, 33uf and 22uf were NPEs before so the ESR ratio changed there - maybe there's a bit too much high-mid to treble output. Or it was just congested before? Then again, I trust this speaker was originally voiced to NOT be congested.
The coils would be next - here's what I would want to do if I had money:
A Jantzen C-coil for the bass, copper foils for the rest. That would be about 400 euros. Where would you see no need for a foil coil here? I made the hypothetical shopping list keeping in mind the coil resistances so that the ratio of resistance decrease from the originals would be approximately proportional, which adds some expense, considering the C-coil is down to 0,07ohms.
Do you see that I should maybe try any bypass capacitor "magic" here, in what value? Anything I should attempt especially to lessen/avoid fatigue?
I don't mind that I need to learn to design a new speaker essentially now that I changed anything, that's pretty much ideal but I need some tips.
I don't fully understand this design as it is, either. What order is the midrange circuit? Is it a 3rd order with a correction filter, or a 4th order? There is no resistor in line with the 22uf and 0,018mH so is it then not a notch filter?
I understand that I'm asking too much to analyze this without knowing more but I just need something thrown to me, until I can afford a DATS, and so forth.
Anything.
There is resistance (there always is, and should), it's the parasitic resistance of the coil and capacitor (ESR). It's near zero and you are planning to make it even smaller.
The combination of L2 and that notch filter are filtering the highs from the mid. It is not clear what order it is due to the notch potentially being steep.
The tweeter has a third order electrical filter but when combined with the natural tweeter rolloff it will be greater than third order.
Why the secrecy? Which brand and model?
Unnecessary expensive modification, the 100 uF non-polar el. was just fine. Other values - maybe OK upgrade.
Try to tame mid-treble output with 0.47 - 1 0hm/10 W resistor placed in series between L2 and C3+C4+C5 bunch (or before C3+C4+C5).
Do not change the coils (except maybe L5)!
With beefier coils you will lower the intrinsic resistance of the coils, which will change (slightly) the frequency response - and that is not always a good thing! Also, lower resistance of L2 will counteract the change to tame the mid-treble with the additional 0.47 ohm resistance.
Lower resistance of beefier L5 nay bring somewhat firmer bass with slightly more output across the whole bass band.
JBL is using such very small capacitors as bypass in some of their very expensive models. I am not convinced with that "magic", but you may try.
Electrically, midrange high-pass filer is 2nd order and low-pass filter is 2nd order. Notch filter (L4+C6) is at 8 kHz, so it shouldn't change filer slope significantly at the crossover frequency (presumably at least one octave lover). I suppose the intrinsic resistance of L4 is tuned by the coil wire diameter, so the notch filter do not need additional resistor.
Audio Physic Tempo V
That is really what makes me cautious but I do want to change them, even to get some experience with sonic qualities of different coil constructions. Would you say it's definitely not so linear that if I changed them in proportion (all DCRs divided by 4.7 if the Jantzen C-coil was to be the lowest reference for L5, since its original DCR is 0.33ohms and the C-coil is 0.07ohms), the balance would be kept? This would change the frequency response in equal proportion everywhere where those coils act but then again, this isn't across the whole summed response. So, not good?
I'm starting to think this is a stupid question already, but I want to understand more where it starts crossing the line where lower DCR is no longer of importance to performance. For control of bass woofers it knownly is important, but there is some controversy found and my personal lack of piquant knowledge on how much higher frequency, lower power signals "just don't care" about additional resistance and here I'm talking about signal integrity in all aspects. We want to extract the subtlest cues from a signal and resistance is always loss, while mandatory still.
Perhaps I would be better off replacing the coils other than L5, with similar DCR ones but of a different construction and conductor quality?. (I personally "believe" that conductor quality is important much beyond being 99.9% pure)...
Interestingly L4 is the lowest DCR coil in the circuit, it's a negligible 0.09ohms. C6 was an electrolytic before, though, but that can't have amounted to much either. Is a negligibly resistive parallel leg like that still called a "notch"?
If you want to explore whether there is a difference between two coils with different construction, but with same L, you must keep the same DCR! Otherwise, you will simultaneously change two different ingredients (DCR and construction), so you will not know which of the two bring the difference (if any)!
Keeping the same 4.7 proportion of DCR between coils will not bring the same change in total frequency response!
Coil DCR is of no importance (in a reasonable limits) for midranges and tweeters. Lower DCR in the low-pass filter for woofers is beneficent for lowering the woofer Qts parameter.
Resistance, per se, do not lower the sound quality! On the contrary, midranges and tweeters may work better.
Zero resistance in a LC notch filter makes infinity big attenuation, so it makes a perfect/ideal notch filter. (Update: I made some simulation of the midrange filter - this notch filter makes big frequency changes in a wider frequency band than I anticipated in my previous post)
Keeping the same 4.7 proportion of DCR between coils will not bring the same change in total frequency response!
Coil DCR is of no importance (in a reasonable limits) for midranges and tweeters. Lower DCR in the low-pass filter for woofers is beneficent for lowering the woofer Qts parameter.
Resistance, per se, do not lower the sound quality! On the contrary, midranges and tweeters may work better.
Zero resistance in a LC notch filter makes infinity big attenuation, so it makes a perfect/ideal notch filter. (Update: I made some simulation of the midrange filter - this notch filter makes big frequency changes in a wider frequency band than I anticipated in my previous post)
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