you couldnt be more right , i bought recently a dsp and i cant get close to the sound i had with what i tought were cheap JBL crossovers
The way I see it, the preference for the passive crossover is another one of those folk-superstitions that account for 90% of the audiophile industry. I can understand where it comes from: the physical form of a purely active system in no way resembles a musical instrument so how can it sound musical? Even worse, digital audio is just numbers and bits, that, at heart produce a stepped output that simply must sound "grainy"; it stands to reason. By using old fashioned coils, glowing vacuum tubes and animal-based glue, we can restore the audio to its natural state; it stands to reason. The beauty of the passive crossover is that it is able to purify the signal at the actual output of the amplifier, so even solid state amplifiers with their plastic output devices can be purged of their inevitable plastic sound with some good old fashioned components glued down using techniques familiar to musical instrument makers.
But it's not easy to enter the guild of crossover designers; to a normal person the passive crossover may just look like a very small selection of components that can't possibly produce an optimal design, but this is where the long apprenticeship pays off. It turns out that there is a permutation of two or three components that always produces the optimum filters for any selection of drive units. It sounds unbelievable, but it's true, and the good crossover designer can find it.
Truly they are the Stradivarii of our age.
But it's not easy to enter the guild of crossover designers; to a normal person the passive crossover may just look like a very small selection of components that can't possibly produce an optimal design, but this is where the long apprenticeship pays off. It turns out that there is a permutation of two or three components that always produces the optimum filters for any selection of drive units. It sounds unbelievable, but it's true, and the good crossover designer can find it.
Truly they are the Stradivarii of our age.
Some of you have seen these, some have not. Good read..
Linkwitz-Riley Crossovers: A Primer
A Bessel Filter Crossover, and Its Relation to Others
Linkwitz-Riley Crossovers: A Primer
A Bessel Filter Crossover, and Its Relation to Others
rubbish psycholgy bable
and offending to insinuate Im that stupid
I can build a violin, if I want to
and I still like electric guitar, and bass
and I can build those too
but got nothing to do with any of this
am I not a free intelligent person who is able to form my own opinion, and free of some kind of screwded and weird deeper psycho psychology ?
Boscoe, I don't want to sound arrogant, but I think it is you who don't fully understand the roll of damping in speaker design, particular at low frequency for woofers, which is pretty much the only place it matters. Certainly I agree with your explanation of electromotive damping, but there is a lot more to the story. As I said before, the damping force applied to the driver cone, both mechanical and electrical, plays a significant roll only near the resonant frequency. To each side of resonance the magnitude of the damping force drops off at 6dB/octave. Don't take my word for it, write the system differential equations and figure it out for yourself. You can do that, correct? The damping is characterized by the parameter Q in the system response. Q is made of two parts, Qe and Qm, the electrical and the mechanical components of damping. They combine as 1/Q = 1/Qe + 1/Qm. It makes no difference how each contribute to the system Q. What ever Q comes out describes the system damping. Qes is given as Qm = (1/Rm) sqrt (Mm/Cm). Qe is given as (Re/(BL)^2) sqrt(Mm/Cm). If a series resistor, Rs, is added between the amp and driver, then the system consisting of the resistor and driver (not the driver alone) will have the same Qm but Qe will change since now we must substitute (Re + Rs) for Re. This yields a new system Q, Q'; 1/Q' = 1/Qe' + 1/Qm. So yes, the system Q is higher. But this is no different that placing the driver in a sealed box. When a driver is placed in a sealed box the compliance, Cm, appearing in the relationships for both Qe and Qm changes to be the suspension compliance in parallel with the compliance of the air in the box, Cab. So we now have a new compliance, Cm'; 1/Cm' = 1/Cm + 1/Cab. Thus, due to placing the driver in the box, Cm' will be less than Cm along and Qe and Qm will both increase, yielding an increase in Q which means lower damping, both electrically and mechanically, compared to the driver in free air.
The point here is that any lost electrical damping due to the series resistance between an amplifier and the driver, from the DC R of a typical inductor, can usually be compensated for by adjusting the box alignment. It must be realized that when the woofer system of a speaker is designed to be used with a passive crossover it is not a matter of designing the enclosure and then designing the crossover. The enclosure, driver and crossover compose a system and the task at hand is to design the system as a whole. Additionally, this system should include the amplifier, or at least consider the range of amplifier output impedances for which the system is appropriate. If an active crossover is used it does not preclude the need to consider the effect of the amplifier's output impedance on the system response. The amplifier's output resistance is just another series resistance in the loop.
So, in summary, the series resistance associated with passive crossover can and will affect Qes of a woofer system. However, that does not mean that the system can not be designed to have the correct, desired damping, what ever that may be. The question of what the proper system Q should be is an entirely different topic.
in a few years, and it may not be so far away, any ordinary sound systems will have a voice controlled computer
and you just ask it to play any kind of music, in any way you like, slower, faster, brighter, anything
it will even do that with absolute 100% perfection, no errors, nada
but if we are still around we will probably sit back and remember the days when there was more fun in life
and you just ask it to play any kind of music, in any way you like, slower, faster, brighter, anything
it will even do that with absolute 100% perfection, no errors, nada
but if we are still around we will probably sit back and remember the days when there was more fun in life
john, it all sounds very scientific. As a non-passive crossover designer myself, but a bit of a software person, it sounds as though, given appropriate measurements, I should be able to set a computer the task of finding the optimum crossover network within a set of possible topologies and real world components that I specify. Part of the mystique of the guild of crossover designers, however, is a suggestion that while they home in on some sort of optimum crossover, including taking into account series resistance, temperature changes, humidity, tidal activity etc. like a computer could, they also 'play' the design like a violin and imbue the speaker with 'magic'. If it wasn't for that mysterious magic, it would appear that all they are doing is replicating what a computer could do, but not quite as well..? And then it would follow that a digital active setup could get much closer to the real 'optimum' than a handful of old coils, caps and resistors.
Can you give an example where you have deviated from the on-paper 'optimum' passive crossover, and imbued the system with some magic that only a passive crossover can deliver?
ahh, funny again I guess 
copper top, with all respect, can I please ask you, how old are you ?
copper top, with all respect, can I please ask you, how old are you ?
You compensate in the alignment. Again, it is a matter of system design. In simple terms, instead of designing the enclosure based on the driver's short circuit TS parameters you need to design it based on the real TS parameters which include the impedance load the driver sees at resonance. That includes contributions from the crossover and the amplifiers output impedance. It's not that hard to visualize. It is a system approach.
You don't build a house without first considering the foundation, nor do you build a foundation without consider the structure which will sit upon it. That is what engineering is about, designing the complete system, not just the components.
I have never and would never do that. It makes no sense. Either it is Hi-Fi or it is not. You can "deviate" and optimized design to add some "magic" and call it Hi-Fi. Its called "coloring the sound to suite your taste".
The DCR of a "good" inductor need not be so high as to be problematic to a woofer damping. A typical value of .25 ohms DCR in my designs does not yield an even noticable difference in the response.
And what about the tube amps that are so popular and claimed to sound so good? They can have very high series resistance (I've seen 4->5 ohms) - to the point of actually detuning a passive crossover (1-2 dB changes across the bandwidth). To me, this is the maor reason that they "sound different" (that often being perceived as "better.) Taking the inductors DCR into account in a crossover is certainly doable. I have often used a smaller inductor to increase the DCR to get what I am looking for.
John Kreskovsky, you're on FIRE! Loving it. Always a pleasure to listen to someone who knows his stuff.
The issue in this thread is whether an active system rather than passive will get better tighter deep bass. Yes?
People fret about half an ohm of resistance in a bass coil ruining "Damping". As john_k and gedlee are saying, damping is a system consideration, more to do with enclosure, placement and, yes tinitus, room acoustic. Here's what Joachim Gerhard says about his fine Anima speaker:
What's hard to understand about Morgan Jones' diagram of speaker Q here?
Resistance and Inductance is built into the speaker and optimised for different applications. In the below 10" midbass examples, SEAS let you add inductance externally (which opens up more options for filtering) or run it crossoverless to be flat. You choose. I could work with either.
The issue in this thread is whether an active system rather than passive will get better tighter deep bass. Yes?
People fret about half an ohm of resistance in a bass coil ruining "Damping". As john_k and gedlee are saying, damping is a system consideration, more to do with enclosure, placement and, yes tinitus, room acoustic. Here's what Joachim Gerhard says about his fine Anima speaker:
An externally hosted image should be here but it was not working when we last tested it.
What's hard to understand about Morgan Jones' diagram of speaker Q here?
An externally hosted image should be here but it was not working when we last tested it.
Resistance and Inductance is built into the speaker and optimised for different applications. In the below 10" midbass examples, SEAS let you add inductance externally (which opens up more options for filtering) or run it crossoverless to be flat. You choose. I could work with either.
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when ? i would like that , sitting in the couch saying " brighter , more bass , less mids "
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