Passive Crossovers -- YES?
Posted: April 22nd, 2017, 12:57 pm
A lot has been said in this forum about electronic crossovers and yet I still cannot understand how additional electronics comprised of I.C.s and digital processing improves anything other than the bottom line of the manufacturers selling those devices. Then to add insult to injury you have also additional interconnecting cables of variable pedigree from bad to somewhat better. Even the high $$ cables, and there are many to pick from, are nothing to brag about. This brings me to a request from a guy I met at the CAF two years ago that had the same needs as you DIY’ers yet not having the training or skill base to do upgrades for himself.
To make a long story short he contracted SoundMods (me) to upgrade his speaker’s passive crossovers. WHAT?! PASSIVE?! Yep! As with anything there are ways to provide exceptional performance when one does not follow convention. As some of you that know me, I have no use for so-called “audiophile” parts when in my experience they just do not serve the music as some of the U.S. and Russian military and aerospace goodies that were not designed for “audio” yet surpass and beat the audio stuff at their own game.
The speakers upgraded were the B&W 802 series 80 F models with a complex fourth-order Butterworth crossover network that B&W bragged about using a computer program to optimize.
WOW! Yet – they used polyester capacitors for the tweeter networks (tizzy and edgy sound), bipolar aluminum electrolytics for the mid-range networks (muffled and indistinct), and aluminum electrolytics for the woofer networks -- and to add insult to injury they capacitively coupled the woofer networks to the drivers through 1,000-ufd electrolytics (grungy and muddy sound).
Additionally, it seems that they were a bit too aggressive with the crossover points because I presume that when you take into account the series and parallel L/C reactance combinations there were numerous resonances that could be mistaken for mechanical issues created by the drivers.
Yet B&W used high-quality inductors , PC boards with nice thick traces, and their drivers are probably the best available even compared to now.
The attached photos are of the speakers and the component and foil sides of a crossover prior to the upgrades.
To make a long story short he contracted SoundMods (me) to upgrade his speaker’s passive crossovers. WHAT?! PASSIVE?! Yep! As with anything there are ways to provide exceptional performance when one does not follow convention. As some of you that know me, I have no use for so-called “audiophile” parts when in my experience they just do not serve the music as some of the U.S. and Russian military and aerospace goodies that were not designed for “audio” yet surpass and beat the audio stuff at their own game.
The speakers upgraded were the B&W 802 series 80 F models with a complex fourth-order Butterworth crossover network that B&W bragged about using a computer program to optimize.
WOW! Yet – they used polyester capacitors for the tweeter networks (tizzy and edgy sound), bipolar aluminum electrolytics for the mid-range networks (muffled and indistinct), and aluminum electrolytics for the woofer networks -- and to add insult to injury they capacitively coupled the woofer networks to the drivers through 1,000-ufd electrolytics (grungy and muddy sound).
Additionally, it seems that they were a bit too aggressive with the crossover points because I presume that when you take into account the series and parallel L/C reactance combinations there were numerous resonances that could be mistaken for mechanical issues created by the drivers.
Yet B&W used high-quality inductors , PC boards with nice thick traces, and their drivers are probably the best available even compared to now.
The attached photos are of the speakers and the component and foil sides of a crossover prior to the upgrades.