I'm looking to build a 3 or 4 way active design using a pair of DBX 234X active XO. I like some of the designs on Troels and Zaph, but they are all passive. Will a DBX active XO sound as good as their passive designs?
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Also, do I have to worry about flattening the response curves and baffle step using an active XO? I see the passive XO designs online fix the freq response bumps by using resistors, caps or whatever. But if I use speakers which the mfg claims have flat curves, such as the Fountek X3.0 ribbons and Scan Speak 8531 woofers with an alalog active XO, do I still have to worry about the response curves? Or will they be generally flat with an active XO?
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I want to go active because I already have a pair of DBX which I don't use, and several extra amps. I figure I can save upto a grand if I don't use the expensive caps on Troels and Zaph's passive designs? Thanks in advance all!
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Also, do I have to worry about flattening the response curves and baffle step using an active XO? I see the passive XO designs online fix the freq response bumps by using resistors, caps or whatever. But if I use speakers which the mfg claims have flat curves, such as the Fountek X3.0 ribbons and Scan Speak 8531 woofers with an alalog active XO, do I still have to worry about the response curves? Or will they be generally flat with an active XO?
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I want to go active because I already have a pair of DBX which I don't use, and several extra amps. I figure I can save upto a grand if I don't use the expensive caps on Troels and Zaph's passive designs? Thanks in advance all!
"Flat curves" that will change the moment you mechanically load the driver. I.E. by placing it in a box.
I have been so well satisfied with passive crossover designs that I have never considered active to be worth the trouble. It's nice in cars when your response is so wacky already that heavy EQ/DSP is always acceptable so I usually recommend active installs to customers who want high end systems in cars/on boats. In a home setting I see no need for it.
I have been so well satisfied with passive crossover designs that I have never considered active to be worth the trouble. It's nice in cars when your response is so wacky already that heavy EQ/DSP is always acceptable so I usually recommend active installs to customers who want high end systems in cars/on boats. In a home setting I see no need for it.
I used P-Xover before for my 3 way tower, costed me more than $700 on parts, sounds good as it should. Using ARC D-115 to drive the dual 12" woofer towers.
Recently I changed to A-xover DCX2496 (two way) as I am using SET monos but single one is not enough for full range, so i used two pairs of SET monos (845 at 25WPC and Kt88 at 18WPC). 2496 Xover at 350Hz and 845 monos drive M+H and the KT88 monos drive bass. I still keep the H/M P-xover in the cabinet. Planning to change the KT88 to KT120 to get more power from the monos, for that KT88 I have to use +3dB gain on DCX to get teh same level as 845. Also I did soem setting for EQ and delay time, The new system sounds better than P-xover.
But i do notice some more noise than before that is from the DCX2496 but not that bad. I tried ARC EC-2 tube xover before teh DCX, too much noise that I cannot stand for. With DCX 2496 it can EQ and adjust delay and phase, so if your DBX can do the same thing, I will suggest you give a try and save the high cost of P-Xover parts that maybe you don't need it but you do need 2 or 3 sets of power amps that I assume you already know.
Recently I changed to A-xover DCX2496 (two way) as I am using SET monos but single one is not enough for full range, so i used two pairs of SET monos (845 at 25WPC and Kt88 at 18WPC). 2496 Xover at 350Hz and 845 monos drive M+H and the KT88 monos drive bass. I still keep the H/M P-xover in the cabinet. Planning to change the KT88 to KT120 to get more power from the monos, for that KT88 I have to use +3dB gain on DCX to get teh same level as 845. Also I did soem setting for EQ and delay time, The new system sounds better than P-xover.
But i do notice some more noise than before that is from the DCX2496 but not that bad. I tried ARC EC-2 tube xover before teh DCX, too much noise that I cannot stand for. With DCX 2496 it can EQ and adjust delay and phase, so if your DBX can do the same thing, I will suggest you give a try and save the high cost of P-Xover parts that maybe you don't need it but you do need 2 or 3 sets of power amps that I assume you already know.
The DCX is set up for Pro levels. That's why you are getting noise. There is much written about the problem on diyAudio. You can even look in the Articles section for my article about Gain Structure. It can be fixed by using proper levels.
Also, you owe it to yourself to bypass or change the analog sections of the DCX, but get your gain worked out first. That's the most important.
Also, you owe it to yourself to bypass or change the analog sections of the DCX, but get your gain worked out first. That's the most important.
Hi,
Active x/o's with preset filters will not work as well as passive
or DSP where you can optimise BSC, EQ and the filter functions
for optimum resultant classic acoustic filter functions. Can also
be done by designing bespoke active EQ and filters, e.g. see
Linkwitz, but is rapidly being replaced by doing it in DSP.
rgds, sreten.
Active x/o's with preset filters will not work as well as passive
or DSP where you can optimise BSC, EQ and the filter functions
for optimum resultant classic acoustic filter functions. Can also
be done by designing bespoke active EQ and filters, e.g. see
Linkwitz, but is rapidly being replaced by doing it in DSP.
rgds, sreten.
My 2 bits worth:
Analogue active XO is good, with decent drivers used in an arrangement wither their frequency response is "behaved" can be very good indeed. Do watch the time alignment / phase of the drivers though.
DSP crossover has the potential to address issues that a conventional crossover cannot dream of fixing. Not the least time alignment, odd sensitivities in drivers, frequency response abberations etc.
As a bonus, active crossovers deliver you a massive increase in dynamic range (on normal material) before clipping.
Analogue active XO is good, with decent drivers used in an arrangement wither their frequency response is "behaved" can be very good indeed. Do watch the time alignment / phase of the drivers though.
DSP crossover has the potential to address issues that a conventional crossover cannot dream of fixing. Not the least time alignment, odd sensitivities in drivers, frequency response abberations etc.
As a bonus, active crossovers deliver you a massive increase in dynamic range (on normal material) before clipping.
Why not use minidsp, one per channel? It can do all that is required in this application.
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I might have to go the misidsp route. I already have a pair of dbx 234X and Fountek X3.0 ribbons, and was hoping to save funds by only buying the mids and woofers (accuton mids and seas/ss woofers possibly). But I might have to start from scratch. Considering the LX521 or Selah Ottavo at this point, unless anyone has other suggestions?
Hi halibutman,
A really excellent book entitled "The design of active crossovers" by Douglas Self gives a huge amount of info on the subject. Here is a google books link that shows several pages defining the advantages and disadvantages of active filters.
https://books.google.co.uk/books?id=E01DvO2nsH0C&pg=PA1&source=gbs_toc_r&cad=2#v=onepage&q&f=false
Just scroll down to the bottom of page 8 section 1.7
Peter
A really excellent book entitled "The design of active crossovers" by Douglas Self gives a huge amount of info on the subject. Here is a google books link that shows several pages defining the advantages and disadvantages of active filters.
https://books.google.co.uk/books?id=E01DvO2nsH0C&pg=PA1&source=gbs_toc_r&cad=2#v=onepage&q&f=false
Just scroll down to the bottom of page 8 section 1.7
Peter
Discussion of crossover dynamic range split to new thread:
http://www.diyaudio.com/forums/multi-way/276102-dynamics-range-active-crossovers.html
Because class D amps have become so cheap these days, and many quite HiQ, I think any crossover that deals with many components reaching in hundreds of $$ might be better as an active low-power solution. This way even gross mismatches in sensitivity can be overcome by bi(tri)amping, which in a passive crossover might waste many W of amp power.
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