Where can I find a beginner's guide to active crossovers

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I've been building passive crossovers for years now and I can see in my head the changes that will happen when I increase or decrease a component value.

Now I would like to learn how to build active crossovers. Is there an easy to understand guide that explains how to design them and how to manipulate components to get the desired results?

I've been searching and really haven't seen anything simple. I don't want a DSP based system because I haven't seen any that can deliver on the sound quality I'm looking for. The DEQX comes close but.......... I would rather let my dCS Elgar plus to the conversion and filter in the analog domain.

Thanks in advance!!! Sorry if this is a repeat question. I actually did search first.......
 
Hello mp006tlk,

Going analogue active is unfortunately a bit more complicated than Douglas Self (whom I greatly admire btw) describes. The topologies are OK, the implementation pretty useless with real world loudspeakers.

The real problem is that real loudspeakers-in-a-box do not have a flat SPL characteristics, which no-ideal behaviour has to be taken into account when calculating the filter component values. Text book values for R s and C s are not going to do the job properly.
Furhermore, inter-driver delay has also to be taken into account, complicating matters even further.

You actually need a simulation program with proper optimizing capabilities to come up with something useful, on the basis of real in -box measurements.

But hey, I only stated this half a dozen times before in the various active x/o threads.

Good luck,

Eelco
 
@ mp006ltk
Addendum: I just by chance discovered you postred in the Linear X thread. LEAP used to be one of the very few filter optimizing packages that could do this job properly, being both capable of doing active circuitry plus having a very good optimizer. LspCad, Calsod and Soundeasy are the others.
 
To Boden:

Yes, I have CLIO for measurements and plan to manipulate actual response the same way I do passive crossovers. Since I'm starting from scratch, I literally don't know what the circuit should even look like. If I can understand how they work, I'm hoping I can then use those skills to get where I need to go.

For software, I have soundeasy, but haven't tried it on active circuits. Personally, I prefer LEAP, but that's a dead end.....
 
Elliot sound products (ESP) in Sydney Australia is a good site with an article on active x-overs.
Cheers from Oz.
Sorry! Didn't see scottjoplin's post Number #4.................

Exactly what I had in mind. And he even saved you the trouble of searching the site ha ha............
 
Last edited:
I've been searching and really haven't seen anything simple. I don't want a DSP based system because I haven't seen any that can deliver on the sound quality I'm looking for. The DEQX comes close but.......... I would rather let my dCS Elgar plus to the conversion and filter in the analog domain.

It is true that most digital filters sound horrible, but cheap analog filter is worse. Weiss digital mastering EQ or some mastering grade computer softwares sound much better than the most opamp based analog filter out there, and they are much more versatile. You can even blind ABX test with them. The problem is you need multiple DCS. :rolleyes:
 
so it is marketing rather than any technical parameters?

I guess some companies use the term for their marketing, of course, but mastering guys are very selective. Those mastering products are designed for mastering purpose, so it is technical, but most of them are rejected by mastering people. You will find only a few products that are actually used.
 
Last edited:
Mastering <>active crossover. Bob ludwig for example may use a weiss box for mastering, but he isn't using it as an active crossover or room management system. So I am really not sure where you are coming from on this.

I just said that DSP option should not be instantly omitted from OP's active crossover's list, because some of DSP based filters sound better than most of the other option available, whether digital or analog. I actually use one of them for crossover purpose.

The point is all DSP filters are not the same. Some are much better than the other. It's the same thing with the analog filters. :)
 
Texas Instruments have published lots of info on how to use their opamps for active crossovers. Some is very simple, some is more complicated and some goes pretty deep. You read and remember the bits you can understand and ask about the bits you can't follow.

TI also has "freeware" "Filter Pro" which you can use to good effect.

Walt Jung's "Op-Amp Applications" should be on your bookshelf too.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.