Making active speakers with 4 Gallo A'Divas


In the process of researching new speakers for my office I've read about the benefits of active speakers over passive speakers. It came to me that I could use 4 Gallo A'Divas, controlled by an active crossover, and powered by two ROTH MC4s, to create 2-way active speakers.

A'Diva as the mid/bass and A'Diva Ti as the mid/treble. A subwoofer would take everything from 120hz down. My question is...how do I determine the best crossover point? Most speakers seem to cross the mid/treble between 1.7k and 2.2k. With full-range speakers I imagine it could be anywhere. I'm just thinking of how to make them produce the same volume/workload, so they blend well.

Any ideas?
What's a good inexpensive crossover?

Thanks!
Mot
manoterror
Hi Manoterror,
Determining crossover points requires experience. Understanding speaker resonance, crossover slopes and curves as well as time alignment and phasing. If I were doing what you are doing and had minimal experience. I would duplicate the crossover points of the manufacturer and use at least as steep of crossover slopes as they did. This information should be published, if not, the info is not trade secrets and the manufacturer should tell you.
Example would be, if the manufacture used a 3k @ 12db per octave, then your active should stay at 3k and be 12 or possibly 24 db per octave. Probably 24.... Drivers have a natural rolloff on their own and a 12db per octave passive may actually roll @ 18 or 24 db per octave actual. An Electronic crossover will help control this as well as making alot of other variables better.
I am an old guy and haven't done any electronic crossing in 30 years, but I would look for a unit that had variable frequencies as well as slopes. If the slopes are fixed, I would look for 24db per octave or more. Good listening, Tim
The benefit of using an active crossover is eliminating the passive components (crossover) between the amp and the driver. Since those speakers don't have a crossover I don't see any benefit in adding an active crossover to the signal path, and if you do it why use 2 different speakers that have the same frequency range when Gallo says one sounds better than the other?
My main thought was that its tough for a single 3" driver to produce everything from 100hz to 22khz. So if I split the signal between two of them, the load on each speaker should be much less taxing, and thus much more efficient at producing music. Simply put: going from a 1-way to a 2-way speaker, without adding the problems of a passive crossover.

I own everything except the A'Diva Ti (better treble), and the crossover. So just a fun, inexpensive project.

@Timlub: These speakers are single, full-range, and have no crossover. So I don't think (he says hesitantly) that I have to worry about the slope, etc. But I could be very wrong. :-)
Hi Manoterror,
If these are single full range drivers, Why would you need an electronic crossover? All my above comments were made assuming that you would not use any passive components. I would recommend however that you cross your mid driver as low as possible, keeping the crossover point out of the vocal region for best results. Unless of course your drivers require being crossed in that region.
@Timlub: Technically, I don't need one, as I could run two sets of them full-range, in tandem...which I will try as well. I felt that splitting the signal, and letting them each produce a part of the full signal would be easier on each one, and thus produce fuller sound.

For instance, the Gallo Reference AV uses 4 of these fullrange drivers, with a tweeter, as a single speaker. The outter 2 drivers only handle 100hz down, to free the inner 2 from having to work so hard to produce the full range.
Hi Manoterror,
It seems that you have answered all of your own questions. I was confused by your question when you asked about using an electronic crossover, but overall Herman is right on.
Your only benefit of the electronic crossover would be to select a good crossover and use one amp on a subwoofer and another on your spheres. Your hipass amp would be cleaner. If you decided to do that, I would recommend lower than 120hz as a crossover point, the Gallo A'Divas are capable of 76 hz. 120 hz in many rooms would be directional, if at all possible go to 100hz. Good Listening , Tim
Good Listening. Tim
My main question is still unanswered. I am using a sub for 100hz and below, and still need to figure out how to determine the best crossover point for the two A'Divas. I am not interested in running them full-range...thats the point of my project. To create a 2-way speaker, using an active crossover and 2 full-range single driver speakers on each side.

I need to figure out how to determine the crossover point that will provide a balanced volume from each speaker, along with not cutting into a vocal range, etc. I suppose I will just have to play with it until I figure something out.
You have no great advantage to use a crossover in this configuration. What ever problems one driver has the other will share, the idea would be that if you had a low region coloration to cross it out to a woofer below or if you had a dip or peak in the upper mids to high end to cross it over to a tweeter, but with two identical drivers, your results will be similar with or without biamping, other than the upper amp should be a little cleaner not playing any bass. Good Listening, Tim