Zobel networks in an active speaker/crossover

[SteveVaiRules]

I am designing a speaker around an active crossover. and the only passive component I had in mind was a tweeter protection circuit.

But I am wondering if by using 1 amp/driver I would really benefit from the introduction of a zobel network(s). If so should I attach one to every driver or just a specific driver. Of course I am designing the crossover points around the frequency response curves of the drivers and am largely ignoring the impedance curves (doing this because I have gone active). Now I don't know if this is to become a detrimental choice. And how should I fit a zobel network into this equation, if at all?

These are the drivers I am using. And this isn't my first speaker.
accuton® Carefully selected loudspeaker drivers.
accuton® Carefully selected loudspeaker drivers.
accuton® Carefully selected loudspeaker drivers.

Looking at the impedance curves I don't really think that I will be really anywhere near the peaks in the curves for any of the drivers. So does that mean that a zobel network in this case is just extra hassle for little to no gain?


Matt

[mrfeedback]

Amplifiers always prefer resistive load, so yes I would compensate the rising impedance characteristic.
Even better results are obtained ime by compensating the electrical resonance of the drivers also.
This does take more time and incurs more cost but is well worth while, especially considering the prices of the Accutons that you are specifying.

Eric.

[SteveVaiRules]

this is my first active build, so I am wondering if there is going to be any negatives to having a zobel in the signal path; other then the time, cost, and complexity issues, which I am willing to go through if it's worth it? Considering I am using accutons as a sign that I will be pushing the boundaries and willing to spend the extra time and money and willing to put up with additional complexity.

Will the zobel network have a negative impact on the sound or is the trade off of a flatter impedance and a nice resistive load on the amplifier be more then an ample consolation?

I don't really have a tonne of experience with zobels in my own designs, my only experience is in implementations of others work.

Thanks for the reply Eric!

Matt

[Henry8]

I would concentrate on getting right your active setup, crossover points, amp choice, achieving desired acoustic response via the xover etc.
A amp driving a sole driver is the easiest load for it, since there are no caps and inductors.
Once the system is running then if your bored you can add a zobel to flatten the inductive rise, and evaluate its benifits....
If your really bored then you can try to add l-c-r for the imp res peak.
Zobel design via software is easy if you have the actual measured imp.
Imp res peak is slightly more tricky.
I can say zobels can offer a very slight, smoother sound with some tweeters.

[mrfeedback]

Thanks for the reply Eric!

You are welcome.
My experience is that the effects are only positive.
One thing to note is that the networks should be right at the driver away from the magnets as far as is practical, and not on the cabinet input terminals.
If you impedance eq the individual drivers correctly you get smooth highs way out past your hearing, lows that are clean all the way down to the floor, and mids/vocals that sound right.
Another benefit is being able to run the system significantly harder (higher spl) before nasties creep in, and therefore better reliability of drivers.
Cooler running of amplifiers and perceived higher efficiency is another plus.
Sweep your drivers from the amplifier end of your cables at realistic sound pressure levels and mounted into the cabinets to get correct component values by selecting on test.
Some more background....you can do more searching if you like.
Zobel network - Wikipedia, the free encyclopedia
Passive Crossover Network Design

Any more info, just ask.

Eric.

[sreten]

Hi,

FWIW I cannot see any point in zobelling the drivers in a fully active setup
with low output impedance amplifiers, it only makes some sense with high
output impedance amplifiers, and that effect can be alternatively EQ'd.

rgds, sreten.

[mrfeedback]

Originally Posted by sreten

Hi,

FWIW I cannot see any point in zobelling the drivers in a fully active setup
with low output impedance amplifiers, it only makes some sense with high
output impedance amplifiers, and that effect can be alternatively EQ'd.

rgds, sreten.

Sure.....in a perfect world. Reactive load = return energy that the amp and internal feedbacks have to deal with.
Resistive load means one way transmission of energy and is ideal as can be.
Reducing load inductance is always better ime, and that includes speaker cables.
Matt is forking out $2k++ for drivers + cabinets +++ etc.
Extra passives are not going to break the bank and will polish his project.

Eric.

[bigfishe]

I'm with you on that Eric .I run a DEQX and find the zobel smooths out the sound of my two way fullrange/sub system.brines fb20/goldwood H frame

[benb]

Originally Posted by sreten

Hi,

FWIW I cannot see any point in zobelling the drivers in a fully active setup
with low output impedance amplifiers, it only makes some sense with high
output impedance amplifiers, and that effect can be alternatively EQ'd.

rgds, sreten.

I agree with this, a zobel would be much more important sound-wise for any driver(s) driven by a tube amplifier where its higher output impedance would cause a rising voltage where the driver has a rising impedance.

[Charles Darwin]

Personally I think that any inductor in the signal path between amp and driver does more damage than an uneven impedance with regards to transistor amps.