Unable to decide

[rs1026]

I have a 8 inch woofer + 4inches tweeter.At present I have connected them to a lm3886 based amp. The speakers employ a passive cross over filter.The speakers sound quite OK.I want to know instead of a single 8inches woofer and a tweeter will using two 6inches woofer + one 4inches mid range and one 1inch tweeter sound better.I have tested the speakers with active filter also but could not make out any sonic improvements.Both sounded almost same.Why is it?? I dont know if my hearing capabilities has decreased!

[richie00boy]

The best results will probably be 2x 6 inch woofers and the 1 inch tweeter. The 6 inchers will be fine for midrange and avoid the phase problems of going 3 way.

As for the active crossover bringing no improvement, you probably just didn't implement it well enough or your drivers are totally naff

[rs1026]

The drivers that I am using are quite good so that may not be the problem.I actauuly employed the exact designas given on Rod's web site. It is a 24db linkwitz I have used only a lpf for the mid range and high pass I am not suing any filter.So the setup is like input signal goes to lpf filter and the midrange directly.

But with passive filter the quality is almost similar.

[rs1026]

My previous post is a bit confusing. I have just bulit a lpf 24db roll off filter to drive a woofer.For the midrange the input signal is fed directly without filtering.

In the passive setup I am using 8 inches woofer +1 4 inches tweeter.

I never realised that 2 6 inches were better than a single 8 inch one .Should I conenct them in parallel.?

[RJ]

[[I have a 8 inch woofer + 4inches tweeter.At present I have connected them to a lm3886 based amp. The speakers employ a passive cross over filter.The speakers sound quite OK.I want to know instead of a single 8inches woofer and a tweeter will using two 6inches woofer + one 4inches mid range and one 1inch tweeter sound better.]]

The 6 inchers would be better, but watch for the Xmax. Some 6 inchers are quite lacking in this area. With the smaller diameter or cone size the woofer has to increase it's linear motion to produce sound or pressure in the low bass frequency range. The smaller mass of the 6 inchers will improve the midbass to upper midrange area.

[[I have tested the speakers with active filter also but could not make out any sonic improvements.Both sounded almost same.Why is it?? I dont know if my hearing capabilities has decreased!]]

The only improvement with the active filter is phase coherence.
Passive crossovers introduce phase shifts. A correctly built passive will not have this problem at least aurally.

[rs1026]

How will phase non coherent sytems sound like?May be it will help me if my set up is speakers are coherent or not.

[richie00boy]

Originally posted by richie00boy
As for the active crossover bringing no improvement, you probably just didn't implement it well enough or your drivers are totally naff

Originally posted by rs1026
I have just bulit a lpf 24db roll off filter to drive a woofer.For the midrange the input signal is fed directly without filtering.

I rest my case

Originally posted by rs1026
I never realised that 2 6 inches were better than a single 8 inch one .Should I conenct them in parallel.?

2x 6 inches are not necessarily always better, just that they will be likely to extend up a little higher so you don't need a midrange. And 2x 6 inches is slightly more cone area than a single 8 inch. However, the depth may be slightly less due to higher Fs.

Can connect in series or parallel. It depends on your amp and the speaker impedance.

[richie00boy]

Originally posted by RJ
The only improvement with the active filter is phase coherence.
Passive crossovers introduce phase shifts. A correctly built passive will not have this problem at least aurally.

Not true. Both passive and active crossovers can have almost identical phase shifts and amplitude responses, hence a passive phase coherent crossover (such as Linkwitz-Riley) is achievable. What you gain by going active is greatly simplified design as they are not influenced by driver impedance changes. Also driver damping around the crossover frequency is hugely superior with active crossovers as there is no impedance in the way.