Bringing 828 cabs up to snuff...

[alancohen]

So are you saying if I am taking a measurement at LFout, and I change the value of an inductor or resistor in the HF leg, then the values measured at LF out will change?

[GM]

Two wires feed the speaker an AC signal, i.e. it's a closed loop system till something lets its 'smoke' out of course, ergo any change in a component's electrical parameters will impact the entire system to a greater or lesser extent. You want isolation, you'll need to use an amp/driver.

GM

[Audio_by_Goodwill]

If you are agreeing to the fact that the loads are not resistive, then this itself is proof enough of the fact that both the sides are not independent....

I guess I don't see how it matters if the load is resistive or reactive when the loads are in parallel. It's been awhile since I had an electrical class.

[alancohen]

Two wires feed the speaker an AC signal, i.e. it's a closed loop system till something lets its 'smoke' out of course, ergo any change in a component's electrical parameters will impact the entire system to a greater or lesser extent. You want isolation, you'll need to use an amp/driver.

GM

I get that, but I'm seeing two speakers and two separate closed loop systems (per channel).

[Phil-G]

Two wires feed the speaker an AC signal, i.e. it's a closed loop system till something lets its 'smoke' out of course, ergo any change in a component's electrical parameters will impact the entire system to a greater or lesser extent. You want isolation, you'll need to use an amp/driver.

GM

I was thinking this , in that every speaker has an effect on the system. large speakers in particular. with the cyclical collapse and reversal of the field of the coil and the coils physical movement through the field of the magnet. there is certainly going to be feed back.

[GM]

I get that, but I'm seeing two speakers and two separate closed loop systems (per channel).

What's isolating them?

GM

[aditya]

I guess I don't see how it matters if the load is resistive or reactive when the loads are in parallel. It's been awhile since I had an electrical class.

You are welcome....

In the case of reactive loads the impedance varies with frequency, and thus the decay of the LF driver at the x-over point & beyond does not stay where it should be. Here the HF section's component choice helps in putting up a compensating path for the signal to flow out into the HF portion and thus restore the slope. This interactive nature between the different sections makes it difficult to design a good passive x-over, compared to an active one where the loads are resistive, as they are fed into separate amps. But this very interactive nature also helps in getting a particular type of sound easily which otherwise would be almost impossible to get in an active design unless a chain of filters/DSP are used in the signal path.

- - - Updated - - -

So are you saying if I am taking a measurement at LFout, and I change the value of an inductor or resistor in the HF leg, then the values measured at LF out will change?

You need not measure it. You can hear it very easily. You can do a simple experiment to find it out for yourself.

You have 2 sets of inductors & capacitors for the 16 ohms 515s at your disposal. Just hook them up as the 16 ohms Hiraga version, minus the other compensating components in the HF leg. I mean...just the coil+cap for the 515, and cap+coil for the 288. Hook up the 515 but not the 288. Hook up a 16 ohms resistor in its place, as we want to listen to the effect on the woofer. Now connect the setup to an amp & source and play some music. While listening disconnect the HF side's cap (the cap which goes to the amp) and see what you hear.....

[GM]

Yeah, a mix of active n' passive is the best performing overall for me with the latter for getting the right 'tone'.

GM

[alancohen]

You need not measure it. You can hear it very easily. You can do a simple experiment to find it out for yourself.

You have 2 sets of inductors & capacitors for the 16 ohms 515s at your disposal. Just hook them up as the 16 ohms Hiraga version, minus the other compensating components in the HF leg. I mean...just the coil+cap for the 515, and cap+coil for the 288. Hook up the 515 but not the 288. Hook up a 16 ohms resistor in its place, as we want to listen to the effect on the woofer. Now connect the setup to an amp & source and play some music. While listening disconnect the HF side's cap (the cap which goes to the amp) and see what you hear.....

That sounds like a fun experiment. As a matter of fact, I might just want to build a "breadboard" crossover and play around with it until it does what I want it to.

If the whole thing is reactive with the amp, then I assume output impedence plays a role.

[GM]

Duh! This is a given even if it has a flat impedance as it increases the driver's effective Qes, Qts and why I'm a 'broken record' on how important it is to factor this in when making a driver, alignment choice.

GM