Adding resistance to the tweeter circuit shunt coil

Turn2

I delved into XSim recently and really like it. I was noodling around with a 2.5 or MTM arrangement yesterday and while I could get close, well, it just wasn't happening. I tried many iterations, mainly rearranging resistors on the tweeter circuit and the magic was not "perfect". Finally I just decided to throw a 1.5 ohm resistor after the shunt coil and within a few tiny moves, BOOM, there it was.

I know this configuration is used from time to time but it seems pretty rare. Is there a predictable situation where this is a solution or is this just one of those "shit happens" moments?

jr@mac

If it works, it works - there is no way of easily knowing looking at raw measurements if additional resistance is needed anywhere. 

Although, to be perfectly honest, I learned several years ago that things sounded better when I used 20awg air core coils on tweeter shunt circuits. One of those "secrets", I suppose.

Mzisserson

jr@mac said:

If it works, it works - there is no way of easily knowing looking at raw measurements if additional resistance is needed anywhere. 

Although, to be perfectly honest, I learned several years ago that things sounded better when I used 20awg air core coils on tweeter shunt circuits. One of those "secrets", I suppose.

Shhhhhh.......Its a secret!

I have been doing this for several years now after talking to a fairly talented guy with a speaker company who explained that a balance of resistance on the shunt can actually soften the "overshoot" of the alternating feild of the inductor. 

It can be seen if you hook up an O-scope and throw some square waves through. the leading edge of the wave typically is higher in a very small time before settling flat. think Q. 

We do not listen to square waves but but the program signal is a highly complex waveform. 

Too much, though, and things can get too soft and sound flat and lifeless because you begin to slow the rise time of the leading edge. 

Unfortunately for us, this effect while completely normal in a reactive circuit, varies from crossover to crossover and application to application. 

It is one of those things that is a reminder of why voicing is critical, and you cannot live by simulations and measurements alone. Analog, reactive circuits are tuned in many diciplines by skilled professionals looking for specific results.It is soley the nature of the beast and many times only after it is tuned they will plug in the values to see what is going on on paper. 

The math is there. the science is there, and you need it to get you close, from there there are details that sometimes are not seen, but are meaningful that need to be wrapped up by "tuning" a circuit. 

$0.02/YMMV it is not about golden ears, rather leaveraging your ears as another tool once you coorelate the sound, to the soultion like the OP has.