Lowering the crossover point.

**juniper** · August 15th, 2012, 01:23 PM

I run my 604's at 1250 per what my tech measured? and they sound really good to me, with a little eq. I have GPA crossovers, and that mellowed the sound a bit, and they sounded more like M19's, so I put the original xover that came with the speakers back in. I am glad I have never put more than 3 watts into them after reading this thread.

GM · August 15th, 2012, 05:57 PM

Apparently ya'll haven't seen Jeff's 604E HF measurements, which should be pretty typical. Ditto his thoughts WRT loading caps [which mirror mine]: Altec Compression Driver Rear Loading Caps

GM

**aditya** · August 16th, 2012, 06:42 AM

Originally Posted by cradeldorf

I was not aware of that. Is that because your calling the DCR the ohm resistance? I didn't think they are the same? Because measuring DCR and measuring ohms seem like two different processes when I read up on testing inductors it wasn't a simple measurement like a DCR measurement is?. I was calculating them using the 16 ohm rating.

The 16 ohm thing is called as the impedance, which is DCR+reactance. DCR is constant, but reactance varies with frequency, and as a result impedance varies. To calculate xover component values at a particular 'f' one has to know the impedance at that 'f'. The specified impedance (ohms value as you have said) for a driver generally means it to be valid at 1KHz. At other freq it will be different, even may become the same as the DCR. So here comes the 'impedance-graph'. Now just b'coz the graph is in hand does not mean that the computed values will be the workable ones. This is so b'coz, as the graphs are not straight lines, the resultant filter response slopes will be far from what what was calculated. So now comes the difficult part, that is to adjust the values of the components, type of the filters, choice of xover-'f' etc., so that it can deliver the goods.

**Alien_Shore** · August 18th, 2012, 08:26 PM

Originally Posted by cradeldorf

I'm never touching them again.

hahaha ok, if you say so!

**Alien_Shore** · August 21st, 2012, 05:06 PM

35422-SMARTYPANTS.jpg
OK Let us know how they sound!

**Old Guy** · August 21st, 2012, 06:59 PM

Originally Posted by cradeldorf

I was not aware of that. Is that because your calling the DCR the ohm resistance? I didn't think they are the same? Because measuring DCR and measuring ohms seem like two different processes when I read up on testing inductors it wasn't a simple measurement like a DCR measurement is?. I was calculating them using the 16 ohm rating.

DCR is DC (direct current, or zero Hz) resistance. There is no such term as ohm resistance. If specified as resistance, it is DCR. If specified as impedance, a much bigger can of worms opens. To vastly over simplify, impedance is effective resistance at a specified frequency, an impedance curve is specified at enough points to allow a curve to be drawn between. Impedance is higher than DCR, which is why an 8 Ohm speaker measures less on DC multimeter. 8 Ohm would be "nominal" generally a mean figure. Not to be confused with Sports Illustrated models, who have mean figures of their own.