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Alan,
I agree with dbale, use the 0-50 ohm side of the L pad for P1, and start with about a 10-12 ohm setting. P1 "stands" on a 3 Ohm resistor to ground, which adds a bit of total resistance to P1, but also prevents it from becoming a dead short to ground.
Jeff
Thanks for confirming that Jeff.Quote:
Originally Posted by jmarkwart
Copy that...thanks guys!!
Houston, we have a small problem. Got the other crossover done and I'm in the process of installing them when I noticed that the LF driver in one speaker has two 1s instead of a one and a two. On the other speaker the left LF terminal is a 2, and the left HF terminal is a 1. Is this correct? According to Jeff's drawing it is.
http://www.hostboard.com/forums/hbmc...2013/06/14.jpg
So...the 604s are playing in place of the A6s. In a word...wow!
They definitely go much lower. They also offer up a wall of sound stage. With the A6s I always know exactly where the speakers are. Now, if I close my eyes the 604s disappear. I could get used to this
do the 9v battery test on it to confirm which terminal is the +Quote:
Originally Posted by alancohen
1.5V battery is safer and you only touch it on briefly. Do the driver with the 1&2 terminals first and then compare the other one.
I got better bass putting the "+" on the left one, but put where ever you want it to be.
I was hearing a funky intermittent sound in my left speaker so I decided to break out the measuring equipment.
The good news is that measuring the right speaker yielded the uppermost teal-colored curve. Not bad.
The bad news is measuring the left speaker that was making the noise, I got the bottom blue curve. Not so good.
http://www.hostboard.com/forums/hbmc.../2013/06/1.png
So I switched the crossovers and the right speaker now had the bad curve and the left speaker was fine, so I guess the good news is...it's the crossover.
Since it's appearing to pass HF OK, I'm thinking the issue is one of the coil connections. Those thing are a bear to solder since they act as a huge heat sink.
Stay tuned...
- - - Updated - - -
So it appears I needed to solder all the connections, not just most of them. Jeez. I neglected to solder one of the L-pad connections which makes sense since it now left the 3W resistor "open" and passed too much high end.
Here's a scan of the repaired bad crossover, but with a little extra L-pad so you can see the effect.
http://www.hostboard.com/forums/hbmc.../2013/06/2.png
All in all, I'm pretty satisfied. I think I ended up with a pretty usable crossover. Thanks Jeff and Co.
Does anyone happen to have the impedance curve for a 604C or D? When you get down to the lower bass, how high can the impedance get, at say 35-40Hz?
I did somewhere, I may have deleted them off my flickr account but pretty sure I have them at home, will post up tomorrow as I am at work right now.
http://www.flickr.com/photos/82812412@N03/7902706654/
Nice curves. I was surprised that the low freq Z peak was so high (in freq).
My 605s were 22 Hz when new and a year later around 30 Hz.
Please add a Zobel R & C and rerun the curves. I calculate Rz= 11.1 (25 // 20) and Cz= 10.7 (8.2 // 2.5) .
I can send you the parts , PM me.
I think I only had my sweeps starting at 30Hz, Don. I should probably start at 10. PM sent...Quote:
Originally Posted by donaldpatten
CRADELDORF
Nice curves. I was surprised that the low freq Z peak was so high (in freq).*
My 605s were 22 Hz when new and a year later around 30 Hz.
Please add a Zobel R & C and rerun the curves. I calculate Rz= 11.1 (25 // 20) and Cz= 10.7 (8.2 // 2.5) .
I can send you the parts , PM me.
The DATS curves you posted from Flicker, were they free air? Say with the speaker hung on a rope from a sky hook ...
The low freq peak IMHO , should be in the 30 Hz ball park not 54.
The 604D has a published 40 Hz Fs, so 54 Hz seems reasonable for such an old driver. The 605 series replacement had a 25 Hz published Fs, which carried over into the 604E when this series was reinstated.
GM
GM
Thank you for your input .
You wouldn't recall what Fs spec was for the 604C ?
Don
You're welcome! AFAIK, all the early horn loaded duplexes till the E had around a 40 Hz free air Fs [Fsa], though I've seen postings that the original was around 60 Hz, but I'm pretty sure that was its in-cab tuning [Fsb] based on reverse engineering some early cabs since the pioneers decreed that a sealed cab that raised Fsa by 1.56x would yield an extra 1/2 octave of flat response when reflex tuned to Fs.
GM
alancohen
The curves you did in #59, were dB SPL. To do Impedance curves you need to plot the voltage across the XO input, with the speaker connected to the XO.
First connect a 1k Ohm series resistor between the power amp hot output and the XO input. Connect the speaker com. to the amp common.
Plot the voltage across the XO input. To calibrate your test ckt, sub a resistor for the XO and speaker. I like to do calibration resistors for 8, 10, & 16 Ohms . If you can, change the vert scale from log to lin.
see the Lansing form .
Don
Hi Don, It was taken free air but not hanging. It was standing on end on shag carpet balancing on a 4" long piece of 6" pvc pipe.Quote:
Originally Posted by donaldpatten