What is the source of this drawing ? Are you sure its correct?
With the 3uf and the 15 ohm resistor, it would seem
that this is a circuit for a driver with a 16 ohm diaphragm.
Art J
Try this thread about N501-8B Inductors http://www.hostboard.com/forums/showthread.php?t=147402&highlight=N501-8b
The person on the above thread has a pair of these xovers, this is what he sketched.
As the Model 19 has a 6uF compensating cap parallelled with 3.9 ohm resistors, the same value as the 9846 Studio Monitor, I suppose this is the best way to go. Instead of using the 6.5 ohm resistor as in 30923 (R2) I'll propably try using 8 -10 ohm first.
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
Very good Altec Man. I read through that thread and I guess the uncertainty remains.
With the capacitor on the wrong terminal and an additional 5 ohm resistor, it appears
to been hacked at some point. The 18236 coil is also different. My guess at this time
is that they used 16 ohm on top and 8 ohm on the bottom. Some altec units did this.
Go ahead with the 30904. I completely tested it years ago and found it worthwhile.
I'll be around if you need more info. Art...........
Hey GM, we always like a good mystery to solve. I'm surprised that Bfish hasn't jumped in.
.
I woulda, but I misplaced my Sherlock Holmes pipe...
"[I]We're going all the way, till the wheels fall off and burn[/I]!"
Bob Dylan, from [I]Brownsville Girl[/I]
[I]"Time wounds all heels"[/I]
John Lennon, referring to the Nixon/Hoover deportation fiasco.
Art J
Thanks for your help. I tried adding various tweeters e.g JBL Slots and RCF Horns to make up the deficiencies in the top end with some mild success but hopefully by utilising the 30923 this will make the top end come through as the midrange will attenuated. As I have only have good 6.8uF caps hopefully this won't be a concern. By the way did you ever add a tweeter to enhance the top end or were you happy to leave it alone.
I did place one on top for a while being curious to what others were doing.Originally Posted by altec-man
No matter how I placed it , the phase cancellation was just too much.
Using pink noise, any movement would sound like a capichino machine.
Trying to be brief, this is the setup I used for my tests.
http://webpages.charter.net/artj/testing1234.JPG
I hope your not putting too much expectation on the 30923.
The results from the 30923 are much more impressive on the test equipment
than my hearing. The SPL readings showed very strong, almost flat output all the way to 20k.
Only my youngest daughter and the cats could hear it that high. Instruments do not lie.
Its not going to add the exaggerated sparkle that some seek and its not going to compensate
for hearing loss either. It only flattens the response. I hope it works well for you.
Some info on the 30923
Using Altec 30904 atteuator with 511/416 - AudioKarma.org Home Audio Stereo Discussion Forums
I'm using a L-pad for R-2. Set at 10--12 ohm with 16 ohm 806A.
Thanks everyone and this forum for putting me in the right direction. I finally built the 30923 network and have listened to the result, the only circuit difference being R2 was changed from 6R5 to 8R2 ohms. You guys were right about the noticeable overall dB drop but I suppose the 1 -6 kHz band delivers alot of information. I had to adjust the attenuation setting on the N501-8A to compensate for the overall drop, I originally had it set at the number 6 position but am listening now at the number 5 setting, will have to play around further.
Once again, thanks from Down Under, keep up the good support!!
Posting Permissions
Bookmarks