Nuuk said:
Maybe. Maybe not. It gives you an idea for a starting point.
I choose caps that give me an XO about an octave above where i think it should be. Then keep adding parallel caps (i have a big stash of 0.1 uF for this) until the tweeter becomes a bit too noticable, then back off a bit. It will take a while of listening and it is by ear, but the curve gives you your starting point and shows if you have any little wrinkles to deal with.
The ballpark here is to start with 1 uF and work your way upwards (i'd guess you won't reach 3 uF) -- this is for an 8 ohm tweeter. Larger values if the actual impedance is lower, smaller if higher.
dave
I ran my active system for over two years with the amps connected directly to the drivers (woofer and tweeter). However, I did use Velleman speaker protection modules so the connection was not made until everything had 'settled down'.
Now I must make the decision whether I use protection again! (I will need to buy another module for a start).
Nuuk said:I think Dave was offering to see if the Radio Shack tweeters have the same impedance curve.
Exactly. They are in their pods so i need to dissassemble to get past the XO.
The scale on the Fostex FT17 sheet is a bit deceptive. Very squashed scale & the impedance magnitude axis is logarythmic. Still pretty flat.
dave
OK chaps, the Radio Shack bullet tweeters are now playing in my open baffles and sound pretty good to me!
I have installed them with a 1 uF cap and no padding. I decided that the Goodmans 201's would be a close enough match in sensitivity and that appears to be the case.
The change in tonal balance is immediately discernable. After a listen to a few Jack Johnson tracks, I put on Roger Waters (Amused to Death) and with this CD the changes are even more apparent. All those little sound effects are moved further out into the room such that they surround the listening position even more than before.
After an hour of continuous listening I haven't heard anything that I dislike but I'll need to listen to many more recordings to find out if these are my 'final' tweeters.
I have installed them with a 1 uF cap and no padding. I decided that the Goodmans 201's would be a close enough match in sensitivity and that appears to be the case.
The change in tonal balance is immediately discernable. After a listen to a few Jack Johnson tracks, I put on Roger Waters (Amused to Death) and with this CD the changes are even more apparent. All those little sound effects are moved further out into the room such that they surround the listening position even more than before.
After an hour of continuous listening I haven't heard anything that I dislike but I'll need to listen to many more recordings to find out if these are my 'final' tweeters.
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