If the sound is good, you've done it right.
Using the wrong inductor tap on the
woofer crosses too high (800 Hz), and the woofer and midrange would overlap at the low end of the midrange (400 Hz to 800 Hz). This over-emphasizes the frequency band and causes comb artifacts which may or may not be audible.
Using the wrong inductor tap on the
midrange causes the midrange to cross too low and this chops off the high end of the midrange band (1,250 Hz to 2,500 Hz) leaving a hole.
Most definitely audible.
It sounds really, really bad. Another thread details that effect and I explained all the math. I'll just paste it in here.
At 8 Ω, the points are 400 Hz (
full large inductor for woofer, N-102 & N-104 tap) and 2,500 Hz (
half small inductor for midrange, N-101 tap).
Given the crossover frequency for an inductor is calculated as:
f = R / (2 x π x L)
we can see that doubling
L will halve the frequency, while halving
L will double the frequency. So we want a small midrange value to move the midrange frequency higher and a large woofer value to move the woofer frequency lower.
If the full-value is used for the midrange, it will cross at 1,250 Hz (well, actually 1,157 Hz). So that will remove the upper end of the midrange, aside from what the tweeters provide via a first-order rolloff.
From what was originally described, it sounded like the woofer was doubling the midrange because the woofer was using the half tap instead of the full tap. That would also create comb artifacts as two drivers not within 1/4 wavelength were at the same frequency, but since the drivers are vertical that tends to not be as horrible sounding as horizontal drivers.
If the woofer was running with half the inductor it would cross at 800 Hz, and if the midrange were running at full the lower end would be 400 Hz (controlled by the capacitor) and the upper end be 1,250. So we'd have woofer(0 to 800 Hz) and midrange (400 Hz to 1,250 Hz). This will sound terrible. So I think this had to be the problem. Even if the midrange were correctly wired for 2,500 Hz, the doubling from 400 Hz to 800 Hz would be a problem, more so than might be expected because of the first-order rolloff.
Easy way to tell: hook up a signal generator and sweep the range, see where the sound comes out. A signal generator can be built using a 555 if you don't have one. You don't need a scope or frequency counter for this, as accuracy is not imporant. One is looking for overlaps or gaps in the response.
Ix-nay on the oam-fay.
I'd go with the cotton batting since we know it properly functions and doesn't degrade. The foam disintegrate over time and liberate fine dust which can get into the voice coil. Foam off-gasses a variety of VOCs, and since the cabinet and midrange cover are sealed that is going to end up deposited on the driver.
Also, the foam tends to work less well as frequency drops, so while it might work fine on the middle to upper part of the midrange, I don't know how well it works in the lower (< 800 Hz) range.
Awesome Info!! Will do on the Batting. No problem.I never thought about foam doing that. I mean I know it does, so why that didnt occur...idk. Thats why I love these forums!
Moving the tweeter high greatly improves the sound. So does switching to a modern soft dome. Biggles can tell you all about that.
I suggest using the soft dome and putting the original tweeters in the cabinet underneath the cotton batting with a note about where to find them.
Ahahahah!! @ putting the orignal tweeters back. That made me laugh. I totally hear where you are coming from. I think like a lot of people, I have this thing to try to keep them as original as possible. I mean, yeah the crossover has been modded. IDK, I can see myself adding a nice tweeter like was suggested down the road...
Yes, permits on to dial in the exact amount of treble which varies by the type of music, room, and person.
Question: you restored the polarity for the midrange so it now matches the other drivers?