Advent /4 woofer problem

bluepine27

bluepine27

Active Member
Hello,

I just scooped up a pair of Advent /4's for not too much money and were told they were both working but the one speaker's woofer doesn't produce any signal when the speaker wires are connected to the back of the terminals. I connected the wires straight to the woofer and got a signal out of it so it seems to be something in the crossover maybe? I'll be recapping these tomorrow since it seems the originals are still in there but wasn't sure if that would help the problem. Any ideas of what could be going on or what to check for?
 
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It depends on what the crossover circuit looks like. Many Advents have an inductor in series with the woofer. It may well be that the inductor is toast or there is a broken wire in the crossover circuit. If the woofer works when tested from the driver terminals, I suggest working backwards. Check the continuity of the wiring from the driver terminals through the crossover and to the speaker terminals on the back.

Trace out the crossover. It would be great if you could post the crossover schematic since such a schematic does not seem readily available on the interwebs. I've been known to sketch it out on paper and post a picture of my drawing. :D
 
Ok I think I’m about to be pissed. I took out the driver that suspiciously looks pretty fresh and it appears that these woofers are RadioShack woofers. I doubt the original Advent /4 woofers were made by RadioShack but would like to confirm what the originals look like if anyone can post a picture of them. Thanks in advance.

still going to recap and see how they sound though I’m not as excited about having these. The tweeters are beat up to hell too, as well as the cabinets.
 
RTally said:
It depends on what the crossover circuit looks like. Many Advents have an inductor in series with the woofer. It may well be that the inductor is toast or there is a broken wire in the crossover circuit. If the woofer works when tested from the driver terminals, I suggest working backwards. Check the continuity of the wiring from the driver terminals through the crossover and to the speaker terminals on the back.

Trace out the crossover. It would be great if you could post the crossover schematic since such a schematic does not seem readily available on the interwebs. I've been known to sketch it out on paper and post a picture of my drawing. :D
Click to expand...


I hit the inside terminal with some contact cleaner and worked that screw on each side a bunch of times. Also put in new Dayton caps and that seemed to do it, works now.

Still wondering what the drivers are supposed to be for these and imagine there was a few shared drivers for different Advents with 8 in woofers.
 
Cool thank you. Also to add insult to injury, the tweeters are sounding a lot different from each other and I think it might be the one tweeter being punctured completely in the dust cap which I think was the one didn’t check when I went to buy them. Feeling pretty dooped even though it was only 20 dollars but I think I would rather get the tweeters replaced than the woofers anyways.
 
So I'm thinking the T-125 from Simply Speakers would work as a replacement tweeter https://www.simplyspeakers.com/replacement-speaker-tweeter-t-125.html, or at least it would fit.

The hole cutout in the cabinet is measuring around 2 1/4 inches. The frequency response for the T-125 tweeter is 3500 - 20,000 hz. The tweeter is rated for 10 watts. The Radioshack 40-1016a woofers in there are 45 - 4000 hz. The woofer is rated 50 watts RMS

How much crossover in frequencies is fine/too much between a two way, tweeter and woofer? Seems like tweeters are usually lower rated wattage compared to woofers in a speaker so wasn't sure of the 10 tweeter watts to 50 woofer watts was probably fine?

Also would take other recommendations for tweeter pairings with these Radioshack woofers I have in here.

I attached the spec sheet for the Radioshack woofers, and the pics of the original 80-000-152 tweeters that are in the Advent /4
 

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The phrase "throwing good money after bad" comes to mind, but if you're happy with the way the RS woofers sound then just purchasing replacement tweeters might not be too bad. When choosing replacement tweeters, the important specs are impedance, sensitivity and resonance (Fs). As you already know, the sensitivity should be as close as possible to the other drivers. The Fs should be no higher than half the crossover frequency to the tweeter. So, for example, if your crossover frequency is 4khz, you want an Fs of 2khz or lower.

Power handling is an unimportant spec.
 
swechsler said:
The phrase "throwing good money after bad" comes to mind, but if you're happy with the way the RS woofers sound then just purchasing replacement tweeters might not be too bad. When choosing replacement tweeters, the important specs are impedance, sensitivity and resonance (Fs). As you already know, the sensitivity should be as close as possible to the other drivers. The Fs should be no higher than half the crossover frequency to the tweeter. So, for example, if your crossover frequency is 4khz, you want an Fs of 2khz or lower.

Power handling is an unimportant spec.
Click to expand...


I hate to agree with you on the money part, but it might be true. I just felt stuck with these speakers and want to at least get them into working order to see how they are even if i have to pass them along to a friend.
 
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