Infinity Column II Woofer...Need help/advice please

[flyingfinn]

Greetings to all. I recently got extremely lucky, and scored a pair of Infinity Column II's for $20 on fb marketplace. The bad news: Someone had replaced all 4 woofers with the cheapest ones you can buy from PE. So, I have a couple of questions regarding replacing them:

1. Were the original woofers 8-ohm, or 4-ohm wired in sequence? The current garbage woofers are 8-ohm. Also, the front firing woofer is spliced into the main BEFORE the low pass coil for some reason (see photos).

2. Recommendations on which replacement woofers to purchase? OE woofers seem to be non-existent. The ones from Mavin seem to have pretty good specs for the price, but are they any good? My other idea was to use a high efficiency PRV for the front, but they only go down to 75hz. So, I was then going to use a subwoofer for the downward-firing woofer. Thoughts?

The good news is that all of the other drivers appear to be original, and working properly. Thanks!

 

[tubed]

Greetings to all. I recently got extremely lucky, and scored a pair of Infinity Column II's for $20 on fb marketplace. The bad news: Someone had replaced all 4 woofers with the cheapest ones you can buy from PE. So, I have a couple of questions regarding replacing them:

1. Were the original woofers 8-ohm, or 4-ohm wired in sequence? The current garbage woofers are 8-ohm. Also, the front firing woofer is spliced into the main BEFORE the low pass coil for some reason (see photos).

2. Recommendations on which replacement woofers to purchase? OE woofers seem to be non-existent. The ones from Mavin seem to have pretty good specs for the price, but are they any good? My other idea was to use a high efficiency PRV for the front, but they only go down to 75hz. So, I was then going to use a subwoofer for the downward-firing woofer. Thoughts?

The good news is that all of the other drivers appear to be original, and working properly. Thanks!

Yeah, those woofers are hard to come by and have no idea of the original crossover configuration.
I doubt the top woofer would have been run full frequency bypassing the coil.
Perhaps wired in parallel yours might work well.
I suppose you could also try to emulate the originals by removing the the dustcaps, replacing with some flat facsimiles, then doping accordingly.
Have fun.

 

[flyingfinn]

Wow. That's a quick response. (This was my first post to AK). Trying to get an aftermarket to look like the originals can be a fun art project, but these $17 woofers do LITERALLY next to nothing. I'm as far as can be from a big-thumping bass head. It's like they have half the volume of the mids/highs. I've been running a little Polk 8" powered sub to fill the gap.

 

[tubed]

Wow. That's a quick response. (This was my first post to AK). Trying to get an aftermarket to look like the originals can be a fun art project, but these $17 woofers do LITERALLY next to nothing. I'm as far as can be from a big-thumping bass head. It's like they have half the volume of the mids/highs. I've been running a little Polk 8" powered sub to fill the gap.

The dust caps weren't altered, I was thinking of the WTLC model.
Only the bottom woofer was doped.
Perhaps the woofers you have are wired incorrectly, out of phase thus cancelling bass response.

 

[goodolpg]

I'm thinking the same thing after reading this---> "these $17 woofers do LITERALLY next to nothing."
Check that that they are wired properly, especially since we KNOW they've been replaced, and we know Infinitys with dual woofers and lack of bass is often caused by them being mis-wired after refoam/repair/replacement.

 

[seifreit]

Is it possible that the lower doped woofer is the same one used in the 3000/4000 speakers. They sure look an awful lot like the woofers in the 3000s I have. Same time frame model/production for both. If that is the case, you should be able to find some at a reasonable price. I see them show up on eBay occasionally

 

[elnaldo]

Being the woofers in parallel, I guess they are 8 ohm.

 

[waggs098]

View attachment 1700090

Being the woofers in parallel, I guess they are 8 ohm.

Follow the diagram and make sure your speakers are wired correctly and if not fix them and see how they sound.

 

[goodolpg]

Is it possible that the lower doped woofer is the same one used in the 3000/4000 speakers. They sure look an awful lot like the woofers in the 3000s I have. Same time frame model/production for both. If that is the case, you should be able to find some at a reasonable price. I see them show up on eBay occasionally

Interesting idea. The 5000 appears to use the same 12" svc as the RSM so it's not out of the realm of possibility.

 

[flyingfinn]

Update: I rewired the front woofer so that everything is now correct. That helped, but something was still way off. Then I noticed that whoever did this hack job also jam-packed the entire cab too tightly with poly-fill. These woofers simply couldn't breathe. I would say he used at least twice the amount he should have. However, I'm a novice, so I have no idea what's the right amount. I ended up removing most of it from the woofer area, and didn't touch the rest filling the top half of the cab. The result is a dramatic difference. I was running them through my JVC JR-S 300 (50wpc). It had the proper amount of bass, it really wasn't up to the task of driving these speakers. I recently purchased my first actual amp (Carver TFM-45), but was reluctant to use it since I don't have a pre-amp yet. I ended up using the JVC as a pre-amp, and it worked. It not only fixed my problem, but radically transformed the overall sound. I swear that the Carver has enough watts to make virtually any speakers sound good. Thanks for all the help, especially the wiring diagram. It confirmed what I was thinking.

 

[goodolpg]

It's very possible Infinity did the "hack job" with the poly fill as that was the right amount for the OEM woofers in their opinion.*
It's possible the "hack" who put in the replacement woofers simply reinserted the amount of polyfil he removed.
Some Infinitys have lots of polyfil and these may have been one.

*About the only way to know for sure is from someone who has an unmolested pair and could or has checked them.

 

[flyingfinn]

View attachment 1700090

Being the woofers in parallel, I guess they are 8 ohm.

Thanks again. This schematic has been very helpful. I do have a question: According to the diagram, the coil for the woofers is 4.3mH. At 8 ohm, wouldn't that create a first order low-pass of 300hz, or am I miscalculating? According to hifiengine.com, the first crossover point is 750hz. BTW, is there any crossover calculator that factors in resistors? It seems that lots of crossovers use them in order to use lower value caps and inducers, but I can't find a way to calculate those values.

 

[elnaldo]

Don't overthink about crossover points and so. Just replicate the original design if you find original woofers.

I've seen many (many) crosovers where the "book calculated" values don't match the advertised "crossover point". And measured many of those speakers where the roll off freq is near what the spec sheet says, but cap and inductor values are not what the book says. Speakers are very non linear devices. You calculate a "crossover point" based on a calculator, and then, real world measurements show a different behavior.

BTW, two 8 ohm woofers in parallel are a 4 ohm load to the crossover inductor. My web based calculator says "150 Hz" xover point using a 4.3mH inductor. As you see, very far from 750Hz. It could be a typo on the datasheet too (wrong crossover point, or wrong inductor value). Infinity is famous for this kind of errors.