Woofer output low.

msg

Reading back my last, in case it wasn't clear - it wasn't thoroughly clear to me - I meant to say to clip the wire at about 3" from where it's soldered to the driver. Then crimp and solder your fastons here, to each end of the snipped wire. I'd add heatshrink to both ends prior to crimp/solder, so that you can cover the crimping collar on the male side, and collar and receiver on the female side. This way, you wouldn't have any exposed connector material. I'd probably also consider strain relief or some means of immobilizing the chassis side wire to prevent pull-out.

Looking at this photo, you'd probably want to make your snips beyond the driver body and magnet, but you get the idea. The immobilize the wires, binding to cabinet or something with ziptie or velcro.

Jetmaker737

Update. (TL;DR - The woofer is bad and is open circuit. No obvious defect)

It appears I have a bad woofer. In the end, I didn't need to do any swapping. First I set up the speakers and ran the same 30 seconds of a track, in mono, while taking sound measurements of each of the four woofers. Measurements were 1 inch from the center of the cone. Three of the woofers all measured within 1 dB on max, min and average. The bad driver was significantly lower. Measurements from the two woofers of the "bad" speaker:



I then popped the two drivers off the speaker and started probing around with my VOM. I found that if I put the VOM at the 1 Ohm setting and placed the probes across the terminals of either speaker that I would hear static from the "good" speaker and silence from the "bad" one. These two speakers are hooked up in parallel as can be seen here:



I unsoldered the bad driver and verified that all the connections to the crossover are good (continuity from + to + and - to - lead wires):



I then measured resistance across each set of driver terminals. The good driver measured 5.5 Ohms. The bad driver was open circuit. This is my setup. I figured someone might get a kick out my ancient VOM (it was my dad's):



So now I'm looking at the leads and coil wires on this driver and not seeing any sign of a break. Any suggestions or is this driver trashed?

pitdogg2

I'd say the voice coil is kaput. Unless you want to tear it completely down and install a voice your only "easy" option is buy a new woofer.
Sorry to hear 😞

Use the numbers to see if the OEM has one or call the speaker company to see how to acquire one.

Jetmaker737

Good suggestion, thanks. I googled the driver part number 18W/8531G03. It is nowhere to be found. But another Scanspeak driver, 18W/8531G00 is available. The G03 is a modded G00. So I've sent emails to both Scanspeak and Sonus Faber on the feasibility of substituting the G00 for the G03.

pitdogg2

Excellent my man!
Post back your findings, I'd be interested to know as well.

txcoastal1

Jetmaker737 wrote: »

Good suggestion, thanks. I googled the driver part number 18W/8531G03. It is nowhere to be found. But another Scanspeak driver, 18W/8531G00 is available. The G03 is a modded G00. So I've sent emails to both Scanspeak and Sonus Faber on the feasibility of substituting the G00 for the G03.

Glad you have narrowed the down and hope the Scanspeak is a viable alternative. They are really good drivers but damn not cheap at 250 each and the time and travel you put into it

Clipdat

Good detective work. Hopefully Sonus Faber can get you a new driver shipped out with no fuss at a good price. This should be a good example in regards to how they take care of their customers.

After you swap in the new driver, do you think the original buyer will want to drive up again to buy them?

msg

Good job!
Hey, I'm curious about this bit here, below, as I've not seen this before and am no audio electronics expert. This is with the drivers still connected?

I'm not understanding how static was generated.

Jetmaker737 wrote: »

I then popped the two drivers off the speaker and started probing around with my VOM. I found that if I put the VOM at the 1 Ohm setting and placed the probes across the terminals of either speaker that I would hear static from the "good" speaker and silence from the "bad" one.

Gardenstater

https://www.youtube.com/watch?v=g3zbjHxVVxM

Jetmaker737

msg wrote: »

Good job!
Hey, I'm curious about this bit here, below, as I've not seen this before and am no audio electronics expert. This is with the drivers still connected?

I'm not understanding how static was generated.

Yeah, I was surprised by this. It was with drivers connected (one or both, didn't matter). I'm no expert either. The Ohmmeter puts a DC voltage across the terminals, with very low current, so somehow that got converted to sound. I'm sure some of the more knowledgeable members can explain.

Jetmaker737

Clipdat wrote: »

After you swap in the new driver, do you think the original buyer will want to drive up again to buy them?

I'm sure he would like to but my price will likely be higher. He let slip in talking to me that he had put up the speakers on Offerup and was getting offers. I don't know what he was asking, but obviously north of the $3K he paid me. If the woofer hadn't been kaput he would have sold them quickly I think. I found out later that this guy frequently sells audio gear on Offerup and USAM.

msg

Jetmaker737 wrote: »

msg wrote: »

Good job!
Hey, I'm curious about this bit here, below, as I've not seen this before and am no audio electronics expert. This is with the drivers still connected?

I'm not understanding how static was generated.

Yeah, I was surprised by this. It was with drivers connected (one or both, didn't matter). I'm no expert either. The Ohmmeter puts a DC voltage across the terminals, with very low current, so somehow that got converted to sound. I'm sure some of the more knowledgeable members can explain.

Wow, that's a good tidbit, thanks!

msg

Jetmaker737 wrote: »

Clipdat wrote: »

After you swap in the new driver, do you think the original buyer will want to drive up again to buy them?

I'm sure he would like to but my price will likely be higher. He let slip in talking to me that he had put up the speakers on Offerup and was getting offers. I don't know what he was asking, but obviously north of the $3K he paid me. If the woofer hadn't been kaput he would have sold them quickly I think. I found out later that this guy frequently sells audio gear on Offerup and USAM.

Sounds like a flipper then. Nothing wrong with trying gear out, but he sounds a bit opportunistic and it's a bit off-putting to me.
Like a version of the lowballer.

I agree, definitely more if you were previously letting them go for less than market. I'm always a little surprised to hear people bragging about the great deals they get by squeezing people, as if it's some great skill or accomplishment in maneuvering, when all they really did was take advantage of someone. It's like, hey, way to out yourself Sleazy Mortinson.

pitdogg2

Jetmaker737 wrote: »

I'm sure he would like to but my price will likely be higher. He let slip in talking to me that he had put up the speakers on Offerup and was getting offers. I don't know what he was asking, but obviously north of the $3K he paid me. If the woofer hadn't been kaput he would have sold them quickly I think. I found out later that this guy frequently sells audio gear on Offerup and USAM.

Personally he'd be the last person I'd offer them to if that was the case.

Clipdat

Jetmaker737 wrote: »

Clipdat wrote: »

After you swap in the new driver, do you think the original buyer will want to drive up again to buy them?

I'm sure he would like to but my price will likely be higher. He let slip in talking to me that he had put up the speakers on Offerup and was getting offers. I don't know what he was asking, but obviously north of the $3K he paid me. If the woofer hadn't been kaput he would have sold them quickly I think. I found out later that this guy frequently sells audio gear on Offerup and USAM.

What a schmuck.

Jetmaker737

Update: Success! (TL:DR - Replaced failed woofer with Scanspeak Revelator. Functions perfectly)




So I never heard back from Sonus Faber. However, Scanspeak responded immediately. After swapping a couple of emails they said that, unfortunately, they could not share the specs for the Sonus woofer 18W/8351G03 which i was hoping to use to confirm that the Scanspeak woofer 18W/8351G00 is equivalent. The Scanspeak specs are published and I was able to confirm that all dimensions of the frame, magnet, voice coil, etc are the same. I was also able to confirm that DC resistance was exactly the same at 5.9 Ohms. So I ordered the Scanspeak driver from Madisound.

I used an LC meter to measure voice coil inductance of both speakers. They were slightly off, like 20%, which seems high but not really when you realize that even slight finger pressure on the cone moves the values dramatically. Inverting the cone onto the carpet changes it by 2 orders of magnitude. So I concluded that the 20% is likely due to break-in. I suppose I could have gotten a Dayton DATS system and wrung out both drivers, but I think I have enough info to conclude that the drivers are equivalent.

Since my soldering skills are newb-level, at best, I elected to use fastons as suggested by some members. They would be easier to get a good solder joint I figured. I got some gold-plated ones from Madisound along with the new driver.






Today I soldered them on and verified mechanically- and electrically-solid connections and hooked up the two drivers (I had removed the upper driver to do the electrical measurements). Speakers are back in the system and functioning perfectly as the new driver breaks in. Big thanks for all the input, especially @pittdog2 suggesting the PN search which led me to the Scanspeak driver.

Rick

F1nut

Good job!!!

Jetmaker737

F1nut wrote: »

Good job!!!

Thanks! Appreciate the help.

Clipdat

Thanks for the update, glad everything worked out in the end.

Can't believe you never heard back from Sonus Faber, how unfortunate that they would ignore a simple replacement driver request from a customer.

maxward

Looks great! Let us know how it sounds once broken in. Will you have it back on the market?

Jetmaker737

I have a buyer lined up. I didn't realize that when I refunded the first buyer that USAM put my ad back up, so I was surprised when this gentleman responded next day. He's retiring in a couple years and needs to downsize from his Martin Logan CLX due to a smaller home. He was very excited to have these Cremonas. I gave him full disclosure on the woofer issue and provided updates along the way. Now that it's fixed he wants them. In mid-August I will drive a couple of days away to deliver them, which I'm cool with because I've been jonesing for a solo road trip and this is a convenient excuse to begin that trip (which will be much longer, cross-country, see family, etc).

maxward

Enjoy your trip. The speakers look great.