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I have a pair of 2Ce Signature II speakers from 2007.  

This week I've been setting up two new SUB THREE subwoofers into my system and that has involved playing pink noise through various channels and level matching both with and without the subwoofers.  

Its been about a decade since I've done this sort of thing, and I noticed right away that the timbre sounds different now between my mains.  I do not recall there being so noticeable a difference in the past, in fact I remember being more impressed with how similar they sounded.

Let me start out by saying this is mostly a curiosity, and I'm not unhappy with the overall performance of the system.  It does sound very good and before listening to it with the pink noise I would have not said there was anything wrong.  

When I play the same frequency range pink noise and pan between the mains, the timbre does clearly change even when the SPL is the same.  So I guess my first question is whether that is normal?  I accept certainly that in different room positions the speakers are expected to sound different.

I did some experiments with changing wires, interconnects and channels on the preamp/amplifier and have convinced myself that looking at frequency response room sweeps, none of those changes were measurable or obvious to my ear.  So it seemed like it was either room positions or the speakers themselves.

So I moved the speakers out and did some measurements with each one in the center of the room, one speaker at a time.  Here are the frequency response graphs for that.  What I observe is that between 600Hz and 5kHz the differences are more pronounced than the frequencies above and below that.  The contour of the responses are different, not just the levels.

 

 

Center_01.jpg

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Then I moved the speakers out so that the speakers were next to each other in the middle of the room.  Taking measurements like that, we do still see differences in the same range.  But sure, at this point they are in different positions and the room could be coming into play.

Middle_01.jpg

 

Edited by Robertsmania
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What do you guys think? Is hearing this kind of timbre difference between speakers to be expected, or something that might have changed, been damaged or aged differently between the two?

They are about 14 years old now, and we play lots of music and watch lots of media with them but I don't recall ever having an event or specific incident that I thought would have hurt anything.

And like I said above, I would not have said there was a problem with the system in general.  It was just interesting to hear an obvious difference, look at the frequency responses and confirm that the right sounds like the right wherever it is and the left sounds like the left...

Middle_Measurement_01.jpeg

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Man, having wrestled a couple of 2ceSigs around the room over the past 15 years, I have to commend your devotion to this project. Looks like you're out for extra credit and will most definitely be in line for a gold star! 🤩

best, John

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I agree about the extra credit.. all this empirical proof in itself merits investigation into this anomaly.. it’s like the smoking gun in a court case..

On a serious note, it has certainly piqued my curiosity about whether my 2CE Sig ii’s have the same issue..

The questions that come to mind are: 

Are the serial numbers consecutive?

Have they ever been biamped with mismatched amps?

Years ago, a friend of mine in NYC had a pair of speakers where one of them had constantly been placed close to the heater and over time there was some visible changes inside the enclosure especially with the surround. Because it had occurred gradually my friend had gotten used to that sound and didn’t think too much about it. It was only when he auditioned another pair of speakers he realized that  there was something different with his.

Eager to hear some experts weigh in...

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On 2/8/2021 at 4:45 PM, stratocaster said:

The questions that come to mind are: 

Are the serial numbers consecutive?

Have they ever been biamped with mismatched amps?

Years ago, a friend of mine in NYC had a pair of speakers where one of them had constantly been placed close to the heater and over time there was some visible changes inside the enclosure especially with the surround. Because it had occurred gradually my friend had gotten used to that sound and didn’t think too much about it. It was only when he auditioned another pair of speakers he realized that  there was something different with his.

Yes, the serial numbers are sequential.  They were purchased together, new, as a pair back in 2007.

No, they have never been biamped.

The story about your friend with the speaker near the heater might be similar, but neither of mine have been subjected to environmental stress like that.  But perhaps if the difference is due to something like the surround on a midrange deteriorating I guess it could have been progressive but gradual?

Are there other tests to do that might help indicate whether the issue is in a driver, crossover or elsewhere?  I also have no idea whether both speakers have changed, or if one is still within spec and the other has deviated?

As far as the comments about moving them around, I "walk" them on the spikes across the carpet rather than try to lift them.  Just leaning and then spinning on a single spike is pretty easy and you can get them in different locations quickly.  Re-positioning them accurately to have the spikes go through holes in tape are also pretty easy if you just aim one spike at a target hole - I just try to visualize the circle arc the spike will move in if I rotate about either of the other two to hone in on the destination. 

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If there is indeed a problem, I suspect that its with the speaker I've been referring to as L.

Here's what I see looking at the total harmonic distortion.  The higher midrange values are always from the L speaker, in all measurements and from every position in the room.  I see consistent results in this set of experiments, as well as looking back at other measurement sessions as well.

distortion_01.jpg

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I found the repair instructions and trouble shooting guide:
https://www.vandersteen.com/media/files/vandersteenrepairins.pdf

Checking the terminals on the speaker with an Ohm meter does not reveal anything unusual.  The reading on the low frequency +/- terminals does fluctuate a bit on both speakers between 6-8Ohms.  All the other combinations are way above 10K Ohms.  On both speakers, the +/- terminals does show a ~36 M-Ohm reading initially but that increases gradually and eventually goes off the maximum range for my meter.  So both speakers give values consistent with the guide.

I have isolated it to that speaker and triple checked that switching wiring it stays with the speaker and is not tied to any position in the room.

As far as the extent of the problem, I guess that gets a little odd.  I dont have a musical selection I can play that I feel brings out the problem.  But its totally consistent and reproducible with frequency sweeps in REW.  The way I noticed the issue was playing wide band pink noise and panning between the speakers - the change in timbre was obvious.  But I dont have anything as far as a natural recording that demonstrates the issue.  The top of the troubleshooting guide warns NOT to use CDs or signal generators, but I think I'm way past that at this point.

I did try adjusting the contour controls on each speaker.  What I see is the same between the two.  With the midrange dial at maximum its a dB or so above in the midrange, but the readings between noon and minimum on the dial are almost identical.  On the L speaker, showing the distortion - the position of the contour dial does not seem to affect the THD in any significant way.

 

My hunch is the next step would be to remove the cloth and try transplanting the midrange drivers from one speaker to the other and see if the distortion follows the midrange or stays with the speaker/crossover.  Any other suggestions?

vandersteen_repair_01.PNG

Edited by Robertsmania
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I think it's time to seek professional help.  Ha!  How many times have I heard that...

My thought had been to remove the midrange drivers from both speakers, swap them and test to see if the problem goes with the driver.  If there is an issue and I can just send in one or both that would be great, but perhaps Vandersteen support will want me to send the entire speaker(s).

Taking up the fabric, nothing appears visually wrong with the midrange on the L midrange driver.  It is sealed on pretty well and does not seem easy to pop off with the screws removed.  So even though the instructions say "carefully remove the suspected driver by removing the screws and gently prying up one edge of the driver with a flat blade screwdriver" - I'm reluctant to get aggressive with it until I'm sure removing the driver is the appropriate next step.

-

To try and make the visual aids a little more consolidated, below this is what I see as the THD comparing both speakers in the same location.  Then each speaker from the same measurement showing the harmonics.  I've also included the REW .mdat file for the measurements in the unlikely situation someone is motivated enough to open it up and take a look and provide insight.

distortion_THD_01.jpg

distortion_R_harmonics_01.jpg

distortion_L_harmonics_01.jpg

Robertsmania_2CeSigII_Comparison.mdat

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On 2/10/2021 at 9:32 AM, Robertsmania said:

If there is indeed a problem, I suspect that its with the speaker I've been referring to as L.

Here's what I see looking at the total harmonic distortion.  The higher midrange values are always from the L speaker, in all measurements and from every position in the room.  I see consistent results in this set of experiments, as well as looking back at other measurement sessions as well.

distortion_01.jpg

This higher distortion indicates a defective mid-range which needs to be rebuilt.  Usually a sign of a damaged voice coil but a lot can happen in 15 years.  Distortion this high would never get through QC as every pair goes through the chamber.

RV

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7 minutes ago, Richard Vandersteen said:

This higher distortion indicates a defective mid-range which needs to be rebuilt.  Usually a sign of a damaged voice coil but a lot can happen in 15 years.  Distortion this high would never get through QC as every pair goes through the chamber.

RV

Yes, I sent the midranges in for repair last week.  UPS says they are out for delivery today.  

Amazingly quick turn around and excellent communication from Ray in the service department.

I'll report back once the speakers are back together and I've had a chance to evaluate them with the newly rebuilt midranges, but I have supreme confidence all will be well.

Edited by Robertsmania
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Robert, I echo your sentiments exactly regarding Ray Etchegoin.  I had my Quatros up to him last July.  As I didn’t want to attempt removing the drivers from their cabinet, I drove both speakers up.  Was pretty sure it was only one needing driver rebuilds, but I wanted to be sure all was good. 

Ray was awesome, explaining the issues and theorizing how they could have incurred.   After the repair and retuning / calibrating both speakers, my system sounds better than it ever has. 
 

Yes, Ray is the man!

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SOLVED!

The repair has been successful.  I received the rebuilt midranges today and have installed them back in the speakers.  Everything appears to be significantly better.  

Measuring the speakers one at a time in the center of the room the frequency response is way more consistent across the whole range and the distortion is also much more symmetrical.  

I still need to finish putting everything back in terms of stapling the fabric and re-mounting the bases and stuff.  Looking forward to a listening session tonight.

Thanks to everyone who replied to this thread and I'm very grateful to Vandersteen service for their help and amazingly quick turn around on the repair.

 

IMG_6793.jpeg

distortion_THD_Mids_01.jpg

frequency_Mids_01.jpg

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16 hours ago, MNSki said:

Glad you figured it out. What a cool room. It must be a blast to watch movies with that huge screen!

 

15 hours ago, GdnrBob said:

... I didn't know the room was that large.  Vandy's seem to fill a room with sound, despite their small size, yet never overwhelm it.

At least in my opinion☺️

B

Thanks guys, and yes the room is pretty large.  It's a second story addition to the home which a previous owner built back in the '90s.  It's a single room which is nearly two thirds as large as the entire downstairs.  High vaulted ceilings and what would normally be an odd extruded section following the architecture of the structure below that makes a natural proscenium for our home theater projection surface.

In full frame 16x9 the image is 168" on the diagonal (that's 14 feet).  We sit about 23 feet back from it, so its not super overwhelming but it is certainly a lot like being in a real movie theater.  Its getting long in the tooth now, but we still use a Sony G90 9" CRT projector for movies.  For computer stuff, games and casual viewing there is a also a reasonably good digital LCD projector.  But for film, the CRT still looks amazing.  Analog still holding on for anyone else?

Here are some sketchup diagrams that might help give a sense of the dimensions and scale of the space.

Office10a.jpg

Office10_02.jpg

Office10_01.jpg

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