...it's easy enough to measure. Don't you think?
To clarify, I had a customer come to me with AE drivers they had purchased directly from AE. They were measured in a variety of ways - some in a cabinet, some close-mic'ed, some with crossover connected - but they were also measured farfield without a crossover, as per my instructions. They measured as shown in the links posted above, with deep notches around 750Hz and 950Hz, and jagged response above that.
I later measured a few other TD12S drivers and found this response from them too. To be specific, I measured four drivers that acted this way. I did not see this behavior in AE drivers I measured a few years back, and I have some other customers that had TD12S drivers that measured nicely too.
I see now that John has suggested the drivers might have been defective. I would agree that is a possibility. The first person that noticed this behavior complained that the voice coil did not appear to be centered. Since he told me this, I would only assume he told John this too. Could have been a manufacturing defect, possibly one that could have been corrected by warranty service.
Whatever the reason for the defects, I think the first step is validation. When you get your drivers, measure them. What happens beyond that is between you and AE.
To clarify, I had a customer come to me with AE drivers they had purchased directly from AE. They were measured in a variety of ways - some in a cabinet, some close-mic'ed, some with crossover connected - but they were also measured farfield without a crossover, as per my instructions. They measured as shown in the links posted above, with deep notches around 750Hz and 950Hz, and jagged response above that.
I later measured a few other TD12S drivers and found this response from them too. To be specific, I measured four drivers that acted this way. I did not see this behavior in AE drivers I measured a few years back, and I have some other customers that had TD12S drivers that measured nicely too.
I see now that John has suggested the drivers might have been defective. I would agree that is a possibility. The first person that noticed this behavior complained that the voice coil did not appear to be centered. Since he told me this, I would only assume he told John this too. Could have been a manufacturing defect, possibly one that could have been corrected by warranty service.
Whatever the reason for the defects, I think the first step is validation. When you get your drivers, measure them. What happens beyond that is between you and AE.
I can say with certainty that this is the case. The majority of TD12S woofers made before January 2013 were placed in three Pi loudspeakers, and most were very good. It was only around 12 months ago that this problem presented itself.
I saw the problem myself, so I know that it wasn't a botched measurement. And I saw it in four drivers, so it wasn't an isolated problem, there were multiples that went out that way. But not every driver is that way - I've measured other TD12S drivers that were very good.
I guess I'd probably characterize this as a QC consistency problem. That's understandable too - It's hard to keep a handle on QC when you're a busy job shop. So I would suggest to anyone that buys AE drivers, just measure them and hopefully John will make good on any that don't match your expectations.
I saw the problem myself, so I know that it wasn't a botched measurement. And I saw it in four drivers, so it wasn't an isolated problem, there were multiples that went out that way. But not every driver is that way - I've measured other TD12S drivers that were very good.
I guess I'd probably characterize this as a QC consistency problem. That's understandable too - It's hard to keep a handle on QC when you're a busy job shop. So I would suggest to anyone that buys AE drivers, just measure them and hopefully John will make good on any that don't match your expectations.
It really doesn't matter. If you (or anyone) get just one out of two bad drivers then what's the point?
John should have serial no.s on each driver and a standardized Impedance plot of each driver saved for his own records. It's a very basic quality control measure, and there are plenty of programs that do this cheaply. It's also a good source of "security" when people start complaining of suspect drivers. For instance if it's the result of shipping damage then you can say "hey, it left here in perfect condition and I've got the plot to prove it". Moreover IF it's the result of "monkey handling".. then that lets the manufacturer know that it's time to change shipping Co.s and/or improve packaging.
While Wayne's customer's measurements might have been suspect, Wayne's aren't in the ART post. The impedance is clearly showing problems that are reflected in the linear response of the driver (..and as you would expect).
The reliance on Brandon's own measurements from quite some time ago is IMO
They aren't current production. They only represent a trivial sample even when they were current production. Most particularly: not a single one is the driver being discussed.
Just how difficult is it to pull a small group of drivers (within each "model") randomly out of a "batch" for full testing for a Co. that makes drivers and prides itself on its superior product?
The reason I set aside the TD15M for this project was Gary Dahl's one-year wait for a pair of TD15M's I ordered for my own prototypes (I asked for them to be shipped to Gary D for initial evaluation and testing.)
The wait for the beryllium diaphragm version of the Radian 745Neo was longer than that, but that was for an item that required new design. There was always the possibility that Materion had signed a contract with JBL giving them first rights to the technology, and there's no way of knowing how long that exclusive contract might have run (since it falls within the scope of NDA agreement). None of my business; I'm just a potential customer for Materion and Radian, and don't buy these things in the hundreds or thousands, as JBL would. As it turns out, the beryllium version of the Radian 745Neo made its first appearance in November or December of 2013, and is now in regular production.
From what I've heard, the one-year wait for the TD-15M was the result of a Chinese frame/basket supplier not delivering product, or maybe going out of business. I don't know the details of what happened. Gary did eventually receive my pair of drivers ... minus the polished aluminum phase plug, which arrived a month later. Since I'd already decided on the GPA 416 Alnico six months before, I had Gary sell the pair of TD15M's.
How would would the TD15M sound in a 2.5 cubic foot closed-box with a 700 Hz crossover? I don't know, I haven't auditioned it. The only two drivers I've directly compared are the current-production JBL 2226 and Great Plains Audio 416 Alnico (8-ohm version).
The new speaker is a limited-bandwidth 2-way system (60 Hz to 12 kHz) that uses independently powered subwoofers in the 20~60 Hz region and optional supertweeters in the 10~20 kHz region, depending on the choice of diaphragm material for the compression driver.
The new loudspeaker is a modern version of Jim Lansing's Iconic studio monitor, which first appeared in the late Thirties. The basic concept of a 15" paper-cone bass driver and HF compression driver has been around for eighty years.
Here's a picture of Les Paul, famed guitar player and pioneer of multitracking, with a Lansing Iconic monitor in the background. The amp-looking objects on top of the speaker are very likely field-coil power supplies, which means the speaker was probably built before WWII.
The wait for the beryllium diaphragm version of the Radian 745Neo was longer than that, but that was for an item that required new design. There was always the possibility that Materion had signed a contract with JBL giving them first rights to the technology, and there's no way of knowing how long that exclusive contract might have run (since it falls within the scope of NDA agreement). None of my business; I'm just a potential customer for Materion and Radian, and don't buy these things in the hundreds or thousands, as JBL would. As it turns out, the beryllium version of the Radian 745Neo made its first appearance in November or December of 2013, and is now in regular production.
From what I've heard, the one-year wait for the TD-15M was the result of a Chinese frame/basket supplier not delivering product, or maybe going out of business. I don't know the details of what happened. Gary did eventually receive my pair of drivers ... minus the polished aluminum phase plug, which arrived a month later. Since I'd already decided on the GPA 416 Alnico six months before, I had Gary sell the pair of TD15M's.
How would would the TD15M sound in a 2.5 cubic foot closed-box with a 700 Hz crossover? I don't know, I haven't auditioned it. The only two drivers I've directly compared are the current-production JBL 2226 and Great Plains Audio 416 Alnico (8-ohm version).
The new speaker is a limited-bandwidth 2-way system (60 Hz to 12 kHz) that uses independently powered subwoofers in the 20~60 Hz region and optional supertweeters in the 10~20 kHz region, depending on the choice of diaphragm material for the compression driver.
The new loudspeaker is a modern version of Jim Lansing's Iconic studio monitor, which first appeared in the late Thirties. The basic concept of a 15" paper-cone bass driver and HF compression driver has been around for eighty years.
Here's a picture of Les Paul, famed guitar player and pioneer of multitracking, with a Lansing Iconic monitor in the background. The amp-looking objects on top of the speaker are very likely field-coil power supplies, which means the speaker was probably built before WWII.
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Absolutely
The impedance plot was a dead give away that the speaker was faulty. That's why I didn't question the acoustic measurements, because the impedance had an obvious resonance at 750 Hz - among several others. Its hard to fool the impedance curve and its hard to mess up such a simple measurement.
As I mentioned a few posts before, I have learned that over the years you simply can't please everyone. Nor can you educate everyone and help them become experts in loudspeaker design. In reality I am asked to assist with the design of many speaker projects every day. Projects that frequently use the best drivers available at any cost. Mundorf, Accuton, RAAL, Feastrex, Lowther, Cogent, and many others are paired with Acoustic Elegance woofers. The reality is that there are some out there who desire to use expensive drivers in systems but don't fully have the knowledge to pull off the implementation. While I enjoy giving advise on systems, the reality is that I cannot design a speaker system that costs $5000, $20,000 or even $100,000 for free, from a remote location, without ever seeing or touching it. There are so many variables in a system that all need to be addressed and accounted for. I do what I can to support every woofer produced here, but I cannot offer support for completed systems that introduce other variables.
This specific situation with the TD12S is one that has been discussed on many occasions yet it keeps being brought up by Wayne. There were multiple sets of measurements sent to me over a period of time from the same drivers that were vastly different on every occasion. If a measurement cannot be repeated, you simply cannot trust the results or draw conclusions from them. If accurate and repeatable data is not able to be produced, the measurements need to be questioned before questioning the driver itself. Furthermore, to make a broad statement about EVERY TD12S based on inconsistent measurments is also not realistic. Without ever being given a chance to recreate the measurements here, I cannot offer any assistance as to what is really happening.
One set of measurements provided to me showed a 3rd order rolloff starting around 800hz. Wayne insisted this was due to a problem with the woofer. I tried to get details on how his customer was time gating the measurements, distance of the mic, crossover installed, etc but the customer refused to provide me with any further information. I asked for impedance curves of the driver in cabinet but he was unable to provide any. This 3rd order rolloff shown is a complete impossibility for a driver with such small inductance. Even with extremely high inductance a driver simply cannot achieve a 3rd order rolloff like that. Wayne later confirmed that the measurements showing the high frequency rolloff were taken with the crossover in place. That then leads to a whole different possibility of issues with the passive crossover in line with the driver.
Issues with movement of drivers during testing can create issues in impedance curves. Reflections off the back of the enclosure, wall behind the baffle, floor, ceiling, baffle diffraction, etc will all alter the response curve. Air leaks in enclosures will cause blips and dips in the impedance curves as well that can translate to the response curve. To eliminate all possibilities associated with user error, I asked for the drivers to be returned. I wanted to put them on an infinite baffle here and measure the drivers only, without cabinet or crossover to eliminate all other variables with the drivers. I offered to pay the shipping cost both ways to do so. This was refused and his customer apparently sold off the drivers and put something else in.
The reality is that the parts we are using today are identical to the parts that were used as far back as 2001 when Nick at Lambda Acoustics originally started producing the drivers. Wayne had taken measurements of drivers and was extremely happy with them. The drivers continue to be identical to those he approved of. This was even verified by one of his other own customers who has multiple drivers built and delivered over a larger period of time. He stated the following in the same thread but Wayne refuses to acknowledge the verification.
"No evidence of cone breakup at all! These examples of the TD12S woofer range from less than one to about 3 years old and all demonstrated tight clustering of T/S parameters measured during the construction phase of the projects. The rough response posted doesn't correlate with my measurements or listening impressions. There is obviously a disconnect somewhere in all of this."
He goes on to state:
"The amplitude curves are very smooth with the 3 Pi at 1 meter. The new H290C tweeter and modified crossover seem to make almost no difference to the frequency response either. It is a shame if this is all just a bad run of cones, the TD12S is a significant improvement over the Eminence 12LFA."
I am very disappointed that the whole situation was handled so unprofessionally by Wayne. None of this was brought to my attention when it was an issue. It was 6 months or a year later when I had found Wayne had been commenting publicly on many forums about this and telling people not to buy woofers from me. It was brought to my attention by other customers and I had to approach him about it. He never once contacted me regarding the issues so I could have an attempt to address them. I am always glad to handle issues and want people to be satisfied with their results. If there was a problem with a driver, I would of course take care of it. I cannot do that if the customer refuses to send a woofer back for evaluation though.
Again, I cannot make everyone happy, nor can I address every situation where someone may not have the knowledge to properly implement a woofer as part of a complete system. When implemented properly, the woofers will do exactly what they are designed to do. You can take a look at several of the other drivers we offer that were measured independently and see very clean, extended response and extremely low distortion.
https://sites.google.com/site/drivervault/driver-measurements
The TD12S is not on the list but the TD12M, IB15, TD15X, and LO15 all are. The main benefit of our drivers is specifically the low inductance and very extended high frequency response. This is what we have been known for over the years. It is what you will find in all of our drivers. It is why companies like Avalon Acoustics, Evolution Acoustics, Soulsonic Speakers, Kyron Audio, Seaton Sound, Vapor Sound, Audio Kinesis, and many who do recording studio installations all use our drivers in their flagship products.
If there are questions, I can measure a TD12S next time we build one. I can also send one out for klippel testing for additional verification of what is going on in the driver. You will start to see much more information along these lines as we begin to put together complete data sheets.
I think that would probably be a good idea.
Actually, I didn't bring it up here. But when I saw it mentioned, I did comment on it. And I think I'll respond to your statement as well.
I approached you privately by E-Mail, hoping the problem was just a manufacturing defect that could be warrantied. Bad batch of cones, improper assembly, something.
But instead of taking steps to remedy the situation, you questioned the measurements. You were dismissive. I even asked if you had measurements, to know what to expect from current production units. You had none, and still don't. I do. I have measurements of good TD12S drivers, and I have measurements of bad TD12S drivers. So do some of our mutual customers. Some units are good, and some aren't.
And it isn't just the measurement conditions as you keep implying. It's drivers mounted on a baffle. You can argue that's not the case, but I'm telling you it is. Do with that information what you will.
Customers sent you a variety of data. Some measurements taken with the driver in a box. Some with the crossover connected. Some without. Some close mic'ed, some farfield. It isn't that the measurements were all over the place, it's that the test conditions varied. There is no harm in the customer providing you with that information. Disregard all but the anechoic farfield amplitude response and impedance data, and you easily see that the bad drivers are ragged above 750Hz.
And beyond that, I obtained a sample of current TD12S drivers myself, to confirm them. You didn't have to depend on customer measurements - I sent you measurements I had made. Not just one driver but four. So you have a situation. Something went wrong at your end, and nobody needs any help analyzing it. I think people needed your help correcting it. They wanted their drivers fixed. They didn't want your interrogations, they wanted your warranty service.
I told you then and I'll tell you again, some of your drivers were defective, or at least they measured exactly as I showed you in the link above. It could be that's the way they all are now, I don't know. I know they weren't like that a few years back, last time I checked. Not sure if they're all like that now, or if you just had a few bad apples go out the door. But I know I've seen four that measured just like the charts in the link above.
I would have preferred to keep using your drivers. They look cool and the good ones are nice. But there are some bad ones too, and you don't seem to be too keen on addressing that. Seems to me the best thing to do is to call it a case of bad assembly on a few drivers, to deal with that, and to quit blaming your customers for bringing it to your attention. If you think that statement is unprofessional, OK, cool. Just don't forget that I brought this to your attention immediately, silently, asking you to warranty the drivers and you said it wasn't possible they measured like they do. So what is anyone supposed to do with that?
15 inch bass mid alternative...
This maybe too late if you guys have finalised woofer choice, but I can promise you that this driver is special...
It covers 80Hz to 800Hz in the attached open baffle design and then blends with an open baffle Manger.
The OB Manger is arguably the fastest rise / settling time driver on Earth...Rise time 13 micro seconds!
Ok a plasma tweeter might edge it!
But my point is the Precision Devices 158 is able to keep up and yet still deliver 118dB peaks without compression...
PD drivers don't measure as smoothly as the AE drivers, so that may deter some from trying them, but OMG they sound like music!
Hope that helps
Cheers
D.
This maybe too late if you guys have finalised woofer choice, but I can promise you that this driver is special...
It covers 80Hz to 800Hz in the attached open baffle design and then blends with an open baffle Manger.
The OB Manger is arguably the fastest rise / settling time driver on Earth...Rise time 13 micro seconds!
Ok a plasma tweeter might edge it!
But my point is the Precision Devices 158 is able to keep up and yet still deliver 118dB peaks without compression...
PD drivers don't measure as smoothly as the AE drivers, so that may deter some from trying them, but OMG they sound like music!
Hope that helps
Cheers
D.
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First of all, I do not want to hijack this thread as it is not about AE or Wayne. Lynn has put in significant amount of time over the years in this thread and I do not want to disrespect him by making this about us.
Standard warranty procedure is for Acoustic Elegance to issue a UPS return label at OUR expense to return the driver in question to our facility. Once the driver is here we would go through an inspection process that may include a combination of any of the following evaluations: visual inspection, rub/buzz testing, parameter measurement, measurement of impedance curve and response curves in comparison to reference units, and even klippel measurement. If an issue is found, we will rebuild/replace the driver at our expense and send the repaired/new replacement driver back to the customer also at our expense. I know of very few companies willing to stand behind their product and offer to cover shipping both ways in the case of a warranty issue. This was all explained to you and paying for a return was offered as in any other warranty case. The last email I received from you was in reply to this offer dated May 20, 2013 stated:
"Very good. I contacted each customer that has expressed dissatisfaction to see if any of them wanted to send their woofers back to you. I think Vincent might."
I have not yet heard from Vincent, nor you again regarding this. Yet you have continued to post on multiple forums for nearly another year regarding your dissatisfaction. You make continued claims that I am unwilling to warranty woofers. Clearly from your quoted response, you know this to be untrue. I am unsure exactly what you expect me to do to remedy this situation if the supposed drivers in question are ever returned to evaluate.
I would also like to point out the zoomed resolution of the impedance curve you posted. No matter what impedance curve you look at there will be small blips. Other drivers used in the 3Pi speaker have much more significant bumps in the impedance curve than the ones you measured. For comparison I would like to show the normal scale impedance curve you measured and sent to me.
The offer for me to pay return shipping to receive the drivers in question back here for evaluation still stands. I have not been able to replicate this issue, nor have others using our drivers. Until I can evaluate one of these exact drivers and replicate the problem you are seeing, there isn't anything I can do. If you are not going to allow me a chance to evaluate the drivers, I would appreciate if you stop telling others I am unwilling to warranty them as that is completely untrue.
Standard warranty procedure is for Acoustic Elegance to issue a UPS return label at OUR expense to return the driver in question to our facility. Once the driver is here we would go through an inspection process that may include a combination of any of the following evaluations: visual inspection, rub/buzz testing, parameter measurement, measurement of impedance curve and response curves in comparison to reference units, and even klippel measurement. If an issue is found, we will rebuild/replace the driver at our expense and send the repaired/new replacement driver back to the customer also at our expense. I know of very few companies willing to stand behind their product and offer to cover shipping both ways in the case of a warranty issue. This was all explained to you and paying for a return was offered as in any other warranty case. The last email I received from you was in reply to this offer dated May 20, 2013 stated:
"Very good. I contacted each customer that has expressed dissatisfaction to see if any of them wanted to send their woofers back to you. I think Vincent might."
I have not yet heard from Vincent, nor you again regarding this. Yet you have continued to post on multiple forums for nearly another year regarding your dissatisfaction. You make continued claims that I am unwilling to warranty woofers. Clearly from your quoted response, you know this to be untrue. I am unsure exactly what you expect me to do to remedy this situation if the supposed drivers in question are ever returned to evaluate.
I would also like to point out the zoomed resolution of the impedance curve you posted. No matter what impedance curve you look at there will be small blips. Other drivers used in the 3Pi speaker have much more significant bumps in the impedance curve than the ones you measured. For comparison I would like to show the normal scale impedance curve you measured and sent to me.
The offer for me to pay return shipping to receive the drivers in question back here for evaluation still stands. I have not been able to replicate this issue, nor have others using our drivers. Until I can evaluate one of these exact drivers and replicate the problem you are seeing, there isn't anything I can do. If you are not going to allow me a chance to evaluate the drivers, I would appreciate if you stop telling others I am unwilling to warranty them as that is completely untrue.
Honestly, John, this is between AE and your customers that bought the defective drivers. I didn't buy those drivers from you, they bought them directly. I did test them though, just as a confirmation more than anything else, and I suggested they return them for warranty service. I also approached you on their behalf.
My decision to stop using AE drivers was mostly a matter of confidence. Your good drivers are nice but the defect rate seems a little high.
My decision to stop using AE drivers was mostly a matter of confidence. Your good drivers are nice but the defect rate seems a little high.
I hadn't noticed the degree to which that impedance graph was zoomed in.
That is significant; the blips do look trivial at a more normal scale.
Also, in all of this discussion about the measurements of the TD 12S, I don't think there has been any comment on the sound quality. Has this deteriorated as the measurements imply, or is this all about measurements?
That is significant; the blips do look trivial at a more normal scale.
Also, in all of this discussion about the measurements of the TD 12S, I don't think there has been any comment on the sound quality. Has this deteriorated as the measurements imply, or is this all about measurements?
There are companies out there that provide good warranty service. While its a number of years ago now I had exceptional warranty service from Visaton when I had a faulty driver.
In 2003 I ordered a pair of Visaton W300S 8 ohm 12" woofers from them - the fact that they would even sell such a small quantity directly to an end user was impressive to start with - especially given at the time I lived in New Zealand where there was no local distributor and the shipping from Europe was relatively expensive. (I think I had to do a wire transfer to pay for it too as they didn't have an end-user on-line payment system)
A few months after I received them when using them properly for the first time I noticed a slight buzzing on bass from one driver and realised that the plastic ring glued onto the front of the butyl surround was not centred properly - so when the cone moved forwards to near its full excursion the rubber surround was lightly touching against the offset plastic rim.
Expecting difficulty ahead, and expensive return shipping I emailed them to ask how to proceed with a warranty replacement, and thinking that they might perhaps be sceptical I took a photo of the offset ring and attached it to the email as evidence. (Although it was difficult to see in the photo)
The next day I got a reply asking for my shipping address, I provided that and asked them how to send the original back - they said don't worry about it, we don't want it back, just keep it! Less than a week later the replacement arrived from half way around the world and the two good drivers are still working to this day.
That's what I call warranty service.
That leaves a very favourable impression with me and I would certainly be buying from them again if they had other drivers that I wanted for a project. Granted in this case it was a visible defect not something more subtle like a resonance problem, however given the way they sent a new one without question I don't think it would really have mattered what the fault was - they were willing to take my word for it.I still have the faulty driver and one day I will get around to removing and re-gluing the strip (at my own risk) hopefully without having to re-centre the cone, and perhaps make a sub woofer out of it...
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I think if we'd seen that kind of response from Acoustic Elegance we wouldn't be having these recurring discussions about them. But in fairness to John, it's very hard to handle situations like these when you're essentially a job shop. Not only does he have to fill the orders in the queue, but he has to deal with customer support. It makes for very long days.
What I saw was a sort of an avalanche. There were a lot of complaints about lengthy delays at AE. Some were reorted to be botched parts from overseas suppliers. Some were from an overload of orders from a group buy. I had been telling people interested in the AE option that they needed to expect a one year delay, and that way if the parts came sooner, they would be pleasantly surprised. But still, I think people were anxiously waiting for their drivers, some sort of growing impatient.
So when customers received defective drivers in 2013, there was already some tension between them and AE. One, in particular, provided a lot of measurements that indicated a pretty clear problem with his TD12S drivers. These reports started coming in in early 2013, around January and February. This is when the email dialog about TD12S problems began.
The feeling most had was that John was pretty dismissive about the defects. On the one hand, I knew he was probably overwhelmed and this made him unable to really pay attention, maybe even prone to wanting problems to "just go away." On the other hand, there really was no argument, no analysis that needed to me made. So when I saw the back and forth exchanges about measurements, with John continually questioning them, I must admit I thought this was excessive. There really was no debate - the drivers were defective.
The initial approach about the defective drivers was made in February 2013. I think the back and forth about measurements lasted about two months, maybe three. By mid-May, when John suggested that the drivers be sent back for service, I'm pretty sure the customers that complained the loudest had already given up on AE. I too, realized that this wasn't something I could work with, so I stopped using AE in my line of speakers as well.
I look at AE products sort of like I do automotive machine shops. You send them the crank and the block and tell them what you want them to do, but then you measure them to be sure they're right. That's always good practice when building a motor. If you deal with AE this way, you can probably build great speakers with their parts. But some DIYers want a more turnkey kit solution. They don't want to make measurements, maybe don't even have the equipment. They just want to assemble the parts and listen. For that kind of customer, I think they probably want to go a different way than to use a boutique driver builder.
What I saw was a sort of an avalanche. There were a lot of complaints about lengthy delays at AE. Some were reorted to be botched parts from overseas suppliers. Some were from an overload of orders from a group buy. I had been telling people interested in the AE option that they needed to expect a one year delay, and that way if the parts came sooner, they would be pleasantly surprised. But still, I think people were anxiously waiting for their drivers, some sort of growing impatient.
So when customers received defective drivers in 2013, there was already some tension between them and AE. One, in particular, provided a lot of measurements that indicated a pretty clear problem with his TD12S drivers. These reports started coming in in early 2013, around January and February. This is when the email dialog about TD12S problems began.
The feeling most had was that John was pretty dismissive about the defects. On the one hand, I knew he was probably overwhelmed and this made him unable to really pay attention, maybe even prone to wanting problems to "just go away." On the other hand, there really was no argument, no analysis that needed to me made. So when I saw the back and forth exchanges about measurements, with John continually questioning them, I must admit I thought this was excessive. There really was no debate - the drivers were defective.
The initial approach about the defective drivers was made in February 2013. I think the back and forth about measurements lasted about two months, maybe three. By mid-May, when John suggested that the drivers be sent back for service, I'm pretty sure the customers that complained the loudest had already given up on AE. I too, realized that this wasn't something I could work with, so I stopped using AE in my line of speakers as well.
I look at AE products sort of like I do automotive machine shops. You send them the crank and the block and tell them what you want them to do, but then you measure them to be sure they're right. That's always good practice when building a motor. If you deal with AE this way, you can probably build great speakers with their parts. But some DIYers want a more turnkey kit solution. They don't want to make measurements, maybe don't even have the equipment. They just want to assemble the parts and listen. For that kind of customer, I think they probably want to go a different way than to use a boutique driver builder.
Again, the offer is always there to you or to your customers who have bought the drivers. I only had one customer contact me. This was prior to the contact with you. I asked him some questions about his measurement process, time gating, and requested an impedance curve. I did not hear back from him since then. No others have contacted me. I cannot do any kind of warranty service on drivers if the customer never even contacts me to let me know there is a problem.