These drivers have gotten a lot of press on a lot of forums lately. Lots of hype, but no hard data. Frequency response and impedance measurements are available...but they only tell so much about the driver.
How good are these drivers really? What are their limits? How does their Apollo motor + 2" coil compare to drivers with 4" coils? How do the impedance glitches in the lower midrange affect the transient and distortion profile of the woofers? etc
I've petitioned over on the AE forums to get a driver sent in for testing, but to no avail. Stereo Integrity has shown an interest in providing Klippel measurements for their customers, why AE has not chosen to do likewise I'm unsure. Would anybody be willing to send their driver to MVM over on DIYMA for Klippel testing?
How good are these drivers really? What are their limits? How does their Apollo motor + 2" coil compare to drivers with 4" coils? How do the impedance glitches in the lower midrange affect the transient and distortion profile of the woofers? etc
I've petitioned over on the AE forums to get a driver sent in for testing, but to no avail. Stereo Integrity has shown an interest in providing Klippel measurements for their customers, why AE has not chosen to do likewise I'm unsure. Would anybody be willing to send their driver to MVM over on DIYMA for Klippel testing?
If I had a dollar for everyone that wanted a free driver for testing.............
I designed it so I am biased. IMHO - its that good, and I have rebuilt probably a few thousand drivers from other brands. Its 2" motor has less power compression than most 4" motors. Its not the size that matters here but rather the materials next to the coil and their ability to absorb heat quickly. Those glitches can be seen in the impedance curve because they are not hidden/filtered by a large series inductor that most other woofers have built in.
I will let John know about this thread, but he would need some more details as to the testing, can the results be made public, etc.
I designed it so I am biased. IMHO - its that good, and I have rebuilt probably a few thousand drivers from other brands. Its 2" motor has less power compression than most 4" motors. Its not the size that matters here but rather the materials next to the coil and their ability to absorb heat quickly. Those glitches can be seen in the impedance curve because they are not hidden/filtered by a large series inductor that most other woofers have built in.
I will let John know about this thread, but he would need some more details as to the testing, can the results be made public, etc.
nickmckinney said:
These drivers have been available since what? 1998? 10 years and we still don't have any objective data to quantify their performance capabilities. All that would be required would be a single driver for a few days, you wouldn't have to donate it if that would be a problem. The whole focus of the test is to educate consumers, no monetary gain. I can see this being extremely positive for AE, consumers who may be on the edge about your products will finally be able to see actually how good they are and take the plunge.
I think its essential, from a consumers standpoint, that we demand intensive measurements that accurately reflect a drivers performance so that we can objectively compare drivers. If we begin to demand objective measurements and become educated on the drivers we are purchasing, companies may allocate more funding to engineering a superior driver rather than using costly exotic solutions (solutions that are not necessarily an improvement over a less exotic solution, but are more "flashy") that their marketing departments demand. By making this objective information easily available and accessible to the average consumer, they are able to educate themselves and are less susceptible to the cyst of misinformation. Although we (DIYers) represent a small niche of the total market, we may be able to shift the market if we begin to demand such information from companies.
Example: Japanese Audio Market compared to US Audio Market. The Japanese market (as a whole) is more interested in quality products whereas the US market (as a whole) is more interested in convenience.
This isn't directly about AE drivers but hype, price and a lack of real evidence showing greater benefits for that investment often go hand in hand.
With a good number of expensive drivers there's an amount of prestigious hype that follows. If you buy or plan to buy into the brand then your happy to have that wash all over you.
Happens all the time. I've bought a few myself and always get more excited with expensive drivers than cheap ones. Even before I've heard them.
The lack of objective data doesn't mean a product is bad or good but to me it shows the company either:
A) Can't afford or doesn't want to buy the testing equipment(not really an excuse because you can have drivers tested for reasonable fee's)
B) Doesn't believe in testing
C) Has something to hide
D) Has such great sales anyway so why rock the boat.
Unless I can get data I rarely buy into that brand and that's why I haven't touched AE/Lambda for all these years. I'm happy spending money with others that do provide that such as RAAL, ATC, Audiotechnology etc.
BTW I do believe Zaph was going to test a Lambda but that fell through after an agreement on testing conditions couldn't be reached.
With a good number of expensive drivers there's an amount of prestigious hype that follows. If you buy or plan to buy into the brand then your happy to have that wash all over you.
Happens all the time. I've bought a few myself and always get more excited with expensive drivers than cheap ones. Even before I've heard them.
The lack of objective data doesn't mean a product is bad or good but to me it shows the company either:
A) Can't afford or doesn't want to buy the testing equipment(not really an excuse because you can have drivers tested for reasonable fee's)
B) Doesn't believe in testing
C) Has something to hide
D) Has such great sales anyway so why rock the boat.
Unless I can get data I rarely buy into that brand and that's why I haven't touched AE/Lambda for all these years. I'm happy spending money with others that do provide that such as RAAL, ATC, Audiotechnology etc.
BTW I do believe Zaph was going to test a Lambda but that fell through after an agreement on testing conditions couldn't be reached.
I reckon they are as good as any other good driver out there
The only problem I have is that I cant buy them in EU
And I really dont trust foam surrounds
But sure, I dont either like drivers with no response curves
As fore the distortion, you can have it if you want, dont bother me much
But I agree that claims to be better than others should be documented to be trustworthy
The only problem I have is that I cant buy them in EU
And I really dont trust foam surrounds
But sure, I dont either like drivers with no response curves
As fore the distortion, you can have it if you want, dont bother me much
But I agree that claims to be better than others should be documented to be trustworthy
I don't have any TD's, but do have SB15LEs and PB12s from an earlier version of Lambda (second series). Not really interested in having them measured as they sound so good - don't need to fix something that ain't broke.
If someone does want to play around with the SB15s to measure them - as they're currently not in a box - then let me know.
Also, mine have rubber surrounds. I don't think any had foam - are they on the new series? And as far as expensive goes, I think they were some of the cheapest on the market at that stage.
thadman, you want to test them, why not buy a pair? I've seen them resell for very little under purchase cost (and I doubt you'd get rid of them once you've got them anyway.
If someone does want to play around with the SB15s to measure them - as they're currently not in a box - then let me know.
Also, mine have rubber surrounds. I don't think any had foam - are they on the new series? And as far as expensive goes, I think they were some of the cheapest on the market at that stage.
thadman, you want to test them, why not buy a pair? I've seen them resell for very little under purchase cost (and I doubt you'd get rid of them once you've got them anyway.
thadman said:
The TD15M was released in the spring of 2001, Lambda was broke by 2002 and closed its doors 2004. John at AE bought the parts stock and I left the scene at that time for a few years. Did intensive detailed public measurements save Altec, Adire, or TC Sounds? You should probably read my other post about my other job and my unique insight on the current consideration quality audio has in the current marketplace. If its not in a headphone connected to an MP3 player, speaker in a flatscreen hanging on the wall, or stock car system, 99+% of consumers just don't care anymore. There is no market left to shift, rather the ones that care are getting older with fewer people to take their place.
ShinOBIWAN said:
For Lambda it was a combination of A and having so many different models. I probably had $800 invested by the time the first prototype was playing and $500 of that was a minimum purchase of the special copper tubing for the Faraday. I built the first prototypes in my parent's garage while attending college on the GI bill. Basically Lambda was started and running for less than one months rent of a nice apartment.
Cloth Ears said:
Very few paper cones were released with rubber surrounds, 99% have coated foam surrounds that look somewhat like rubber, last like rubber, but perform like doped cloth when it comes to damping the cone resonances. Yours are foam surrounds as can be told by those part numbers.
Its up to John if he wants to send out free drivers for DIY testing, but it ain't gonna happen unless certain criteria is met. We have been down that road many times before.
I took the plunge for a pair of Lambda TD12H's after hearing the driver in a prototype 3way designed by Jeff Bagby for Jim Salk and after then comparing it to what else was available and would work in the design I had in mind. The only driver that came close that I also considered was a Ciare and it had no distortion information published either, was not readily available in the States, and I had not had the benefit of hearing it in a completed system.
The TD12H is the best woofer I have used and, IMO, I believe it to be the best I have heard while attending numerous DIY events over the last 3 years. If the TD15M is similar in it's performance, and it should be because it shares the same motor, etc., I'm relatively sure it is indeed excellent.
At this point, I'm no longer concerned about distortion testing, because I have done extensive listening to it as I've completed my design over the last few months and I don't recall hearing a cleaner sounding woofer. Of course this is all subjective opinion, which may not be worth much to others. All I can say is that it would be the first driver on my list for any future, similar design application.
The TD12H is the best woofer I have used and, IMO, I believe it to be the best I have heard while attending numerous DIY events over the last 3 years. If the TD15M is similar in it's performance, and it should be because it shares the same motor, etc., I'm relatively sure it is indeed excellent.
At this point, I'm no longer concerned about distortion testing, because I have done extensive listening to it as I've completed my design over the last few months and I don't recall hearing a cleaner sounding woofer. Of course this is all subjective opinion, which may not be worth much to others. All I can say is that it would be the first driver on my list for any future, similar design application.
I see testing to have 3 purposes. One to verify design goals have been met. Two to determine the source of any issues and aid in the ability to correct them. Three to accurately be used as a method to compare to other drivers.
For the first standpoint we have internally verified the goals time and time again. Our customers have also verified that they live up the the claims. In reality there is much less voodoo to good driver design than one would believe. Much of it is understanding how things vary when excursion and power are applied, and understanding the options available to correct these non-linearities. The copper sleeve on the pole addresses these issues in theory an has been verified by many customers over the past 8 yrs or so.
As far as determining issues and sources, klippel is quite good at this. You can pinpoint non-linearities in the motor, cone, spider resonances, etc. This is one of the primary klippel functions as a distortion analyzer. Much of the same can be determined by experimentation though. That is what both Nick and myself had to work with because we didn't have money available for a klippel at the time. For example, klippel can easily help you pinpoint that a blip in an impedance curve is due to a spider resonance. It is very quick and can save a lot of time. The same can be determined through experimentation with various spider materials, profiles, damping applied to the spider, etc. In the end you will often reach the same conclusion and solution. I do plan to buy a klippel system primarily to aid in this area. I need to get a home sold that is currently up for sale first though.
Finally we get to the accurate comparison to other drivers. All the Klippel data in the world doesn't mean anything if you have nothing to compare to. Where is the Klippel data for the TAD1601, JBL2226, Altec/great plains 15's, EV, 18sound, B&C, etc that people have been replacing with the TD15M's? It was for this same reason that I chose not to have Zaph do the testing on the TD12. There were admitted limitations and issues with the method and there had been a total of 2 other 12" drivers he had ever tested, neither of which I had ever heard another person compare our drivers to.
The issue is not in providing a TD15M for klippel testing. I would be glad to do that. The issue is in having the other drivers provided so there is a means for comparison. If someone wants to send in a TAD 1601, Altec 416, JBL2226, B&C, etc as well and pay for all of those drivers to be tested, then I would be glad to donate a driver free and clear. The key is that other drivers need to be tested in the same way for accurate comparison. We have had many customers with this kind of measurement capability over the years and their internal data has proven to them that the TD drivers are superior to any other options available. The Klippel testing for public comparison would verify this which I agree would be very beneficial to us. Just be aware that the "big companies" and their legal teams will definitely have their say in the matter once they realize the results are posted.
John
For the first standpoint we have internally verified the goals time and time again. Our customers have also verified that they live up the the claims. In reality there is much less voodoo to good driver design than one would believe. Much of it is understanding how things vary when excursion and power are applied, and understanding the options available to correct these non-linearities. The copper sleeve on the pole addresses these issues in theory an has been verified by many customers over the past 8 yrs or so.
As far as determining issues and sources, klippel is quite good at this. You can pinpoint non-linearities in the motor, cone, spider resonances, etc. This is one of the primary klippel functions as a distortion analyzer. Much of the same can be determined by experimentation though. That is what both Nick and myself had to work with because we didn't have money available for a klippel at the time. For example, klippel can easily help you pinpoint that a blip in an impedance curve is due to a spider resonance. It is very quick and can save a lot of time. The same can be determined through experimentation with various spider materials, profiles, damping applied to the spider, etc. In the end you will often reach the same conclusion and solution. I do plan to buy a klippel system primarily to aid in this area. I need to get a home sold that is currently up for sale first though.
Finally we get to the accurate comparison to other drivers. All the Klippel data in the world doesn't mean anything if you have nothing to compare to. Where is the Klippel data for the TAD1601, JBL2226, Altec/great plains 15's, EV, 18sound, B&C, etc that people have been replacing with the TD15M's? It was for this same reason that I chose not to have Zaph do the testing on the TD12. There were admitted limitations and issues with the method and there had been a total of 2 other 12" drivers he had ever tested, neither of which I had ever heard another person compare our drivers to.
The issue is not in providing a TD15M for klippel testing. I would be glad to do that. The issue is in having the other drivers provided so there is a means for comparison. If someone wants to send in a TAD 1601, Altec 416, JBL2226, B&C, etc as well and pay for all of those drivers to be tested, then I would be glad to donate a driver free and clear. The key is that other drivers need to be tested in the same way for accurate comparison. We have had many customers with this kind of measurement capability over the years and their internal data has proven to them that the TD drivers are superior to any other options available. The Klippel testing for public comparison would verify this which I agree would be very beneficial to us. Just be aware that the "big companies" and their legal teams will definitely have their say in the matter once they realize the results are posted.
John
ShinOBIWAN said:
Regarding RAAL, ATC and Audiotechnology, can you please link me links to their testing results? The RAAL is a great driver. I use them in high end installs here and they are the best I have found, but testing was done by RAAL. It is also much easier to do testing on a tweeter than woofers as room interaction is nowhere near the issue that it is on a large driver. Time gating in a small room at 1m distance can give good results for a tweeter but that doesn't work for measuring woofers.
I would love to see the Klippel data for the Flexunits 15 E 102 25 10. This would be a quite meaningful comparison to our TD15H as they both have quite similar motor strength and efficiency. We have nearly over 60% longer Xmax though, 1/3 the inductance, and much greater heat sinking ability all at 1/3 the price. This is another case where I would be glad to put up a woofer for comparison if there was relevant data to compare to. The same goes with the ATC drivers as they are also excellent.
Regarding the Zaph testing, here was my response over on AVS as to why it didn't happen.
http://www.avsforum.com/avs-vb/showpost.php?p=14581118&postcount=612
The klippel is a good option as you can get a 3d distortion plot which shows distortion vs frequency vs drive level. This can be valid for comparing drivers at any frequency and any input power.
John
John_E_Janowitz said:
I'm sure Alex at RAAL will have already provided you with the extended test results via email. Unfortunately he has elected to keep these off his website due to the nature of the agreement between him and the tester. If your an interested party or have bought drivers from you can get the test data by asking.
ATC have extensive testing facilities but are another who don't publish data. However ask and they have will give it out.
Unsurprisingly Audiotechnology also have a large amount of data on their drivers. A nice touch is you once you order you get measurements of your actual drivers too. Again ask and ye shall receive.
I'm not sure if you can remember but back in early 2005 before Nick came back you were building Lambda on special order using parts you'd bought from him after he moved out the business. I asked about test data to help in a bass driver selection process I was going through at the time, sadly you had none so I went with ATC.
Unless you have a lot of money to throw at this then sometimes that data and opinion is all you have to go on. This is never more true with these less widely used and higher priced drivers.
This is one persons preference but I'd go with AT any day over Lambda or other offerings. I know where I stand and the drivers are rock solid with no weaknesses. The company is great to deal with and you get a bespoke service rather than an off the shelf part.
thadman said:
I think we need to look at the cost to do comparisons vs just the cost of one measurement. Providing a driver is one thing, paying for the testing is another. I would be curious to see what the cost of each driver would end up at, and of course make sure we are getting the right data for comparison. Klippel can measure many things and you could spend a week measuring everything about one driver if you wished.
The Aurasound could be one to be compared to the AV15. The Dayton could as well although with much lower Xmax. Drivers that TC Sounds did, CCS SDX15, DIY Cable Tempest X, the list goes on. As far as I know, none of these drivers have had klippel testing for the same reasons. Without drivers to compare to the data isn't too meaningful so those selling them don't see it as a wise investment. As I said, I'll be glad to provide any drivers for testing if there are others who will do the same. I don't however have the money available now to send one of every one of our drivers to be tested. We'd have to agree on maybe two that would make sense. If we had say the 6 drivers mentioned here be submitted for a higher excursion driver comparison and then 5-6 options comparable to the TD15M, I would be all for it. I think you will see more resistance from others though.
augerpro said:
That could be an option to compare to a TD15M. The ones I'd like to see as mentioned are the TAD's which are considered to be the holy grail of woofers, JBL 2226 with differential drive, ATC, the 18sound with the AIC coil, etc as these are considered the best. Again I am totally for putting up a TD15M, giving it away if necessary, but the question remains as to who would pay for all the testing of the other drivers.
The TD15X/H would be good in comparison to the Audio Technology. I don't see many other options in the 92-25dB efficiency range that would fit similar applications.
ShinOBIWAN said:
Again, the data for a tweeter is much easier to validate. With woofers you end up having to deal with enclosure type an size specifications, baffle sizes, driver and mic placement and on and on. Klippel is nice because it eliminates these issues when simply measuring distortion with a mic. However we could easily open a discussion as to creating a method that could be duplicated to measure drivers. Mark Seaton and I discussed this in the past. One thing that could work well is with a driver in a set size sealed enclosure on the ground with mic at 2m distance. The driver would be angled directly to the mic. This would be quite accurate for comparison between drivers. Once a reference is setup, data could be saved and someone else could be able to do a measurement under the same conditions at other locations.
Again I am all for doing a comparison. What I don't want to do is spend money getting drivers measured or spend time measuring data that doesn't mean anything. I guess I don't see why we are being singled out to publish this data publicly when the others mentioned do not either.
If we can determine a set method, I'd even be willing to host a DIY meet here where we could spend all day measuring drivers for comparison in the parking lot. I could also potentially setup something to use the gym at the church to do the same inside. I'd love to see someone from ATC, Audio Technology, JBL, TAD, etc be involved too if anyone can bring them into the discussion.
As with Audiotechnology, I thoroughly test every driver after assembly and measure parameters. Anyone who wishes can receive the parameters for the driver as it is measured as well as a saved impedance curve. Anyone interested can come by as their drivers are being built and see the process.
I can generate distortion plots, close mic response, 2m ground plane measurements, waterfall plots, power compression, etc. Anything someone desires can[/] be measured. It again comes down to repeatability and validity of comparison. Should distortion be measured close mic, 1m time gated, 2m ground plane? Should they be on an open baffle or sealed enclosure? If sealed how large? If open baffle, what are the dimensions of the baffle so someone else can repeat the measurements? If you look at the testing methods of EV, JBL, 18sound, etc, they all greatly vary. While they all publish data none of it is able to be compared directly as it is taken in different ways. Without something to compare to it is just numbers on paper.
If multiple drivers were measured under exact conditions then you could accurately compare the drivers to one another. ATC's drivers are great as are audio technology, but again even their measurements without comparison are as meaningless as measurements I would do without comparison. You mention ATC and Audio Technology both have data available. If your design goal was to achieve 110dB at say 30hz with the lowest distortion, can you accurately compare the data from both to make this conclusion? If not then there is no point to the data.
I believe the first statement wasn't only directed to the Lambda woofers. Something to point out though is that the TD woofers compared to TAD's, ATC, and Audio Technology are much lower in cost. You will find people who have used all of the other three who now prefer the TD woofers. I am not aware of anyone who has ever replaced a TD woofer with one of the others.
I believe the same as you mention goes for us. I am easy to find for advice on drivers and any support after the process, although I am one person doing everything most often. Currently I hand build every driver myself from start to finish as it is ordered as I am training new people. Every steel part is machined by hand to to .003" tolerances. We have many customization options. For example a TDX series can be ordered with 4, 6, 8, or 16 ohm coils. I often do small modifications to a driver at no extra cost if they are practical to incorporate. This has been my life and my passion for over 10 years now. If a driver does not meet MY standards, it will never leave the door.
John
John_E_Janowitz said:
So what is it we hear about an 18", I want one...two
only, I can get nice quality FaitalPro an PrecisionDevices at fair prices, but some compromise in specs
preferably with 97db(?), 23-24hz, mms 160gr, Qts 0.36-0.39 or so, VAS 300(?) to fit 180-200liter closed/Q 0.6, Xmax 15mm(P-P)
maybe underhung 
Forget the measurements, only the right specs and good build quality means anything
John,
Thanks for the insights within your reply. Its clear you care about what you ship but that was never in question.
I think trying to ratify and standardise testing amongst driver manufacturers isn't really achievable. If you wait for that to happen you'll never publish data, which I guess is why you haven't so far.
As far as measurements go a little intuition and familiarity with such things helps bridge some gaps between testing conditions if they're known. Meaning you can make some useful comparisons.
But let's face it, if you don't provide data what do I do? Buy a driver for myself is the answer and its the best way. Buy a bunch of 'em your interested in and go about testing and auditioning - never fails. That route is no problem for drivers that are cheap but its not so easy when your talking about $300-700+ per driver and you've got 3 or 4 you'd like to pick from.
I can't speak for others but for myself the more knowledge I have when entering a purchase, the better I feel about it. There's a lot of choice out there so at some point you have to start setting criteria for culling. Some data is better than no data for me.
Thanks for the insights within your reply. Its clear you care about what you ship but that was never in question.
I think trying to ratify and standardise testing amongst driver manufacturers isn't really achievable. If you wait for that to happen you'll never publish data, which I guess is why you haven't so far.
As far as measurements go a little intuition and familiarity with such things helps bridge some gaps between testing conditions if they're known. Meaning you can make some useful comparisons.
But let's face it, if you don't provide data what do I do? Buy a driver for myself is the answer and its the best way. Buy a bunch of 'em your interested in and go about testing and auditioning - never fails. That route is no problem for drivers that are cheap but its not so easy when your talking about $300-700+ per driver and you've got 3 or 4 you'd like to pick from.
I can't speak for others but for myself the more knowledge I have when entering a purchase, the better I feel about it. There's a lot of choice out there so at some point you have to start setting criteria for culling. Some data is better than no data for me.
nickmckinney said:
For Altec, I don't know.
But we both know what killed Adire and TC Sounds. It's not extensive detailed public measurements. Adire was weakened by an insider fraud in South America, which made Dan Wiggins bored so he pulled the plug to kill it. TC Sounds was killed because the owner wasn't a good businessman in general.
TC Sounds was destined to fail. On the other hand, I think Adire would be well alive today without that insider fraud.
ShinOBIWAN said:
I wasn't talking about necessarily standardizing testing among manufacturers. I am being asked to submit drivers and pay for Klippel testing. To submit a driver and pay for testing that compares it to several of the other highly regarded drivers out there makes sense. To have only one driver with data only raises more questions about whether the results show it is better or worse than the others.
Just coming up with a standard method that DIYers can repeat so they can compare results to others. Zaph has a standardized test that gives some comparison between smaller drivers, although it has some limitations. Lets talk about the best way DIYers can do this to be easily repeatable. Maybe there are a few DIYers throughout the globe who can synchronize their methods so that their results are directly comparable. Ilkka did this with subwoofer tests.
The interest in really in the comparison between drivers, and not in an absolute distortion number, etc. The key is to remove the variables for accurate comparison. The method Mark Seaton suggested, sealed box, mic at 2m on the ground is going to be accurate for low frequencies. Two people using the same measurement equipment and conditions should be able to get the same results no matter where their location. Maybe someone in the US could be doing it and someone in Europe, Asia, etc. Then any drivers measured by either person can be compared. It doesn't need to be expensive equipment. I'd see having distortion measurements at increasing input levels as a good first step. There needs to be a way to account for efficiency differences though.
In all honesty, the data provided by most manufacturers is next to useless. You can compare manufacturer data from competing drivers by JBL, EV, B&C, 18sound, etc, and each claims their own driver to be the lowest distortion on the market with the best power compression. One may do distortion measurements at 2m or greater distance on a large baffle at 2.83V. There are no baffle effects but some room effects come into the measurements. How do you know what percentage of distortion is good or bad with this measurement? One may do distortion measurements close mic in a sealed enclosure at 1W. No room effects come into play but distortion measurements close mic are skewed by diffraction and reflections issues with the surround, edge of frame, etc. The absolute distortion numbers aren't comparable between the tests. You have the results but nobody knows what a "good" result even is.
It is in these cases that you will want to rely on those who have used the drivers. dlneubec, Jeff Bagby, Duke LeJeune, Mark Seaton, and many others, those using our drivers for critical monitoring in recording studios, etc have all used and measured multiple other drivers over the years. The list has been steadily growing. They have been able to do testing to make objective comparisons to other drivers and also have done the listening to give subjective opinions as well. You will find that most of them are all willing to talk about their experiences.
John
My opinion is that all these endorsements are great from other users/customers but if you have date proving that the motor is that much superior and competes with distortion measurements of much smaller drivers then even if you have nothing to compare it to, the results of a 15" driver keeping up with 4" midranges will only help increase sales. Then that will encourage more larger drivers to be tested to try to come close to the Lambda TD motor. And if what you are saying is true about the motor being that much better with the tight tolerances then it will show that none of these other motors will come close when they are tested. But it shouldnt matter because it keeps up with smaller midranges, so lets just compare it to those for now. All I've seen for now is subjective opinions and people stating that they have tested them with no proof of results, and what design attributes of the motor are good in theory but haven't been proved to have a noticable impact (such as adding more aluminum plates in the Apollo motor - it must change the magnetic fields and symmetry at least some, even though it helps in cooling the vc). I am willing to send my two new drivers, and if I sell them (selling for personal reasons) I would work out a discount with the buyer if he allowed me to send them to get klippel tested and tested by zaph, assuming they agree to test the drivers as well. Let's get the ball rolling on testing these and others. Have to start somewhere.
Edit: My drivers are the TD15H Apollo.
Edit: My drivers are the TD15H Apollo.
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