TD15M, does anybody have one willing to donate for Klippel testing?

[thadman]

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?

[nickmckinney]

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.

[thadman]

Originally posted by nickmckinney
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.

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.

[ShinOBIWAN]

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.

[tinitus]

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

[Cloth Ears]

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.

[nickmckinney]

Originally posted by thadman


These drivers have been available since what? 1998?

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.

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.

Originally posted by ShinOBIWAN
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)

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.

Originally posted by Cloth Ears
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.

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.

[Cloth Ears]

Originally posted by nickmckinney
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.

Mystery solved - I wondered how you got them to work so well with rubber surrounds. Certainly feels like rubber to touch!

[dlneubec]

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.

[John_E_Janowitz]

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