td12s response issues

Posted In: Lambda Drivers

  • Member
    buzzforb on #1262

    I have the opportunity to buy two lambda acoustics td12s. I would assume that they are very similar, if not the same as, the current td12s. That’s is where my question arises. Wayne Parham measured two Td12s and found them to have a response that was much worse than those posted. Much worse. They model very well in a small ported box and woofer u of be perfect for for a large bookshelf style speaker I would like to build, but this assumes an smooth response, as posted for other rd woofer. Wayne stated that he had another member who had a pair that confirmed his measurements.

    stryke on #11073

    Hi Buzzforb,

    I have discussed this with Wayne on a few occasions. There were very serious inconsistencies with the measurements his customer provided me. I tried to get details on how he was time gating the measurements, distance of the mic, etc and he refused to provide me with any of that information. I asked for impedance curves of the driver in cabinet but he was unable to provide any. The driver showed a 3rd order rolloff starting around 800hz if I remember correctly. This is something that is impossible for a driver to do that has such small inductance. Even with extremely high inductance it simply cannot roll off like that. There was also a deep, narrow dip around 500hz I believe, again almost definitely not caused by the driver. This would indicate a reflection, most likely off the back wall of the cabinet coming back forward and being out of phase at the given wavelength. Wayne later admitted that the measurements showing the high frequency rolloff were taken with the crossover in line. I asked for the drivers to be returned so I could put them on an infinite baffle here and measure the drivers only, without cabinet or crossover to verify the other issue as an internal cabinet reflection. I offered to pay the shipping cost to do so. This was refused as his customer apparently sold off the drivers and put something else in.

    The whole situation was handled very 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 forums about this and I had to approach him about it.

    You can take a look at a lot of other drivers we offer that were measured independently.

    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. You can see a lot of information on those who use our woofers on our facebook page.

    buzzforb on #11074

    Thank you for the response. I did not respond because i did not realize you had. I bought the Td12S as i figured it was a worthy gamble based upon the reputation of the drivers. Unfortunately one of them buzzes. Do you recone the older models? I have sent an email just now to the general email.

    stryke on #11075

    I hadn’t seen this reply here. If one woofer was buzzing like something was damaged, that may very well be a reason for the faulty measurements. I know we have discussed this but I did not hear more back from you. Please let us know if you are still wanting these reconed.


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