TDM15 on open baffle?

Posted In: Lambda Drivers

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    keto on #684

    Would a TDM15 be flat from 150hz to 300hz on a small open baffle, of 20″x24″? If not, would making the baffle larger work? Thanks!

    paulspencer on #7219

    First work out what the driver would be in a sealed box, then add dipole roll off with this forumula:

    f = 58 / (half baffle width in metres + wing fold back)

    at f you get a first order high pass added to the sealed roll off (one octave higher than fs)

    stryke on #7220

    The first thing you’d want to do is model your baffle. The EDGE is very good for this. That will give you only the rolloff of the baffle itself. Then model the driver and add the 2 rolloffs. The TD15M itself is about -3dB at 100hz, – 1.5dB at 150hz, and -.35dB at 300hz. You could easily use it in that range if your baffle allows for it.

    Most likely the LO15 would be a better option for you in that range though. Is 150-300hz the only region you plan to cover with the driver? That would be quite a waste of the wide bandwidth of the TD15M.

    best Regards,

    keto on #7221

    Looks like I’ve got 3 good options for the TDM15’s, then. A 6ft3 box tuned to 40hz, a 3ft3 sealed box (looking here for both a smooth 1st order, acoustic high pass and maximum LF extension), and a horn modeled with the “horn response” program thats about 36″ long and has a 30×30″ mouth (the horns model pretty smoothly from 70-300hz, but for the moment I’m hoping to resolve the system as also sounding good in the nearfield). First step though is to wait for the 16ft3 boxes to arrive for the TDX15’s, and hear what they and the TDM15’s sound like with a LR-4 lowpass at 300hz. If the TDM15’s sound a lot better, then I’ll put them in the 3ft3 sealed boxes and add a first order low pass around 80hz for the TDX’s in their new bass bins. Should be interesting, however it works out. Yeah, I now see that the TDM15 is not an open baffle speaker, that’s what the Dipole 15 is for, right? Congrats on the new TD6’s. If using just the TDX15’s works out in the main system, I’ll build a second one around the TDM15 in the 6ft3 40hz vented enclosure and the TD6M — as a sealed midrange, it looks like from the curves you posted that its a12dB/octave, 2nd order roll-off at 150hz. Nice. Thanks for the input.

    simon5 on #7222

    Yes dipole much more suited for open baffle, much more Xmax and also underhung.

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