[OBF]

Hi Dave.  In theory, if a person was using something like the DEQX with your 1801Bs and bypassing the crossover would the OW1 tweeter be able to safely produce more SPLs if it had a very steep crossover?  Maybe the crossover point could even be raised slightly too if you were using, say, 300db/octave slopes?

I'm not intending to do this now, just wondering if the speakers with their high quality drivers and rigid cabinet would be a decent platform for an active system or if the tweeter would still be fragile at high output.

Thanks.

[David Ellis]

Dennis and I discussed this a few years ago.  

Initially I had your perspective.  I thought the OW1 was the weak link in the power handling department.  It's not.  The W18 woofer suffers thermal compression in the voice coil before the tweeter surrenders.  I believe this is true by a fair margin.  Dennis fiddled with the OW1 in a crossover requiring more power/spl from the OW1, and it continued to perform nicely.  

There is something "different" about very good tweeters and their power hanlding.  The very good ones will tolerate significant power without distortion.  I was surprised to see some tweeters being crossed around 1500hz, until I did this with an OW1FS.  I believe the difference maker in a good tweeter that will handle a low crossover point (high energy) is the surround material.   I am only guessing here, but have a hunch this is is true.

The very good dome tweeters have a very refined coating on the SURROUND of the tweeter dome.  This provides good mechanical dampening even when at higher excursion.  This well damped surround on a tweeter effectively IS the "spider" and "surround" for the tweeter.  Getting some degree of mechanical dampening here really makes a difference.  The trick is... what dampening material to use, how do apply it, and how to accomplish this consistently.   Those who know this information aren't willing to share their trade secrets.  They are fine grey haired gentlmen and ladies, that still wish to retire berfore EVERYTHING is built in China with poor quality control and terrible manufacturing tolerances.  These mature European gentlmen and ladies continue to build SS Revelators, Dynaudio Esotars, and Hiquphons.  This is all just my theory though.  

Sorry about  the soap-box.  This was a very long way of conveying that your digital crossover simply won't matter with regard to 1801 power handling.

Dave

[OBF]

Thanks for the info, that makes a lot of sense and it's good to hear about the OW1.

Regarding the W18 and my lack of design knowledge, is the thermal compression from lower frequencies where a lowpass would help, or does it result from high SPLs in the midrange area?

[David Ellis]

The low frequency energy carries the propensity of the heat & current & thermal issues for the W18.  Given this an active crossover with a high pass circuit will work.  It'll give the 1801 more power handling ability.