FR Measurements KIT61

Kevin P · « **on:** 30 Mar 2005, 04:10 pm »

I thought I'd post these here since I've had a couple request.

These were made yesterday. The low frequency isn't spliced so take it with a grain of salt as they were measured in our warehouse. All measurements are from 1M with calibrated mic that is good out to just over 20K. All plots 1/6th octave smoothed.

Here is the on-axis response.

Here is off-axis 15 degrees above the plane.

Here is 30 degrees off-axis to the side. Note very little difference at crossover and the Usher starts to show narrowing at high frequencies.

And here is 45 degrees horizontal off-axis. Once again well behaved at crossover.

klh · « **Reply #1 on:** 30 Mar 2005, 06:41 pm »

Thanks for posting your results. Please correct me if I'm wrong... the off axis fall off of the higher frequencies of the Usher is d/t it having a mid sized dome (as opposed to having a smaller dome). I read that once, but wanted to be sure. Also, how far out does the on axis response continue (25kHz, 30kHz, etc) before falling off?

Kevin P · « **Reply #2 on:** 30 Mar 2005, 07:19 pm »

The Usher has a 1" dome which is the most common sized dome tweeter. Any 1" dome will give similiar off-axis response numbers (within reason). A smaller 3/4" dome will give you better off-axis response because the size. You trade off other aspects of performance though. Larger domes tend to play lower in frequency without the same problems that a smaller dome will have. Overall the 1" domes provide very good off-axis performance and this particular tweeter has some other attributes that caused us to choose it over some of the better 3/4" domes.

I'm not sure how far it goes above 20K.... my mic is only good to about 21-22K so I don't have a measurement. I don't think it's real important because of the limitations of human hearing. Why certain tweeters sound better than others subjectively is somewhat of a mystery to me. I choose this one based upon both measurements and my own subjective preference. The other factors that came into play was manufacturing consistancy (I can order them and get the same performance on every sample), availability, shielding and price/performance.

klh · « **Reply #3 on:** 5 Apr 2005, 06:44 pm »

Thanks, Kevin.

The argument of >20kHz FR not being necessary because human hearing doesn't go that high makes sense. Then again, it usually comes from companies selling speakers whose response doesn't go that high. On the contrary, companies selling speeakers whose response goes that high may be doing that merely as a marketing tool to make their speakers appear better and thus sell more units at higher prices. It makes sense to take advantage of the increased bandwitch of DVD-A / SACD; then again, having not heard a system fully capable of such a bandwidth, it's hard to tell if that will make a difference, let alone one worth the extra $. I find it hard to beleive SACD or DVD-A would have such a high bandwidth if it wasn't necessary given their horrible job of marketing, but that's another topic. I don't know, the hole thing might just be BS.

Kevin P · « **Reply #4 on:** 5 Apr 2005, 09:14 pm »

We could have choose any tweeter we wanted. I didn't have any preconceived notions or limitations. From a subjective standpoint I'm very happy with the Usher. It strikes a nice balance between detailed/laid back and it performs incredibly at higher output levels. It's off-axis response is well behaved and it's distortion numbers are excellent.
Dr. D'Appolito has said it's one of the best tweeters he's ever measured and I'm sure he has measured a lot.

klh · « **Reply #5 on:** 6 Apr 2005, 12:02 am »

Sounds like a winner