Thiel Owners

I was playing around with a three-way mock-up. Basically I use a setup with what I already have. Making the cabinets would just take a lot of time. The tweeter is ScanSpeak AirCir, Seas Nextel 5.5in. as mid, and Scanspeak Illuminator 5.5 in as woofer. I don’t current have a dedicate cabinet for 8in. woofer but the freq/phase behavior should not be that different.

Measurement was done at 1Meter distant between the tweeter and the mid which is about 33in. high. There are quite a bit of ripples on the freq. response probably due to room reflection which also shown in the step response being taking a bit longer time to settle at the low frequencies.

The xover seems a bit complicated, but that’s typical of first order, time-phase coherent, time-coincident speakers. The 50uf cap on the tweeter should only affect the lower freq. so it probably will be OK. Actually I don’t need it there for freq. response, but I put it there to protect the tweeter.

Pic:
https://www.flickr.com/photos/185616271@N05/49129808921/in/album-72157711891600612/

Xover:
https://www.flickr.com/photos/185616271@N05/49129320988/in/album-72157711891600612/

As I said a few posts above, I believe that one of the differences in sound signature of first-order filter is that high order filter, there is a faster change in phase, which results in excess overshoot and undershoot in time domain. And the reasons why were explained in my previous posts.

I here compare different impulse response of different filters. An ideal first-order time-phase coherent has the "best" impulse response. The 3rd order electrical filter has the worst. There are a total of six different filters here:

1. First order ideal
https://www.flickr.com/photos/185616271@N05/49129364003/in/album-72157711891600612/

2. Third order electrical: shows the most undershoot, overshoot:
https://www.flickr.com/photos/185616271@N05/49129853971/in/album-72157711891600612/

3. First Order, No Time-Phase Coherent
https://www.flickr.com/photos/185616271@N05/49130037747/in/album-72157711891600612/

4. Three-Way Time-Phase/Time-Coincident:
https://www.flickr.com/photos/185616271@N05/49129363963/in/album-72157711891600612/

5. Another Three-Way Time-Phase/Time-Coincident:
https://www.flickr.com/photos/185616271@N05/49129363973/in/album-72157711891600612/

6. A Two-Way Time-Phase/Time-Coincident:
https://www.flickr.com/photos/185616271@N05/49130076182/in/album-72157711891600612/

tomthiel

Safe travels to Lexington. Looking forward in reading about your visit with Rob. Have fun!

Happy Listening!

A Blessed and a Happy Thanksgiving for all our USA friends.

George

Someone pointed me to Bang & Olufsen Uni-Phase xover design.  At least based on theory, the filter will be able to achieve 0 degree phase shift across the frequency band, hence the name Uni-Phase.  I have not seen the step response but the square waves all look very good - not too unlike that from a time-phase coherent/time-coincident design.

Unlike the Thiel or Vandersteen, though, the Uni-Phase uses 2nd order filters, not first order filters.  The advantage is 2nd order does not stress out the drivers as much as first order filter.  

For reference :  https://www.tonmeister.ca/wordpress/2015/10/29/bo-tech-uni-phase-loudspeakers/