Thanks, guys! And thanks again for all the great tips along the way. About 8 months from start to finish (working at a very slow, methodical pace on a part-time basis). The wedges that Ken printed fit perfectly and create a very unique "floating cabinet" type profile.
Before loading up my speakers for the long trip, I ran harmonic distortion plots at 1/2 meter at about the 98dB average SPL level. This is a fairly high level, equal to about 92dB at 1 meter or 86dB at 2 meters for a single speaker. So, with two speakers playing this would be about 89dB at the listening position. Distortion runs no higher than 0.2 to 0.3% from 400Hz to 20kHz. This includes the 1.3kHz Bozhen tweeter xover point, so this plot seems to show that this tweeter can certainly handle xover points as low as 1kHz, as claimed by the manufacturer. From 400Hz down to 200Hz, the distortion ramps up to a little over 1%, but this is mainly 2nd harmonic. 3rd harmonic is 0.5% or lower in this range. This seems to show that my decision to cross the quad set of 3" midrange drivers at a very low point of 175Hz was not a poor decision. In the 30 to 70Hz range, the two Tang Band 6.5" woofers are running in the 2 to 3% distortion range. Again, this is almost all 2nd harmonic and will therefore probably be inaudible.
Thanks, guys! Much appreciated. Based on a lot of positive feedback and also based on what my own two ears are telling me, this is probably the best sounding speaker that I have designed to date. I'll be bringing them to Ankeny for demo this October.
The "Beer Budget Window Rattlers." Found a couple of old 4x6 photos from yesteryear. These were Madisound 12204 DVC 12" woofers (2), Phillips AD02110/SQ8 2" midranges (2), and a Peerless 1545 SR-10 one inch soft dome tweeter. They were 57.5" tall, 21" deep, and 16.5" wide. BR port was 4" x 6.25" x 5" long. Per the Robert Bullock/Bob White DOS based BOXRESPONSE computer program that I was using at the time, these speakers could belt out 115.9dB @ 25Hz at a maximum power input of 400 watts.
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Thanks, guys! And thanks again for all the great tips along the way. About 8 months from start to finish (working at a very slow, methodical pace on a part-time basis). The wedges that Ken printed fit perfectly and create a very unique "floating cabinet" type profile.
Before loading up my speakers for the long trip, I ran harmonic distortion plots at 1/2 meter at about the 98dB average SPL level. This is a fairly high level, equal to about 92dB at 1 meter or 86dB at 2 meters for a single speaker. So, with two speakers playing this would be about 89dB at the listening position. Distortion runs no higher than 0.2 to 0.3% from 400Hz to 20kHz. This includes the 1.3kHz Bozhen tweeter xover point, so this plot seems to show that this tweeter can certainly handle xover points as low as 1kHz, as claimed by the manufacturer. From 400Hz down to 200Hz, the distortion ramps up to a little over 1%, but this is mainly 2nd harmonic. 3rd harmonic is 0.5% or lower in this range. This seems to show that my decision to cross the quad set of 3" midrange drivers at a very low point of 175Hz was not a poor decision. In the 30 to 70Hz range, the two Tang Band 6.5" woofers are running in the 2 to 3% distortion range. Again, this is almost all 2nd harmonic and will therefore probably be inaudible.
1.3kHz Bozhen tweeter xover point?
Yep, the B version is rated to 1kHz, Leon.
InDIYana Event Website
That's right. I forgot about that.
Just got the PE email, Congrats on the write up, Bill !! Fantastic job on dolling them up for the show🤘🏼😎👍🏻
Sounded great, Bill! If I had to choose, the Plumber's Delights, Totally Flat, and these are at the top of your build list. Congrats!
InDIYana Event Website
Aye! Congrats 4thtry (Bill).
Way to go Bill!
Thanks, guys! Much appreciated. Based on a lot of positive feedback and also based on what my own two ears are telling me, this is probably the best sounding speaker that I have designed to date. I'll be bringing them to Ankeny for demo this October.
My full write up just appeared on the PE customer project gallery:
https://projectgallery.parts-express.com/speaker-projects/micro-grand-utopia/
Did they give you your $25 coupon?
Yup. Just got it.
Bill, you have certainly come a long way from the days of your Beer Budget Window Rattler. Speaker Builder magazine, 1986 I believe.
The "Beer Budget Window Rattlers." Found a couple of old 4x6 photos from yesteryear. These were Madisound 12204 DVC 12" woofers (2), Phillips AD02110/SQ8 2" midranges (2), and a Peerless 1545 SR-10 one inch soft dome tweeter. They were 57.5" tall, 21" deep, and 16.5" wide. BR port was 4" x 6.25" x 5" long. Per the Robert Bullock/Bob White DOS based BOXRESPONSE computer program that I was using at the time, these speakers could belt out 115.9dB @ 25Hz at a maximum power input of 400 watts.