Steve,
Before you go down this particular rabbit hole I would advise you a few things I had to unlearn. One of them is that the synergy is its own beast with its own set of requirements so typical two- and three-way thinking is not going to help. Like a conventional HF horn, a compression driver is mounted at the apex of the horn. Unlike a conventional horn, the CD is crossed over to one or two pair of mid-woofers mounted very close to the compression driver. Based off what I've seen of builds here, these mid-woofers are anywhere from two to four inches in diameter and are of the closed-back variety. You do not really see HiFi brands here. Further down the horn, closer to the mouth, a pair of woofers are mounted (usually on the horn sidewalls). Since the synergy horn is in an enclosure, the volume of the enclosure can be tuned for these woofers so closed back woofers are not a requirement here. Both the woofers and mid-woofers are coupled to the horn via injection ports, the volume of which has to be accounted for in the crossover design. This is the black art of synergy design.
You're correct, the oblate spheroid horn profile is a continuous curve. I am eventually going to experiment with kerfing plywood and hopefully not lose a finger in the process. A lot of compound angles to deal with.
Keep in mind not all Synergy horns end up being extremely high efficiency. Some are only in the mid-90 dBs.
Here's a search I did here, Bill Waslo (bwaslo) developed a spreadsheet to help calculate cutting angles. It's in his signature: diyAudio - Search Results
Before you go down this particular rabbit hole I would advise you a few things I had to unlearn. One of them is that the synergy is its own beast with its own set of requirements so typical two- and three-way thinking is not going to help. Like a conventional HF horn, a compression driver is mounted at the apex of the horn. Unlike a conventional horn, the CD is crossed over to one or two pair of mid-woofers mounted very close to the compression driver. Based off what I've seen of builds here, these mid-woofers are anywhere from two to four inches in diameter and are of the closed-back variety. You do not really see HiFi brands here. Further down the horn, closer to the mouth, a pair of woofers are mounted (usually on the horn sidewalls). Since the synergy horn is in an enclosure, the volume of the enclosure can be tuned for these woofers so closed back woofers are not a requirement here. Both the woofers and mid-woofers are coupled to the horn via injection ports, the volume of which has to be accounted for in the crossover design. This is the black art of synergy design.
You're correct, the oblate spheroid horn profile is a continuous curve. I am eventually going to experiment with kerfing plywood and hopefully not lose a finger in the process. A lot of compound angles to deal with.
Keep in mind not all Synergy horns end up being extremely high efficiency. Some are only in the mid-90 dBs.
Here's a search I did here, Bill Waslo (bwaslo) developed a spreadsheet to help calculate cutting angles. It's in his signature: diyAudio - Search Results
Please, Brinkman, whatever else you do, watch out for your fingers. I came across the tips of the first three fingers of my left hand on a table mounted router. I thought that my guitar playing days were at an end. They did heal eventually.
I think that I will leave the synergy horn to you and wish you the best of luck.
I have been toying with the idea of a Patrician IV design using a JBL 2245H 18" woofer and other JBL units that I have been collecting over the years. For the present, I shall be content with the construction of an 8 cu ft. ported cabinet for the 130As. Home Depot sells 3/4 in. oak plywood.
There is still the Mk IIIs to think about and I can still listen to the Mk IVs as they blossom into maturity. Just as I expected them to.
I think that I will leave the synergy horn to you and wish you the best of luck.
I have been toying with the idea of a Patrician IV design using a JBL 2245H 18" woofer and other JBL units that I have been collecting over the years. For the present, I shall be content with the construction of an 8 cu ft. ported cabinet for the 130As. Home Depot sells 3/4 in. oak plywood.
There is still the Mk IIIs to think about and I can still listen to the Mk IVs as they blossom into maturity. Just as I expected them to.
Last edited:
- Status
- Not open for further replies.