Ok, it’s an oxymoron. But, as I kind of expected, my daughter’s budget for an Oris horns system evaporated in the realities of rehabbing a house built in 1900. So, I looked in my cabinet of unloved hifi parts to see what we might be able to do. What I’m thinking:
Tapped horn, Volvotreter’s DIY 30hz Tangband, 30-80hz (pair)
Mid bass, EVM-15B on DIY straight exponential horn, 80-400
Midrange, JBL 2105 on DIY Edgar tractrix horn, 400-3500 or 4000
Tweeter, Jensen RP-103 horn 4000-12000
Super tweeter, Radio Sack 40-1310, 12000 up
I have all of the drivers except for the Tangbands, but they’re fairly inexpensive. Amp is a Pilot SA-232 she has (may convert to triode). No DSP to start, traditional crossovers midbass up. TH’s crossed with midbass electronically and powered by plate amp (TBD). Biggest outlay will be for wood; a lot of fabrication but my son-in-law and his brother are wanting the challenge.
Yes, without DSP level matching will be an issue, and it’s a guess on how flares and dispersions will integrate in the room. DSP may be in the future.
I’m trying to not stretch the limits of any given horn. Thoughts and rationalizations:
TH – proven design, plans available, though the current W6-1139SIF sims differently in hornresp than the W6-1139SC Volvotreter uses. Adding an inductor, as he does on his 38hz version, smooths the response considerably. Probably as low as I can go with a TH and cross at 80hz without issues.
Midbass – inspired by Volvotreter 77hz horn, modeled in hornresp, changed to an exponential flare and increased the mouth to be 1/2 size. Plan to use multiple layers of bending plywood to fashion the exponential side profiles. May be a challenge to build, but that’s why I have a son-in-law.
Midrange – from Dr Edgar’s Speaker Builder article. May cross at 3500 instead of Bruce’s 4000 to reduce beaming potential and the 2105 running out of gas. Thoughts?
Tweeter – the Jensens are sweet sounding, and I have them, came out of a Pilot console with above amp. Crossing higher on the bottom and lower on the top than typical should keep them out of any mischief, and easy to cross gently. A 16 ohm driver in the midst of 8’s, tho. Potential future upgrade.
Super tweeter – decent performers, and I have them. Fill in before the Jensen phenolics run out of gas.
As an alternative, I could build the tractrix mid for a discontinued Polydax dome driver up to 5k and cross it to a JBL 076 I have, to make it a 4-way, but I am afraid of the tractrix beaming and reliability; correct 076 diaphragms are long unavailable and Bruce switched from domes, as he found they tend to burn out. My daughter and her husband should be able to recone or replace any of my choices (except The Tangbands) for a number of years.
Any comments or criticisms welcomed!
Tapped horn, Volvotreter’s DIY 30hz Tangband, 30-80hz (pair)
Mid bass, EVM-15B on DIY straight exponential horn, 80-400
Midrange, JBL 2105 on DIY Edgar tractrix horn, 400-3500 or 4000
Tweeter, Jensen RP-103 horn 4000-12000
Super tweeter, Radio Sack 40-1310, 12000 up
I have all of the drivers except for the Tangbands, but they’re fairly inexpensive. Amp is a Pilot SA-232 she has (may convert to triode). No DSP to start, traditional crossovers midbass up. TH’s crossed with midbass electronically and powered by plate amp (TBD). Biggest outlay will be for wood; a lot of fabrication but my son-in-law and his brother are wanting the challenge.
Yes, without DSP level matching will be an issue, and it’s a guess on how flares and dispersions will integrate in the room. DSP may be in the future.
I’m trying to not stretch the limits of any given horn. Thoughts and rationalizations:
TH – proven design, plans available, though the current W6-1139SIF sims differently in hornresp than the W6-1139SC Volvotreter uses. Adding an inductor, as he does on his 38hz version, smooths the response considerably. Probably as low as I can go with a TH and cross at 80hz without issues.
Midbass – inspired by Volvotreter 77hz horn, modeled in hornresp, changed to an exponential flare and increased the mouth to be 1/2 size. Plan to use multiple layers of bending plywood to fashion the exponential side profiles. May be a challenge to build, but that’s why I have a son-in-law.
Midrange – from Dr Edgar’s Speaker Builder article. May cross at 3500 instead of Bruce’s 4000 to reduce beaming potential and the 2105 running out of gas. Thoughts?
Tweeter – the Jensens are sweet sounding, and I have them, came out of a Pilot console with above amp. Crossing higher on the bottom and lower on the top than typical should keep them out of any mischief, and easy to cross gently. A 16 ohm driver in the midst of 8’s, tho. Potential future upgrade.
Super tweeter – decent performers, and I have them. Fill in before the Jensen phenolics run out of gas.
As an alternative, I could build the tractrix mid for a discontinued Polydax dome driver up to 5k and cross it to a JBL 076 I have, to make it a 4-way, but I am afraid of the tractrix beaming and reliability; correct 076 diaphragms are long unavailable and Bruce switched from domes, as he found they tend to burn out. My daughter and her husband should be able to recone or replace any of my choices (except The Tangbands) for a number of years.
Any comments or criticisms welcomed!
Beancounter,
Given the components you want to reuse, I'd suggest the nested horn approach, the tweeter centered in front of the RP-103, the RP-103 in front of the JBL 2105, the EVM-15B exponential horn around that, making a virtual point source.
The rear of the tweeter and mid horn could use some felt dampening "cones", effectively a tunable acoustic low pass, reducing crossover parts count and phase shift, also expanding the polar patterns through diffraction.
Some throat modification may be required for the Edgar tractrix horn, and the compression chamber made pyramid shape to fit in the expanded low mid horn throat.
No existing photos left of the horn that surrounded the mid/ high shells above, but it's dual trapezoid 67" depth and 45" x 45" mouth made it intractable for road use 😳.
Art
Given the components you want to reuse, I'd suggest the nested horn approach, the tweeter centered in front of the RP-103, the RP-103 in front of the JBL 2105, the EVM-15B exponential horn around that, making a virtual point source.
The rear of the tweeter and mid horn could use some felt dampening "cones", effectively a tunable acoustic low pass, reducing crossover parts count and phase shift, also expanding the polar patterns through diffraction.
Some throat modification may be required for the Edgar tractrix horn, and the compression chamber made pyramid shape to fit in the expanded low mid horn throat.
No existing photos left of the horn that surrounded the mid/ high shells above, but it's dual trapezoid 67" depth and 45" x 45" mouth made it intractable for road use 😳.
Art
