Corner placement and active amplification are not mandatory.
Also, there's published crossover schematics for almost any conceivable woofer/tweeter/horn combo.
Thanks for all the cool ideas. I left out quite a few of the constraints that I am working within in order to stay on topic with the original thread.
The basic problems that I am trying to solve:
a) My current speakers, a set of North Creek Rhythm custom bookshelf speakers aren't cutting it. They have little low frequency extension, the bass that they have sounds disconnected from the music and they sound a bit "plasticky" (as if they are cheap computer speakers in a plastic cabinet) with certain musical passages such as classical concert crescendos.
b) I have a pair of 300B SET amplifiers that I like, so I need high sensitivity, consistent impedance speakers.
c) I have limited tools and woodworking skill and I don't want to deal with having to get vintage drivers reconed, etc.
Furthermore, I have a small, odd shaped room and I don't live alone, so I need to keep the "CFO" happy. She also uses the music room to play musical instruments so just closing the door to the man cave isn't an option.
The Denovo 88 Special kit that @brinkman mentioned actually looks about perfect for what I want to do. I'm not sure how I didn't find it previously. I thought I looked at all their kits in the size range I need, but I guess not. I may yet do something with the Faital compression drivers, but this kit seems to be what I'm after!
@hollowboy that link to Rutcho's design is awesome! What a cool idea!
The basic problems that I am trying to solve:
a) My current speakers, a set of North Creek Rhythm custom bookshelf speakers aren't cutting it. They have little low frequency extension, the bass that they have sounds disconnected from the music and they sound a bit "plasticky" (as if they are cheap computer speakers in a plastic cabinet) with certain musical passages such as classical concert crescendos.
b) I have a pair of 300B SET amplifiers that I like, so I need high sensitivity, consistent impedance speakers.
c) I have limited tools and woodworking skill and I don't want to deal with having to get vintage drivers reconed, etc.
Furthermore, I have a small, odd shaped room and I don't live alone, so I need to keep the "CFO" happy. She also uses the music room to play musical instruments so just closing the door to the man cave isn't an option.
The Denovo 88 Special kit that @brinkman mentioned actually looks about perfect for what I want to do. I'm not sure how I didn't find it previously. I thought I looked at all their kits in the size range I need, but I guess not. I may yet do something with the Faital compression drivers, but this kit seems to be what I'm after!
@hollowboy that link to Rutcho's design is awesome! What a cool idea!
The only issue with the 88 Special is it is a ported design that only extends to 60Hz, so you are missing the bottom two octaves of a full range (20Hz-20kHz) design. It is also 22 inches wide, though you could reduce that a little with some toe-in. (See this article: Setup of Controlled-Directivity Waveguide Speakers)
I would suggest you consider augmenting the 88 Specials (if you go this route) with pair of midbass module. This would do three things: 1) fill in the missing octaves from the 88 Special; 2) eliminate floor bounce interference, and 3) act as a stand for the mains.
Integrating a midbass can be done one of two ways, active or passive. To do it passively, you would need to have a woofer of the appropriate impedance and sensitivity for the mains you are using them with. Luckily, the 15” midbass from the above link is pretty dang close. For more about integrating passively, read this document: The Kairos and Continuum Three-Ways
(And other possibilities too)
The advantages of going at it actively are 1) impedance and sensitivity mismatches are not an issue; 2) “recouping” speaker sensitivity that would otherwise be attenuated in baffle step compensation, and 3) your SET amplifier power supply is going to be happier driving your mains only. The disadvantages are the added cost of plate amps (though this is somewhat mitigated by the added expense of poly capacitors & inductors were you to go passive) and the two extra power cords.
I’m not sure what the natural roll-off frequency is of the custom hemp woofers used in the 88-Special. I could take mine out and hook them up to my woofer tester. This would give us an idea of what size enclosure would be best if you wanted to run the 88-Specials in a sealed enclosure, of which there is a benefit vs ported (when bass extension is no longer a requirement of the mains).
I would suggest you consider augmenting the 88 Specials (if you go this route) with pair of midbass module. This would do three things: 1) fill in the missing octaves from the 88 Special; 2) eliminate floor bounce interference, and 3) act as a stand for the mains.
Integrating a midbass can be done one of two ways, active or passive. To do it passively, you would need to have a woofer of the appropriate impedance and sensitivity for the mains you are using them with. Luckily, the 15” midbass from the above link is pretty dang close. For more about integrating passively, read this document: The Kairos and Continuum Three-Ways
(And other possibilities too)
The advantages of going at it actively are 1) impedance and sensitivity mismatches are not an issue; 2) “recouping” speaker sensitivity that would otherwise be attenuated in baffle step compensation, and 3) your SET amplifier power supply is going to be happier driving your mains only. The disadvantages are the added cost of plate amps (though this is somewhat mitigated by the added expense of poly capacitors & inductors were you to go passive) and the two extra power cords.
I’m not sure what the natural roll-off frequency is of the custom hemp woofers used in the 88-Special. I could take mine out and hook them up to my woofer tester. This would give us an idea of what size enclosure would be best if you wanted to run the 88-Specials in a sealed enclosure, of which there is a benefit vs ported (when bass extension is no longer a requirement of the mains).
It's my understanding it's near enough a 16 ohm Eminence Beta 8A, so curious how close yours are to this spec, though for sealed they should be good enough: https://www.parts-express.com/pedocs/specs/290-404-eminence-beta-8a-specifications-44309.pdf
Spec wise, looks like vented is required to safely use a THX spec'd 80 Hz XO point though.
GM
Spec wise, looks like vented is required to safely use a THX spec'd 80 Hz XO point though.
GM
- Status
- Not open for further replies.