I wanted to start this thread to share my progress on a custom 3-way speaker design that I have been working on. This design heavily draws inspiration from hifijim's LLCAM speakers due to the great technical details and well explained design process. Other aspects come from people such as Augerpro for the waveguide desing and Troels Gravvsen for the general cabinet shapes and crossover design.
The goal of this project is to be a moderate cost 3-way passive speaker design with good technical details and act as a solid home stereo setup in my living room. I have built and designed other speakers in the past with a much less technical design process, so I wanted these to leverage as much of the community knowledge that I could understand. I would still say that much of this project is "half-assed", where some of the technical aspects were added in spirit as opposed to objective testing.
For driver selection, I went through many iterations myself, including much of FaitalPros, SB, and Daytons driver choices. After much thought, I basically settled on the same driver selection as hifijim did in his LLCAM speakers that I drew inspiration from. As this is a passive design, I went for components that had a relatively flat response and that I thought would be somewhat straightforward to design an XO for, but this is yet to be seen in practice. The parts include:
Woofer - Dayton RS270-4, ~300-400 Hz XO
Mid - SB15NBAC30-4
Tweeter - SB26ADC in Augerpro 4" waveguide, ~2200-2500 Hz XO
The enclosure design includes a ~30L vented enclosure tuned to 32Hz for the woofer and a 4L sealed enclosure for the mid. I have done some work on designing a custom port that will be 3D printed (due to the space constraints of the internal volume) which will have a roughly 3" diameter and 13" length. The port design is not yet finalized, but I have been looking at stv's thread on port design and may see if I can design something using the findings that he has been making over there.
The front baffle was orignally designed using a similar method in Vituix that hifijim mentioned, using varying baffle chamfers for each driver to "simulate" the chamfered corner. For this, I initially designed the baffle with full downwards cuts, similar to what Troels uses in some of his speaker designs, for aesthetics. With simulated baffle diffraction, traced speaker SPLs from spec sheets, and a very rough XO design, the results seemed promising enough for me to continue. During the process of building the cabinet, I decided to not add the chamfers due to a waveguide already being used and the mitered corners with custom red elm veneer looking too good for me to cut it off. I am hoping this will not affect performance greatly, simulations did show it was marginally worse but not awful.
The inside of the cabinet is supported by two braces, one which is integrated with the mid chamber and the other which supports the woofer. The front baffle thickness is nominally 3/4" on the mid and tweeter, but a second MDF baffle piece was added to the woofer making it a 1.5" baffle thickness. Most free faces of the cabinet were covered in 80mil butyl/bitumen sound deadening pads and then in ~1/2" denim/cotton mats. I plan to later add natural wool stuffing to the enclosures by ear. The rough outside dimensions of the boxes are 14.5" width, 25.5" height, and 11" depth, making them "bookshelf plus" in my mind. Overall, the building process went well (other than not cutting the chamfered edges), and the cabinets look amazing with a wipe on poly coating on the red elm veneer.
I don't plan on making any significant progress in the coming weeks/months as I will be moving cross-country shortly to begin a new job. When I make sufficient progress on this project, I will make another longer update post. I'll try and be somewhat active if anyone has suggestions/questions about this project.
Cheers - O
The goal of this project is to be a moderate cost 3-way passive speaker design with good technical details and act as a solid home stereo setup in my living room. I have built and designed other speakers in the past with a much less technical design process, so I wanted these to leverage as much of the community knowledge that I could understand. I would still say that much of this project is "half-assed", where some of the technical aspects were added in spirit as opposed to objective testing.
For driver selection, I went through many iterations myself, including much of FaitalPros, SB, and Daytons driver choices. After much thought, I basically settled on the same driver selection as hifijim did in his LLCAM speakers that I drew inspiration from. As this is a passive design, I went for components that had a relatively flat response and that I thought would be somewhat straightforward to design an XO for, but this is yet to be seen in practice. The parts include:
Woofer - Dayton RS270-4, ~300-400 Hz XO
Mid - SB15NBAC30-4
Tweeter - SB26ADC in Augerpro 4" waveguide, ~2200-2500 Hz XO
The enclosure design includes a ~30L vented enclosure tuned to 32Hz for the woofer and a 4L sealed enclosure for the mid. I have done some work on designing a custom port that will be 3D printed (due to the space constraints of the internal volume) which will have a roughly 3" diameter and 13" length. The port design is not yet finalized, but I have been looking at stv's thread on port design and may see if I can design something using the findings that he has been making over there.
The front baffle was orignally designed using a similar method in Vituix that hifijim mentioned, using varying baffle chamfers for each driver to "simulate" the chamfered corner. For this, I initially designed the baffle with full downwards cuts, similar to what Troels uses in some of his speaker designs, for aesthetics. With simulated baffle diffraction, traced speaker SPLs from spec sheets, and a very rough XO design, the results seemed promising enough for me to continue. During the process of building the cabinet, I decided to not add the chamfers due to a waveguide already being used and the mitered corners with custom red elm veneer looking too good for me to cut it off. I am hoping this will not affect performance greatly, simulations did show it was marginally worse but not awful.
The inside of the cabinet is supported by two braces, one which is integrated with the mid chamber and the other which supports the woofer. The front baffle thickness is nominally 3/4" on the mid and tweeter, but a second MDF baffle piece was added to the woofer making it a 1.5" baffle thickness. Most free faces of the cabinet were covered in 80mil butyl/bitumen sound deadening pads and then in ~1/2" denim/cotton mats. I plan to later add natural wool stuffing to the enclosures by ear. The rough outside dimensions of the boxes are 14.5" width, 25.5" height, and 11" depth, making them "bookshelf plus" in my mind. Overall, the building process went well (other than not cutting the chamfered edges), and the cabinets look amazing with a wipe on poly coating on the red elm veneer.
I don't plan on making any significant progress in the coming weeks/months as I will be moving cross-country shortly to begin a new job. When I make sufficient progress on this project, I will make another longer update post. I'll try and be somewhat active if anyone has suggestions/questions about this project.
Cheers - O
