My advise for nearfield....
If you will always be in the same spot, a compact full-range driver will image better in nearfield than a multi-way, however, if you want something that has more even power response and sounds good all over the room while also sound good at the design listening position, then a tweeter will be required, Get the tweeter as close to the midbass as possible (use something with a very tiny flange or no flange) and cross over as low and steep as possible.
I would be inclined to use a big 1.125" or larger dome tweeter, crossed over at like 1500hz to a 4" midbass. This will help ensure the speaker behaves as a point source when you're close to them.
Concentric technically means two circles have the same center point (aligned in 2-dimensions, plane and axis), while coaxial means they share the same axis (aligned on 1-axis).
In practice, I think they're used pretty much interchangeably. Concentric may be more often used to describe drivers like KEF's, where the central driver is set into the center of the woofer. While coaxial would more commonly refer to drivers with the tweeter in *front* of the woofer.
You could also do a WAW/FAST build - basically a larger mid/tweeter, say 3”, with another driver (4-6”) for 400hz and below. It’s a middle of the path approach, between using only 1 driver and using 1 big + 1 tweeter. Crossover/transition is easier too compared to tweeter as it’s a longer wavelength.
There's a number of published designs along the line you're thinking of (and can be front ported):
- Overnight Sensations
- S2000 MT
- Micro Statements / Finalist Monitor
Even just for aesthetics alone I would never put the tweeter on the bottom. It's too bad the RSL CG3M is so hideous, else I would probably just buy a pair and be done 😜
I'd advise you to choose an already designed speaker.
Way easier to get a decent result if you've never done it before ! Designing a crossover is definitely not a simple task ...
Once fixed on the design, you just pick the BOM and order from internet, many websites are a good source; depending on your location obviously.
What bandwidth do you want it to be capable of, since you're integrating a sub? Have you built a crossover? Do you care about it being traditional domes/cones or open to planars and air motion or ribbons? Ever used full range drivers?
Considering the size constraints, I am hoping to build something I can cross with a sealed subwoofer at 80-90Hz.
This will be my first DIY speaker build (other than a car subwoofer).
I am open to different tweeters however I am not a big fan of bright treble, so for that reason I assumed silk dome was best, but I could be wrong.
A cabinet volume this size will struggle to get to 80hz sealed, you would likely need to do a bass reflex (ported) to get it to go that low. These small volumes cost you efficiency. You could probably get to 100hz with the right driver before heavy roll off. You could consider a 3\~4 inch full range driver and port the box at 85hz and integrate with a sub. That would simplify things greatly. If you want to do a 2 way with a woofer and tweeter you'll have to build and measure a crossover, way more complicated, and without the right tools you're just gamling and pre-made crossovers are just stabs in the dark.
I was planning to do front ported like the RSL CG3M, and go slightly bigger/deeper in the cabinet.
When you say full-range driver, do you mean something like the KEF concentric designs? It would be interesting if I could get my hands on a pair of drivers from their 4" LSX line.
Yes, an actual full range driver, or a full range coaxial driver. No need for crossover. Just design an enclosure based on the driver and port it to your lowest useful frequency. Greatly simplifies things if you don't have the tools needed to properly measure and build a crossover (including baffle step compensation and z-offset or time delay, etc).
The [FR124B8-19F](https://www.solen.ca/en/products/fr124b8-19f) was designed to give decent bass in a small enclosure in mind. Its frequency response is not perfect, but it sounds good. It’s not the cheapest though.
You will most likely need a small crossover for the baffle step (unless you are going active).
I'm using Kartesian Sub120s on my desktop build and reaching a clean 30Hz in-room with 2 liters of enclosure. 80Hz is absolutely not a problem with modern amps
My advise for nearfield.... If you will always be in the same spot, a compact full-range driver will image better in nearfield than a multi-way, however, if you want something that has more even power response and sounds good all over the room while also sound good at the design listening position, then a tweeter will be required, Get the tweeter as close to the midbass as possible (use something with a very tiny flange or no flange) and cross over as low and steep as possible. I would be inclined to use a big 1.125" or larger dome tweeter, crossed over at like 1500hz to a 4" midbass. This will help ensure the speaker behaves as a point source when you're close to them.
Just go coax and avoid all the issues with full range.
Is coaxial the same as concentric? (Like KEF?)
Concentric technically means two circles have the same center point (aligned in 2-dimensions, plane and axis), while coaxial means they share the same axis (aligned on 1-axis). In practice, I think they're used pretty much interchangeably. Concentric may be more often used to describe drivers like KEF's, where the central driver is set into the center of the woofer. While coaxial would more commonly refer to drivers with the tweeter in *front* of the woofer.
yes
Also a fantastic plan. The CX120-8 comes to mind as a good inexpensive start with data files already available to design a crossover from.
Thanks for the info. Yes, I think I'll go with a tweeter design for versatility.
You could also do a WAW/FAST build - basically a larger mid/tweeter, say 3”, with another driver (4-6”) for 400hz and below. It’s a middle of the path approach, between using only 1 driver and using 1 big + 1 tweeter. Crossover/transition is easier too compared to tweeter as it’s a longer wavelength.
There's a number of published designs along the line you're thinking of (and can be front ported): - Overnight Sensations - S2000 MT - Micro Statements / Finalist Monitor
I would not put the tweeter on the bottom (secondary reflection from desktop).
Even just for aesthetics alone I would never put the tweeter on the bottom. It's too bad the RSL CG3M is so hideous, else I would probably just buy a pair and be done 😜
I'd advise you to choose an already designed speaker. Way easier to get a decent result if you've never done it before ! Designing a crossover is definitely not a simple task ... Once fixed on the design, you just pick the BOM and order from internet, many websites are a good source; depending on your location obviously.
What bandwidth do you want it to be capable of, since you're integrating a sub? Have you built a crossover? Do you care about it being traditional domes/cones or open to planars and air motion or ribbons? Ever used full range drivers?
Considering the size constraints, I am hoping to build something I can cross with a sealed subwoofer at 80-90Hz. This will be my first DIY speaker build (other than a car subwoofer). I am open to different tweeters however I am not a big fan of bright treble, so for that reason I assumed silk dome was best, but I could be wrong.
A cabinet volume this size will struggle to get to 80hz sealed, you would likely need to do a bass reflex (ported) to get it to go that low. These small volumes cost you efficiency. You could probably get to 100hz with the right driver before heavy roll off. You could consider a 3\~4 inch full range driver and port the box at 85hz and integrate with a sub. That would simplify things greatly. If you want to do a 2 way with a woofer and tweeter you'll have to build and measure a crossover, way more complicated, and without the right tools you're just gamling and pre-made crossovers are just stabs in the dark.
I was planning to do front ported like the RSL CG3M, and go slightly bigger/deeper in the cabinet. When you say full-range driver, do you mean something like the KEF concentric designs? It would be interesting if I could get my hands on a pair of drivers from their 4" LSX line.
Yes, an actual full range driver, or a full range coaxial driver. No need for crossover. Just design an enclosure based on the driver and port it to your lowest useful frequency. Greatly simplifies things if you don't have the tools needed to properly measure and build a crossover (including baffle step compensation and z-offset or time delay, etc).
Any recommendations for 4" full range drivers?
Madisound, Dayton reference, Fostex, Lii
The [FR124B8-19F](https://www.solen.ca/en/products/fr124b8-19f) was designed to give decent bass in a small enclosure in mind. Its frequency response is not perfect, but it sounds good. It’s not the cheapest though. You will most likely need a small crossover for the baffle step (unless you are going active).
I'm using Kartesian Sub120s on my desktop build and reaching a clean 30Hz in-room with 2 liters of enclosure. 80Hz is absolutely not a problem with modern amps
Here's a pretty good budget friendly option https://techtalk.parts-express.com/forum/tech-talk-forum/1423033-duane-brown-dayton-4-deluxe-version