Hi all. I'm considering building a pair of desktop speakers around a 4 - 4.5" full-range driver. I've found a number of threads on this, but none match what I've been envisioning:
Driver center about 40cm high
Any port or vent also high up on front baffle, either immediately above or below driver
Total height can be 50cm high
Width can be 17 - 18cm
Depth 30cm or a bit more
40cm driver height puts it at my ear level when seated
If port or vent, high up as possible to minimize interaction w/desktop
That's a lot of volume, so lots of flexibility in design. Kinda drawn to transmission line since there seems to be volume to do so. If I could get to F3 of 50-ish Hz, I'd probably call it a day. I have the ability to crossover at line level to a sub, but I was really after a fairly minimalist setup. I have built speakers before and have access to the right tools (and help). But have never designed TLs before.
I found a site with a nice calculator: mh-audio.nl - Home
Don't want the TL exit facing up, but I sketched an alternative (note TL will taper, just not easy to do when roughing it out in Excel).
Questions:
The website implies that you can get the effective wavelength you want from the amount of long fibre wool you use (click link at the bottom of the linked page). If so, I don't need to be so precise, I can tune after the fact with how I stuff it? Are there tradeoffs with getting crazy with the stuffing?
Very curious about 1/4 vs 1/3 wavelength tuning; does F3 keep getting lower as length increases? I think I can get 1/3 in my volume with enough fill, and according the calculator that gets me down into the 50s depending on driver.
What would you pick as a driver? ATM, mostly considering MarkAudio Pluvia 7 or Alpair 7 because of resonant frequency and overall response.
Pluvia 7 looks like it might need tamed down at the top, but will BSC be needed in any case?
Or maybe I'm out of my mind. I'm sure you'll let me know, looking forward to responses.
Brian
Driver center about 40cm high
Any port or vent also high up on front baffle, either immediately above or below driver
Total height can be 50cm high
Width can be 17 - 18cm
Depth 30cm or a bit more
40cm driver height puts it at my ear level when seated
If port or vent, high up as possible to minimize interaction w/desktop
That's a lot of volume, so lots of flexibility in design. Kinda drawn to transmission line since there seems to be volume to do so. If I could get to F3 of 50-ish Hz, I'd probably call it a day. I have the ability to crossover at line level to a sub, but I was really after a fairly minimalist setup. I have built speakers before and have access to the right tools (and help). But have never designed TLs before.
I found a site with a nice calculator: mh-audio.nl - Home
Don't want the TL exit facing up, but I sketched an alternative (note TL will taper, just not easy to do when roughing it out in Excel).
Questions:
The website implies that you can get the effective wavelength you want from the amount of long fibre wool you use (click link at the bottom of the linked page). If so, I don't need to be so precise, I can tune after the fact with how I stuff it? Are there tradeoffs with getting crazy with the stuffing?
Very curious about 1/4 vs 1/3 wavelength tuning; does F3 keep getting lower as length increases? I think I can get 1/3 in my volume with enough fill, and according the calculator that gets me down into the 50s depending on driver.
What would you pick as a driver? ATM, mostly considering MarkAudio Pluvia 7 or Alpair 7 because of resonant frequency and overall response.
Pluvia 7 looks like it might need tamed down at the top, but will BSC be needed in any case?
Or maybe I'm out of my mind. I'm sure you'll let me know, looking forward to responses.
Brian
Forget about the mh calculator.
You ar enot taking advantage of many TL design opportunities.
Read everything at Quarter Wavelength Loudspeaker Design to give yourself some solid background.
They are good. And you will find lots of designs for them to give you some examples to inspre you.
dave
You ar enot taking advantage of many TL design opportunities.
Read everything at Quarter Wavelength Loudspeaker Design to give yourself some solid background.
They are good. And you will find lots of designs for them to give you some examples to inspre you.
dave
Best free TL calculator are LeonardAudio's and Hornresp.
Unfortunately, LATL has been discontinued, but you can still download it from the thread over here at DIYAudio. I like its graphical interface.
Hornresp is still actively supported. A bit harder to grasp at first look.
There is someone who folded a TABAQ for their centre channel, so it might worth looking into that.
BSC is a matter of taste, but if the speakers are mounted or placed on the wall, it often doesn't need one.
Unfortunately, LATL has been discontinued, but you can still download it from the thread over here at DIYAudio. I like its graphical interface.
Hornresp is still actively supported. A bit harder to grasp at first look.
There is someone who folded a TABAQ for their centre channel, so it might worth looking into that.
BSC is a matter of taste, but if the speakers are mounted or placed on the wall, it often doesn't need one.
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Homework! I'll be reading for the next couple days, thanks @planet10 & @perceval for the references.
@onni - the objective is to keep all emitting elements away from the desktop and the rear wall to avoid peaks & nulls from reflections; I figured TL terminus and driver toward top of front baffle was optimal, but as I read through the design literature, I may find that there are other compromises to consider. Your lower drawing looks like it does exactly that.
@onni - the objective is to keep all emitting elements away from the desktop and the rear wall to avoid peaks & nulls from reflections; I figured TL terminus and driver toward top of front baffle was optimal, but as I read through the design literature, I may find that there are other compromises to consider. Your lower drawing looks like it does exactly that.
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