I also have the thin wire tweak on it.
This might be the finished build because what finally would be the difference of redoing in upscale materials? I'm not showing it off to anyone in particular. The only change would be to go tot the 48" length-- a bigger elephant.
The flutter is heard at the vent end like something is cycling-- maybe 60 cycles-- I don't know that much about electricity.
Yeah the MLTL is flanked by some bins that hold my socks and whatnot in lieu of owning a dresser. I got the idea from seeing displays in stores.
The seal with foam used at top and bottom does not seem to undicate any leakage.
I dropped the ball on finding any 3/4 felt locally. The stores that are open don't have and the other ones are by appointment to sell a houseful of carpet. The final stuff used is a more dense fiberfill pad than the gauzy type.
Working with the router for the first time was a good experience.
Right now the MLTL 167e build is connected to a boom box and playing one FM classical music station. I'm amazed at what this setup accomplishes. I did it to get access to another setup with a cd player. But the cd player has since failed. The output is given at 3 watts per channel in the manual.
This might be the finished build because what finally would be the difference of redoing in upscale materials? I'm not showing it off to anyone in particular. The only change would be to go tot the 48" length-- a bigger elephant.
The flutter is heard at the vent end like something is cycling-- maybe 60 cycles-- I don't know that much about electricity.
Yeah the MLTL is flanked by some bins that hold my socks and whatnot in lieu of owning a dresser. I got the idea from seeing displays in stores.
The seal with foam used at top and bottom does not seem to undicate any leakage.
I dropped the ball on finding any 3/4 felt locally. The stores that are open don't have and the other ones are by appointment to sell a houseful of carpet. The final stuff used is a more dense fiberfill pad than the gauzy type.
Working with the router for the first time was a good experience.
Right now the MLTL 167e build is connected to a boom box and playing one FM classical music station. I'm amazed at what this setup accomplishes. I did it to get access to another setup with a cd player. But the cd player has since failed. The output is given at 3 watts per channel in the manual.
bARTaudio said:
The knowledgeable builders here like Bob Brines place the port in the
the front in the traditional manner.
In some instances a port is placed out the bottom because of it's length-- example would be the suggested Fostex build for the FE167e.
Also there was one designed by GM which has a bottom port placement because it is 6 in long in a triangular design for the Jordan 92s.
I chose the bottom firing position because... well because of an unresolved question about how the port radiates sound. No one has confirmed for me that the port produces it's action on the terminus.
For this design the terminus action would radiate toward the ear rather than parallel to the baffle. Since there is no absolute answer to this and because I've used it in the GM design for the FE127 shown at zillaspeak, I've continued with the technique in this current MLTL build.
It's not scientific, just a preference at this point.
Perhaps Greg (GM) will come in here give additional details. It's his design based on the Mathcad worksheets from Martin King.
listening continues
Not many posts on this lately because listening continues to my satisfaction.
I have found no improvements to my ears that are needed.
Still, as the above question asks, the port maybe could be in a more convenient position for moving and adjusting the speaker with or without a stand to bring it up a bit.
If, as someone said, the port radiates at the plane of the terminus then it could be moved to the side-- (inside panel on a stereo pair.}
I've just sort of left it alone til now but would be interested in others trying this build.
Phase plugs and Enabl still beckon but I haven't taken that plunge.
Not many posts on this lately because listening continues to my satisfaction.
I have found no improvements to my ears that are needed.
Still, as the above question asks, the port maybe could be in a more convenient position for moving and adjusting the speaker with or without a stand to bring it up a bit.
If, as someone said, the port radiates at the plane of the terminus then it could be moved to the side-- (inside panel on a stereo pair.}
I've just sort of left it alone til now but would be interested in others trying this build.
Phase plugs and Enabl still beckon but I haven't taken that plunge.
loninappleton said:
??? Don't remember anything being unresolved WRT vent location. Normally a bottom firing vent is used to both use the floor to load it and either place an absorber or set it above a carpeted floor to damp any unwanted mids/HF vent output, ie. not a good plan for a hard reflective floor if the vent's not internally damped.
Visualize an incredibly thin membrane covering the vent which acts as a small, high excursion vibrating piston, i.e. a separate narrow BW baffle mounted driver. From this we see that ideally it should be right up against the main driver and indeed, this was the way all BR cabs were originally designed in a variety of layouts from a simple slot to multiple tubes positioned around its perimeter regardless of the cab's aspect ratio.
We now know that in high aspect ratio cabs it's not the best overall performing layout and the pioneers of audio probably did too, but their main concern was acoustic efficiency above all else WRT bass/mid-bass design. By 1950 though, there was enough power and other advances to allow better overall performing cab layouts, though most of the established manufacturers continued to trod down the familiar path until the 'Johnny-come-latelys' started affecting their bottom line.
GM
GM your replies are always appreciated. Given that this build is raised and that the the down firing port has a lot of free air with boundaries
about 12 in down and equal on the sides this may indeed be the best of all possible worlds. A 'from scratch build' should then include the proper height as well as the down firing port and what sort of wave guide to best direct the port?
In an earlier experiment I was unhappy with an angled baffle at the port end similar to the design for the Jordan 92s. That had a 45d angle plus the 90d angle side boundaries.
The question above by bartAudio compares this approach with the more conventional placement by Bob Brines.
Maybe there is no absolute here. The result of this build is pleasing and thank you for taking the time on it.
It is so pleasing I am twiddling trying to think of anything that might be a fresh project.
I still have those Roland piano 8 inchers with whizzers. Lots of talk of open Baffle of late. I have a good place for an OB but do not want to take down and sacrifice a BIB.
about 12 in down and equal on the sides this may indeed be the best of all possible worlds. A 'from scratch build' should then include the proper height as well as the down firing port and what sort of wave guide to best direct the port?
In an earlier experiment I was unhappy with an angled baffle at the port end similar to the design for the Jordan 92s. That had a 45d angle plus the 90d angle side boundaries.
The question above by bartAudio compares this approach with the more conventional placement by Bob Brines.
Maybe there is no absolute here. The result of this build is pleasing and thank you for taking the time on it.
It is so pleasing I am twiddling trying to think of anything that might be a fresh project.
I still have those Roland piano 8 inchers with whizzers. Lots of talk of open Baffle of late. I have a good place for an OB but do not want to take down and sacrifice a BIB.
Full disclosure: I think GM had this one originally at 4 ft tall. I used some 3 ft edge glued shelving to make the sides and particle board front and back on a total length of 3 ft. This was a compromise design for the FE167e but I think it might have gotten honky at 4 ft tall or more. Those details are higher up in the thread.
These are box variations. More experimentation may reveal other enhancements.
These are box variations. More experimentation may reveal other enhancements.
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