My model of the tapered line was for its simplest form, a continuous line without folds, because that was the quickest modeling I could do. When a line is folded, one needs to model how the line's area actually changes as it goes around corners, turning right or left or through U-turns. So, to be absolutely accurate, it would have to be modeled exactly how you'd want to build it, with presumably one U-turn and one right angle turn, and might need some tweaking in line length and/or tapering in order to end up with the results as my modeling predicted.
Paul
Paul
Thanks a lot for taking your time to design that cab, Pkitt!
I have a question though. Would it affect the performance if I was to fold the line 90 degrees near the open end, to make the "port" face forward above the woofer?
Oops ok, *takes it back* hadnt read the whole thread. I'd assumed it wd need a crazy size box, plus the qts looked a little lowAssuming the woofer's specs posted by the OP are reasonably representative, I used them and the predicted performance of the TL I modeled looks quite good to me.
Paul
I am lurking in the background, reading and thinking. I am about to adventure into designing and building TL loudspeakers myself, but as someone stated earlier, the art of listening is somewhat lost with all the calculations. Calculations are useful yes, but I am advocating more listening and measurements after the cabinet is built. The TL is only part of a whole build. The shape of the cabinet is equally as important. Take baffle diffraction as an example and the material used on the front, both will dictate the overall sound emanating from the drivers / cabinet.
Anyway, here is another older debate that might be interesting for the OP to check out. An Improved Transmission Line Alignment.
Anyway, here is another older debate that might be interesting for the OP to check out. An Improved Transmission Line Alignment.
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Indeed. not new but very useful information.That was Patrick, discovering that offset drivers can be used to almost kill the 1st unwanted harmonic — something that has been known long before he made that post. So improved yes, new not.
dave
Short version: for a given pipe, end loading (as in sealed end or throat if you prefer) provides maximum excitation to the fundamental and all its harmonic modes. As you shift the driver along the pipe (change its tap location) you will reduce excitation of different harmonics, which & how much depending on the specific placement. See MKJ's alignment tables for some basic guidelines for driver placement on pipes of various geometries.
Hi Ingborg,All
Here is an attempt to Design a ML-TL Tower (f-3dB=~27Hz) using a Minimum Volume Box that if the Port is closed resembles a Sealed Box with Qtc= ~0.707( f-3dB=~37.5 Hz).
You may object(anyone) to the suggested placement of M and T Driver but if put them above the B Driver, your TV would IMO be elevated to high up if a Central Phantom is expected at dead center of the Screen.
There is more to say of your Room lay-out if using only two Main Speakers.
I will Post later some Simulations showing plausible Room interaction and Spatial Standard Deviation from the B Driver when placed High and low with the respect of the Floor.
b
Here is an attempt to Design a ML-TL Tower (f-3dB=~27Hz) using a Minimum Volume Box that if the Port is closed resembles a Sealed Box with Qtc= ~0.707( f-3dB=~37.5 Hz).
You may object(anyone) to the suggested placement of M and T Driver but if put them above the B Driver, your TV would IMO be elevated to high up if a Central Phantom is expected at dead center of the Screen.
There is more to say of your Room lay-out if using only two Main Speakers.
I will Post later some Simulations showing plausible Room interaction and Spatial Standard Deviation from the B Driver when placed High and low with the respect of the Floor.
b
Attachments
I'm doing my best to decipher all the stuff you posted!
Right now I'm most confused about the stuffing and XO points. 147Hz XO for woofer/mid, right? The 47Hz confuses me. Care to explain the numbers a little, please?
I would love to place the mid and tweet ontop (becouse I love that look) since the TV has its own sound system, and the TLs will only be used for music.
Thank you so much for taking your time to help me out, bjorno!
Right now I'm most confused about the stuffing and XO points. 147Hz XO for woofer/mid, right? The 47Hz confuses me. Care to explain the numbers a little, please?
I would love to place the mid and tweet ontop (becouse I love that look) since the TV has its own sound system, and the TLs will only be used for music.
Thank you so much for taking your time to help me out, bjorno!
Transient response is also not likely any better than vented.
I disagree with the above statement.
I disagree with the above statement.
I tend to agree with you. Given the wide range of possible TL alignments oly the most “ragged” would have transient response like th etypical BR.
dave
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