I recently built two subwoofers. The first is a 1/4 wave TL with Fs = 34 Hz, the second needed to be fairly small, so it's a sealed woofer with a lot of stuffing. These aren't expensive or anything, but here are my thoughts.
The 1/4 wave TL does create earth-shaking bass, but it's really not well-defined bass. The sealed sub also thunders, probably not quite as low or as efficiently, but the quality of the bass is so much better.
Interestingly, it's what I always thought of TL speakers - definitely excellent bass extension, but not crisp. My guess is this is why a low Qts is more suitable in a TL.
I will need to do some direct and extended comparisons next.
The 1/4 wave TL does create earth-shaking bass, but it's really not well-defined bass. The sealed sub also thunders, probably not quite as low or as efficiently, but the quality of the bass is so much better.
Interestingly, it's what I always thought of TL speakers - definitely excellent bass extension, but not crisp. My guess is this is why a low Qts is more suitable in a TL.
I will need to do some direct and extended comparisons next.
Actually, it is opposite - with high Qts drivers the only way to go is TL (and open baffle, of course).
As planet10 pointed out, TL must be carefully designed.
Hi,
Another question would be how many subs are you running in this assembly? Timing and all that in terms of summation. If one sub, moot point. If several subs, it starts to matter more.
Otherwise, what do you want out of this next sub? How big can you go? Is it for movies or music? How low do you want it to go and at what SPL?
Very best,
Another question would be how many subs are you running in this assembly? Timing and all that in terms of summation. If one sub, moot point. If several subs, it starts to matter more.
Otherwise, what do you want out of this next sub? How big can you go? Is it for movies or music? How low do you want it to go and at what SPL?
Very best,
I did a lot of reading and theory research, and then I simulated a few speakers with different designs to see how parameters and designs affect the response. It came out quite well - definitely gets a lot more out of the driver than other enclosures, but it's not tight. The same driver in a very small (for the Q) sealed box doesn't go as low or loud, but it does have more clarity, if I can put it that way. In the TL it's almost as if any note lights up that resonance, so you don't hear separate notes clearly. It does make tons of bass though.
Note that I don't have specs for the driver, so I had to measure what I can and make some assumptions.
It's just a single sub.
Note that I don't have specs for the driver, so I had to measure what I can and make some assumptions.
It's just a single sub.
The short compact TL and TLonkens I've made (by inserting dividers into single-slot Onken to lengthen the line) all have tight, exact-pitch bass -- of course cab resonance has to be eliminated first, using the boards as bracing.
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Maybe that's what I'm experiencing - the notches. What I've also notice is that the room kills bass and there is a different response at different locations, but I think that's solely room response.
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Yes, the room is a big thing and cant be readily ignored.
I'd also suggest you check for cabinet resonance, that's one way the bass can seem to be drawn into one frequency.
I'd also suggest you check for cabinet resonance, that's one way the bass can seem to be drawn into one frequency.
This didn't seem to 'ring' true, but never having compared the two, used an extreme example of an old Altec 12" = 26.6 Hz/296.81 L/0.2 Qts:
0.707 Qtc = 25.82 L 94 Hz Fc
TL absolute min. to fit driver = 47.2 L, but the high tuning Vs Fs was too great to get enough pipe length to get a similar roll-off, i.e. ~800 Hz Vs 200 Hz and to get the TL to same-same it required a 'fatter' pipe = 154.9 L, yet didn't perform nearly as well WRT group delay below the sealed's 100 Hz roll-off, so not a good plan to compare 'apples to apples' re Fc Vs Fp (at least 'stuffed' according to Hornresp).
