If the EBP calculator suggests that your woofers can be utilized in both sealed and ported enclosures, in which direction will you go? And what are your reasons for choosing either sealed or ported?
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Depends on your LF extension and SPL goal, but also whether you design a 2 or 3 way system which may have challenges dealing with the lower midrange radiated into the enclosure and port resonances.
With low EBP, a high Fs and Qts woofer would do better in a sealed box due to less alignment choices which end up flatter and still have good transient response with low group delay. Ports end up being too small for target tuning and keeping air velocity low enough with higher tuning frequency.
Low Fs with low EBP would be better for a ported design but that means a considerably larger box, especially with larger woofers that have higher Vas. Tuning frequency ends up being very low as well, which may not be practical as the port needs to be smaller or longer. Again, you have rather limited box alignment / tuning options which work out to have lower ripple and GD.
In a nut shell, I'd steer clear of ported designs with higher Fs / low EBP woofers. The weaker motor will give poor results with the required relatively high box tuning frequency Fb.
With low EBP, a high Fs and Qts woofer would do better in a sealed box due to less alignment choices which end up flatter and still have good transient response with low group delay. Ports end up being too small for target tuning and keeping air velocity low enough with higher tuning frequency.
Low Fs with low EBP would be better for a ported design but that means a considerably larger box, especially with larger woofers that have higher Vas. Tuning frequency ends up being very low as well, which may not be practical as the port needs to be smaller or longer. Again, you have rather limited box alignment / tuning options which work out to have lower ripple and GD.
In a nut shell, I'd steer clear of ported designs with higher Fs / low EBP woofers. The weaker motor will give poor results with the required relatively high box tuning frequency Fb.
Personally I just ignore EBP as it's only a not-very-useful approximation / back-of-fag-packet guide. Decide on your performance goals & let those determine the enclosure type, and the alignment you want to target.
Historical note: EBP essentially dates from a time when few had access to anything other than an electronic calculator; it was there purely to save people time & provide a very quick & dirty way of helping narrow down potential driver choices, rather than needing to manually calculate various fixed alignments (which themselves were mostly taken from electrical filter theory to save time) & even plot out spot-frequencies on graph paper. It doesn't have a whole lot of other meaning / value beyond that.
Historical note: EBP essentially dates from a time when few had access to anything other than an electronic calculator; it was there purely to save people time & provide a very quick & dirty way of helping narrow down potential driver choices, rather than needing to manually calculate various fixed alignments (which themselves were mostly taken from electrical filter theory to save time) & even plot out spot-frequencies on graph paper. It doesn't have a whole lot of other meaning / value beyond that.
If solely based on TSPs I'd consider any woofer for a ported alignment if it had a Qts of between .30 - .45 and Fs wasn't higher than 50 hz.
If Fs is higher than 50 hz, the port output goes too high exciting port resonances and standing waves. It also runs into the lower midrange and ruins midbass transient precision. The interaction with room modes is also much stronger and less predictable.
If Fs is higher than 50 hz, the port output goes too high exciting port resonances and standing waves. It also runs into the lower midrange and ruins midbass transient precision. The interaction with room modes is also much stronger and less predictable.
Of course, I can't argue with what you like or don't like. But remember that the T/S parameters (including Fs) are not fixed values, because they changes with different drive levels. Either way, if there is too much ripple, it can be EQed out at any time, otherwise the room generally has a much greater effect to the sound quality (flatness) than the box alignment used.
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I just asked about a LG sub that came with a ported box and has Fs around 71Hz. Perhaps to keep free air resonance and high impedance far from the port tuning? That's what I see when modeling with it. Even when it has high Qts (around 0.9) it doesn't look good in a closed box. Wondering...