I’m guilty of the former. My experience with sealed subs has been considerably better than with ported...but then again, I’ve only tried a few different ported subs.
All the ported subs I've heard I didn't like except for one. So I can conclude that the ported subs I've heard weren't done properly. The only ported sub I actually liked was an 8" slot ported that was part of a Klipsch iPod speaker system I had maybe 10 years ago.
Also drivel that preamp out is always better.
Agreed.
While I prefer preamp out with a two way active 24 dB/octave active crossover, I've had good results at work using the high level inputs of a sub fed from the speaker output of an amplifier and adding a capacitor in each speaker to form a proper high pass at the desired crossover frequency of the sub.
I've tried both in a 2 channel system and hands down line level is superior in every instance. My high end sub doesn't even offer high level inputs. It's an inferior connection and at it's price point it was assumed only separates would be used and high level connections that most receivers etc would require weren't needed.
I have both ported and sealed servo controlled, and agree on the servo being superior with "music".
One thing not mentioned is phase shift which determines how well a particular subwoofer connection sounds. An amplifier or preamp may be flat to 20 or below 20Hz, but still have phase shift of the lower frequencies.
I discovered all about phase shift when I was working on a mono system consisting of a radio driving a full range plate amp driving a speaker with four woofers one midrange and one tweeter.
When I replaced certain coupling caps in the plate amp with higher values (initially done to provide flat bass response to 20Hz) I noticed the bass sounded better so I proceeded to replace all the coupling caps in the amp with large enough values such that there is virtually no phase shift at 20Hz as shown on an oscilloscope and the bass sounded even better.
A subwoofer that has the high level inputs connected to the speaker outputs of an amplifier may not sound good if the amplifier has any phase shift at all in the bass.
That may explain why line level sounded better for you as the amp you may have used to drive the high level inputs and main speakers may have had some phase shift, whereas the line level output may have had no or much less phase shift.
Checking for phase shift requires a dual channel oscilloscope and an audio generator capable of going down to 20Hz.
Any and all tone controls are set to flat or bypassed with all processing turned off as that can affect the results.
One channel connects to the audio generator which also goes to the input of the device under test.
The other channel connects to the output.
The generator is set for a higher frequency (I prefer 400Hz for full range amps) and the output of the generator set to a decent level with the device under test set to a decent output level and the volts/div controls on the scope are set so that both waveforms are equal in amplitude.
One waveform is placed directly on top of the other and the frequency is lowered down to the lowest frequency the amp is expected to reproduce. If there is any phase shift at all one waveform will start to lead the other.
Then if there is phase shift, check the signal at each coupling capacitor in the device until you find the one causing the phase shift. Odds are it is multiple coupling caps and if so at each stage working from the output to the input the phase shift should be smaller.
You then select a coupling cap value that completely eliminates all phase shift. An easy value to start with is double the existing capacitor value.
For amplifiers which capacitor couple the amp to the speaker jacks, it isn't practical to try to totally eliminate the phase shift as the capacitor would need to be high enough to where the resultant charge current may ruin the speakers, output transistors, blow the protection fuses or at minimum cause a very loud pop. In that instance the scope connects before the speaker coupling cap and the test is done as specified to eliminate all phase shift before the speaker coupling cap. Now the speaker coupling cap can be increased in value if so desired up to perhaps 4700uF without any problems, but I haven't tried anything larger than that.
All the facts point towards Yes.
.
