Hi efficient speaker, bass problems

"Duke, we have all read that bass is omni-directional, and yet very often it's very easy hear where the sub-woofer is (perhaps it's because the overtones appear to come elsewhere?)." - Unsound

"Bass localization is detectable indoors" - Weseixas

Hearing the location of a subwoofer is not necessarily the same thing as hearing the direction that low frequencies are coming from. Subs can be generating harmonic distortion that is more audible than the actual fundamental, and they can be passing lower midrange energy at a level that is still audible. We easily hear where a bass instrument is in the soundstage from the overtones and other higher frequency sounds (drumskin).

"Despite the theories, some of us clearly prefer the sound of sealed boxes over ported ones. As the old cliche' goes; "the proof of the pudding is in the eating"." - Unsound

If you re-read my theory, it is consistent with your observation.

"...get the math wrong and you will know, phase is absolutely critical." - Weseixas

Phase is audible in the bass region only to the extent that it impacts frequency response. So when you hear a difference after adjusting the relative phase of your subs, or their distance relative to the mains, what you are hearing is the effect on the frequency response.

Duke

Hello Unsound ,

Are you talking acoustic or time , the rise time on a sealed cabinet is slower than that of a reflex, compare the square wave response.

Now if running tubes, subjectively there is some argument, tubes have poor damping and hence very little bass control to speak off , a sealed enclosure might be an advantage here, TL too , due to the loading.

regards,

Phase is audible in the bass region only to the extent that it impacts frequency response. So when you hear a difference after adjusting the relative phase of your subs, or their distance relative to the mains, what you are hearing is the effect on the frequency response. - Audiokinesis

Ok Duke ... LOL, Hence Bass localization.

Now if you move the woofer outputs closer to mid ceiling the effect will be minimized to almost nothing.

Bass column-circa 1988

Regards,

My question for you guys is what is having the most affect on our perception? More even pressure front? Or simply better stereo effect?

I have experienced the localization Wes is talking about and at frequencies below 80 Hz, which is where some claim our ability to localize is severely diminished. Adding an additional sub has rectified this issue for many and adding second bass horn did the same for me. And I find both don't need to be driven as hard as a single.

Now if running tubes, subjectively there is some argument, tubes have poor damping and hence very little bass control to speak off , a sealed enclosure might be an advantage here, TL too , due to the loading.

Actually in practice the reverse is true. Vented boxes usually need less damping of the driver for optimal response if I have my theory right- so less damping from the amplifier will be needed. So you can have plety of bass control!

No speaker known requires a damping factor of above 20:1. That can be created by any tube amplifier, given enough feedback. However you pay a price for adding feedback- while you get more damping, you also add odd-ordered harmonic distortion, which essentially is audible as brightness and harshness.

So if you want tubes to give you the best they can offer, its in your best interest to use an amplifier without feedback, and a speaker that is intended for an amplifier with a higher output impedance.

The only thing about this is that loop feedback contributes to harshness in transistor amplifiers too. Since the ear/brain system uses the 5th, 7th and 9th harmonics as a means of determining how loud a sound is, messing with these harmonics will cause the system to sound louder than it really is, plus the odd orders are perceived as harshness. So there is a powerful argument for eliminating feedback altogether, as figuring out how loud a sound is is arguably one of the more important rules of human sound perception.

IOW, the model of an amplifier with an output impedance of zero ohms may not hold water, given other real-world issues. So designing a speaker for that may not make a lot of sense either.