Heresy or....

[PunkSweeper]

This requires synergism between the driver selection, crossover components and topology, crossover points...
Dave

See Pete!? See!!!??? I'm not crazy! HAHA! All Al!


WAAAAAHAHAHAAAAAA!!!!

[brianpowers27]

The frequencies covered by the tweeter are localized higher by the hearing system.

Sorry, 15 hour day, too bagged to to cite exact HRTF details.

Understood regarding the localization of high frequencies. What is unclear to me is how an upside down speaker would lend itself to image stability.

[JRT]

This topic of woofer/tweeter overlap effects also facinates me. We tend to hear height based on spectral notches, caused by the pinnae. A single tone played over a speaker in front of you will (unless swamped by the room) fluctuate in apparent height as the tone is swept. From my analysis, the tone's position is most stable if the tweeter is located under the woofer.

Why?

The frequencies covered by the tweeter are localized higher by the hearing system.

Understood regarding the localization of high frequencies. What is unclear to me is how an upside down speaker would lend itself to image stability.

Brian...

HRTFs cause some of those higher frequencies to be perceived having more altitude in the sound field than is really the case. If the midrange is placed above the tweeter, then that image altitude shift in perception causes the midrange and tweeter to be perceived as being more nearly co-located, as some tweeter radiation is perceived as shifting higher (image altitude) toward the midrange. If the tweeter is placed above the midrange, then the same HRTF would cause them to be perceived as being more widely separated, as some tweeter radiation is perceived as shifting higher (image altitude) away from the midrange.

Its more an issue with wider driver spacings and nearer listening distances. A smaller CTC spread between the tweeter and a smaller midrange combined with listening at least several meters distant should pretty much remove that particular problem from consideration.


Sorry if the above was already clear, and maybe you were asking something else?






.

[DDF]

Brian...

HRTFs cause some of those higher frequencies to be perceived having more altitude in the sound field than is really the case. If the midrange is placed above the tweeter, then that image altitude shift in perception causes the midrange and tweeter to be perceived as being more nearly co-located, as some tweeter radiation is perceived as shifting higher (image altitude) toward the midrange. If the tweeter is placed above the midrange, then the same HRTF would cause them to be perceived as being more widely separated, as some tweeter radiation is perceived as shifting higher (image altitude) away from the midrange.

Its more an issue with wider driver spacings and nearer listening distances. A smaller CTC spread between the tweeter and a smaller midrange combined with listening at least several meters distant should pretty much remove that particular problem from consideration.


Sorry if the above was already clear, and maybe you were asking something else?






.

That's what I was saying.

[brianpowers27]

Brian...

HRTFs cause some of those higher frequencies to be perceived having more altitude in the sound field than is really the case. If the midrange is placed above the tweeter, then that image altitude shift in perception causes the midrange and tweeter to be perceived as being more nearly co-located, as some tweeter radiation is perceived as shifting higher (image altitude) toward the midrange. If the tweeter is placed above the midrange, then the same HRTF would cause them to be perceived as being more widely separated, as some tweeter radiation is perceived as shifting higher (image altitude) away from the midrange.

2 things.

1.What does HRTF stand for?
2. Wouldn't an upside down speaker still have the same associated image wander but now instead of the image moving up, it would move down.

[Deward Hastings]

1.What does HRTF stand for?

http://en.wikipedia.org/wiki/Head-re...nsfer_function

[romanbednarek]

2 things.

1.What does HRTF stand for?
2. Wouldn't an upside down speaker still have the same associated image wander but now instead of the image moving up, it would move down.

Most speakers which place the tweeter below the woofer choose to use the woofer as the design axis which should be placed at ear height in order for the best phase integration between the tweeter and the woofer in the crossover region. Hence, if the tweeter image is shifted upwards it may coincide with the woofer axis better due to the HRTF properties (Head Related Transfer Function).

This may be part of the reason why I found the imaging to be so good with my Proteus jr. speakers which are a 2.5 way MTM design with the primary midbass driver above the tweeter (but there are other factors involved with this design including very shallow crossover slopes due to the use of a 1st order series network as well as time aligned drivers required for this type of crossover to achieve the proper phase integration between the tweeter and primary midbass). See pic below for reference...