phase linear 400

[gene french]

my speakers with white noise .... the other graph was a 20 to 20k sweep....
with polarity of midrange reversed....i think it looks good....
that app generated the numbers....i imported into excel to graph it...
name deciphers as whitenoise flat midrange reversed....

 

[gene french]

xsim representation of the electrical properties of the crossover components....in a perfect world the audio would be the same....

i did a lot of reading and youtube watchin....lol
i did all of this in the mid 70s....i figured a lot would have changed....i was surprised....
it really has not....basics are basics...
the big thing i noticed was the drivers are much more effecient....than they used to be....
the designs have not changed much....
i want to hear a set of voight pipes....
they have always fascinated me...
lol....

 

[gene french]

the frd files were available on the parts express website on the drivers i bought....one reason i went with parts express and dayton audio....
that is my speakers with the components i selected for the xover...you can see the crossover at 500 and 4500.....
plenty of documentation.....the youtube diyers all preached about both of those....i agree....

 

[Gepetto]

my speakers with white noise .... the other graph was a 20 to 20k sweep....
with polarity of midrange reversed....i think it looks good....
that app generated the numbers....i imported into excel to graph it...
name deciphers as whitenoise flat midrange reversed....

Not sure flipping the phase of the midrange is the right thing to do. It may flatten the curve at the expense of out of phase midrange. Sometimes it isn't all about amplitude. Ideally the voice coil position of all drivers should be in the same plane. It appears in your photo that your midrange voice coil is well proud of where the woofer voice coil is.

Are you sure the polarity markings on your midrange produce the same cone motion that the woofer does?

 

[gene french]

polarity is reversed on the mid...according to what i studied....that is trial and error...we all know what is theoretical...but, what happens in real life is not so cut and dried...
this is the graph with the midrange in normal polarity....refer to the file names...
and the graph with the midrange reversed....
a subtle but visible difference....you can plainly see the dip go away....just as youtube said it would....lol...

 

[gene french]

not sure how much of this my old ears can differenciate...lol
i cant hear 14000 and up....

 

[gene french]

Not sure flipping the phase of the midrange is the right thing to do. It may flatten the curve at the expense of out of phase midrange. Sometimes it isn't all about amplitude. Ideally the voice coil position of all drivers should be in the same plane. It appears in your photo that your midrange voice coil is well proud of where the woofer voice coil is.

Are you sure the polarity markings on your midrange produce the same cone motion that the woofer does?

maybe when i get the wopl installed i can revisit these.....that is why i put the xovers outside the box...
but, as i remember i could not hear the difference....and probably did not understand what i was supposed to hear and not hear...

 

[gene french]

btw....the 400 put out a full 10 hours today....it sounds nice...or at least it does to me...lol
maria liked it too...
we hit it hard at times...up to 110db....but not more than an hour at a time...so we dont lose our sanity....
that is loud...

 

[gene french]

maybe when i get the wopl installed i can revisit these.....that is why i put the xovers outside the box...
but, as i remember i could not hear the difference....and probably did not understand what i was supposed to hear and not hear...

sure seems to me that this is a graph of the sound pressure waves hitting the mike....not sure about the rest...
i sure would like to learn more...

 

[gene french]

Not sure flipping the phase of the midrange is the right thing to do. It may flatten the curve at the expense of out of phase midrange. Sometimes it isn't all about amplitude. Ideally the voice coil position of all drivers should be in the same plane. It appears in your photo that your midrange voice coil is well proud of where the woofer voice coil is.

Are you sure the polarity markings on your midrange produce the same cone motion that the woofer does?

no, i am not...did not check....still have plenty to learn...

 

[gene french]

if i remember....we used a aa battery to check push/pull....on unmarked speakers...
if the pluses matched it pushed the cone out...
if no matched the cone pulled in....
all of these were marked....and i assumed they were correct....
i dont know enough to know otherwise...

 

[gene french]

white noise graphs....

 

[Gepetto]

not sure how much of this my old ears can differenciate...lol
i cant hear 14000 and up....

Your dip is at 550 Hz, right in the peak hearing range...

 

[gene french]

Your dip is at 550 Hz, right in the peak hearing range...

if you are talking about the last two graphs .... the dip is why i reversed the polarity....on the mid...
if i am understand you correctly....
left graph is normal polarity all speakers...
right graph is polarity reversed on mid...
is that wrong thing to do??

 

[Gepetto]

if you are talking about the last two graphs .... the dip is why i reversed the polarity....on the mid...
if i am understand you correctly....
left graph is normal polarity all speakers...
right graph is polarity reversed on mid...
is that wrong thing to do??

The graphs in 1745

 

[gene french]

same story....the graph on the left is with all 3 speakers in normal polarity according to the markings on the speaker...
the graph on the right is with woofer and tweeter in normal polarity with midrange reversed....
same test 20 to 20k sweep...both graphs....when i reversed the midrange....the dip picked up...

seems like that is what one would want to do????

 

[Gepetto]

same story....the graph on the left is with all 3 speakers in normal polarity according to the markings on the speaker...
the graph on the right is with woofer and tweeter in normal polarity with midrange reversed....
same test 20 to 20k sweep...both graphs....when i reversed the midrange....the dip picked up...

seems like that is what one would want to do????

Not without considering the phase impact...

 

[gene french]

Not without considering the phase impact...

ok....how do i consider the phase impact??
by ear??
by another measurement??
teach me...

 

[gene french]

when speakers are out of phase they tend to cancel each other and .the closer to 180 degrees they are the more silent they become....
as carver did with his infamous challenge....
seems the canceling was in the first graph and when phase was changed the dip or cancelling was less....thus the increase in amplitude????

 

[J!m]

Usually set drivers further back as they increase in frequency. So they arrive at your ear roughly the same time.

One reason for the massively complex crossovers in Jim Thiel’s designs. Getting phase and time coherent- CS stood for “coherent source”. Jim Vandersteen is good at it as well… probably others I do t know of too…