Good write up, but it's on a level that takes a bit of prior experience to fully understand.

To summarize, driver's phase response varies throughout it's bandwidth. Different X.O. slopes exibit different phase responses, and that too varies throughout it's bandwidth.

....I hear and echo....

Hmmmm

 

I thought the discussion talked about the woofers natural roll off causes a phase shift.. minimal at that but when you add "slope" you get a larger phase shift. (Phase shift aside caused by the electrical function of the crossover.)
Can you hear it?.. [img]graemlins/dunno.gif[/img]

Still tying to understand it myself..

Imo, That artical should be the foundation for passive filter design. A great Introduction to driver phase shifting

 

Yes it is audible. Bag End built a Bass processor that counter acts this phenomenon call the ELF-1. I had one in my car for some testing about a month ago.

www.bagend.com/bagend/elf-1.htm

[ April 24, 2004, 09:24 AM: Message edited by: PEI330Ci ]

 

I can understand a phase shift, but i can't grasp how it affects the sound from my speakers. The hole in the sound stage experianced when you swap the +/- is over the full range of the driver. How does a phase shift over a smaller bandwidth affect your stage if both the left and right channels are reproducing th same signale with the same phase shift?


How did the ELF-1 Processor affect the sound, and if, how did it improve it?

 

mister steve,

Very good questions!

I'll start with the easy stuff. The ELF-1 Processor corrects for the average phase response of most subwoofers. How does it sound? Well, at any volume the bass sounds full and well reproduced. This processor doesn't work magic, but it does help you run drivers in very small enclosures and get good bass response at all volume levels. The biggest difference I found was at very low listening levels, I could actually hear the bass. Where as when you turn the volume down normally, the bass disappears. This unit was designed for pro-sound applications where people run 15s or 18s in TINY boxes and want a low F3. The retail on the ELF-1 was about $4000 canadian, and they pretty much went for that. The model has be discontinued though.

Phase shift over the frequency range of a driver will affect how REAL it sounds. What is affected the most are harmonics. Harmonics are a big part of music, they are caused when accoustical energys interact with each other. Having one frequency delayed in relation to another will affect the harmonics that are created when the 2 frequencies are played together.

Your brain can tell the difference, and it says "that doesn't sound right" to your ego which says to your wallet, "damn that's a waist of money!"


It's happened to me many times, I can tell you....the wallet hates hearing from the Ego.

Adam

[ April 29, 2004, 01:57 AM: Message edited by: PEI330Ci ]

 

What happens when the wallet goes on strike?

can an extra set of tweeters help or hurt the harmonic.

And
Does slope (weather digital or analog) hurt harmonics?


Dont mean to hijack...

 

I am not a theory guru.

My comment on harmonics is right on the outer boundary of my knowledge. Throwing a tricky question at me won't get a good answer, but I'll try.

The wallet: Same as women, it stops talking to you and won't put out.

Second set of tweeters: Same as women; if 2 "speakers" are talking to you at the same time, it will confuse you unless they are saying exactly the same thing simultaniously.


Slope: Same as women: the steeper the slope, (learning curve) the less each "speaker" hurts each other's HARMONY.

...man I'm bad...

Adam

 

When I strum a cord on my guitar the strings are hit by the pick at different times, the chances of them being in phase are very unlikely, but it still sounds like I am playing a real guitar.

 

The difference in phase consistently deffines how a guitar sounds. Reproducing that sound in stereo is what I am refering to, NOT mono.

 

ok