Is baffle step loss phaseless?

[EC8010]

Because if it is, then using an electrical equaliser (LR, CR, etc) will correct the amplitude response but upset the phase response. My gut feeling is that baffle step loss is phaseless (just like aperture effect), but is there an acoustics whizz out there who can give a definitive answer?

[MJK]

No, baffle step loss is not phaseless. Adding a filter improves both the magnitude and phase associated with a baffle step loss. If you look under the General Speaker Related Articles link on my site, and look at the baffle step calculation document you will see both the magnitude and phase plots for a square baffle sample problem.

Hope that helps,

[soongsc]

Baffle diffraction caused by baffle step is best solved by the baffle itself. This is because it is acoustically generated wave mixed into the original signal like a mixer. If you mix two signals together electrically, there is no way you can unmix it to create the two original signals. Same with acoustic waves. You may be able to correct it so that it looks good in the FR, but may not sound correct, just different.

[EC8010]

Originally posted by MJK
If you look under the General Speaker Related Articles link on my site, and look at the baffle step calculation document you will see both the magnitude and phase plots for a square baffle sample problem.

Should have looked there first... Thanks for that.

soongsc: I'm hoping to minimize baffle step loss in the first place...

[MJK]

I think the original question was about baffle step and not baffle defraction. I agree with your statements about baffle defraction but I don't know how to solve baffle step without a very large baffle or a filter of some form (either stand alone or as part of the crossover). I tend to look at baffle step and baffle defraction separately.

[EC8010]

I hadn't got to the stage of considering whether diffraction at the edges was phaseless. To minimise baffle step, I plan to make the loudspeakers as thin front to back as possible, have quite a large frontal area, slope the sides at a 45 degree angle, and hang them directly on the wall.

[MJK]

Sounds like a plan. The only potential down side might be the excitation of room modes.

[EC8010]

Originally posted by MJK
The only potential down side might be the excitation of room modes.

I'm constrained by WAF and not even sure that this plan will gain approval, so room nodes are the least of my worries...

[SY]

To minimise baffle step, I plan to make the loudspeakers as thin front to back as possible

Beware the dread bounceback, especially if you have a light cone. I had a terrible time straightening out the response of an early attempt at an MTM until it hit me that the interference dip corresponded very well to the distance front-to-back of the cabinet.

BTW, a useful way to look at the diffraction dip is to analogize it to a filter made by mixing a direct signal with a time delayed one.

[EC8010]

Originally posted by SY
Beware the dread bounceback, especially if you have a light cone.

I don't plan to make it easy for myself - it will be a light paper cone. Some diffusors around the back of the magnet may be in order.

BTW, a useful way to look at the diffraction dip is to analogize it to a filter made by mixing a direct signal with a time delayed one.

Good thought. That makes it easy to conceptualize.