I won't because the terms are not interchangeable, and I strive for accuracy in portrayed or given information.
A series notch has series LC(R) components in it, which are then placed across the driver (in most cases).
A parallel notch has parallel LC(R) components, that are then placed in series with the driver.
This is the way it is, and quite a few builders unknowingly call them the opposite.
A series notch has series LC(R) components in it, which are then placed across the driver (in most cases).
A parallel notch has parallel LC(R) components, that are then placed in series with the driver.
This is the way it is, and quite a few builders unknowingly call them the opposite.
I'm with Wolf here. Forget for the moment we are in the speaker design hobby, and just take a simple electronics perspective on the notch filter. If the components are in series, it's a series notch. If they are in parallel, it's a parallel notch. Any electrician or EE will see it this way. It's only in this hobby where we look at it relative to another unrelated component (the driver) that we get it all backwards.
The parallel notch needs a well behaved driver (compensated impedance and VC inductance) to work well. The series notch forces the voltage drop away from the driver with help of decreased resistance, diverting it onto the series xover filter components. It's less sensitive to changes and drifts in driver impedance.
Moving on from terminology, here's a v2 of the XO.
I looked again at Goran's circuit and found that unlike the Millenium 5", the L15 4ohm doesn't need two shaping circuits; just one series 😉 notch around 8k is enough. This also claws back about 1db for a system SPL of 85db with 1 less part.
I looked again at Goran's circuit and found that unlike the Millenium 5", the L15 4ohm doesn't need two shaping circuits; just one series 😉 notch around 8k is enough. This also claws back about 1db for a system SPL of 85db with 1 less part.
Thank you for the work Way above my head, now should I build it ? BTW I think the drivers are still available
@motokok - did you input a 20mm ~(57usec) Z offset for the L15 in VituixCAD? I can't see one on the driver tab nor on the R1 crossover in the VXP file.
I have a revision with a couple of less parts, but want to check with motokok first
No, Dave - I dunno the ins and outs of offsets, so I'd be interested to see how you might iterate.
Given the phase is all derived rather than measured, is it still good practice? One would enter 20mm (plus) to the tweeter, I presume? Or is it minus to the woofer?
Does the LR2/BW3 filter have an influence?
Given the phase is all derived rather than measured, is it still good practice? One would enter 20mm (plus) to the tweeter, I presume? Or is it minus to the woofer?
Does the LR2/BW3 filter have an influence?
You add the Z offset to the woofer in this case, in the driver tab in the Z area of VituixCAD (then it applies to all crossover revisions where that driver is used).
I also wasn't sure if you were targetting in phase behaviour in the crossover (aka LR acoustic target). When I put the Z in for the L15 (20mm is what I've measured), then the drivers were not in phase.
This version uses Madisound available parts. I'll also post the reverse null. The XO point is around 2100Hz
If you use manufacturer data then using some method to add an offset is the right thing.
Once you add that offset then asymmetrical filtering may become necessary, if that's the method you will use.
Looking at the reverse null is something people do when their simulator doesn't show phase, yet all do. Maybe the reason it became popular.. I noticed many new users to Xsim couldn't work out how to turn on phase for each range.
Yes that's true, but I am used to seeing the FR and symmetry or not of the null. I can read it off the phase data, but not as quickly. Maybe I am too conditioned to old tools.
Very cool, Dave. 👍
Question - how does an LR2-LR2 work on a flat baffle? I thought one must go for asymmetric / tilt the baffle / use an all-pass filter.
Or is the tweeter target 3rd order acoustic with second order electrical?
Can you explain how you designed the XO?
Very neat to notch with just the small cap across the woofer coil.
P.S. I don't see the offset in your project file.
@4KAOss ....I thought you already bought these! OMG.
Yeah, well hell, I'd try Dave's XO in a 180 x 266mm baffle in one of Madisound's suggested vented alignments and box volumes.
Question - how does an LR2-LR2 work on a flat baffle? I thought one must go for asymmetric / tilt the baffle / use an all-pass filter.
Or is the tweeter target 3rd order acoustic with second order electrical?
Can you explain how you designed the XO?
Very neat to notch with just the small cap across the woofer coil.
P.S. I don't see the offset in your project file.
@4KAOss ....I thought you already bought these! OMG.
Yeah, well hell, I'd try Dave's XO in a 180 x 266mm baffle in one of Madisound's suggested vented alignments and box volumes.
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If you go to the driver tab and select the L15, you should see this at the bottom:
The acoustic target here is LR4 - both tweeter and woofer. Both drivers have a phase difference of 360 degrees, so this means they remain with the same wired polarity. You are correct, in that if an LR2 acoustic target was chosen, then the drivers would be 180 degree out of phase through the crossover region, requiring polarity for one driver to be inverted to bring back into phase (and this would assume there is a slanted / stepped baffle with a zero offset on both drivers - that is they are time / acoustically aligned).
Fair enough, do it if it helps.
There are two reasons it has no meaning from where I sit. First, if both slopes are at different rates (one is steeper) but they cross at the crossover frequency, you'll still get a null. Second, I don't necessarily like to line up phase, but may have a shift between them.
There are two reasons it has no meaning from where I sit. First, if both slopes are at different rates (one is steeper) but they cross at the crossover frequency, you'll still get a null. Second, I don't necessarily like to line up phase, but may have a shift between them.
