Svante's the EDGE

[Pano]

Got a question for Svante about the filter generator in the Edge. I sent you an email a week or 2 ago, but never heard back. We must have missed each other.

Maybe it's better to ask here?

[Vikash]

don't ask if you can ask, just ask.

[Pano]

Hehehe, OK. Just didn't want to make fool of myself in public.


The Edge software will calculate a passive BSC filter and an active OB low pass shelving filter.
See the active filter below. It's an inverting filter, but the component layout looks more like a non-inverting version to me - but not quite.

Can someone explain?

[soongsc]

Originally posted by panomaniac
Hehehe, OK. Just didn't want to make fool of myself in public.


The Edge software will calculate a passive BSC filter and an active OB low pass shelving filter.
See the active filter below. It's an inverting filter, but the component layout looks more like a non-inverting version to me - but not quite.

Can someone explain?

R2 and C set the higher turning point frequency, R1 and C sets the lower turning point frequency. it is the inverted configuration.

[Pano]

OK, makes sense. The more I look at it, the more sense it makes.

I ran a spice simulation of the filter and am having a hard time getting the low end to shelf. It shelves nicely on the top end, but not the bottom . I'll try some different values to see what happens.

Below is the type of LP shelf filter that Linkwitz has on his site. It simulates well.

Comments?

[Svante]

Originally posted by panomaniac
Got a question for Svante about the filter generator in the Edge. I sent you an email a week or 2 ago, but never heard back. We must have missed each other.

Maybe it's better to ask here?

Sorry, I must have missed that. The lower panel in the compensation designer is intended for open baffles, and using the suggested values, there will be no shelving towards lower frequencies.

One can, however, click on "suggest f1 & f2!" in the upper panel and copy the suggested values for f1 and f2 to the lower panel, this will result in shelving towards lower frequencies.

You can view the response of the circuit by checking "enable" and look for the blue curve in the response window. You do not need to simulate it separately (but it may of course be educating to do it anyway).

Below is a compensation using f1=205 Hz and f2=410 Hz.

[Pano]

Thanks Svante! That works. I understand why you didn't do the shelf in OB. Just thought I was missing something.

Will be trying it out here soon. I'll let you know.

[grantnsw]

Hi Svante, are you still here? I'm a 'newbie' and have a few questions please? I've just tried out 'the Edge' - it looks excellent - thank you! I'll try to be brief...

I'm trying to model a (passive) 3way in Speaker Workshop, but I don't have MS Excel to use most of the 'FRConsortium tools'. Could I assume the Edge suggested RL contour network in series with both the mid and woofer xo's would negate the need to use all that FRC stuff? The tweeter xo would connect directly to the source.

Also, is it possible to define the various driver sizes in the same Edge simulation? I hope all this makes sense. many thanks, grant

[grantnsw]

Hi Panomaniac!
I hope you didn't mind my post here? I was a windsurfer at Kihei many times. grant

[Pano]

No worries Grant!

And I live across the street from where you went windsurfing.