weiss

Maselec MTC elliptical filter
« on: February 28, 2019, 12:42:27 PM »
I am asking myself what kind of filter would come closest to the one used in the maselec mastering transfer consoles.
Does anyone know what exact type of filter is used there?
I want to cut lows in the side signal, but the bx_control plugin (although very customizable) only allows me to cut the whole signal so i am trying to find something equal.


abbey road d enfer

Re: Maselec MTC elliptical filter
« Reply #1 on: February 28, 2019, 07:52:13 PM »
I am asking myself what kind of filter would come closest to the one used in the maselec mastering transfer consoles.
Does anyone know what exact type of filter is used there?
I want to cut lows in the side signal, but the bx_control plugin (although very customizable) only allows me to cut the whole signal so i am trying to find something equal.
An elliptic filter is deceively simple.
The graph is the side response to out-of-phase signals according to the various positions of the potentiometer.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

Gold

Re: Maselec MTC elliptical filter
« Reply #2 on: February 28, 2019, 08:36:58 PM »
Wayne Kirkwood has an EE PCB that is a pretty unique design.

I had some boards made up for the Neumann EE77 circuit. I don’t have any boards available but I have a unit made up that’s for sale.

I also have  extra cards for the older EE66 version. That uses an LC for the crossover instead of a RC used in the EE77.

weiss

Re: Maselec MTC elliptical filter
« Reply #3 on: March 01, 2019, 02:58:43 AM »
An elliptic filter is deceively simple.
The graph is the side response to out-of-phase signals according to the various positions of the potentiometer.

thank you very much!
So that’s actually a 6db/oct filter in the sides, am I right?


Wayne Kirkwood has an EE PCB that is a pretty unique design.

I had some boards made up for the Neumann EE77 circuit. I don’t have any boards available but I have a unit made up that’s for sale.

I also have  extra cards for the older EE66 version. That uses an LC for the crossover instead of a RC used in the EE77.

Oh yes, now i found it! Didn’t  know he offered that as well.

What does your unit look like? Maybe i‘m interested.

abbey road d enfer

Re: Maselec MTC elliptical filter
« Reply #4 on: March 01, 2019, 03:18:58 AM »
thank you very much!
So that’s actually a 6db/oct filter in the sides, am I right?
The nice thing is it does it only if the input signals phase prompt it, and the Mid signal is correlatively compensated.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

weiss

Re: Maselec MTC elliptical filter
« Reply #5 on: March 01, 2019, 05:24:18 AM »
The nice thing is it does it only if the input signals phase prompt it, and the Mid signal is correlatively compensated.

Oh that's indeed nice!
I bought an M/S matrix and harrison ford filters from don to make a Filtering/M-S Routing unit for mastering, it would be great to include an elliptical filter there as well.

abbey road d enfer

Re: Maselec MTC elliptical filter
« Reply #6 on: March 01, 2019, 05:43:15 AM »
Oh that's indeed nice!
I bought an M/S matrix and harrison ford filters from don to make a Filtering/M-S Routing unit for mastering, it would be great to include an elliptical filter there as well.
Realizing an elliptical filter just takes introducing a high-pass filter in the S path.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

weiss

Re: Maselec MTC elliptical filter
« Reply #7 on: March 01, 2019, 10:47:15 AM »
how can i be so dumb..  ::) ::) ::)
yeah. i'm just gonna put the second filter in the sides. i always thought i'd first cut and then encode but that way it makes much more sense.

SKJGProject

Re: Maselec MTC elliptical filter
« Reply #8 on: March 02, 2019, 12:45:07 PM »
Isn’t the mono maker in bx control doing exactly this?
I used to date a blind girl. Her name was ::… ..:.: .:::. .::.. ….: .:.::

abbey road d enfer

Re: Maselec MTC elliptical filter
« Reply #9 on: March 02, 2019, 01:06:29 PM »
Isn’t the mono maker in bx control doing exactly this?
Is it mono-ing only low frequencies?
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.


Gold

Re: Maselec MTC elliptical filter
« Reply #10 on: March 02, 2019, 01:56:17 PM »
None of the dedicated analog EE's  do an M/S encode decode. They use a crossover. It's mathematically the same as a 6dB/oct HPF on the S channel but not sonically.

abbey road d enfer

Re: Maselec MTC elliptical filter
« Reply #11 on: March 02, 2019, 02:41:37 PM »
None of the dedicated analog EE's  do an M/S encode decode. They use a crossover. It's mathematically the same as a 6dB/oct HPF on the S channel but not sonically.
Care to describe the method? What type of cross-over? If the order of the x-over is higher than 1st, it can't be "mathematically the same as a 6dB/oct HPF". To my knowledge, most hardware x-overs are at least 2nd order.
« Last Edit: March 02, 2019, 02:45:39 PM by abbey road d enfer »
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

weiss

Re: Maselec MTC elliptical filter
« Reply #12 on: March 02, 2019, 03:44:25 PM »
Care to describe the method? What type of cross-over? If the order of the x-over is higher than 1st, it can't be "mathematically the same as a 6dB/oct HPF". To my knowledge, most hardware x-overs are at least 2nd order.

IIRC the Neumann filters were using 6db/oct ?
What exactly would i have to do to sonically come closer to an elliptical filter compared to a 6db hpf in the sides? is it even possible?

sorry for the noob questions.

abbey road d enfer

Re: Maselec MTC elliptical filter
« Reply #13 on: March 02, 2019, 05:47:52 PM »
IIRC the Neumann filters were using 6db/oct ?
What exactly would i have to do to sonically come closer to an elliptical filter compared to a 6db hpf in the sides? is it even possible?
An elliptic EQ is strictly identical to inserting a 6dB/octave in the S component.
Inserting a higher-order filter results in  a different response.
For a 1st-order (6dB/oct) HPF, a left-panned bass sound will result in a -6dB low-shelved signal on left, and a -6dB Low-passed version of the signal on the right. So, the LF energy that was concentrated on the left channel is now shared between the two outputs.
For a 2nd-order (12dB/oct) HPF, the signal on left is unchanged, but the right signal is very different, with a hump at the filter's cut-off frequency. No doubt it sounds different.
Depending on the speaker's position and directivity pattern, it can result in significant perceptual differences.
The graph represents the outputs after matrixing, HPF and de-matrixing.
Dark blue and red are the left and right outputs with 1st-order filtering of the S component. Note that dark blue is hidden by green that is identical.
Green and cyan show same outputs with 2nd-order filter in S component.
« Last Edit: March 03, 2019, 03:59:44 AM by abbey road d enfer »
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

Gold

Re: Maselec MTC elliptical filter
« Reply #14 on: March 02, 2019, 05:57:35 PM »
This is the EE77 circuit.

abbey road d enfer

Re: Maselec MTC elliptical filter
« Reply #15 on: March 03, 2019, 02:42:23 AM »
This is the EE77 circuit.
Yes. The heart of it is C53...56 and the variable resistors built around SW1&2.
Exactly like C1, C2 and the potentiometer in my simulation. The rest is just buffering needed to provide the correct impedances and terminations for interfacing with other equipment.
« Last Edit: March 03, 2019, 02:47:55 AM by abbey road d enfer »
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

Gold

Re: Maselec MTC elliptical filter
« Reply #16 on: March 03, 2019, 06:31:04 AM »
There is no M/S encode/decode in the EE77. It is equivalent to putting a 6dB/oct HPF on the side channel but is not the same circuit.

The EE77 is more elegant than doing an M/S matrix and putting a filter on the side channel.
« Last Edit: March 03, 2019, 06:38:07 AM by Gold »

abbey road d enfer

Re: Maselec MTC elliptical filter
« Reply #17 on: March 03, 2019, 07:21:02 AM »
There is no M/S encode/decode in the EE77. It is equivalent to putting a 6dB/oct HPF on the side channel but is not the same circuit.

The EE77 is more elegant than doing an M/S matrix and putting a filter on the side channel.
I agree totally. However, processing the M/S components offers other unique possibilities, such as compressing or EQ'ing the S component in order to manipulate the stero image.
For vinyl mastering this is mostly irrelevant.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

SKJGProject

Re: Maselec MTC elliptical filter
« Reply #18 on: March 03, 2019, 07:35:59 AM »
Is it mono-ing only low frequencies?

Iirc it‘s just an highpass on the s channel, so yes :)
I used to date a blind girl. Her name was ::… ..:.: .:::. .::.. ….: .:.::

weiss

Re: Maselec MTC elliptical filter
« Reply #19 on: March 03, 2019, 09:44:31 AM »
Iirc it‘s just an highpass on the s channel, so yes :)

It is :)


 

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