Anyone know of a good de esser circuit to build?

[jfrabat]

Looking for the final piece of my vocal studio hardware build...  Already have the EQ, compressor (waiting for the boards and some compoennts to arrive), and will build myself a new pre-amp (actually, 2; a tube and a transformer one; ordered some kits and the are on the way).  Just missing a de esser.  I looked online, but could not find any.  I could always build another compressor and use it for de-essing (side chained), but I would need an EQ in addition and to split the signal, so I rather just build a dedicated de esser...  Anyway, any help greatly appreciated!

[11-90-an]

Do you happen to have some extra lm13700's or any other OTAs...? 

Choose one of the types of de-essing, and I think we can all start there...
https://en.m.wikipedia.org/wiki/De-essing

Why don't you use digital plugins for this one? Is it just for the satisfaction of building something...?

[aron]

Yeah, with this special at $8, kind of hard to beat that - plus comes with RX Elements!
https://www.pluginboutique.com/product/2-Effects/54-Vocal-Processing/6705-Vocal-Cleaner

[PRR]

> Why don't you use digital plugins

Whipping out 8 bucks does not impress anybody. If it has dad's bloody fingerprints, he's a family hero.

[11-90-an]

Yeah, with this special at $8, kind of hard to beat that - plus comes with RX Elements!
https://www.pluginboutique.com/product/2-Effects/54-Vocal-Processing/6705-Vocal-Cleaner

why pay $8 when you can get it free...?

https://www.best-free-vst.com/plugins/effects/de-esser-01.php

> Why don't you use digital plugins

Whipping out 8 bucks does not impress anybody. If it has dad's bloody fingerprints, he's a family hero.

no bloody fingerprints here... only burnt skin flakes that smell like chicken...

[kraal]

Why don't you use digital plugins for this one? Is it just for the satisfaction of building something...?

In a previous post I think jfrabat wrote that his daughter is using an old computer, which does not have the computing power for audio processing (if I'm not wrong).

@Jfrabat, you can have a look at DBX 902. DBX publishes all schematics, parts lists, user manuals, block diagrams (everything they have) of thier discontinued products.
https://dbxpro.com/en/products/902

You should have a look at it.

Side note: you can have access to their whole vintage section of products: https://dbxpro.com/en/discontinued_products

[11-90-an]

@kraal that site is GOLD!!! 
Thanks for sharing...
I could get lost staring at all the schems....

EDIT: After looking and skimming through the schems, the DBX 263 seems to also be good, but I noticed that it requires UPC1253H2's... and they seem kinda pricey...

[kraal]

Another side note: in the schematics there is a 8 pin "RMS Module" /QA1 and QA2). This is a DBX chip, however you can find its internals in the schematics zip file (902 HP & FWB RMS Schematics.pdf).

[kraal]

@kraal that site is GOLD!!! 
Thanks for sharing...
I could get lost staring at all the schems....

EDIT: After looking and skimming through the schems, the DBX 263 seems to also be good, but I noticed that it requires UPC1253H2's... and they seem kinda pricey...

The 263X is a modern version of the 902. Feature-wise, from what I read, the main difference is that unlike the 263x, the 902 has a range control, better THD and noise performance.

About the UPC1253H2: these 2 chips that are required to build a 263x cost ~20$ + shipping, and you can find a 263x for 65$ + shipping on ebay.

[11-90-an]

If I may ask, what IC this is?



Is it this?

[kraal]

If I may ask, what IC this is?



Is it this?

I would say "yes".

[jfrabat]

Do you happen to have some extra lm13700's or any other OTAs...? 

Choose one of the types of de-essing, and I think we can all start there...
https://en.m.wikipedia.org/wiki/De-essing

I do have them, in fact.  3 of them anyway.  As for type of de-essing, I do not have a preference, as long as it is hardware based.

Why don't you use digital plugins for this one? Is it just for the satisfaction of building something...?

3 main reasons:

1. As Kraal mentioned:

In a previous post I think jfrabat wrote that his daughter is using an old computer, which does not have the computing power for audio processing (if I'm not wrong).

This is correct.  It is an old tablet type PC, which only has about 120GB of SSD and is VERY limited as far as chipset speed and RAM.

2. You are not far off in your question...

Is it just for the satisfaction of building something...?

It actually partly is. 

3. The most important reason, hardware just looks cool!

I know you have a billion more options with plugins, but I just like to make stuff and have it physically visible.  I am not making this because it is cheaper or because it sounds better.  I am making it because (1) making it entertains me, and (2) it has some sentimental value.

Let me give you an example of the latter; last weekend, I was talking to my daughter and was telling her all the stuff I will be making, and how she will inherit all the purchased / commercially available stuff I am currently using (compressor, pre-amp, and EQ).  Her reaction?  "But that, you are not giving me anything you made; I want the ones you make.  Those are special!"  Now imagine I tell her to use a plugin...

@Jfrabat, you can have a look at DBX 902. DBX publishes all schematics, parts lists, user manuals, block diagrams (everything they have) of thier discontinued products.
https://dbxpro.com/en/products/902

You should have a look at it.

Side note: you can have access to their whole vintage section of products: https://dbxpro.com/en/discontinued_products

Thanks!  I will look into these for sure!

[Mark Hammer]

I was always under the impression that a de-esser was simply a limiter with a highpass or bandpass filter in the sidechain, such that the amplitude of sibilants would be selectively reduced.  Of course, given that sibilants are still considerably lower-amplitude than fundamentals and bass content, that filter would likely need a bit of boost as support, so that it would result in appropriate gain reduction.

I suppose one of the things a person might do to optimize such a setup is to assess just what the band any sibilants from singer X might fall in, and tweak the sidechain filter appropriately.

[11-90-an]

I was always under the impression that a de-esser was simply a limiter with a highpass or bandpass filter in the sidechain, such that the amplitude of sibilants would be selectively reduced.  Of course, given that sibilants are still considerably lower-amplitude than fundamentals and bass content, that filter would likely need a bit of boost as support, so that it would result in appropriate gain reduction.

I suppose one of the things a person might do to optimize such a setup is to assess just what the band any sibilants from singer X might fall in, and tweak the sidechain filter appropriately.

Here's my take on the circuit...



I wonder if it makes sense, though...

It's basically a EQ with multiple outputs. One goes to a compressor and the other just mixed back in... i wonder if there will be any phase mismatches and sound cancellation though...

[Rob Strand]

Here's my take on the circuit...

My understanding is it has two modes:

1) Full band compression with de-essing.
     The full band-signal is passed through the VCA.
      De-essing is achieved by emphasizing *detection* of esses in the  VCA side-chain.
      This mode is like the de-essing switch on some compressors.

2) Multi-band de-essing.
     Here the signal is split into a high and low-band using a second order crossover/band-splitter.
     Only high-band passes through the VCA.
     The same side-chain is used as mode (1).
     The idea of this mode is to compress the esses with less impact on the other bands.

It's worth noting the side-chain has two inputs a full-band input and a high-pass input.    There is additional high-pass filtering on the rms converter for the high-pass input.

There's still one mystery, why pass the full-band signal through the side-chain in mode 2.   (Maybe I need to read the manual  )

FWIW, it is possible to add a full-band de-esser (mode 1) to an existing compressor.

It's basically a EQ with multiple outputs. One goes to a compressor and the other just mixed back in... i wonder if there will be any phase mismatches and sound cancellation though..

It gets the high-pass by subtracting Low-pass - 1, the idea is it helps stop that.

[Rob Strand]

This paper shows how a basic full-band mode de-esser can be incorporated into a standard compressor by switching in a filter.

http://ajoliveira.com/ajoliveira/gen/pdf/preprints/paris88.pdf

p9     Section 8          ;  description of side-chain with De-Esser
p15   Figure 18          ;  note switchable DS block  (De-Esser block)
p17   Figure 9            ;  Filter response of DS Block

[bowanderror]

I just posted about an optical compressor-saturator (XQP Optical Disruptor) I recently built that is based on a 500-series 531A De-Esser circuit w/o the lowpass filter in the sidechain. They actually offer a schematic for the de-esser on their website if you want to try and build something similar.

To simplify the design, you could:
- Select just 1 or 2 of the frequency filter circuits that are selected by the Frequency switch (S2)
- Remove the clean/soft switch and just go with one type of vactrol.
- Take a look at the 545 Optical Disruptor schematic for more ways to simplify the circuit.

Another option would be to take an easy-to-build optical compressor (e.g. Bajaman Optical Limiter/mictester cheap compressor/Johan's LA2A Limiter) & add an adjustable HPF in the sidechain.

[jfrabat]

I just posted about an optical compressor-saturator (XQP Optical Disruptor) I recently built that is based on a 500-series 531A De-Esser circuit w/o the lowpass filter in the sidechain. They actually offer a schematic for the de-esser on their website if you want to try and build something similar.

To simplify the design, you could:
- Select just 1 or 2 of the frequency filter circuits that are selected by the Frequency switch (S2)
- Remove the clean/soft switch and just go with one type of vactrol.
- Take a look at the 545 Optical Disruptor schematic for more ways to simplify the circuit.

Another option would be to take an easy-to-build optical compressor (e.g. Bajaman Optical Limiter/mictester cheap compressor/Johan's LA2A Limiter) & add an adjustable HPF in the sidechain.

That looks like an interesting build...  Does not look overly complicated.  Just a couple of questions:

1. Mouser does not seem to carry the VTL5C1; anyone know where to get it?
2. What are RL1 and 2?  Seems like 2p2t switches with a transformer?
3. Based on the number of trimmers, looks like tuning it is a full time job; how is your experience with this?

[kraal]

Hi,

1. Mouser does not seem to carry the VTL5C1; anyone know where to get it?

Aliexpress, ebay, etc. But I would first try with a ledr + led.
https://www.diystompboxes.com/smfforum/index.php?topic=120722.0

2. What are RL1 and 2?  Seems like 2p2t switches with a transformer?

RL usually stands for relays. Your description kind of confirms it.
https://en.wikipedia.org/wiki/Relay

Cheers and have a good Sunday,

[bowanderror]

I've only built the Disruptor, and some tuning was involved as I used homemade vactrols rather than the VTL5C1. I think the Opto Trim sections are more to match the gain reduction between the different types of vactrols. That way there is no tweaking needed when you switch between soft/clean modes.