In-ear finalizer/mastering device: anybody interested???

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Rogy,
you are spot on
... on all fronts ... those bloody radios ... both to and from the artist. :roll:

Looks like you might have some budget to work with.
Hire a TC DB-Max for a day or so and put some of your theories to the test.
Not going to try to sell you one here but spend some time in one and you will see it has the guts to do everything you said. From this experimenting you may gain some specific knowledge to help develop an analog DIY version of the effect string you need/want.

We are using some of these units to feed our transmitters to the smaller TV broadcast markets.
 
Hi Kev,

Thanx for the hint! I used the TC Finalizer 96K a couple of times, the only complaint being the lack of ease of operation; I don't like to go thru a thousand menus to find the correct parameter to adjust. After all it's live stuff I'm doing, so we'll be two songs further in the set before I found the makeup gain of the Mid band...

Audiowise these are great machines! I just want a "grab the knob and turn it" device for fastest operation.

I will definately check out the DBMax!

Concerning the Width control schematic discussed above, I added the extra Input trim which could be set up from the same rotary as the original trim. This way the input and output amplitudes will always remain constant, no matter how narrow or wide the mix is made.

Schematic and plots can be found here:
http://users.pandora.be/Rogy/IEMFinalizer/Width%20control/Constant%20Amplitude%20width%20control/

One day we'll have to check if our ear/brain combination agrees with the simulator concerning "constant amplitude" :? ...


Greetz,


Rogy
 
Did someone said he want's it loud? Check this:
[removed]

This is from a test series with different broadcast processors. I did lower the amplitude (6 dB) to avoid clipping from the mp3-coding. Note that this sample is made with a preset from a product that costs you 15'000$. Incredible crapp...

Sorry, a bit OT but I couldn't help!

Samuel
 
[quote author="Samuel Groner"]This is from a test series with different broadcast processors. I did lower the amplitude (6 dB) to avoid clipping from the mp3-coding. Note that this sample is made with a preset from a product that costs you 15'000$. Incredible crapp...
[/quote]

6 dB for the mpg3 is one thing ... I'd love to say more about this but with very little to go on it is difficult to comment.

We had this same trouble with these units at my work place and I believe to comes down to a little knowledge is dangerous and for the most part a lack of knowledge at the complicated of the actual RF Broadcast and Transmission. No dis-respect intended. :thumb:

I don't know what test you did but to grab a preset and send AES straight in from a Pro CD player or DAT, with normalized source material, it doesn't surprise it would be crap.

Many of my people just didn't get the real meaning of limiting, compression and the effect of attack times .... then there was AGC and the Pre-emphasis of the Analog RF Transmitters.

big subject !!

note
Song Digi Beta's have a line up at -20dBFS and the Broadcast world does tend to waist 6dB of headroom right at at the top. So using a modern CD AES connected will spend all of it's time up in overload.
big subject ....
 
I don't know what test you did but to grab a preset and send AES straight in from a Pro CD player or DAT, with normalized source material, it doesn't surprise it would be crap.

In this unit, there's this AGC in front of the processing chain and you can feed in whathever level you want - it will get smashed to the top after a few seconds. Really nothing to do about that... Of course there were other presets, but the multiband comp is such a horrible thing that it will sound ugly 'till you bypass it (unfortunately they forgot to implement that). Now I stop and we get back to work! :wink:

Samuel
 
Hi all,


It's been a while but I'm still working on this project.

The multiband comp is gonna be a slightly modified version of the JBL/Urei 7110, which has a very good detector design.

There's both a true RMS and a peak detector, and the peak detector's threshold is 20dB above the average. By turning the "detector" knob, the peak threshold can be lowered and brought closer to the average detector's threshold.

The only mod that I would like to do is implement a "dual release time" on the average detector, kinda like what's been done on the What comp.

For the rest the schematic should be simplified; I am gonna link the "detector" pots of the three bands and have a look at the attack/release settings, as suggested by Samuel in an earlier post.

So, that's it for now; again all comments/suggestions are very welcome!

Greetz,

Rogy
 
Hi Rogy, that sounds very interesting. I must look at the 7110 circuit diagram to see if I can lift the peak detector for my VCF sweep generator that I'm working on. I'd certainly be interested to see how you have changed the 7110 electronics at some point.
Stephen
 
What happend with this project?
I was wondering if it is possible to build a high quality crossover to use exteernal analog compressors like La2a, Poorman, GSSL... for a multiband mastering.
Did somebody already try this?

Cheers Jonas
 
Hi Jonas,

As usual, I got as far as getting the schematics finished and the circuits simulated; due to a lack of time I didn't make a prototype yet.

Some students "digitalized" the crossover section and the compressor as a thesis. So digitally controlled analog multiband compression was the result.

Of course it is possible to use an external analog crossover to split full range audio in bands and get these bands processed by your favorite compressors; and then mix the results together again. Just be aware that the energy in each of the three bands will require a different set of time constants to process them in a natural sounding way.

Regards,

Rogy
 
Rogy said:
However I think I will give Steve Dove's CAPS (Constant Amplitude Phase Shift) design a go. I'm looking at it for years but never came to building it. A description of the topology can be found on Fred Forssel's website www.forsselltech.com in the excellent article "Evolution of an EQ design"
http://www.forsselltech.com/Evolution%20of%20an%20EQ%20Design2.pdf
I just read the mentioned article and I can't help expressing disagreement with the basic foundation of the whole concept:
Quote: "It may be obvious to the reader that connecting 5 amplifiers in series will have a greater
sonic impact than using a single amplifier in the entire signal path."
This is not true for two reasons:
A) one single amp with a very high noise gain can be worse than five with a low noise gain.
B) discounting the rest of the circuitry is a big mistake, the filters ARE in the signal path.

Quote: “There are no significant trade-offs to a one amplifier EQ design”
Yes there is: the different bands are interactive, i.e. when you boost or cut one of the bands, it changes the boost/cut of the adjacent bands.
 
Rogy said:
Potmeters are clearly indicated (these will one day be replaced by rotaries; anyone who can provide me with a conversion graph showing linear potentiometer turn vs log and reverse log potentiometer value change?).
Rogy
It depends! First, all "log" curves are made using a restricted number of linear segments that only approach the theoretical target. Good (expensive) log pots will use 4 segments, but most use only two, so in fact the log curve is just two linear segments. Usually, so-called "audio" pots have 20% of total value at mid-travel, log pots have 10%. But really, what you want to do is actually install a pot, rotate it until you reach the desired boost or cut, and then disconnect the pot and measure it.
 
Rogy said:
The schematics and some curvers for the Constant Amplitude Phase Shift EQ are now available on my site.
Rogy
This is gonna be a noisy EQ. For two reasons:
A) Intrinsically, because the filters' noise is directly reflected in the output, multiplied by the amount of boost OR cut.
B) Because of the pots that are connected across the opamp's inputs; with no EQ, the noise gain is already 15 dB. The only way to avoid that is to use "W" curve pots or antilog pots that are switched in boost or cut position (easy to do with rotary switches).
 
Hi Abbey Road D Enfer,

Thanks for your valuable comments!

I'll receive an EQ based on the CAPS principle next week, so I will be able to measure/listen what's going on.

To avoid interaction, in general only three sections are used with non-overlapping frequency range per opamp (eg low, mid, hi non-overlapping) and if five bands are desired, an extra opamp is used for the low-mid and hi-mid non-overlapping frequency bands.

Steve Dove wrote an excellent article about this topology; it's been published in the Handbook for Sound Engineers. If I find the time I'll try to scan it and post a link.

Best regards,

Rogy

 

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