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Texar make up gain circuit

F

fm_engineer

Guest
Well, for those of you that sent a few e-mails over the past year or so concerning my journey down make-up gain circuit lane, I must report that all my attempts failed. I originally was looking at band 2 and 3, but later on I wanted to do something with band 1. I thought this may be the answer to bad sounding classical through the texar's. I started with a study of the CBS stuff from the early days. They had a circuit that was basically a DC coupled slow-fast switch. A more automatic or program dependant control is what I was looking for, but all my attempts yielded terrible IM, especially on band 1. The op-amps were really pulling up the IM when I used a simple transistor gate to gauge the program density. Just thought I would pass it along those that were interested.
 
> Well, for those of you that sent a few e-mails over the past
> year or so concerning my journey down make-up gain circuit
> lane, I must report that all my attempts failed.

Sometimes you can go only so far when trying to teach an old dog new tricks. In particular, it seems to be much easier to take a processor which was designed for clean, high-quality sound and make it louder, than it is to take a processor which was designed for maximum loudness and make it cleaner and more audibly transparent. There are people who say "if it sounds good loud, then it'll sound even better when used lightly", but that often just isn't true, as heavy compression and limiting can easily mask the inadequacies of a poor AGC design.
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> There are people
> who say "if it sounds good loud, then it'll sound even
> better when used lightly", but that often just isn't true,

I thought I was alone in concluding this very same thing! ;-)


Regards,
Goran Tomas
 
> > Well, for those of you that sent a few e-mails over the
> past
> > year or so concerning my journey down make-up gain circuit
>
> > lane, I must report that all my attempts failed.
>
> Sometimes you can go only so far when trying to teach an old
> dog new tricks. In particular, it seems to be much easier
> to take a processor which was designed for clean,
> high-quality sound and make it louder, than it is to take a
> processor which was designed for maximum loudness and make
> it cleaner and more audibly transparent. There are people
> who say "if it sounds good loud, then it'll sound even
> better when used lightly", but that often just isn't true,
> as heavy compression and limiting can easily mask the
> inadequacies of a poor AGC design.

Sorry, but this doesn't make sense. Analogy: You can't add more horsepower to a 4-cylindar engine, unless you add mechanism(s) to increase the horsepower...BUT...you can take a high-performance engine and reduce horsepower.

The same is true in an audio processor. Naturally, the trick is in knowing what to "tweak" to accomplish this.

-Frank Foti
 
> Sorry, but this doesn't make sense. Analogy: You can't add
> more horsepower to a 4-cylindar engine, unless you add
> mechanism(s) to increase the horsepower...BUT...you can take
> a high-performance engine and reduce horsepower.

Sure it makes sense, when you consider more than just the engine, to use your analogy. Would you claim that a purpose-built race car would make a grear car for daily street driving as well? Of course not -- not only is a racing clutch hell to drive in normal traffic, you'll also have to deal with a punishingly stiff suspension, racing tires with no traction in wet weather, a complete lack of creature comforts (A/C, radio, power accessories, etc.), and so forth. Even the real nitty-gritty stuff like injection timing, exhaust backpressure, and gear ratios can make a fast car unacceptable when driven slowly.

> The same is true in an audio processor. Naturally, the trick
> is in knowing what to "tweak" to accomplish this.

Yes, but sometimes the most effective "tweak" is to cart the processor off to the dumpster and find something better-suited to your needs and objectives. DSP has allowed us to come closer to the objective of having a truly "all-purpose" audio processor, but it still isn't perfect. That's the whole reason why your company offers a full line of audio processors, each individually suited to AM, FM, TV, or digital broadcasting, even if the technology exists to make a processor which can be easily configured to meet the technical specifications of all of these broadcast media.

Besides, every audio processing scheme works by progressively building loudness as the audio goes through the chain from input to output. Therefore, the best approach is to follow this flow, by first tweaking the AGC, then the compression, then the limiting, then the clipping, etc. Working backwards from the output to the input would be counterintuitive, and that's why you'll often get frustrated trying to make a "LOUD" processing scheme sound good when used lightly. Just ask anyone who owns an 8-band Inovonics MAP, or an Optimod-AM 9000 with the "Disco" modification!
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</P>
 
> > Sorry, but this doesn't make sense. Analogy: You can't add
>
> > more horsepower to a 4-cylindar engine, unless you add
> > mechanism(s) to increase the horsepower...BUT...you can
> take
> > a high-performance engine and reduce horsepower.
>
> Sure it makes sense, when you consider more than just the
> engine, to use your analogy. Would you claim that a
> purpose-built race car would make a grear car for daily
> street driving as well? Of course not -- not only is a
> racing clutch hell to drive in normal traffic, you'll also
> have to deal with a punishingly stiff suspension, racing
> tires with no traction in wet weather, a complete lack of
> creature comforts (A/C, radio, power accessories, etc.), and
> so forth. Even the real nitty-gritty stuff like injection
> timing, exhaust backpressure, and gear ratios can make a
> fast car unacceptable when driven slowly.
>
> > The same is true in an audio processor. Naturally, the
> trick
> > is in knowing what to "tweak" to accomplish this.
>
> Yes, but sometimes the most effective "tweak" is to cart the
> processor off to the dumpster and find something
> better-suited to your needs and objectives. DSP has allowed
> us to come closer to the objective of having a truly
> "all-purpose" audio processor, but it still isn't perfect.
> That's the whole reason why your company offers a full line
> of audio processors, each individually suited to AM, FM, TV,
> or digital broadcasting, even if the technology exists to
> make a processor which can be easily configured to meet the
> technical specifications of all of these broadcast media.
>
> Besides, every audio processing scheme works by
> progressively building loudness as the audio goes through
> the chain from input to output. Therefore, the best
> approach is to follow this flow, by first tweaking the AGC,
> then the compression, then the limiting, then the clipping,
> etc. Working backwards from the output to the input would
> be counterintuitive, and that's why you'll often get
> frustrated trying to make a "LOUD" processing scheme sound
> good when used lightly. Just ask anyone who owns an 8-band
> Inovonics MAP, or an Optimod-AM 9000 with the "Disco"
> modification!
>
OK.....I had the old blackface 9000.(Boy, did that box sound bad!!) So what is/was the "disco" mod? I feel like I missed a party or something.....
 
> > Sorry, but this doesn't make sense. Analogy: You can't add
>
> > more horsepower to a 4-cylindar engine, unless you add
> > mechanism(s) to increase the horsepower...BUT...you can
> take
> > a high-performance engine and reduce horsepower.
>
> Sure it makes sense, when you consider more than just the
> engine, to use your analogy. Would you claim that a
> purpose-built race car would make a grear car for daily
> street driving as well? Of course not -- not only is a
> racing clutch hell to drive in normal traffic, you'll also
> have to deal with a punishingly stiff suspension, racing
> tires with no traction in wet weather, a complete lack of
> creature comforts (A/C, radio, power accessories, etc.), and
> so forth. Even the real nitty-gritty stuff like injection
> timing, exhaust backpressure, and gear ratios can make a
> fast car unacceptable when driven slowly.

You took the analogy out of context. All I was referring to was the engine/horsepower. Horsepower is the key.

> > The same is true in an audio processor. Naturally, the
> trick
> > is in knowing what to "tweak" to accomplish this.
>
> Yes, but sometimes the most effective "tweak" is to cart the
> processor off to the dumpster and find something
> better-suited to your needs and objectives. DSP has allowed
> us to come closer to the objective of having a truly
> "all-purpose" audio processor, but it still isn't perfect.
> That's the whole reason why your company offers a full line
> of audio processors, each individually suited to AM, FM, TV,
> or digital broadcasting, even if the technology exists to
> make a processor which can be easily configured to meet the
> technical specifications of all of these broadcast media.
>
> Besides, every audio processing scheme works by
> progressively building loudness as the audio goes through
> the chain from input to output. Therefore, the best
> approach is to follow this flow, by first tweaking the AGC,
> then the compression, then the limiting, then the clipping,
> etc. Working backwards from the output to the input would
> be counterintuitive, and that's why you'll often get
> frustrated trying to make a "LOUD" processing scheme sound
> good when used lightly. Just ask anyone who owns an 8-band
> Inovonics MAP, or an Optimod-AM 9000 with the "Disco"
> modification!

Sure, those units are long out of date! No disrespect to their creators either. We have quite a few Omnia.6 units placed on legendary Classical stations, and they sound very nice! It is possible to use a full-blown processor and tame it to whatever your desires are.

-Frank Foti
 
> Sure, those units are long out of date! No disrespect to
> their creators either. We have quite a few Omnia.6 units
> placed on legendary Classical stations, and they sound very
> nice! It is possible to use a full-blown processor and tame
> it to whatever your desires are.

The Texar Prism, which I assume "fm engineer" was talking about, is "long out of date" as well, but that's the context of this discussion. Obviously there has been much improvement since the Texar's days, or even since the days of the first Omnias, and now.

The Prism was a great processor for its time, but while there are many people who will fondly recall how it sounded back in the '80s, there seem to be few people who are fond of the way it sounds now, even with the kind of significant modifications that "fm engineer" is trying to do.
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</P>
 
> > > Sorry, but this doesn't make sense. Analogy: You can't
> add
> >
> > > more horsepower to a 4-cylindar engine, unless you add
> > > mechanism(s) to increase the horsepower...BUT...you can
> > take
> > > a high-performance engine and reduce horsepower.
> >
> > Sure it makes sense, when you consider more than just the
> > engine, to use your analogy. Would you claim that a
> > purpose-built race car would make a grear car for daily
> > street driving as well? Of course not -- not only is a
> > racing clutch hell to drive in normal traffic, you'll also
>
> > have to deal with a punishingly stiff suspension, racing
> > tires with no traction in wet weather, a complete lack of
> > creature comforts (A/C, radio, power accessories, etc.),
> and
> > so forth. Even the real nitty-gritty stuff like injection
>
> > timing, exhaust backpressure, and gear ratios can make a
> > fast car unacceptable when driven slowly.
>
> You took the analogy out of context. All I was referring to
> was the engine/horsepower. Horsepower is the key.
>
> > > The same is true in an audio processor. Naturally, the
> > trick
> > > is in knowing what to "tweak" to accomplish this.
> >
> > Yes, but sometimes the most effective "tweak" is to cart
> the
> > processor off to the dumpster and find something
> > better-suited to your needs and objectives. DSP has
> allowed
> > us to come closer to the objective of having a truly
> > "all-purpose" audio processor, but it still isn't perfect.
>
> > That's the whole reason why your company offers a full
> line
> > of audio processors, each individually suited to AM, FM,
> TV,
> > or digital broadcasting, even if the technology exists to
> > make a processor which can be easily configured to meet
> the
> > technical specifications of all of these broadcast media.
> >
> > Besides, every audio processing scheme works by
> > progressively building loudness as the audio goes through
> > the chain from input to output. Therefore, the best
> > approach is to follow this flow, by first tweaking the
> AGC,
> > then the compression, then the limiting, then the
> clipping,
> > etc. Working backwards from the output to the input would
>
> > be counterintuitive, and that's why you'll often get
> > frustrated trying to make a "LOUD" processing scheme sound
>
> > good when used lightly. Just ask anyone who owns an
> 8-band
> > Inovonics MAP, or an Optimod-AM 9000 with the "Disco"
> > modification!
>
> Sure, those units are long out of date! No disrespect to
> their creators either. We have quite a few Omnia.6 units
> placed on legendary Classical stations, and they sound very
> nice! It is possible to use a full-blown processor and tame
> it to whatever your desires are.
>
> -Frank Foti


Mr. Foti,

No disrespect to you and your Omnia which can sound pretty damn good. I have yet to hear ANY digital processor sound as WARM as a Analog Optimod 8100a/Texar. Nor hold level controls quite as good. Also the Optimod Limiter was incredible!
>
 
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