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matteskyk

Silverado

Posts: 66 Member Since:19/05/2011

#21 [url]

May 23 11 9:42 AM

Dave, I was wondering if I could trouble you to post the documents for the Barry Porter EQ, if you still have them.  I figure it would be a nice addition to the other fine documents you've all ready posted in your "hut." 

Thanks,

Kevin Mattesky  

-Kevin Mattesky www.phantomcentermedia.com

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dcollins

Platinum Blonde

Posts: 2,343 Member Since:27/01/2011

#22 [url]

May 23 11 1:48 PM

Dave, I was wondering if I could trouble you to post the documents for the Barry Porter EQ, if you still have them.  I figure it would be a nice addition to the other fine documents you've all ready posted in your "hut." 
Thanks,
Kevin Mattesky  

-matteskyk

Barry Porter Parametric EQ.



DC

 davecollinsmastering.com


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drknob

Gold Finger

Posts: 788 Member Since:02/02/2011

#26 [url]

Jul 28 11 11:02 AM

The above doc outlines the potential for a minor confusion between us audio geeks and the transmitter guys. Yes, dBm is a power measurement where 0dBm = 1 mW. In transmitter land, this is referenced to 50 ohms, which gives a voltage level of .224V. In our biz, we reference to 600 ohms, giving a voltage level of .775V. We arbitrarily call this voltage 0dBu, since dBm is meaningful only in the power domain, and the notion of 600 ohm transmission lines is obsolete in our world.

Harold Kilianski

Music Industry Arts
Fanshawe College

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dcollins

Platinum Blonde

Posts: 2,343 Member Since:27/01/2011

#27 [url]

Jul 28 11 1:58 PM

The above doc outlines the potential for a minor confusion between us audio geeks and the transmitter guys. Yes, dBm is a power measurement where 0dBm = 1 mW. In transmitter land, this is referenced to 50 ohms, which gives a voltage level of .224V. In our biz, we reference to 600 ohms, giving a voltage level of .775V. We arbitrarily call this voltage 0dBu, since dBm is meaningful only in the power domain, and the notion of 600 ohm transmission lines is obsolete in our world.

-drknob

To be explicit, one should probably always express the reference impedance for power measurements like this:  dBm(50), or dBm(600) as I agree there could be confusion otherwise.  Especially if you are willing to admit there are industries other than audio in the world.

Just as an aside, there is actually no such thing as a true transmission line in audio.  This is something the phone company has to worry about, but unless your tie-lines are greater than, say, 5 miles it's just a wire with lumped parameters.


DC

 davecollinsmastering.com


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dcollins

Platinum Blonde

Posts: 2,343 Member Since:27/01/2011

#29 [url]

Jul 29 11 6:37 PM

I've never seen a 50 Ohm reference before. Is this some European standard I wouldn't have run into during the early 1960s (back when Hz. were cycles) here in the U.S.??

-bob_olhsson

RF world is 50 Ohms.


DC

 davecollinsmastering.com


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viitalahde

Gold Finger

Posts: 597 Member Since:04/02/2011

#31 [url]

Oct 7 11 1:41 AM

I'm trying to find more literature on tilt-type tone controls, like those found in Quad preamps.

http://www.keith-snook.info/Wireless-World-Stuff/Wireless-World-1970/Tone-balance%20Control%20DCD.pdf

This Wireless World article by R. Ambler shows the origins of the Quad type tone control. Are there more known approaches?

Personally, I'm wondering if a pink noise filter put in the normal boost/cut feedback loop with and a 2nd attenuator for anchoring the ~800Hz point to unity gain would be worth it to try out.

Jaakko Viitalähde Virtalähde Mastering [url]www.virtalahde.com[/url] [url]www.facebook.com/VirtalahdeMastering[/url]

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dcollins

Platinum Blonde

Posts: 2,343 Member Since:27/01/2011

#36 [url]

Oct 7 11 1:00 PM

I'm trying to find more literature on tilt-type tone controls, like those found in Quad preamps.

-viitalahde

There are more in the "Small Signal Audio design" book by Self, which is a must-read.

As an aside, I went up to the Burning Amp (not man) festival last weekend to hear him speak and was fortunate to have dinner with Douglas.  He's a wonderful fellow, and a true inspiration to anyone in audio .


DC

 davecollinsmastering.com


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strangeandbouncy

Platinum Blonde

Posts: 2,150 Member Since:02/02/2011

#38 [url]

Oct 7 11 3:18 PM

HI Ruairi,


   hope all well with you. Working fine now. Musta been a glitch in the MAtrix . . .


   KIndest regards,


     ANdyP

Ruh Roh . . . . .

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strangeandbouncy

Platinum Blonde

Posts: 2,150 Member Since:02/02/2011

#39 [url]

Oct 7 11 3:31 PM

actually, I am not sure this is correct schemo . . . or am I just being a tad thick . . .


 I remember Quad 34 having Switched Tilt control, and this seems to have a pot for tilt and a pot for bass . . .

I dont remember there being a bass control.


   Hmmmm . .

Ruh Roh . . . . .

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