Go Back   Home > Forums > General Interest > diyAudio.com Articles

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Comment
 
Article Tools Search this Article
Old 29th March 2011, 10:57 AM  
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
Default What is Gain Structure?

Gain structure (AKA Gain Staging) is a concept that gets talked about a lot in pro audio, but most home audio folks have never heard of it. Understanding gain structure can help you get the cleanest signal possible out of your system and avoid some nasty things. Things like noise and clipping,...

Last edited by Variac; 1st April 2011 at 11:34 PM.
  Reply With Quote
15th April 2011
AUDIODH's Avatar
AUDIODH
diyAudio Member
Quote:
My rule of thumb is to keep the signal about 6dB below clipping. That can often be impossible or impractical, but it's a goal to shoot for. You don't want to go above that level - unless you're looking to add distortion. Dropping too far below that means you'll pick up noise.
That's it in a nutshell.
Pano,
well said!
The 6 dB headroom is a very good margin to shoot for. If your a live player and/or sound man....that is a big part of your job.
In home theater/stereo systems, that is taken care of in the mastering process. Often times to the point of destroying dynamic range....can you say 6dB overall headroom!
Pano, I see we completely agree on this subject and I hope it helps all the DIY members when gain staging their system.
15th April 2011
AndrewT
diyAudio Member
Going back to the first Gain diagram.
If the X4 gain stage were switchable to bypass (X1) or to +6dB (X2) then the system as it was could be adjusted to suit virtually all sources
regards Andrew T.
15th April 2011
AUDIODH's Avatar
AUDIODH
diyAudio Member
Quote:
Going back to the first Gain diagram.
If the X4 gain stage were switchable to bypass (X1) or to +6dB (X2) then the system as it was could be adjusted to suit virtually all sources
Hi Andrew,
that is a true statement.
In an ideal world for us tweaks, a continuously variable gain pot is optimum, preferably with an signal/clip indicator for optimum level in the associated device. However, in many systems, that just means more $ to the end user. There is a good argument for a matched system where that engineering has been done up front and isn't a concern.
I sometimes run through as many as ten devices in the signal chain through both analog and digital paths, I have to relay on indicators and my ears to optimize the gain staging.
-Dave
15th April 2011
adason's Avatar
adason
diyAudio Member
Talking about the gain strcture and the levels accross the signal chain...I miss those days where almost any device had its own VU meter, so you knew where is your signal. Reel-to-reels and cassette decks all had nice analog or digital meters, to keep the signal as far from the noise, yet safe from overload...even good pre-amps had the signal meters, not to mention power amps. Its a pitty that those nice fluorescent VU meters dissapeard, they were so much fun to watch, especially the fast ones. If you see complete systems these days, there are barely any VU meters!
15th April 2011
adason's Avatar
adason
diyAudio Member
see what I mean? nothing moving to the signal, no meters...
DIY Rack
15th April 2011
AUDIODH's Avatar
AUDIODH
diyAudio Member
Adason,
yes I use to have a visual on the old McIntosh system with those beautiful blue meters and lights while listening to some Frazier Texas Bull Horn loudspeakers. That system rocked! It was in 1970 when I was young enough to truly sit and listen to really good music!
Your system looks nice. I could see you had Bryston power, and from the looks of it, Bryston preamps too! They design great stuff and the whole gain stage blog is a nonissue with quality matched gear as that you have! I'm sure you don't experience noise, clipping, etc with that system.
-Dave
15th April 2011
danielwritesbac's Avatar
danielwritesbac
diyAudio Member
It would be interesting indeed to see some other examples of amplifiers that have gain strictly in proportion to output potential. The majority of examples like that may turn out to be high power models (prosound scale).

What are some of the more modest (home scale) exceptions that actually work well?

Are there more good examples of high current output buffers (purpose made for driving speakers) to compare and read up on for reference?
15th April 2011
Conrad Hoffman
diyAudio Member
Excellent article. I do have one small complaint- the term has always been and will continue to be "gain distribution".
May the root sum of the squares of the Forces be with you.
15th April 2011
Pano's Avatar
Pano
diyAudio Moderator
Never heard that one, Conrad. In the pro audio I've always heard it called "gain structure."
Maybe it's regional. I'll look into it.

Daniel. Yes, if someone has some good examples from right here on diyAudio, that would be great.
16th April 2011
sandyK
diyAudio Member
Michael
What you are saying is highly desireable.
However, until STBs and DTVs etc. use a gain stage to make up for the <-20dB level used with DTV broadcasts,
( and the level of the L and R from 5.1 Surround broadcasts is even lower)
then many of us are stuck with the need for additional gain, even though it will degrade other sources.
The DTV level via SPDIF is also low, and you really need to take extreme measures to avoid further S/N degradation,
otherwise low level ambience information is severely degraded.
Alex

Comment


Hide this!Advertise here!
Article Tools Search this Article
Search this Article:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Article Article Starter Category Comments Last Post
help on amp gain structure nicoch58 Tubes / Valves 3 16th December 2010 11:09 PM
S/PDIF data structure billbo Digital Line Level 4 14th October 2008 12:16 PM
6M6G Structure of the circuit RCA245 Tubes / Valves 2 11th April 2005 05:51 PM
Anybody know anything about this kind of motor structure? 454Casull Multi-Way 2 3rd August 2004 12:40 AM


New To Site? Need Help?

All times are GMT. The time now is 06:14 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2