How to measure AVR pre-outs for clipping? - AVS Forum | Home Theater Discussions And Reviews
Baselworld is only a few weeks away. Getting the latest news is easy, Click Here for info on how to join the Watchuseek.com newsletter list. Follow our team for updates featuring event coverage, new product unveilings, watch industry news & more!



Forum Jump: 
 
Thread Tools
post #1 of 7 Old 11-25-2013, 06:27 AM - Thread Starter
AVS Special Member
 
Gooddoc's Avatar
 
Join Date: Oct 2004
Posts: 6,422
Mentioned: 101 Post(s)
Tagged: 0 Thread(s)
Quoted: 2065 Post(s)
Liked: 1392
I'm trying to optimize the gain structure of my AVR and amp and I want to measure the pre-outs of my AVR to see where the point of clipping occurs. I have REW and Omnimic software on laptops and a Tascam USB interface for my condensor mic.

Can I use REW or Omnimic and the Tascam to measure the pre-outs for clipping. If so, how do I do that?

If not, what equipment/software do I need/

Thanks very much!
Gooddoc is online now  
Sponsored Links
Advertisement
 
post #2 of 7 Old 11-26-2013, 05:25 AM - Thread Starter
AVS Special Member
 
Gooddoc's Avatar
 
Join Date: Oct 2004
Posts: 6,422
Mentioned: 101 Post(s)
Tagged: 0 Thread(s)
Quoted: 2065 Post(s)
Liked: 1392
I think this may be the wrong place for this, but if anyone happens to catch this on the bump that could give me some guidance, I'd appreciate it.

Turns out I can't find my Tascam USB interface so I will have to buy something new. But I think I"ll wait for guidance so I can buy the right tool for the job.
Gooddoc is online now  
post #3 of 7 Old 11-26-2013, 05:36 AM
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,593
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 851 Post(s)
Liked: 1233
Quote:
Originally Posted by Gooddoc View Post

I think this may be the wrong place for this, but if anyone happens to catch this on the bump that could give me some guidance, I'd appreciate it.

Turns out I can't find my Tascam USB interface so I will have to buy something new. But I think I"ll wait for guidance so I can buy the right tool for the job.

Your AVR might put out up to 10 volts RMS or more on its line outputs before it clips. Most audio interfaces that lack passive input level controls will clip well before that.

I use attenuators of various kinds ranging from 5 K ohm 2 watt potentiometers to custom built fixed resistor attenuators for this purpose.

http://www.jameco.com/1/1/816-rv4naysd502a-rv4-potentiometer-53c35k-5k-ohm-2-watt-10.html



I've also used these:

http://www.amazon.com/Hosa-Female-Male-Input-Attenuator/dp/B000K67U52



I use the audio interface to observe for clipping. I then use an actual DVM to measure the voltage.

http://www.amazon.com/UNI-T-Digital-Ranging-Multimeters-Multitester/dp/B007THZMWi

arnyk is offline  
post #4 of 7 Old 11-26-2013, 08:48 AM - Thread Starter
AVS Special Member
 
Gooddoc's Avatar
 
Join Date: Oct 2004
Posts: 6,422
Mentioned: 101 Post(s)
Tagged: 0 Thread(s)
Quoted: 2065 Post(s)
Liked: 1392
Thanks Arnyk!

I use a pro amp so I have the flexibility to optimize my gain structure directly without the need for attenuators. I would like to not just measure max voltage but see when clipping starts and perhaps even where significant distortion starts prior to actual clipping.
Gooddoc is online now  
post #5 of 7 Old 11-26-2013, 09:50 AM
FMW
AVS Special Member
 
FMW's Avatar
 
Join Date: Jun 2007
Posts: 7,577
Mentioned: 12 Post(s)
Tagged: 1 Thread(s)
Quoted: 1652 Post(s)
Liked: 1670
Quote:
Originally Posted by Gooddoc View Post

Thanks Arnyk!

I use a pro amp so I have the flexibility to optimize my gain structure directly without the need for attenuators. I would like to not just measure max voltage but see when clipping starts and perhaps even where significant distortion starts prior to actual clipping.

The best approach would be to get hold of an oscilloscope. That will measure the voltage and allow you see any clipping visually at the same time.
FMW is offline  
post #6 of 7 Old 11-26-2013, 10:02 AM - Thread Starter
AVS Special Member
 
Gooddoc's Avatar
 
Join Date: Oct 2004
Posts: 6,422
Mentioned: 101 Post(s)
Tagged: 0 Thread(s)
Quoted: 2065 Post(s)
Liked: 1392
Quote:
Originally Posted by FMW View Post

The best approach would be to get hold of an oscilloscope. That will measure the voltage and allow you see any clipping visually at the same time.

Never an oscilliscope around when you need one! biggrin.gif

Mmmm, I'll need to look into that
Gooddoc is online now  
post #7 of 7 Old 11-26-2013, 02:15 PM
AVS Special Member
 
airgas1998's Avatar
 
Join Date: Nov 2007
Location: 43degsN 92degsW
Posts: 2,382
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 92 Post(s)
Liked: 141
not sure if your pro amp has clipping meters, but my crown does. what I have done is disconnect your speakers and set your avr/preamp to reference or what ever max level you would go to and slowly increase your channels gain until it just starts to clip and then back off a hair. use 50-60hz test tone or some heavy music. although, not exact science I've come pretty close into dialing it in.

Habit Forming....Wallet Burning Hobby....55" Oled Lg B6p 55" Samsung B8500 Fald Channel Master Dvr+ Onkyo RZ900 avr Sony 790 BR player Svs Ultra Towers/Center, Svs Satellite Surrounds Svs Pb-13 Ultra Sub
airgas1998 is offline  
Sponsored Links
Advertisement
 
Reply Receivers, Amps, and Processors

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

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