Sound Quality Vs. Measurements - Page 306 - diyAudio
Go Back   Home > Forums > Member Areas > The Lounge

The Lounge A place to talk about almost anything but politics and religion.

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
Reply
 
Thread Tools Search this Thread
Old 4th March 2012, 03:53 PM   #3051
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
T, I will not argue about your 'calculations' but I think a direct measurement by tvr is in order. All he has to do is to short the 1.8K feedback resistor and note the change in gain. Go to it tvr, and don't break anything! '-)
I would do it myself, by my 1200 blew up a channel and I sent it back to Parasound and we both agreed to toss it out, and I replaced it with an A21. If I had the broken unit, I could have made the test, but now it is impossible.
  Reply With Quote
Old 4th March 2012, 05:02 PM   #3052
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Quote:
Originally Posted by john curl View Post
...I think a direct measurement by tvr is in order. All he has to do is to short the 1.8K feedback resistor and note the change in gain. Go to it tvr, and don't break anything! '-)
Couldn't that also be done by applying a signal, measuring the output voltage, then measuring the differential voltage at the input stage?
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
  Reply With Quote
Old 4th March 2012, 05:12 PM   #3053
a.wayne is offline a.wayne  United States
diyAudio Member
 
a.wayne's Avatar
 
Join Date: May 2008
Location: Front Row Center
Quote:
Originally Posted by john curl View Post
T, I will not argue about your 'calculations' but I think a direct measurement by tvr is in order. All he has to do is to short the 1.8K feedback resistor and note the change in gain. Go to it tvr, and don't break anything! '-)
I would do it myself, by my 1200 blew up a channel and I sent it back to Parasound and we both agreed to toss it out, and I replaced it with an A21. If I had the broken unit, I could have made the test, but now it is impossible.
I think you will like it ....
  Reply With Quote
Old 4th March 2012, 05:25 PM   #3054
godfrey is offline godfrey  South Africa
diyAudio Member
 
Join Date: Nov 2009
Location: Cape Town
Quote:
Originally Posted by SY View Post
Couldn't that also be done by applying a signal, measuring the output voltage, then measuring the differential voltage at the input stage?
I imagine that would be more difficult. Poking a probe at the inverting input may send the thing into a fit of oscillation as well, or not? (stray capacitance)
  Reply With Quote
Old 4th March 2012, 06:39 PM   #3055
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: Near Vancouver


Political posts removed as per forum rules.
__________________
Next stop: Margaritaville
Some of Cal's stuff | Cal Weldon Consulting
  Reply With Quote
Old 4th March 2012, 08:33 PM   #3056
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by godfrey View Post
I imagine that would be more difficult. Poking a probe at the inverting input may send the thing into a fit of oscillation as well, or not? (stray capacitance)
Yes, concur. Unless he has a fancy low-pF active probe (how I miss the one I had at UCLA) probing is almost certain to disturb things significantly. And if it is a noninverting amp it has to be a differential measurement, even more difficult to do.
  Reply With Quote
Old 4th March 2012, 09:01 PM   #3057
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
WHY not just short the 1.8K feedback resistor, which will give the full open loop gain?. It takes a small clip-lead, only. The only thing that you must be careful with is that the output will change between 30-70dB, and you HAVE to turn down the drive oscillator accordingly, before shorting. The servo should keep the DC offset OK. Just a guess. '-)
  Reply With Quote
Old 5th March 2012, 01:39 AM   #3058
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by dvv View Post
Really? How so?
Simply look at the Specs...

Quote:
Originally Posted by dvv View Post
And assuming for the moment you are right, that does not change my liking them one little bit. They still sound good to me, and that's all that matters to me. They can measure as they like.
Than maybe you must amend your dictum: "Assuming that the THD levels on both are below say 0.07% PEAK" regarding what THD is inaudible.

Ciao T
  Reply With Quote
Old 5th March 2012, 01:57 AM   #3059
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by vacuphile View Post
Sometimes it does no harm to let half informed blabber go on, but when it comes to discrediting some of the best drivers available to the DIY community, the record has to be set straight.
The record is straight.

Maybe you do not know what is available from the large chinese OEM's? Even more fun is who you tend to meet in their corridors and who has their drivers made there (sorry, signed a NDA so cannot tell).

I must admit that I have a general dislike for typical 1" softdomes. From the cheapest to the most expensive one there is not a lot of audible difference.

The ones I have here have an ND Magnet Stucture and as much chamber as the small magent system allows. Measurements are easily comparable with the best out there. They do not use ferrofluid. And yes, they are 1USD/pcs unselected and bulk packed.

Ciao T
  Reply With Quote
Old 5th March 2012, 02:01 AM   #3060
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by tvrgeek View Post
Don't know which "super" Chinese tweeters you are referring to
Nothing "super", just very soldily engineered OEM Parts.

The actual user must add a faceplate (or insert into an opening machined into the front panel) and they actually are also found in some VERY expensive commercial speakers.

I would suggest to look well past the common 1" Softdome genre.

Ciao T
  Reply With Quote

Reply


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

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
Thread Thread Starter Forum Replies Last Post
Quality Control differences = variations in sound quality? KT Class D 3 4th June 2014 12:02 AM
Sound Card for Measurements Marik Solid State 2 2nd January 2012 08:59 PM
Sound Card Recommendations (For Audio Measurements) dchisholm Equipment & Tools 5 16th July 2011 09:40 AM
How to protect sound card during amp measurements? okapi Everything Else 13 2nd September 2008 03:06 PM
Sound cards - test and measurements jackinnj Everything Else 2 5th July 2003 03:02 PM


New To Site? Need Help?

All times are GMT. The time now is 06:08 PM.


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