Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 15th September 2011, 06:44 PM   #11
diyAudio Member
 
speaker dave's Avatar
 
Join Date: Nov 2009
Location: The Mountain, Framingham
Quote:
Originally Posted by gedlee View Post

Why can't you just look at the voltage or current waveform (depends on the setup) with a spectrum analyzer and note the harmonics? Thats certaily hos I would do it.
The link in the referred to thread had 2 tone IM measurements. The IM products were in the -60dB region (and so pretty inconsequential). I thought a visual approach would show the effect only when it got to a serious level, probably in the 1 to 3 % region, and also give an intuitive feel for what was going on. Not everyone has a distortion analyzer.

Yes, many ways to skin the cat.

David
  Reply With Quote
Old 15th September 2011, 09:12 PM   #12
diyAudio Member
 
mondogenerator's Avatar
 
Join Date: Sep 2009
Location: City Of Villans
Blog Entries: 1
actually I like both methods. Gedlee has a point but the test method you(dave) describe may be more accessable to the more amateur audio amateur

If I had thought to bring them along to work, I have a Voltech I could be testing them with right now, in stead of twiddling my thumbs on a ZPF load run.......

If I get around to it this week Ill be sure to post any results I get, IF they look valid
__________________
Every new piece of knowledge pushes something else out of my brain - Homer.....................Simpson
  Reply With Quote
Old 16th September 2011, 07:59 AM   #13
metako is offline metako  Australia
diyAudio Member
 
Join Date: Jun 2005
Location: Melbourne
ERSE THD distortion test drive - YouTube

a valid test?
  Reply With Quote
Old 16th September 2011, 12:07 PM   #14
gedlee is offline gedlee  United States
diyAudio Member
 
Join Date: Dec 2004
Location: Novi, Michigan
Yes and no. Looking at THD alone is not significant since we do not know if this is high order or low order, THD just lumps it all together. I would want to see the actual spectrum of the nonlinearity once it has actually reached saturation. I would say that the film does agree with my assesment that it takles a lot of power to drive thesae coils into nonlinearity. If, as I suspect, the nonlinearity is low order, then 1% would not be audible. Even 3% of pure second order nonlinearity is not audible.

Dave - a laptop and some free software will do spectrums. There is no excuse these days for not using these tools. The LazyJew figures (no offence intended, I can't spell it either) figures will only show rather large amounts of nonlinearity. I don't think that 3% would even be visible.
  Reply With Quote
Old 16th September 2011, 02:46 PM   #15
diyAudio Member
 
Join Date: Nov 2008
Location: Oakmont PA
Quote:
Originally Posted by gedlee View Post
The LazyJew figures (no offence intended, I can't spell it either)
The secret method to quickly find how to spell just about anything is to hit your second browser tab, go to google and start typing. It will quickly get you to the correct spelling and more.... lissajous! (Did take 5 letters!)
  Reply With Quote
Old 16th September 2011, 02:47 PM   #16
diyAudio Member
 
Join Date: Nov 2008
Location: Oakmont PA
The second issue with any loudspeaker inductor is how it behaves when vibrated! The third is what happens when it see .03 volts of offset for a few days.
  Reply With Quote
Old 16th September 2011, 03:43 PM   #17
diyAudio Member
 
mondogenerator's Avatar
 
Join Date: Sep 2009
Location: City Of Villans
Blog Entries: 1
i thought it was lissaguous...maybe thats the English spelling or im thinking of another word entirely!
Pray tell, what WILL happen if a choke is subjected to 30mV DC offset? Besides little or nothing...
__________________
Every new piece of knowledge pushes something else out of my brain - Homer.....................Simpson
  Reply With Quote
Old 16th September 2011, 03:44 PM   #18
gedlee is offline gedlee  United States
diyAudio Member
 
Join Date: Dec 2004
Location: Novi, Michigan
Yes, I always glue down the windings since the companies do not seem to be bonding the windings like they used to. Very thin super glue works great.

You're saying that the voltage heats the inductor? Wouldn't that also be a real problem for the speaker?
  Reply With Quote
Old 16th September 2011, 03:56 PM   #19
diyAudio Member
 
Join Date: Nov 2008
Location: Oakmont PA
Quote:
Originally Posted by mondogenerator View Post
i thought it was lissaguous...maybe thats the English spelling or im thinking of another word entirely!
Pray tell, what WILL happen if a choke is subjected to 30mV DC offset? Besides little or nothing...
Slowly saturates it! really! A few percent in my last one week test, cut short by a power outage, so I don't know the long term limit.
  Reply With Quote
Old 16th September 2011, 03:58 PM   #20
diyAudio Member
 
mondogenerator's Avatar
 
Join Date: Sep 2009
Location: City Of Villans
Blog Entries: 1
@gedlee ive used VPI resin aka micafil. Epoxy based resin, thinned to a light varnish viscosity. Then wrapped in glasstape or polyester tape, and varnished again. Then the whole lot heatshrinked with raychem HT tubing.
Overkill i admit, but a couple of layers of masking tape is all you get on some ive used. Generally the Murata hi current types are ok since they are at least heat shrinked.
These inductors will see a lot more than 30mv in other apps without effect.
@simon: over a week 30mv MAY weakly magnetise the ferrite, but not saturate it. AC current will demag so its a non issue. Just imagine all those ships with PWM propulsion converters, with their 2000amp harmonic filters...working continuous for years...id imagine that would be a problem that wouldnt be tolerated.
__________________
Every new piece of knowledge pushes something else out of my brain - Homer.....................Simpson

Last edited by mondogenerator; 16th September 2011 at 04:05 PM.
  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
Copper coil inductor vs. round core inductor tomchaoda Pass Labs 7 21st September 2011 04:42 AM
inductor/choke/air core/ferrite core. . . same thing? poolorpond Pass Labs 24 29th March 2008 10:55 PM
air core inductor vs. iron core inductor WBS Planars & Exotics 5 7th May 2007 11:02 PM
broken ferrite core for smps sss Car Audio 4 13th April 2004 01:30 AM
AIR-Core Vs Ferrite-Core Inductor in Class-D amplifiers Workhorse Solid State 13 23rd January 2004 09:14 AM


New To Site? Need Help?

All times are GMT. The time now is 05:05 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