hypex ncore - Page 44 - diyAudio
 hypex ncore
 User Name Stay logged in? Password
 Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read Search

 Vendor's Bazaar Commercial Vendors large & small hawking their wares

 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
 2nd October 2011, 04:19 PM #431 diyAudio Member     Join Date: Feb 2008 That will reduce the damping factor to below 1. Dont want to do that. __________________ dipoles dipoles dipoles dipoles dipoles dipoles dipoles dipoles and dipoles
 2nd October 2011, 05:56 PM #432 diyAudio Member   Join Date: Aug 2011 Umm, perhaps I don't understand how you're calculating the damping factor. With the nCore having an output impedance of about 1.3 mOhms, there's no way you're anywhere near a DF of 1. If you assume 2.6 ohms for the paralleled woofers, you'd still get about 2.6/.0013=2,000 damping factor. Am I doing this wrong? EDIT: Even if you divide in half again, you still have a damping factor of 1000. Perhaps you misread the chart and were thinking the nCore has an output resistance of 1 Ohm? Last edited by FloridaBear; 2nd October 2011 at 06:01 PM.
 2nd October 2011, 06:31 PM #433 diyAudio Member   Join Date: Aug 2011 One other thought on this topic: Why would you be interested in NCores for driving woofers? It would be so much more economical to use the UcD line instead (as you're doing now).
diyAudio Member

Join Date: Feb 2008
Quote:
 Originally Posted by FloridaBear Umm, perhaps I don't understand how you're calculating the damping factor. With the nCore having an output impedance of about 1.3 mOhms, there's no way you're anywhere near a DF of 1. If you assume 2.6 ohms for the paralleled woofers, you'd still get about 2.6/.0013=2,000 damping factor. Am I doing this wrong? EDIT: Even if you divide in half again, you still have a damping factor of 1000. Perhaps you misread the chart and were thinking the nCore has an output resistance of 1 Ohm?
With two woofers in series, one of the woofers act as a series impedance for the other woofer. Thus, the damping factor can never be higher than 1.
__________________
dipoles dipoles dipoles dipoles dipoles dipoles dipoles dipoles and dipoles

diyAudio Member

Join Date: Feb 2008
Quote:
 Originally Posted by FloridaBear One other thought on this topic: Why would you be interested in NCores for driving woofers? It would be so much more economical to use the UcD line instead (as you're doing now).
If economy was the issue, I would not use Hypex products at all......

Maybe sound quality matters?
__________________
dipoles dipoles dipoles dipoles dipoles dipoles dipoles dipoles and dipoles

 2nd October 2011, 08:26 PM #436 diyAudio Member   Join Date: Apr 2004 Location: BE/NL/RW/ZA I take it StigErik considers one woofer's impedance as a series impedance added to the amp's output impedance when calculating the DF the other woofer sees. If you take DF literally you could reason like that. After all, when you knock on one woofer its motion will hardly be damped. The other woofer will even move in the opposite direction. That's what I meant earlier by saying that antiphase motion isn't controlled. Imagine however knocking on both woofers at the same time in the same way. At that moment you will feel significant resistance. If the woofers are identical and they aren't knocked on externally their motion resulting from the audio signal will of course be damped pretty much in the same way as if they'd had their own amp. So no, series connection does not cause the woofers to become undamped as far as the movement is generated electrically. Now for the usual disclaimer: a DF of 1000 does not imply 100-fold better damping than a DF of 10. This is quite a good thing since loudspeaker design relies on some resonance with a defined Q i.e. one with a known and finite amount of damping. What makes it finite is the voice coil resistance (plus some known resistance in the crossover). This resistance is electrically connected in series with the amp and is in the several ohms region. If this amp has 100 milliohms or 1 milliohm of output resistance the change in Q of the loudspeaker system is absolutely minimal. It would be rather different if the voice coil were superconducting. In that case a 1 milliohm amp would indeed have a hundredfold greater stopping power than a 100 milliohm amp. You would feel the difference in that in the former case the woofer would not budge when pushed. Has anyone ever known a speaker of which the woofer could not be moved by hand when the inputs are shorted? Thought not. Voice coils aren't superconducting. It amazes me when people report that a certain amplifier (usually one of mine) is wonderfully capable of stopping the woofer motion and more, that they think they can actually see it happening. This is a physical impossibility. Low output impedance has some value, luckily. Speakers are nonlinear things, so a speaker's back EMF is distorted. If you use biwiring on a very low-impedance amp you can stop distortion generated in, say the woofer, from electrically cross-talking into the tweeter. With moderate impedance amps you can only get the same result with biamping. I think this is the only sensible explanation why biwiring sometimes sounds different. I'm not saying the effect is very big but it's hard to argue that it is always inaudible. That's good news for me because Ncore has unusually low output impedance and if it didn't have any value I'd be embarrassed about boasting about it The current capability of the NC400 is around 27A. The UcD400's is 17A. So you can't safely halve the load impedance and be certain that the amp won't ever run out of steam. In this respect I'd like to second FB: just get two UcD400ST's to drive the woofers instead. I think it unlikely that you'd hear a difference between Ncore and UcD in a pure woofer/subwoofer application. Likewise the HG (and certainly HxR) option is overkill for woofer work. One of our bigger industrial customers insists they do hear a clear difference between UcD and a commonly used Danish amp (to the advantage of UcD of course) though. They're serious people so I'll take their word for it. So we probably can't say the quality of the woofer amp doesn't matter at all, but it's perfectly sensible to be rational about the LF amp and splash out on the mid/high amps only. __________________ There's a time for everything, and this is not it. Last edited by Bruno Putzeys; 2nd October 2011 at 08:32 PM.
 2nd October 2011, 08:35 PM #437 diyAudio Member     Join Date: Feb 2008 I'm in a situation where I will need more power amps anyway, since I will double the number of woofers. I have four UcD400's now. The options are to get four more UcD400's, or get four NC400's and load them with half the impedance. If anyone would like to explain why woofers wired in series sounds sloppy compared to parallell wiring... even if they technically/theoretically should not.... ? __________________ dipoles dipoles dipoles dipoles dipoles dipoles dipoles dipoles and dipoles
 2nd October 2011, 11:12 PM #438 diyAudio Member   Join Date: Mar 2011 StigErik, on what do you base your statement about serial connected woofers to sound sloppy?
diyAudio Member

Join Date: Nov 2001
Location: Belgium
Quote:
 Originally Posted by Juhleren StigErik, on what do you base your statement about serial connected woofers to sound sloppy?
I think an important part of Bruno's answer was "If the woofers are identical..." Identical means also indentical enclosure and acoustical loading. Both also have an effect on the impedance seen by the amp. And we all know from measuring T&S parameters that woofers are never fully indentical. If the above makes a difference, I do not know.

Anaother important fact is power I think. If you hear (feel) only the difference when playing pretty loud, then this will probably be your explenation.

Example: woofers are perfecty 8 ohm (flat impedance) and you amp delivers 400 Watt into 8 ohms. If it is a perfect amp, then it will deliver 800 Watt into 4 ohms. But also only 200 Watt into 16 ohms (limited by output voltage).

This means the difference of available power is quite big between the 2 configurations, and when playiing loud , you just might need this extra headroom...

Edit: corrected typos

Last edited by _Wim_; 3rd October 2011 at 05:54 AM.

diyAudio Member

Join Date: Apr 2004
Location: BE/NL/RW/ZA
Quote:
 Originally Posted by StigErik I have four UcD400's now. The options are to get four more UcD400's, or get four NC400's and load them with half the impedance.
Well it's not good for my business to tell you this but since we're talking about the woofers I think this one is a no-brainer. Get extra UcD400's to complement the ones you already have.

Quote:
 Originally Posted by StigErik If anyone would like to explain why woofers wired in series sounds sloppy compared to parallell wiring... even if they technically/theoretically should not.... ?
It's unlikely that the woofers are identical because at the very least the acoustic loads are different. I replied to a similar question earlier:
Quote:
 Originally Posted by Bruno Putzeys Loudspeaker designers tend to avoid series wiring because any antiphase motion of the woofers is not damped at all. I don't know how serious the problem is with modern units but subharmonic oscillations have been reported in the past.
__________________
There's a time for everything, and this is not it.

 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 OffTrackbacks are Off Pingbacks are Off Refbacks are Off Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Hansms Class D 9 18th August 2013 07:49 AM steveww Class D 14 18th November 2010 02:44 PM avian Class D 12 3rd March 2009 10:30 AM c10h12n2 Swap Meet 7 7th July 2007 04:55 PM Archmage Swap Meet 4 14th November 2006 05:23 AM

 New To Site? Need Help?

All times are GMT. The time now is 12:15 PM.