hypex ncore - Page 415 - diyAudio
Go Back   Home > Forums > Commercial Sector > Vendor Forums > Vendor's Bazaar

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
Reply
 
Thread Tools Search this Thread
Old 23rd May 2012, 06:09 AM   #4141
diyAudio Member
 
Join Date: Jan 2007
Quote:
Originally Posted by StigErik View Post
I almost lost count of them woofers myself.

I run four woofers on each NC400, wired in parallel... ....But then the quality of the bass we can get with dipoles is unmatched.
Re. wires, good, I thought so... but honestly I'm shocked at the price you pay for the bass you get. I'm not making a value judgment, but I've built and tweaked many big systems with >10x less LF cancellation than yours, but which had magnificently accurate and extended bass. I've never seen such a setup as yours. The other thing is given the spacing of those cabinets, I would expect time coherence of the direct LF signal to be acceptable at only a tiny position, and the other drivers would need also delayed and alongside the front bass cabinets. Where are the other drivers? You must use a delay for the front cabinets, but that again would wreck any coherence of room reflections. Are your walls nearly anechoic? I am baffled by the lack of baffles. But consider that I dislike D'Appolito layouts (but enjoy some planar systems) for the same reason, they too spread wide the drivers of a channel, so I sit at the opposite end of the field of design. Thank you for sharing.

Quote:
Originally Posted by Immelman View Post
No, very impressive! And with your comments, puts a stamp on the notion that to achieve ultra low OB bass in a home setting is nearly impossible. I didn't believe it before. Thanks.
Pardon my ignorance, what is OB? Is it something like ohne(without)-baffle, because that is what I see.

EDIT: Doh, never mind (smacks head). When I've heard that term I always assumed *some* baffle: such thing swork fine when the wavelength is less than the baffle radius...

I still don't know what Erlend is trying to achieve, though I feel less alone in that ignorance.

Last edited by Sam Lord; 23rd May 2012 at 06:22 AM.
  Reply With Quote
Old 23rd May 2012, 08:21 AM   #4142
diyAudio Member
 
StigErik's Avatar
 
Join Date: Feb 2008
Quote:
Originally Posted by Sam Lord View Post
Re. wires, good, I thought so... but honestly I'm shocked at the price you pay for the bass you get. I'm not making a value judgment, but I've built and tweaked many big systems with >10x less LF cancellation than yours, but which had magnificently accurate and extended bass. I've never seen such a setup as yours. The other thing is given the spacing of those cabinets, I would expect time coherence of the direct LF signal to be acceptable at only a tiny position, and the other drivers would need also delayed and alongside the front bass cabinets. Where are the other drivers? You must use a delay for the front cabinets, but that again would wreck any coherence of room reflections. Are your walls nearly anechoic? I am baffled by the lack of baffles. But consider that I dislike D'Appolito layouts (but enjoy some planar systems) for the same reason, they too spread wide the drivers of a channel, so I sit at the opposite end of the field of design. Thank you for sharing.

Pardon my ignorance, what is OB? Is it something like ohne(without)-baffle, because that is what I see.

EDIT: Doh, never mind (smacks head). When I've heard that term I always assumed *some* baffle: such thing swork fine when the wavelength is less than the baffle radius...

I still don't know what Erlend is trying to achieve, though I feel less alone in that ignorance.
OB = Open Baffle ....

The main problem with OB's is extremely low efficiency at low frequencies, because of the massive acoustic cancellation. With an OB, required cone excursion and/or area goes up with a factor of 8 per octave - 20 Hz requires 8 times as much as 40 Hz.

I wanted to get 100 dB @ 20 Hz with less than 1% THD, and to really get that you see how much cone area is required.

Sure, a 15" can work well down to 40 Hz or so, but never to 20 Hz.

Both woofer towers are placed at equal distance from the listening position. The main dipoles are B&G RD-75 ribbons placed in the middle between each pair of woofers. The ribbons are delayed to match with the woofers. It is optimized for a single listening position of course.

Front wall is near-anechoic as you suspected.
__________________
dipoles dipoles dipoles dipoles dipoles dipoles dipoles dipoles and dipoles
  Reply With Quote
Old 23rd May 2012, 08:33 AM   #4143
OllBoll is online now OllBoll  Sweden
diyAudio Member
 
Join Date: Nov 2010
Quote:
Originally Posted by StigErik View Post
OB = Open Baffle ....

The main problem with OB's is extremely low efficiency at low frequencies, because of the massive acoustic cancellation. With an OB, required cone excursion and/or area goes up with a factor of 8 per octave - 20 Hz requires 8 times as much as 40 Hz.

I wanted to get 100 dB @ 20 Hz with less than 1% THD, and to really get that you see how much cone area is required.

Sure, a 15" can work well down to 40 Hz or so, but never to 20 Hz.

Both woofer towers are placed at equal distance from the listening position. The main dipoles are B&G RD-75 ribbons placed in the middle between each pair of woofers. The ribbons are delayed to match with the woofers. It is optimized for a single listening position of course.

Front wall is near-anechoic as you suspected.
One thing I've wondered about is why you don't increase the path difference D to increase the low frequency extension. Since you have so many woofers and they are all active you should be able to turn say two of the arrays into pure subs with very long path difference, say 1-2 m but only play up to say 40 hz.
  Reply With Quote
Old 23rd May 2012, 08:43 AM   #4144
diyAudio Member
 
StigErik's Avatar
 
Join Date: Feb 2008
Increasing the path length will lower the upper usable frequency, and I XO at 200 Hz,which is the absolute maximum for the path length I have here.

An other thing is that I want all woofer towers to play the entire 20-200 Hz range. The reasons are two: 1. I want the woofers to have approx the same height of the wave-front as the main ribbons. 2. With only one woofer tower per channel playing up to 200 Hz, stereo image is affected since the distance between L and R channels will not be the same for the woofers as for the ribbons. Its also easy to hear the location of the bass towers with only one of them playing. With both of them covering the same frequency range, they form a phantom source between them, which is exactly where the ribbons are placed. In other words, the entire frequency range sounds like coming from the same location and with the same height of the wavefront.
__________________
dipoles dipoles dipoles dipoles dipoles dipoles dipoles dipoles and dipoles
  Reply With Quote
Old 23rd May 2012, 09:11 AM   #4145
diyAudio Member
 
Join Date: Jan 2007
StigErik, thank you for explaining your design, would love to hear it someday.
Cheers, Sam

Last edited by Sam Lord; 23rd May 2012 at 09:14 AM.
  Reply With Quote
Old 23rd May 2012, 09:36 AM   #4146
Julf is offline Julf  Europe
diyAudio Member
 
Join Date: Oct 2011
Location: Amsterdam, The Netherlands
Quote:
Originally Posted by StigErik View Post
Sure, a 15" can work well down to 40 Hz or so, but never to 20 Hz.
But two of them in a 3 m x 2 m x 1.5 m steel-reinforced-concrete folded horn works pretty well...
  Reply With Quote
Old 23rd May 2012, 10:18 AM   #4147
diyAudio Member
 
StigErik's Avatar
 
Join Date: Feb 2008
I was talking about Open Baffle .... not horns.
__________________
dipoles dipoles dipoles dipoles dipoles dipoles dipoles dipoles and dipoles
  Reply With Quote
Old 23rd May 2012, 05:13 PM   #4148
diyAudio Member
 
Join Date: Nov 2005
Location: Portland. Oregon
Quote:
Originally Posted by StigErik View Post
Front wall is near-anechoic as you suspected.
Stig, you should acquaint yourself with the LEDE work of various studio designers such as Dave Davis if you haven't already.

LEDE = live end dead end

from sweetwater sound site:
LEDE - Live End, Dead End
LEDE is a trademarked term for a particular acoustic design. In an LEDE studio, the area around the monitors is deadened, or made absorbent acoustically. The remainder of the room (behind the listener) is made "live" or reflective. The main principle is that the arrival of reflections at the console is in a specific order: 1. direct sound from the monitors; 2. First studio reflection (from the recording room, through the mics and monitors); 3. First control room reflection (off the back wall, assuming it is 10 feet or so behind the engineer). The idea is that by staggering these arrivals, the control room reflections don't interfere with monitoring recorded studio acoustics.



or

Recording Studio Design, 2nd Edition > Chapter 17 The Live-End, Dead-End approach - Pg. 437: Safari Books Online


There is a lot of previous work in these areas that can be beneficial to know.

Alan Garren
  Reply With Quote
Old 23rd May 2012, 05:44 PM   #4149
diyAudio Member
 
StigErik's Avatar
 
Join Date: Feb 2008
Yup, LEDE is the way I designed the room. However, with a diffusor covering my entire rear wall, there really is no "first control room reflection", as you can see from the ETC below.

Click the image to open in full size.
__________________
dipoles dipoles dipoles dipoles dipoles dipoles dipoles dipoles and dipoles
  Reply With Quote
Old 24th May 2012, 07:47 AM   #4150
diyAudio Member
 
StigErik's Avatar
 
Join Date: Feb 2008
Quote:
Originally Posted by pieter t View Post
But I also like larger scale (symphonic) music, and in that respect I too often miss that very last bit of weight; the feeling of "pressure" at bass attacks as can be experienced in the concert hall is just not quite there with the OB bass.
For me it works OK for 80%, but I want that last bit too; it looks like I will extend OB down as much as possible, but will try a low tuned bass reflex for the lowest two octaves, up to 80 Hz or so.
I found the same thing too, and I almost wanted to accept that OB's could not give the same bass "impact" as boxed woofers, because OB's dont pressurize the room.....

However, when I switched to Ncore amps for my OB woofers, the whole thing changed. Its amazing how much better the Ncore is in the bass range than other amps I've tried (including UcD 400 HG), especially when it comes to transient "attack", overall clarity and control.

( are we back ontopic again now perhaps..? )
__________________
dipoles dipoles dipoles dipoles dipoles dipoles dipoles dipoles and dipoles
  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
Hypex problem, who can help Hansms Class D 9 18th August 2013 07:49 AM
Hypex steveww Class D 14 18th November 2010 02:44 PM
Question for those who have tried hypex smps with hypex modules avian Class D 12 3rd March 2009 10:30 AM
Hypex UcD 180AD + signal wires, Power Supply ST, Hypex Transformer TR100A c10h12n2 Swap Meet 7 7th July 2007 04:55 PM
FS: Hypex UcD 400/180AD, hypex toroid Archmage Swap Meet 4 14th November 2006 05:23 AM


New To Site? Need Help?

All times are GMT. The time now is 11:03 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