NaO Note II RS - Page 2 - diyAudio
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 22nd October 2012, 11:19 PM   #11
diyAudio Member
 
LineSource's Avatar
 
Join Date: Sep 2003
Location: SiliconValley
Quote:
Originally Posted by john k... View Post
Neither tweeter is being pushed very hard in my cases.
John,

Thanks for the tweeter discussion. Your comments match my understanding .... your decision for a high 6Khz xover from the 3.5" ScanSpeak 10F upper midrange in your design allows many tweeter choices, both in diameter and cost.

I have attached the Pdf of the $60 Faital 10" midbass 10FE200 which has a Qts = 0.6, Fs= 55Hz, and Xmax =4.6mm which could be another lower midbass option for your new speaker.

The $80 ScanSpeak 10F allows using low cost 0.75" tweeters and a low cost midbass.
Attached Files
File Type: pdf 10FE200_datasheet.pdf (63.3 KB, 69 views)
  Reply With Quote
Old 23rd October 2012, 12:07 AM   #12
diyAudio Member
 
john k...'s Avatar
 
Join Date: Aug 2004
Location: US
The way it is, it will be all ScanSpeak Discovery except for the Vifa tweeter, 10" woofers, 8" lower mid and 4" upper mid. Tweeter is the Vifa OX20SC00.
And, as I said, it will be all active with dsp crossover. I will provide the specification for the transfer functions so that any dsp crossover can be used (or it someone wants to design an analog version). I will also supply a configuration file for the miniDSP 2x8 (or the newer 4x10 Hd which is the same as the 2x8, but in a finished enclosure).
__________________
John k.... Music and Design NaO Dipole Loudspeakers.
  Reply With Quote
Old 23rd October 2012, 01:06 AM   #13
boris81 is offline boris81  United States
diyAudio Member
 
Join Date: Oct 2009
Location: white plains, ny
Thank you for sharing the design process with us!
As you may know already Lynn Olson has been revealing details of his latest design as well. His goals are arguably different but he insists on using one driver through the most sensitive 1-3kHz region. Similarly to your design he plans to use a supertweeter for improved directivity in the last octave. He advises a steep slopes crossover around 7kHz.

Although a crossover that high in frequency will result in multiple lobes on the vertical axis the common understanding is that they will be difficult to perceive. Would you please share some of your own insights about this design approach?
  Reply With Quote
Old 23rd October 2012, 01:50 AM   #14
diyAudio Member
 
john k...'s Avatar
 
Join Date: Aug 2004
Location: US
Quote:
Originally Posted by boris81 View Post
Thank you for sharing the design process with us!
As you may know already Lynn Olson has been revealing details of his latest design as well. His goals are arguably different but he insists on using one driver through the most sensitive 1-3kHz region. Similarly to your design he plans to use a supertweeter for improved directivity in the last octave. He advises a steep slopes crossover around 7kHz.

Although a crossover that high in frequency will result in multiple lobes on the vertical axis the common understanding is that they will be difficult to perceive. Would you please share some of your own insights about this design approach?
I have been looking at different crossover points and slopes between the upper mid and the tweeter. That is the thing about dsp crossovers, they can be changed easily and quickly. Basically, I design the crossover with a number of active blocks (HP, LP filter, shelving filters and Q boost/notch filters) with typical software and model the response. Once I have determined the circuit parameters they can be used to implement the dsp crossover filters and verify the modeled result, listen and decide if the result is satisfactory. I'll concentrate on the uppermid/tweeter x-o since the lower mid/upper mid x-o really isn't an issue. I'm currently looking at 4th to 8th order slopes between uppermid and tweeter and also lowering the x-o point from 6k to 4k Hz. The lower x-o point and steeper slopes improves vertical lobing between the upper mid and tweeter. But also, recognize that if the lobe give good dispersion of over +/- 15 degrees that means the listening window at 10' from the speaker is about +/- 2.5' relative to the design axis. And, as I said, with a dsp crossover it is a very simple matter to add delay to change the direction of the main lobe. This is one of the very nice features of using a dsp crossover as opposed to analog active or passive where the offset delays are typically fixed to direct the main lobe on the design axis.

I'll also point out that when this design is finalized I will be supplying configuration files not only for the miniDSP 2x8 but for the Bodzio Ultimate Equalizer PC based dsp crossover which will allow the system to be completely linear phase, thus transient perfect on the design axis.
__________________
John k.... Music and Design NaO Dipole Loudspeakers.
  Reply With Quote
Old 23rd October 2012, 07:40 AM   #15
Rudolf is offline Rudolf  Germany
diyAudio Member
 
Rudolf's Avatar
 
Join Date: Mar 2003
Location: Germany
Quote:
Originally Posted by LineSource View Post
To your ears, what sounds better as a dipole tweeter: the NEO3 or a back-to-back pair of 0.75" domes?
Does a back-to-back pair of Dayton ND20FA-6 count as 0.75" domes?
I haven't compared them side by side with the Neo3 - there have been about 2 years between them. But still I can tell you what decides over which is better: the front wall condition.
With those back-to-back drivers you always have the option to attentuate the rear driver somewhat - or even switch it off. With the Neo3 it became inevitable to take absorption measures at the first reflection points of the front wall. In both cases I have tried to keep the baffle around the drivers as small as possible - using none.

It is quite an eye-opener to me when I see how both SL and john k are somewhat ambivalent about the use (or not) of the rear dome.

Rudolf
__________________
www.dipolplus.de
  Reply With Quote
Old 23rd October 2012, 11:01 AM   #16
diyAudio Member
 
john k...'s Avatar
 
Join Date: Aug 2004
Location: US
Quote:
Originally Posted by Rudolf View Post
It is quite an eye-opener to me when I see how both SL and john k are somewhat ambivalent about the use (or not) of the rear dome.

Rudolf
Ambivalent? I wouldn't say that. I've always favored a rear tweeter on a dipole. I did not have a rear tweeter on the Mini, but that was kind of an "introduction to dipoles" speaker intended to show the character of dipole midrange. Bout the NaO II and Note have front and rear radiation all the way up. This new version of the note will probably have a rear tweeter but currently doesn't more due to the way the design has progressed (see post 3). I think the roll of the rear tweeter is a very different when having a crossover at 1.4k (Orion) or 2.2k (NaO II) or 4k-6k (Note).

I agree that the front wall (that behind the speakers) is critical and I highly recommend treatment of that wall, and the room in general, to achieve the optimum sound and image. I fully endorse the idea that the room is a component in the system and a major one at that.
__________________
John k.... Music and Design NaO Dipole Loudspeakers.
  Reply With Quote
Old 23rd October 2012, 02:37 PM   #17
Davey is online now Davey  United States
diyAudio Member
 
Join Date: Dec 2001
Location: Bremerton, WA.
Fellas,

When rear tweeters are used, are you still designing your system(s) for flattish on-axis response?

Cheers,

Dave.
  Reply With Quote
Old 23rd October 2012, 05:27 PM   #18
diyAudio Member
 
john k...'s Avatar
 
Join Date: Aug 2004
Location: US
Hi Dave,

I really don't care to revist the "flat in not correct" argument. My approach has always been to design the speaker to have flat axial response and provide the ability for the listener to make adjustments to the characteristic on the top and bottom ends. With dipole designs like the NaO II and Orion there are issues with tweeter bloom that I believe have an impact on what the top end should be. And while cutting or boosting the top end will have an overall impact on preception, it maintains the ratio of direct to reflected sound. Improving directivity, and adding/removing damping to/from a room, on the other hand, has the effect of changing the ratio of direct to reflected sound. Maintaining flat response and making such adjustments can have the exact same effect on the reverberant sound field as shelving down or boosting the high end response. The differences comes in the direct sound.

I would agree that the reverberant sound field should generally have a downward slope as the frequency rises, but I would hesitate to suggest that the direct sound should be follow suite.
__________________
John k.... Music and Design NaO Dipole Loudspeakers.
  Reply With Quote
Old 23rd October 2012, 07:21 PM   #19
6.283 is offline 6.283  Germany
diyAudio Member
 
Join Date: Aug 2008
Location: Black Forest
Not my intention to start this discussion all over again either. Especially not in this thread. But my omnis have taught me that the flatness of the FR is determined by the diffusivity of the sound field (which is a result of dispersion width and decay properties of the room) and psychoacoustic demands related to diffusivity.
Very directional speakers like Geddes' need a flat on-axis FR. But every moderately wide dispersion speaker should/can deviate from that if the room is not exactly a stuffed pillow. And my dipoles in my room fall clearly into a category for a non-flat equalization.
__________________
2Pi-online.de
  Reply With Quote
Old 23rd October 2012, 10:35 PM   #20
puppet is offline puppet  United States
diyAudio Member
 
Join Date: Dec 2011
Location: The Dells, WI
Hi john k...

What are/is Music and Designs long term goal for audio reproduction?

In what way(s) do you feel that the NaO Note II RS moves you toward that goal?
  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
NaO Note preview gainphile Multi-Way 161 19th December 2012 10:53 AM
NaO II RS gainphile Multi-Way 18 7th March 2012 10:28 PM
NaO II and miniDSP john k... miniDSP 27 31st July 2011 11:51 AM
FS: Audio Note TRANS-010; Audio Note 20H 50mA choke; Black Gate Wk "power tank" Joseph0 Swap Meet 1 24th May 2006 05:17 AM
RS Labs RS-A1 Tonearm New Unused Boxed mozfet Swap Meet 4 6th September 2004 10:51 PM


New To Site? Need Help?

All times are GMT. The time now is 08:34 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