Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

SB Acoustics SB17NAC35-4 measurements!
SB Acoustics SB17NAC35-4 measurements!
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 24th August 2016, 07:52 PM   #11
gornir is offline gornir  Sweden
diyAudio Member
 
gornir's Avatar
 
Join Date: Sep 2007
Location: Sweden
SB Acoustics SB17NAC35-4 measurements!
Quote:
Originally Posted by 454Casull View Post
In your measurements there's a substantial dip at 4.2 kHz. Is this baffle diffraction related or an issue with the measurement conditions, or does the driver actually have a dip there?
No I don't think it's the baffle. SB Acoustics use an IEC 268-5 baffle for their measurement and the dip is almost identical to mine.

/Göran
Attached Images
File Type: jpg Picture 1 -- 6in SB17NAC35-4 AE.jpg (154.2 KB, 810 views)
File Type: jpg Picture 2 -- 6in-SB17NAC35-4.jpg (72.9 KB, 788 views)
__________________
Author of the "AudioExcite Loudspeaker Design" website & Technical Consultant for HULGICHAUDIO
http://www.audioexcite.com http://www.hulgichaudio.com.au/
  Reply With Quote
Old 24th August 2016, 08:31 PM   #12
Juhazi is offline Juhazi  Finland
diyAudio Member
 
Juhazi's Avatar
 
Join Date: Mar 2007
Location: Jyväskylä, Finland
To me this is just the typical dip with hard cones. It is based on wavelength/radiating diameter/cone profile/plug interaction. Right above this directivity suddenly starts to increase.Usually this happens a bit lower for this size drivers.

See this Klippel paper https://www.klippel.de/fileadmin/kli...ion_Poster.pdf

This is SEAS Excel mag W16 - similar dip at 2,5kHz
Click the image to open in full size.
__________________
Radikal aktivist AINOgradient speaker project
  Reply With Quote
Old 24th August 2016, 08:35 PM   #13
Bill poster is offline Bill poster  Thailand
diyAudio Member
 
Bill poster's Avatar
 
Join Date: Jun 2008
Location: Bangkok/London
Default SB Acoustics SB17NAC35-4 measurements!

Now compare to one of the best 5.5" midbass drivers on the market
An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.

I'd say the SB ain't too bad.
  Reply With Quote
Old 24th August 2016, 10:31 PM   #14
5th element is offline 5th element  United Kingdom
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
Well as Juhazi says the dip is just typical of hard cones, they always have a falling response before the breakup.
__________________
What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz! Now with website! www.5een.co.uk under construction.
  Reply With Quote
Old 25th August 2016, 04:46 AM   #15
454Casull is offline 454Casull  Canada
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Quote:
Originally Posted by gornir View Post
No I don't think it's the baffle. SB Acoustics use an IEC 268-5 baffle for their measurement and the dip is almost identical to mine.

/Göran
Hm. Since the off-axis response dips in roughly the same way as the on-axis response, it should be fairly easy to fix with DSP.
  Reply With Quote
Old 25th August 2016, 05:28 AM   #16
5th element is offline 5th element  United Kingdom
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
You would not want to cross that high anyway for off axis reasons.
__________________
What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz! Now with website! www.5een.co.uk under construction.
  Reply With Quote
Old 25th August 2016, 05:54 AM   #17
Juhazi is offline Juhazi  Finland
diyAudio Member
 
Juhazi's Avatar
 
Join Date: Mar 2007
Location: Jyväskylä, Finland
Soft paper cones typically are more shallow and because of deformations of the cone they don't show similar dip (at wavelength=radius).
I was happy to hear the lecture of Peter Larsen of LoudSoft some two years ago at AES conference. He has developed several nice simulator programs, this is a video of FINECone. I bet that the nice people at SB are familiar to this! The new midrange is a masterpiece of an achievement in cone design!

https://www.youtube.com/watch?v=nlaGb67RPwc
__________________
Radikal aktivist AINOgradient speaker project

Last edited by Juhazi; 25th August 2016 at 05:59 AM.
  Reply With Quote
Old 25th August 2016, 06:28 AM   #18
Bill poster is offline Bill poster  Thailand
diyAudio Member
 
Bill poster's Avatar
 
Join Date: Jun 2008
Location: Bangkok/London
5th what's the highest you'd suggest?
  Reply With Quote
Old 25th August 2016, 05:55 PM   #19
gornir is offline gornir  Sweden
diyAudio Member
 
gornir's Avatar
 
Join Date: Sep 2007
Location: Sweden
SB Acoustics SB17NAC35-4 measurements!
Quote:
Originally Posted by Bill poster View Post
5th what's the highest you'd suggest?
Personally, I would aim at no more than 2-2.5kHz.

Regards

/Göran
__________________
Author of the "AudioExcite Loudspeaker Design" website & Technical Consultant for HULGICHAUDIO
http://www.audioexcite.com http://www.hulgichaudio.com.au/
  Reply With Quote
Old 25th August 2016, 06:59 PM   #20
5th element is offline 5th element  United Kingdom
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
Quote:
Originally Posted by Bill poster View Post
5th what's the highest you'd suggest?
2.5kHz if you want a directivity match to a suitable waveguide.

2kHz if to a standard dome.

People have a habit of crossing too high. If you're crossing between direct radiators then ideally you want to cross before the lower driver (in frequency) starts showing any hint of beaming. This doesn't tend to be practical when normal tweeters are concerned so it's more a case of damage limitation. The damage in this case being damage caused to the off axis response and helping to avoid the typical 'wide-narrow-wide' dispersion profile.

2kHz is a good compromise for 6" drivers, but if you can go down to 1.5kHz then all the better.

Really it depends on the system and the tweeter used. Some tweeters are very capable of crossing down at 1.5kHz whereas others aren't. The capable ones will cross at 1.5kHz and play loud until the cows come home, the less capable ones will cross that low but be uncomfortable at high playback levels.

As a stand alone 2 way the 1.5kHz could be the best option, but if you're doing a three way, or high passing the 2 way + sub, then the 2kHz xover might be the better choice, that's if you want to listen loud. Lots of tweeters are good down to 2kHz with a 4th order acoustic slope, so I see little reason in crossing higher.
__________________
What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz! Now with website! www.5een.co.uk under construction.
  Reply With Quote

Reply


SB Acoustics SB17NAC35-4 measurements!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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
New SB Acoustics 3 way from Troels cph2000 Multi-Way 170 22nd January 2019 12:58 PM
SB Acoustics SB65WBAC25-4 - What to do? xrk971 Full Range 15 8th December 2017 07:20 PM
FS: SB Acoustics Kalasan (Original from SB Acoustics Factory) + Woofer modules fishball79 Swap Meet 7 18th April 2016 12:26 AM
SB Acoustics smallangryboy Multi-Way 13 26th April 2014 11:54 PM
SB Acoustics Satori MW16P-4 Measurements! gornir Multi-Way 18 24th June 2013 07:29 AM


New To Site? Need Help?

All times are GMT. The time now is 05:22 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki