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

SBAcoustics SB17NBAC35-4 and SB17NBAC35-8 measurements!
SBAcoustics SB17NBAC35-4 and SB17NBAC35-8 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 14th March 2019, 08:39 AM   #11
LineSource is offline LineSource  United States
diyAudio Member
 
LineSource's Avatar
 
Join Date: Sep 2003
Location: SiliconValley
Quote:
Originally Posted by Tropic View Post
These sound great in the mid range but I found the response in the female talking voice range to be very lumpy.
For typical 2-way cabinet widths, baffle step effects as high as +/- 2db can occur over the vocal range.
1) compare sound between against-the-wall placement and into-the-room placement.

With aluminum 7" midrange using 2kHz LR2 circuits, beaming from upper harmonics cone break-up will only see -18db attenuation.
1) Aim both speakers directly at the listener and run test tracks while listening for SPL bumps.

===========
Even with a physically stepped front baffle for T-M time alignment, Troels Gavensen's SBAcoustics 61-NAC design uses a 2.1kHz crossover frequency with BW3 circuit on the SB26ARC-4 aluminum tweeter and LR4 circuit on the SB17NAC35-5 aluminum midrange. The midrange cone break-up artifacts are attenuated by 30db.

From simulations, a 2kHz crossover frequency using BW3 circuit on the tweeter and BW3 circuit on the midrange models well with midrange cone break-up artifacts attenuated by 27db
  Reply With Quote
Old 14th March 2019, 01:34 PM   #12
celef is offline celef
diyAudio Member
 
Join Date: Nov 2012
Quote:
Originally Posted by Tropic View Post
The frequency response on the left is the SB17NAC35-4 response measured at 1m with Room EQ Wizard (REW) using the USB microphone that came with my Anthem MRX 1120 amp. I graphed it in Excel so there is no smoothing and with a frequency step of 0.4 Hz it is very jagged.



The graph on the right is something I looked up to see the frequency of the human voice since that is the frequency where I have problems with my speaker. The loudest portion of the female voice (in red) is 160-280 hz and you can see the response jump around a lot in that range.


I use a sub-woofer in my system crossed over at 80 hz. Is anyone else using it down to that range or are people exclusively using this in 3-way designs?
thank you for the info, i can not detect anything wrong in the 200hz region, see responsgraphs below for sb17nac, mfc, nrxc, satori.

if you time gate your measurement so that we can see the response without reflections, how does the frequency respons look then? Too much room reflections now obscure the direct sound.
Attached Images
File Type: jpg 17nrxc-200.jpg (40.2 KB, 149 views)
File Type: jpg 17mfc-200.jpg (40.3 KB, 132 views)
File Type: jpg satori-200.jpg (40.0 KB, 130 views)
File Type: jpg 17nac-200.jpg (40.1 KB, 129 views)
  Reply With Quote
Old 14th March 2019, 02:12 PM   #13
LineSource is offline LineSource  United States
diyAudio Member
 
LineSource's Avatar
 
Join Date: Sep 2003
Location: SiliconValley
Quote:
Originally Posted by Tropic View Post
I use a sub-woofer in my system crossed over at 80 hz.
Just noticed sub-woofer added in post #10.

With the subwoofer switched-OFF do you still hear irregular SPLs on female voices? Does the sound-stage change, improve or degrade, with the 80Hz subwoofer OFF? If you change the subwoofer crossover to 60Hz, do vocals or the sound-stage change, improve or degrade?
  Reply With Quote
Old 20th March 2019, 07:07 AM   #14
Tropic is offline Tropic
diyAudio Member
 
Join Date: Dec 2018
I'm fairly new to speaker building so don't understand reading those responsgraphs or time gating my measurement. The sub-woofer makes no difference to how I perceive the spikes in loudness in my system.
I did the measurements in my theatre, horizontally, away from the the walls which all have curtains like a proper theatre so there are virtually no sound reflections and the sub-woofer was not involved.
Attached are the responses from the built speaker (two SB17NAC35-4 in series with a SB26ADC crossed at 2,000 hz 2nd order in 51 litre ported) measured using REW (using 1/48 smoothing) then the raw ARC response as well as the crossover design.
I chose this combination because I was after accurate flat response without colouration especially in the vocal range, and these drivers have people raving about them here. Above the vocal range these are awesome but I'm disappointed of the response within the vocal range.
The response of these drivers seems a lot less smooth than the ones sb published or those by AudioExcite. Maybe I'm doing something wrong? Has anyone else measured these, especially in the low end down to 80 hz?
Attached Images
File Type: jpg REW complete speaker response 1-48 smoothing.jpg (271.9 KB, 63 views)
File Type: jpg ARC complete speaker response.jpg (78.9 KB, 23 views)
File Type: jpg Crossover design.jpg (186.1 KB, 29 views)
File Type: jpg theatre.jpg (290.4 KB, 32 views)
File Type: jpg theatre speaker with old drivers.jpg (340.0 KB, 27 views)
  Reply With Quote
Old 20th March 2019, 02:07 PM   #15
gornir is offline gornir  Sweden
diyAudio Member
 
gornir's Avatar
 
Join Date: Sep 2007
Location: Sweden
SBAcoustics SB17NBAC35-4 and SB17NBAC35-8 measurements!
Quote:
Originally Posted by Tropic View Post
I'm fairly new to speaker building so don't understand reading those responsgraphs or time gating my measurement. The sub-woofer makes no difference to how I perceive the spikes in loudness in my system.
I did the measurements in my theatre, horizontally, away from the the walls which all have curtains like a proper theatre so there are virtually no sound reflections and the sub-woofer was not involved.
Attached are the responses from the built speaker (two SB17NAC35-4 in series with a SB26ADC crossed at 2,000 hz 2nd order in 51 litre ported) measured using REW (using 1/48 smoothing) then the raw ARC response as well as the crossover design.
I chose this combination because I was after accurate flat response without colouration especially in the vocal range, and these drivers have people raving about them here. Above the vocal range these are awesome but I'm disappointed of the response within the vocal range.
The response of these drivers seems a lot less smooth than the ones sb published or those by AudioExcite. Maybe I'm doing something wrong? Has anyone else measured these, especially in the low end down to 80 hz?
Hi Tropic,

How did you come up with this cross-over design? Is it based on any measurements and what target cross-over topology and slopes did you aim for in this design?

From your control measurement it seems like the frequency response is very hot between 2.5-6kHz and a bit elevated between 0.8-1.2kHz. You might need some more baffle step compensation and a single 1.5mH coil might not be sufficient to achieve that. Also the tweeter response probably needs some adjustments. Again, what topology and slopes are you aiming for? An electrical 2nd order cross-over for both the woofer and tweeter is probably not enough for doing the job for you.

I've attached a picture showing two SB17NBAC35-4 connected in series. The measurement is done at 1m exactly in the middle between the two mid-woofers which has a spacing of 29cm between them. The enclosure width is 20cm.

As you can see, your mid-woofer cross-over achieves almost a 3rd order BW topology acoustically, but has insufficient roll-off at higher frequencies and perhaps too little baffle step compensation.

Cheers,

/Göran

Click the image to open in full size.
__________________
Author of the "AudioExcite Loudspeaker Design" website & Technical Consultant for HULGICHAUDIO
http://www.audioexcite.com http://www.hulgichaudio.com.au/
  Reply With Quote

Reply


SBAcoustics SB17NBAC35-4 and SB17NBAC35-8 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
Low cost SBacoustics 2 Way Dandi44 Multi-Way 0 17th January 2019 02:10 AM
SBAcoustics 3-Way Classic VS SBA 16 MTM inetboy Multi-Way 29 27th April 2017 08:49 PM
Commercial design that use SBAcoustics Tw diypass Multi-Way 4 8th July 2016 09:47 PM
SBAcoustics SB29RDC How low would you go? mayhem13 Multi-Way 18 10th September 2015 03:06 AM
SBAcoustics mid diypass Multi-Way 12 1st August 2015 10:59 AM


New To Site? Need Help?

All times are GMT. The time now is 12:30 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