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

2-way active - Looking for peer critique
2-way active - Looking for peer critique
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 April 2019, 02:11 PM   #1
Arnandsway is offline Arnandsway  Netherlands
diyAudio Member
 
Join Date: Nov 2018
Default 2-way active - Looking for peer critique

Hi all,

I opened this thread for anyone to have a look at my design choices and help me in the process in designing my first speaker. Any tips, critique and support is welcome as I am new to this and learning every day.

The monitor should have the following design parameters:
  • Usable for near-field monitoring (1-2 meters)
  • Constant directivity
  • Active XO + bi-amping
  • Low XO point (~1,5 khz)
  • Small woofer-to-tweeter distance
  • Sealed enclosure, for easy integration with subs later on and great transient respons
  • F3 around 60-70 hz
  • Enclosure made out of 25 mm MDF or HDF
  • Budget total max €1000 for the pair
To achieve these goals I have come to the conclusion I want to use these parts:
  • Tweeter: SB Acoustics SB26ADC + 5" elliptical 3D-printed WG made by Augerpro. (can be found here Open source Waveguides for CNC & 3D printing!)
  • Woofer: still unsure so advice is welcome. Right now choice is between Dayton RS180-4 (great for sealed but high 3rd harmonic distortion) or the SB Acoustics SB17NBAC-4 (not great for sealed and f3 goal, but great other parameters.)
  • Hypex FA122 plate amp for digital XO and amp.
  • Enclosure volume ~16L (could change depending on woofer choice).
  • For measuring: a MiniDSP UMIK-1.
For simulating the box enclosure I use UniBox and BoxSim 2.0.

So right now my progress is slowed down by not being able to find the right woofer for my design goals.

After this I would need to know how to properly measure my speaker and set the perfect XO-point. I know there are multiple software-programmes available for this: REW, RePhase and ARTA. I am not familiair with this so I will have to dive deeper into this. Any practical guides or tutorials are welcome.

Hopefully some of you are willing to help. Thanks in advance .

I will keep this thread updated when progress is being made.

Last edited by Arnandsway; 14th April 2019 at 02:14 PM.
  Reply With Quote
Old 14th April 2019, 02:52 PM   #2
AmberMcGuire is offline AmberMcGuire
diyAudio Member
 
Join Date: Apr 2019
the budget is very small
  Reply With Quote
Old 14th April 2019, 03:40 PM   #3
Arnandsway is offline Arnandsway  Netherlands
diyAudio Member
 
Join Date: Nov 2018
Quote:
Originally Posted by AmberMcGuire View Post
the budget is very small
By my calculations, it would fit. If the drivers are around €50-70 each.
Hypex amps are €550
3d-printing can be free or max €30.
Wood ~€50.
Umik €100


totals around €1000

Last edited by Arnandsway; 14th April 2019 at 03:53 PM.
  Reply With Quote
Old 14th April 2019, 08:30 PM   #4
LineSource is offline LineSource  United States
diyAudio Member
 
LineSource's Avatar
 
Join Date: Sep 2003
Location: SiliconValley
The SB17NBAC-4 does not start beaming from the 180-degree baffle-controlled polar directivity until above your 1.5kHz crossover, so a tweeter waveguide would create an abrupt change in polar directivity around the crossover.
====
With DSP time alignment, you could mount the 1.5kHz crossover tweeter for the closest center-to-center spacing on a flat baffle and get baffle-controlled smooth constant 180-degree directivity over the crossover, with just the normal SB26ADC tweeter beaming starting aroung 4kHz. Smooth controlled directivity. To reduce baffle edge distortion, construct a proven low distortion baffle with bevels or rounds. I think this is the best DSP supported design for a 1.5kHz crossover
=============
====
TYPICAL: Controlled Directivity Waveguide tweeter
1) find a midrange with a smooth high frequency, and modest cone break-up artifacts
2) set crossover frequency to where the midrange beaming matches the waveguide directivity
3) design a crossover steep enough to attenuate midrange cone breakup

For the SB17NBAC-4 midrange, if you moved the crossover to 2.0 - 2.2kHz where some beaming narrows the polar pattern to match the polar pattern of the tweeter waveguide, you could maintain smooth controlled directivity. BUT you would require a steep crossover to attenuate SB17NBAC-4 cone breakup.
====

Buchardt Audio uses the SB17NBAC with a round waveguide with a 2,000Hz Crossover on model BA S400. The depth of the waveguide is set to match the tweeter-midrange physical offset with a passive xover.
s400 detailed description — Buchardt Audio

Audioengine builds monitors similar to your goals
Speakers — AudioengineAudioengine
Attached Images
File Type: jpg BA_S400_1.jpg (92.3 KB, 242 views)
File Type: jpg AudioEngine 5.jpg (88.7 KB, 247 views)
File Type: jpg example baffles.jpg (149.0 KB, 244 views)
File Type: jpg Compas Bevels.jpg (114.4 KB, 244 views)
  Reply With Quote
Old 15th April 2019, 11:13 AM   #5
Arnandsway is offline Arnandsway  Netherlands
diyAudio Member
 
Join Date: Nov 2018
Thanks for your reply Linesource.



If I understand correctly, the crossover point should be where both the woofer and the tweeter + WG drop at the same frequency, under the same angle. Should it be -6 dB at 60 degrees?
So of I were to crossover at 1,5 khz both the woofer and tweeter + WG should have their - 6 at this frequency. If so, this would be hard to achieve with a 6-7 inch woofer (haven't found one that suits these criteria). I would have to push the XO-frequency higher, or I would have to choose a bigger woofer, probably an 8 inch.
Please correct me if I am wrong.
  Reply With Quote
Old 16th April 2019, 06:35 AM   #6
mbrennwa is offline mbrennwa  Switzerland
diyAudio Member
 
mbrennwa's Avatar
 
Join Date: Mar 2005
Location: Zurich, Switzerland
What is the reason you want constant directivity / waveguide for a near-field monitor? With a listening distance of 1-2 m, you will mainly hear the direct sound from the drivers, and not so much the sound echoing back from the room. I'd be surprised if the benefits of the waveguide / constant-directivity approach would work out well in this scenario.
__________________
------
Group buy for augerpro waveguides for Scan Speak tweeters here
  Reply With Quote
Old 16th April 2019, 09:34 AM   #7
Arnandsway is offline Arnandsway  Netherlands
diyAudio Member
 
Join Date: Nov 2018
I would want to use them in a later stage at a bigger listening distance, if my living situation will allow this. At least I want to make frequency roll-of as smooth as possible to maintain accurate timbre etc.
  Reply With Quote
Old 16th April 2019, 10:45 AM   #8
mbrennwa is offline mbrennwa  Switzerland
diyAudio Member
 
mbrennwa's Avatar
 
Join Date: Mar 2005
Location: Zurich, Switzerland
Quote:
Originally Posted by Arnandsway View Post
I would want to use them in a later stage at a bigger listening distance, if my living situation will allow this. At least I want to make frequency roll-of as smooth as possible to maintain accurate timbre etc.
What do you mean by "smooth frequency roll off"? What roll off? Where? How? How is this related to timbre?
__________________
------
Group buy for augerpro waveguides for Scan Speak tweeters here
  Reply With Quote
Old 16th April 2019, 11:37 AM   #9
Arnandsway is offline Arnandsway  Netherlands
diyAudio Member
 
Join Date: Nov 2018
Excuses me, trying to search the right words.
I mean the rollof in dB under horizontal and vertical angles. As I learned when the directivity isn't controlled, resulting in peaking frequencys under angles, will make the sound different than when the roll-of is smooth. I learned this from the studys executed by Prof. Toole.
  Reply With Quote
Old 16th April 2019, 12:01 PM   #10
Windforce85 is offline Windforce85  Poland
diyAudio Member
 
Windforce85's Avatar
 
Join Date: Nov 2014
Quote:
Originally Posted by Arnandsway View Post
Hi all,
  • Usable for near-field monitoring (1-2 meters)
  • Constant directivity
You meant controlled directivity, not constant. If constant, specify value and frequency range.
Quote:
  • Active XO + bi-amping
  • Low XO point (~1,5 khz)
  • Small woofer-to-tweeter distance
  • Sealed enclosure, for easy integration with subs later on and great transient respons
  • F3 around 60-70 hz
  • Enclosure made out of 25 mm MDF or HDF
No. 16 mm with dense reinforcements is better from gross volume and weight consideration. You want the thing to be compact. Thinner MDF tends to be stronger per slice area as well.
Quote:
  • Budget total max €1000 for the pair
Budget is too low.
Quote:
  • Tweeter: SB Acoustics SB26ADC + 5" elliptical 3D-printed WG made by Augerpro. (can be found here Open source Waveguides for CNC & 3D printing!)
  • Woofer: still unsure so advice is welcome. Right now choice is between Dayton RS180-4 (great for sealed but high 3rd harmonic distortion) or the SB Acoustics SB17NBAC-4 (not great for sealed and f3 goal, but great other parameters.)
Woofer's choice is wrong from low bass efficiency in small enclosure. After LT linearization to required extension it will run ot of rated power or driving voltage range. Search for woofers with decent power rating and with Bl^2/Re value higher than 12, don't affraid elevated Mms.
Quote:
  • Hypex FA122 plate amp for digital XO and amp.
  • Enclosure volume ~16L (could change depending on woofer choice).
  • For measuring: a MiniDSP UMIK-1
  • For simulating the box enclosure I use UniBox and BoxSim 2.0.
Better use VituixCAD 2, it is a real design-devil for free.
  Reply With Quote

Reply


2-way active - Looking for peer critiqueHide 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
Active Bax Preamp with 6dB gain - design critique tristanc Analog Line Level 10 1st July 2017 08:46 PM
Critique my first drawing / possible build [Active DI] hvergelmir Analog Line Level 33 7th December 2014 06:41 PM
Please critique my active system Studio Au PC Based 11 5th October 2014 11:35 AM
Peer review, UL question dominicbeesley Tubes / Valves 8 24th August 2005 07:21 PM
Peer Critique needed for my new design bvp9223 Solid State 31 9th August 2005 08:23 PM


New To Site? Need Help?

All times are GMT. The time now is 01:08 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