Design and crossovers? - 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 29th May 2013, 02:12 PM   #1
diyAudio Member
 
Join Date: May 2013
Default Design and crossovers?

Hi, I'm 16 and new to the forum. I'm interested in building some floor standing speakers for my sound system. I was wondering, for the enclosure would each speaker require it's own 'box' inside it? An image of what I mean will be below. Also how will I create a crossover for a tweeter, mid-range and sub?


Click the image to open in full size.

Note; it's a rough drawing in paint.
  Reply With Quote
Old 29th May 2013, 03:30 PM   #2
diyAudio Member
 
tuxedocivic's Avatar
 
Join Date: Jan 2011
Location: Ladysmith, BC
Hi MastorMason,

This question should probably be in the multiway forum, but let me try.

First you'll want to learn how to build an enclosure to get the right bass alignment. Try WinISD or Unibox cause they're free. Use the T/S parameters of the selected drivers to determine the box size and vent size. Yes, each of your drivers need their own enclosures.

For the XO design, this question is so large I don't even know where to begin. Start by looking at the sticky thread in the multi way section called designing cross overs without measurements. It's not ideal doing that, but hey, you might get something out of it. Use an active XO on the subwoofer if crossing below 500hz. It's just better and cheaper than trying passive.

Some advice. Build a proven kit or something with lots of information. Maybe pick one where you can talk to the designer and learn some things. Buy a calibrated microphone like you can get here: Cross·Spectrum Labs - Sound | Vibration | Engineering

I have the ECM8000 they no longer sell and just purchased a UMIK-1. It's well worth the money if you're interested in this kind of thing and plan to build more than one speaker. Use the mic to measure your kit and email your measurement to the kit designer and ask him what he thinks.

Can I suggest this kit here: Creative Sound - Product Details

Freakin' insane value. I'm sure you could PM the designer who goes by RAW on here. Ask him if you've measured it right. Reverse engineer the speaker. Add a sub. Try some placement things. Experiment. Learn. Then roll your own. You'll have a much better chance of success this way. Believe me. I've built enough duds to know. I started at 17 years old as well and didn't use the internet (should have). I build some crap and wasted a lot of money. I'm 30 now and make some stuff that sound ok now. Prepare for the long haul. Maybe I'll make some good stuff by the time I'm 50 and my ears are rotten.
  Reply With Quote
Old 29th May 2013, 03:41 PM   #3
diyAudio Member
 
Join Date: May 2013
Problem is I'm 16 and still in education doing GCSE's and going onto Level 3 ICT in collage.. So I don't really have much money.. My dads got some spare 10" 200w bass drivers at his work so I would have to buy the other ones. I can't afford the microphone to test it, so as long it sounds okay in my ears all is good for now. And what do you mean about the bass alignment?

Also if each driver needs it's own enclosure, will I have to have multiple holes at the back of the whole thing or just build a bass-reflex design to have one?

Also how will I use WinISD? Will I need to build it first?
  Reply With Quote
Old 29th May 2013, 03:42 PM   #4
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
Too much information!
I would just say that the tweeter doesn't need any sound to escape !
Maybe neither the midrange.
Since the woofer might move large amounts of air, the back wave needs somehow to be confined .Otherwise the acoustic short-circuit happens ; it could be done also with massive absorption with some acoustic stuff ( such the acrylic inside of the ...pillows ).
But it won't work for the sub-woofer -under 100 Hz frequency.
  Reply With Quote
Old 29th May 2013, 03:45 PM   #5
diyAudio Member
 
Join Date: May 2013
What do you mean it wont work for the subwoofer under 100Hz? What wouldn't? The design?
  Reply With Quote
Old 29th May 2013, 04:03 PM   #6
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
yes, as Tuxedo had stated, this should be moved to 'multi-way'
Since each speaker would work in its preferred audio band
It means that a woofer needs it's own 'treatment'...or enclosure, name it.
If you put in the same enclosure another loudspeaker that is working on the band above- a midrange- the movement of the cone would be induced by the pressure generated by the woofer, and that's no good !
I prefer to keep everything separated, not on the same baffle - I don't even like the 'baffle'-go figure
  Reply With Quote
Old 29th May 2013, 04:32 PM   #7
diyAudio Member
 
tuxedocivic's Avatar
 
Join Date: Jan 2011
Location: Ladysmith, BC
It's pretty clear you're starting on square 1, which is fine. In my opinion, you have to choices.

1. Spend the money on mids and tweets and some text book cross overs. Build "something". Hope it turns out ok and have fun. Be aware the sound is gonna be pretty poor. It just will be. And between wood, paint, cross overs, mids, and tweets, you're probably look at around $250.

2. Buy a kit like the WR30 I linked above. Build the boxes to fit the baffle. Learn the steps of building a good speaker. Be aware this would probably cost a little over $300 in the end, but you'll have something really good. After a while, add the 10" woofers and play with them like subs.

I suppose a 3rd option would be to take some time to learn everything you need to make something ok. In that case, get reading lots of thread and website. Don't even think about picking up a saw for about a year.

Good luck.
  Reply With Quote
Old 29th May 2013, 04:35 PM   #8
diyAudio Member
 
Join Date: Mar 2003
Location: Haarlem, the Netherlands
Quote:
Originally Posted by Mast0rMason View Post
Problem is I'm 16 and still in education doing GCSE's and going onto Level 3 ICT in collage.. So I don't really have much money.. My dads got some spare 10" 200w bass drivers at his work so I would have to buy the other ones. I can't afford the microphone to test it, so as long it sounds okay in my ears all is good for now. And what do you mean about the bass alignment?

Also if each driver needs it's own enclosure, will I have to have multiple holes at the back of the whole thing or just build a bass-reflex design to have one?

Also how will I use WinISD? Will I need to build it first?
Hi Mast0rMason,

Have you got any information on those bass drivers, for example a type number? If so, then you might be able to find a datasheet with Thiele and Small parameters on the internet.

Regarding Thiele, Small and alignments: Thiele and Small are two Australian engineers who wrote classical articles on loudspeaker box design. They characterised the low-frequency behaviour of the loudspeakers (drivers) with a few parameters: the resonant frequency fs, the volume of air that is equivalent to the compliance of the cone suspension Vas, the mechanical quality factor of the resonance Qms, the electrical quality factor of the resonance Qes and the total quality factor of the resonance Qts, where 1/Qts=1/Qms+1/Qes.

If you know these parameters, have a copy of Thiele's and Small's articles and understand transfer functions, you can calculate what kind of box size and vent size (if you go for bass reflex) you need.

If you have the Thiele and Small parameters but haven't got a copy of Thiele's and Small's articles or don't know much about transfer functions, you can leave much of the theoretical stuff to a loudspeaker box design programme. I have no experience with these programmes, but if I understand it correctly, you can let the programme calculate the transfer for you for given Thiele and Small parameters and box and vent size.

The whole box can be seen as an electroacoustic high-pass filter. Depending on the parameters it can be a different type of high-pass filter, for example Butterworth, Chebyshev or quasi-Butterworth. In loudspeaker jargon these are called alignments.

If you have no information about the Thiele and Small parameters of the bass drivers, and don't have the chance to measure the parameters yourself, I would go for a large closed box (so no vent) stuffed with damping material. Usually that will give you reasonable sound, even though it won't be optimal in any sense.

About your original question: whether you need separate compartments for each driver depends on whether they are open on the back side. Tweeters usually have a closed back side, in which case they don't need a separate compartment. Squakers sometimes have an open back, in which case they need a separate compartment, normally a closed compartment with damping material. The woofer definitely needs a box.

Regards,
Marcel
  Reply With Quote
Old 29th May 2013, 04:46 PM   #9
chrisb is offline chrisb  Canada
diyAudio Member
 
Join Date: Aug 2002
Location: victoria BC
Quote:
Originally Posted by picowallspeaker View Post
yes, as Tuxedo had stated, this should be moved to 'multi-way'
Since each speaker would work in its preferred audio band
It means that a woofer needs it's own 'treatment'...or enclosure, name it.
If you put in the same enclosure another loudspeaker that is working on the band above- a midrange- the movement of the cone would be induced by the pressure generated by the woofer, and that's no good !
I prefer to keep everything separated, not on the same baffle - I don't even like the 'baffle'-go figure

Agreed that the conversation could be migrated to multi-way, but it's fair to say that many of us here have some experience with other than only single driver / FR systems.


If budget is a major constraint, and there is a set of bass drivers available at little / no cost, then it might be worth considering starting with a simple 2-way system, using a 3-4" wide band driver - something with which I think all of us here are quite familiar. Those drivers would of course not be sealed backed, and would definitely require separate or sub-enclosures.

Until the parameters of the available bass drivers and selected model(s) of mid(s)-tweeter(s) and their targeted pass-bands are known, the enclosure volumes and choice of sealed or ported alignments for each can't be accurately determined. Without published TSPs for the bass drivers, or ability to measure same, "cook-booking" a crossover circuit with any of the web available calculators will probably yield as good results as anything.

As this is apparently mast0rmason's first foray into DIY building, with a little encouragement and consideration of his budget, the members here can no doubt offer some time and expense saving advice. And let's not be surprised that if he gets infected with the DIY bug and can later devote time to thoroughly studying the field that he catches up with or even surpasses some of us .

I think we'd be remiss by not asking a few standard questions re application:
- size of room
- range of listening material/ anticipated volume levels* (let's not presume anything)
- available amplifier power

* if you don't have availability to a basic SPL meter, try downloading any of the smart phone apps, and surveying loudness levels that you generally listen to - you might be surprised.
__________________
you don't really believe everything you think, do you?
community sites t-linespeakers.org, frugal-horn.com commercial site planet10-HiFi
  Reply With Quote
Old 29th May 2013, 05:16 PM   #10
ra7 is offline ra7  United States
diyAudio Member
 
Join Date: Feb 2009
Blog Entries: 1
You are starting young, but there is lots to learn. Don't be discouraged. Keep at it. This is a very rewarding hobby. It's a confluence of many fields: electrical engineering, mechanical engineering, acoustics, human perception, woodworking.

For your first speaker, the most important thing you want is for it to sound good. It is very discouraging to spend lots of time on a design and then have it sound bad. So, start with a kit. It's the best way to get good sound. These people usually have good kits:
parts-express.com
madisound.com
meniscusaudio.com

For some newer, state-of-the-art designs (and more money):
diysoundgroup.com

Good luck! Folks here are very helpful. Keep at it.
  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
The design of active crossovers- Douglas Self wants your opinions DouglasSelf Analog Line Level 282 7th December 2012 01:56 PM
Software for digital crossovers design krzys Multi-Way 0 27th January 2012 01:55 PM
The design of active crossovers audiohead Solid State 0 7th July 2011 02:35 AM
What to do with these crossovers? Phantom499 Multi-Way 2 26th January 2011 09:26 PM
2.5-way crossovers sriegel Multi-Way 2 30th April 2002 05:47 AM


New To Site? Need Help?

All times are GMT. The time now is 07:03 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