Wx System Speakers - 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 28th July 2002, 06:17 PM   #1
BAM is offline BAM
diyAudio Member
 
Join Date: Sep 2001
Location: Carmel, IN; West Lafayette, IN
Send a message via AIM to BAM
Default Wx System Speakers

I am going to build a pair of speakers that I intend to keep for a long time and I want to do it right. I have decided on a design I call the Wx system. This uses a two-way design with small wide-range drivers as midbasses (4") to push the crossover point up to about 10,000 Hz, out of the critical midrange area. Then to avoid extra intermodulation distortion in the midbasses, they are relieved of any bass information below 150 Hz by a stereo pair of bass modules below the speakers (similar to the Series III 6th-order Bandpass Acoustimass modules used by Bose but rather than being used as the subwoofer, it only fills in the bass range from 150Hz down to 40 Hz). I like the sound of the 6th-order bandpass enclosure.

The mains will use 4" Tangband W4-616S woofers with the paper cones and the aluminum phase plug, crossed over with a 2nd-order crossover at 10,000 Hz with a Dayton kapton-film ribbon tweeter. The Tangbands respond down to 65 Hz, but for a stereo pair which will not be used with a separate powered subwoofer for a long time, this is not suitable for me.

So I have schemed to add a pair of 6th-order bandpass bass modules with 4 Dayton 5.25" woofers each. However, I am not completely set on the 6th-order bandpass boxes yet. I like the round sound of the Bandpass box that came with the Bose Acoustimass 3 series III system but the satellites were too small and the newer Acoustimass woofers (8th-order) are too slow for my liking. I could potentially be swayed to use direct-radiating woofers if that would be the best way to make relatively high output bass modules. This is similar to the way that some speakers have optional bass modules.

So. am I out of my mind on any part of this?
  Reply With Quote
Old 28th July 2002, 11:03 PM   #2
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
Hi Bam

Sorry, but IMHO bandpass boxes do not cut it for real hi-fi, they are just too slow on transient resonse, and the physics of the box causes real problems with resonance after the wave form has died away...

What attracts you to the bandpass configuration? Is it the smaller box size or the apparent need to have no crossovers?

Yes, bandpass boxes can work for HT, but that is all, and you will get a much better result using say a 12" driver with maybe a Linkwitz transorm to achieve a lot better bass with an equally small box size.

Just my ha'porth

Al
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 29th July 2002, 12:45 AM   #3
diyAudio Member
 
Bill Fitzpatrick's Avatar
 
Join Date: Jun 2001
Location: Eugene, OR
I agree with pinkmouse.

Lose the bandpass boxes and go for a 12" woofer crossed at 200Hz to the Tangbands. I would recommend a 4th order crossover because the Tangbands are going to be needing some thermal leeway unless you are willing to go to a MMTMM configuration. You might also consider dropping the upper crossover frequency to 4KHz to 6KHz, using a 1st order crossover and selecting one of the Tangbands which have really great high frequency performance.

May I suggest bi-amping?
  Reply With Quote
Old 30th July 2002, 07:10 AM   #4
diyAudio Member
 
Join Date: Jul 2002
Location: Portland, OR
Send a message via AIM to tomasro
try using fiberfill to deaden the ressonance and it will actually create a sort of crossover effect. Any sound that would be iffy as to how it would affect your other speakers in the system is almost inaudible so that the more specific midrange or tweeter could take over. Equation for faberfill is 1 lb to 1 cu. ft. This method also achieves a clearer bass sound for better imaging as long as the woofer isn't out of it's range according to the crossover. Good luck!
__________________
Bass is a part of music....
  Reply With Quote
Old 30th July 2002, 08:23 AM   #5
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Default Re: Wx System Speakers

Except for the bandpass box -- works for me. Bipolar RS 40-1197 4" FRs, 1st order T at about 10k -- looks like i'll probably end up using a little cone on these (these are due to be replaced by similar bi-poles (push-push) using FE103A. 2x8" Peerless active (4th LR) below 125 Hz.

The tagbands are good. Get a pr of 8s or 10s (push-push) with extended range for the bottom. Go active -- even if it is only 1st order PLLXO to start.

Consider also going to a pr of TBs on each side -- either in 2.5 or bi-pole. This eliminates baffle-step and gives you twice the cone area to move air.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 30th July 2002, 08:40 AM   #6
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
Yup... Definately not hi-fi!

tomasro- the whole point of hi-fi reproduction is a balanced system across all frequency bands, your system may sound good to you, but I can guess that most of what you are hearing is so called "Fast Bass" ie frequencies from about 70hz to 100Hz, and there is just a monotonal Whoomph noise below this, sounding the same whatever you play. Am I right?
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 30th July 2002, 07:20 PM   #7
diyAudio Member
 
Join Date: Jul 2002
Location: Portland, OR
Send a message via AIM to tomasro
Well, timpanies, bass drums, opera basses, bass guitars and electronicly modified noises called bass hits all sound great coming out of the speaker. The point is that the stuffing would help to eliminate all unwanted upper register sounds that might come through on an unfilterd speaker.

It also helps to reduce costs in buying speakers, and chamber resonance.

If the wood naturally vibrates at 200Hz, you are going to end up with a horribly distorted sound, dominated by the resonance of the wood itself. The only other way to eliminate this is to build to cabinet out of 1 inch thick mfd board...that is of course if you aren't going to want speakers that have a high tolerence to wattage.

Good luck!
__________________
Bass is a part of music....
  Reply With Quote
Old 30th July 2002, 07:30 PM   #8
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
Hi tomasro

Quote:
The only other way to eliminate this is to build to cabinet out of 1 inch thick mfd board...that is of course if you aren't going to want speakers that have a high tolerence to wattage.
Gosh a new one on me, - so for 15 years I've been reducing power handling by building my speakers using MDF then?

Hmmm...
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 31st July 2002, 12:36 AM   #9
BAM is offline BAM
diyAudio Member
 
Join Date: Sep 2001
Location: Carmel, IN; West Lafayette, IN
Send a message via AIM to BAM
Default Woofers

I'm using the 5.25" woofers so the woofer box can be small and compact with a 1.5-foot stand supporting the main speaker itself, and also because 4 5.25" woofers moving in unison just seems cooler. Any reason why I would be better off with a larger driver if I'm going to add an actual subwoofer later on (which will only handle mega-low stuff so there's less chance of localization? Should I try to make the main speaker bass-reflex or sealed? I think the Tangbands would be happier in bass-reflex.

There's been some experimentation on the Subwoofer DIY Page that suggests that 6th-order bandpass subwoofers may not lag all that far behind 4th-order bandpass subwoofers in terms of transient response, and since the passband will be narrow, I can get a more even frequency response with high output.

The woofers will be passively crossed-over to the mains (Which, BTW, will be MMTMM) at 150 Hz and I will expect the bandpass response of the box to F3 at around 40 Hz (The Dayton 5's have been measured down to 45 Hz) or I can use them in a direct-radiating box. I will most likely be powering these things with a stereo reciever (loudness switch is a must) and I'm just hoping to get a system that uses good drivers and good design, to be driven with a 100w RMS reciever at the most. These aren't intended to be golden-ear quality (which I cannot afford,) but I will build them out of MDF. and keep them through my college years and for years after that (all the drivers have butyl rubber surrounds.)

My attraction the the Bandpass box is its pleasantly round sound and a design that is out of the ordinary. I was having second thoughts about them, but a couple people who independently studied the waveform of a sinewave coming out of a 6th-order bandpass subwoofer posted their findings on the Subwoofer DIY forum and it was not nearly as far off as expected, suggesting apparently that a properly-constructed 6th-order bandpass woofer (when not especially designed for gain and where suggested improvements for the enclosure's alignment to lower bass boom in most rooms are implemented) are not nearly as bad as most people expect. And they couldn't be worse than the 8th-order bandpass subwoofer, which is a white elephant at best.
Another attraction to Bandpass subwoofing is that the woofer transmits the pressure to the air inside the chamber and while a tiny bit of transient response (unnoticed to my hobbyist-listener ears--I'm not exactly an audiophile, I just love listening to music and designing speakers) is sacrificed, I think that any distortion caused by cone-flex should be removed by the linear properties of air. In addition, my design for a BP subwoofer should have a high SAF for its compactness. The Dayton 5.25" woofer wil do 47 Hz in a .5-cubic foot enclosure. I really want my 5's, but this box doesn't need to shake the room with the later addition of a subwoofer. (Actually, if TC-Sound's new direct-to-the-public thing works out and lasts a long time and offers a really nice 10" woofer, I might do a LT but that's later on once I'm out of college, have a house and nice job, and (hopefully) a wife (then I'll need to worry about SAF, but again, these should be good with that, in a relatively small room.))

(I once submitted a request for information about bandpass subwoofers on this board and got a number of different responses. I took that into account here. Speaker-building is all about tradeoffs, and Bandpass boxes are a niche design, which just happens to fit my tastes.)

OK, I'm done rambling.

What do you mean by "thermal leeway"? You mean overtemperature of the midbass voice coils? These supposedly are good out to 14kHz. So I was going to use a 3rd-order crossover to the Dayton tweeter at about 10kHz because the Dayton tweeter wil take a 3rd-order crossover point of 2500Hz.
  Reply With Quote
Old 31st July 2002, 03:46 PM   #10
CHRIS8 is offline CHRIS8  United States
Account Disabled
 
Join Date: Dec 2001
Location: VA, USA
"I'm using the 5.25" woofers so the woofer box can be small and compact with a 1.5-foot stand supporting the main speaker itself, and also because 4 5.25" woofers moving in unison just seems cooler. Any reason why I would be better off with a larger driver if I'm going to add an actual subwoofer later on "

5.25" are not a practical choice. Use at least 8" drivers, this is a dedictated subwoofer you are discussing.

If you plan to cross at 150 hz, you need to keep the bass module within around 2 feet of the main modules.

A bigger midbass would allow more usalble low frequency output, allowing for a lower crosspoint to thw subwoofer, allowing it to be located farther away.

"The woofers will be passively crossed-over to the mains (Which, BTW, will be MMTMM) at 150 Hz and "

This will not achieve an accpetable amplitude response, when integrated with the mains. 6th order bandpass box has 3 impedance spikes, you will not be able to avoid having this impedance discontinuity within the operating range of the passive crossover. YOu must use an active crossover for good results.

"apparently that a properly-constructed 6th-order bandpass woofer (when not especially designed for gain and where suggested improvements for the enclosure's alignment to lower bass boom in most rooms are implemented) are not nearly as bad as most people expect"

Following this forumla, you have just negated the only redeeming quality of the design: efficiency(gain). If you simply want to build a bandpass to uhm...build a bandpass.....go for it. But you will achieve more linear response and far better transient decay response using a conventional 4th order vented system.

ALso, you mentioned crossing at 10khz????

IF you wish to guarantee poor power response and substandard integration with the midbass, go for it. I would find a 5.25" with at least good power response up to 3khz, and use a BG neo 3 tweeter, the planar you suggest is not nearly as good as the neo 3, and the cost difference is only about $10. If you must use 4", then you need to consider crossing around 175-200hz, and using a suitable bass section that is nor more than a foot from the mid.

-Chris
  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
Panasonic-Thruster-Speakers-System-SB-180-8-ohm StevenOH Full Range 1 21st July 2008 08:59 PM
best UK PC 2.1 speakers suitable for 3rd system jives11 Multi-Way 0 11th February 2007 10:11 AM
Baldwin organ speakers for home system? rcpmac Multi-Way 3 6th July 2005 09:10 PM
Multi-room audio system (speakers & Amp question) dwalter Multi-Way 0 17th November 2004 07:22 PM
DIY speakers for SACD/DVD-A system regal Multi-Way 0 4th January 2004 07:55 PM


New To Site? Need Help?

All times are GMT. The time now is 11:49 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