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

Dayton Reference Open Baffle Project
Dayton Reference Open Baffle Project
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 20th November 2004, 07:27 AM   #1
dswiston is offline dswiston  United States
diyAudio Member
 
Join Date: Feb 2004
Location: Illinois
Default Dayton Reference Open Baffle Project

Hi all. After hearing such good reviews of the Dayton Reference Series, and after trying my first open baffle build using some vifa buyout 7"ers and a the tangband 1-1/8" tweeter (just what I had lying around) I was hooked and impressed and got to thinking I'd like to try a serious open baffle project. I sort of just threw this system together for minimal cost and because I was getting bored and hadn't done any builds in a bit.

I've been thinking about the 7" reference series because of their long x-max over the 6"ers. The system will be completely equalized using a behringer DEQ so the good linearity of the daytons coupled with the 7" good xmax should be a good combo for relatively low frequency extension with good linearity and low distortion.

So I've been pondering an MTM Open Baffle with the 7"ers and some Morel MDT30s (I already have the Morels). Now I've been hearing above 1.5KHz is a sort of no-go with the 7"er so it looks like I'd either have to really push the Morel's with a "conventional" L/R 4th order. However on a discussion on another forum, I came across a few fellows discussing elliptical filters for the dayton 8" reference in a two way. They planned on pairing the 8" with some Seas Millenium Excels with a crossover frequency around 1KHz. I don't have any where near the $ for these tweeters and I love the morels. So I'm thinking of giving the morels and the 7"ers a try with the an elliptical filter such as the one discussed at the link posted on the bottom of this post. Anyone have any ideas/suggestions/impressions. I know the MDT30 has a bit of a large faceplate so I was planning on offsetting it on the baffle to get the two woofers closer.

I'm just really excited about trying the dayton reference series and am impressed with the sound an open baffle brings. Has anyone tried to mate the two yet?



http://ldsg.snippets.org/FILTERS/Cuadra/elliptic.php3
  Reply With Quote
Old 20th November 2004, 07:48 AM   #2
joe carrow is offline joe carrow  United States
diyAudio Member
 
Join Date: May 2004
Location: Oakland, CA
Send a message via AIM to joe carrow
Dswiston, It's good to read of other people working on this sort of project. I just read a very interesting project liked from the PE forum- it's here http://www.mfk-projects.com/in_the_works.htm.

This gentleman's used two 7"s and two 10"s with an Usher tweeter using 4th order LR crossovers and the Behringer. It looks like there's more to it than that, but you're not alone in the idea.

I'd have a good thorough look over at Linkwitzlab.com to learn more of open baffle dipoles (i know i will before I spend money on drivers), but I believe that a wider (larger) baffle can improve the low-end max output of a dipole. This suggests to me that the 6" drivers could be acceptable in an MTM configuration if thier highpass is high enough; and they'll be more capable of crossing to your tweeters.

Your MDT30s can probably go fairly loud as you've used them before- but to push the crossover to its lower limits.... I guess that's just something to consider.

Please keep us updated on what you finally do! These drivers look quite interesting.

Joe
  Reply With Quote
Old 20th November 2004, 08:07 AM   #3
dswiston is offline dswiston  United States
diyAudio Member
 
Join Date: Feb 2004
Location: Illinois
Thanks for the link! That fellow designing that particular project is crossing the daytons above 2KHz, and his distortion and stored energy plots are good to see. Maybe I can push the crossover to 1.8KHz or 2KHz.

BTW, I may have been unclear, but I'm not using the Behringer Crossover but the Ultra Curve Pro for equalization due to the inherent open baffle -6dB/octave bass response. I'm aiming for equalization down to about 80Hz or so, and I don't plan on having these speakers be SPL monsters, so thats why I'd like to use the 7"ers. I'm assuming the xmax/increased cone area will come in handy when equalizing.
  Reply With Quote
Old 21st November 2004, 10:15 AM   #4
HIPCHECK is offline HIPCHECK  United States
diyAudio Member
 
HIPCHECK's Avatar
 
Join Date: Jun 2004
Location: ARKANSAS
Default dayton RS dipoles

rumor has it that darren from Parts Express is going to make a few RS driver more car audio friendly. some discussion on elite car audios forum darren posted, and asked would there be any interest in a 4ohm non-shielded (shallow) version of the RS drivers. Also, in the post was if a higher Qts design would be of interest to the car audio crowd?

from what i got the 6-7- and maybe 8inch Rs drivers will be tested soon and made 4ohm / with no magnet/shield and also of a higher Q

i would think for what your idea is dipole MTM with 7's this would be of some interest.

i have seen a few people talk about the need for EQ for the refraction of the drivers rear baskett, and the non shielded version would prolly help

just a idea, im holding out on the dayton RS drivers in hopes of the car audio specs, should be just what i need
  Reply With Quote
Old 21st November 2004, 06:40 PM   #5
dvdwmth is offline dvdwmth  Canada
diyAudio Member
 
Join Date: Apr 2004
Location: Toronto
what about the 6 inch? I think you might be able to cross it abit higher. Size wise it might be border line for open baffle but linkwitz measured afew 6.5 in drivers for use in open baffle so your pretty close. Maybe solicit opinions on that one from others here.

Are you really fixed on the dayton rs drivers. The peerless 850439 faired very well in linkwitz' distortion measurements, although is more expensive. I have heard on this forum that the csx drivers are very similar but with stamped frames. Perhaps the 6.5 in in that series would be suitable. 850122 i think.

I would like to see someone do an mtm open baffle along the lines of linkwitz with the peerless 850439 and post info but so far I haven't found anyone who's done it. There is the prototype on his site with the vifa p21 and passive xo but the vifa has worse distortion measurements then the peerless.

Anyone measured distortion of the dayton rs drivers in a meaningful way that can be compared to the linkwitz measurements?
  Reply With Quote
Old 21st November 2004, 07:14 PM   #6
ThomasW is offline ThomasW
diyAudio Member
 
Join Date: Oct 2001
Location: 5280'
Quote:
So I'm thinking of giving the morels and the 7"ers a try with the an elliptical filter such as the one discussed at the link posted on the bottom of this post. Anyone have any ideas/suggestions/impressions.
Here's a comment about Mr. Caudra's website from JonMarsh. Jon's the guy that published the article last year in AudioXpress using the high order Cauer/Elliptical filters.

Quote:
Mr. Caudra sort of has the right idea, but if you look at the response profiles of his networks, especially the pass band and stop band ripple, he hasn't fully optimized them.

A single stage cauer-elliptic filter will have equal amplitude pass band and top band ripple. Minimizing that ripple is important, in both areas, because it's a non-ideal component in the main response area, and also is an equal amplitude "bounce back" in the stop band, or attenutaion region, where, ideally, you want to keep the driver pass through at a minimum.

The Cauer-elliptic filters I use in speakers like the 8" two way bookshelf, the Arvo Part, and the M8ta are "hybrid" filters in that they're based on a two stage 4 section design (like any standard 4th order ladder filter), with an additional series or parallel reactive element. The filter coefficients are tuned to produce a corner knee and roll-off rate corresponding to a specific acoustic transfer function target (such as 8th order L-R, or 6th order L-R), INCLUDING the transfer function of the driver. Outside the transition region and stopband region, they're intended to be maximally flat, excepting any contouring for the cabinet/driver response, such as baffle step compensation.

Mr. Caudra basically has a good idea, he just needed to take his understanding of the filters and how to implement them to a specific transfer function target (chosen for specific acoustical properties) a bit further.
Althought not specifically for dipole here's a THREAD where Jon's measiring and commenting on the RS drivers.
  Reply With Quote
Old 21st November 2004, 07:23 PM   #7
dswiston is offline dswiston  United States
diyAudio Member
 
Join Date: Feb 2004
Location: Illinois
HIPCHECK:

Thanks for the info on the talks of new RS drivers. A non-shielded version would be a good thing, I have heard talk about the possible problems with the rear basket. Thatís another reason why I thought the 7" driver might be better suited, the basket seems to take up less of the cone area than on the smaller drivers. My particular situation has two problems with waiting though. One is that having 4Ohm drivers would not allow an MTM configuration with the two woofers in parallel. The speaker impedance would be much to low. I am also very poor being in the third year of college, and these drivers were going to be on my Christmas list for my brother. Waiting to see what happens in regards to car audio versions won't be possible. However, thanks for the information, I will keep my eye out for possible new versions of the RS drivers in the future.


dvdwmth:

It is a tough decision between the two for me (6 vs 7). The only thing that keeps me thinking no to the 6" is that the amount of air the driver can move is not comparable to the 6.5" peerless HDS or CSX because each of the two peerless drivers has an xmax of 5.5mm compared to 4mm for the dayton. I just keep thinking that pushing the 6" driver with EQ will be too much for the driver, resulting in a much larger amount of non-linearity compared to the 7". I am however open to being convinced otherwise. Interestingly enough, I do already have a pair of speakers I designed with two of the CSX 6.5" drivers. They were actually my first pair of DIY speakers. I was impressed with the sound being that I had almost no idea what I was doing at the time. I however would like to try out the new RS series to see if they might become a new inexpensive favorite of mine.
  Reply With Quote
Old 22nd November 2004, 12:09 AM   #8
dvdwmth is offline dvdwmth  Canada
diyAudio Member
 
Join Date: Apr 2004
Location: Toronto
it seems that you will be designing around alot of hurdles. I can see that the price is appealing but are you sure this is the right series of drivers to be looking at. Some of the comments you have made about the RS drivers seem to suggest that these are not appropriate for this application. Since you already have some peerless drivers that have been suggested by an authoritative source as worth considering it seems to me that the most sensible course would be to build an mtm with the peerless driver you already have two of, or just looking at another series of drivers all together.

On linkwitz's site he states the pmt1

http://www.linkwitzlab.com/proto.htm

using one vifa p21 is the smallest practical size for an OB speaker. I imagine if you get the data for air displacement of this speaker you would have a reasonable benchmark to compare other drivers you might be considering to. These considerations are linked to room size and loudness requirements so naturally you'll have to use this info in context of your own situation.

By the way, are you planning to do these passive or active?
  Reply With Quote
Old 22nd November 2004, 01:14 AM   #9
dswiston is offline dswiston  United States
diyAudio Member
 
Join Date: Feb 2004
Location: Illinois
Thanks for the additional link. I understand that the project has some hurdles, I do feel that the 7" driver has two possible downfalls. One is the driver's high frequency extension. It appears as though the crossover frequency will have to be rather low. I have already made an MTM speaker using the morel MDT30 crossed at 1800Hz using a 4th order L/R and it performs well. So I feel that if I invest my time into researching/designing higher order filters, a 1500Hz crossover frequency is obtainable while keeping the MDT30 happy and sounding nice. Secondly the backwave reflection caused by the magnet/sheilding structure might pose a problem but there is not much talk on the web yet that I could find dealing with this issue. However I enjoy the challenge and learning experience of working through such problems as I am still relatively new to this hobby.



The quality, linearity, and performance of the 7" mated with its displacement abilities makes me consider the woofer to be a good match for an MTM open baffle. The two peerless CSX woofers I currently have are also a good option, I 100% agree with you about that (although something tells me an MTM or TMM with the CSX drivers would be a much better idea). It makes it a tough call but something in me wants to try out the Daytons out of curiousity and a challenge is always welcome. Or since I already have the CSX drivers, maybe I'll just make a few test baffles and try out both.

BTW, to add to the mess, I also have a pair of MTM speakers using the exact same VIFA P21 as listed on the link you posted. Theoretically I could just design a new baffle, crossover, and give the vifa a try as an open baffle, but currently this speaker is my SPL monster (for when I feel like listening to music at a high volume), with VERY good bass extension in a sealed box actively equalized, so I do not want to give up such a pair of speakers for a new project.

Finally, I am planning on using a passive crossover. I do not have the equipment (amplifiers) to go completely active yet. I wil rely on the behringer for active equalization though.
  Reply With Quote
Old 22nd November 2004, 04:42 AM   #10
Davey is offline Davey  United States
diyAudio Member
 
Join Date: Dec 2001
Location: Bremerton, WA.
http://home.comcast.net/~dreite/Davey/Davey.JPG

IMHO the Dayton RS drivers are not suitable for dipole usage. A much too large a magnet/basket assembly blocks the side/rear radiation quite a bit. I think the baskets of the Seas drivers are better and the polar response can be made fairly adequate with a non-complicated baffle shape.

You might want to consider the Seas CA18RLY drivers for an MTM configuration dipole setup. I used two of those and a 27TDFC per side to mate with 850146 woofers. The mid/tweet crossover is passive and the sensitivities of these drivers are nearly perfect to support a parallel connection of the CA18 drivers with no pad on the tweeter. A dedicated active crossover/EQ for the woof/mid crossover and you have an excellent dipole system for approximately $650.00.

Cheers,

Davey.
  Reply With Quote

Reply


Dayton Reference Open Baffle ProjectHide 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
First open baffle project Moondog55 Multi-Way 18 10th August 2008 05:35 AM
Open Baffle project with FR punk Full Range 5 18th May 2006 02:47 AM
dayton rs open baffle -or not? help please knifeinthesink Multi-Way 8 29th October 2005 06:34 PM
Dayton 6" reference and dayton silk dome tweeter combo project...input? nerd of nerds Multi-Way 4 2nd December 2004 06:36 PM


New To Site? Need Help?

All times are GMT. The time now is 06:10 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki