Lousy sketch of my thoughts so far
http://farm4.static.flickr.com/3177/3082917444_127c650b91.jpg?v=0
But this is big also on the lines of discussions between significant other and myself
http://farm4.static.flickr.com/3177/3082917444_127c650b91.jpg?v=0
But this is big also on the lines of discussions between significant other and myself
Here is a quick & nasty to get across what i'd do with the woofers ... since i'm stealing time from what i should really be doing, i just grabbed a concept i drew sometime ago... for your ap, i'd forgo the angled bits for the woofer (original was for a pair not a quad), and the other fancy bits (althou there iare a lot of conceptual detail in the drawing to be borrowed)
Forget the woofers up top ... try to make them appear as a single driver.
dave
Forget the woofers up top ... try to make them appear as a single driver.
dave
Attachments
Go back to earning a living Dave, good idea, thanx
I don't remember saying anything about the woofers being high quality, that remark was for the Vifa P-13's, the woofers are cheap and cheerful
Ted
I don't remember saying anything about the woofers being high quality, that remark was for the Vifa P-13's, the woofers are cheap and cheerful
Ted
Moondog55 said:
I don't either, i have 2 each ot the 2 kinds of P13, probably do a TMM just to use them up...
dave
Dave's idea is interesting, but a bit of a complex build, being lazy I'd do something simple like the Visaton 'No-box' with the woofers down one side and the MTM beside them centred at around ear level. Another option is to consider the layouts that Lynn is thinking of in 'Beyond the Aerial'...
tinitus said:
That one reminds me of this thot experiment:
http://www.t-linespeakers.org/FALL/dipole.html
In this case, i'd chop the top half off, and flip one of the pairs around to get push-pull
dave
initus Dave those are both a little complicated for my limited skills.
having discussed this with SWMBO I am probably going to go with the simplest layout of all, a shallow "U" frame maybe 100/150 deep.
AND just because I have everything I need to do it, it will be actively crossed to the sub at 40Hz and I'll actively cross to the Vifa mids at whatever frequency sounds best keeping it as suggested around 200Hz.
This way I can get a little more power handling from the 12's without blowing them out of the gap when I forgetmyself and turn the volume up to 8 on Carmina Burana.
I'd cross to the subs lower but 40 is as low as the CX units go.
I've had this sub sitting on the porch doing nada for over a year so it will be good to get that going again.
Will the woofer get any real benefit from offsetting from the baffle centre-line I could do 35mm easily enough and if I do does it matter if the mids are offset on the opposite side or should I keep the offsets the same??
That question has not arisen for me before as I've never played with a baffle wide enough to allow more than 10mm before, but in the past I have always offset to the same side of the centreline.
I know I'll be loosing something by not using a "H" frame but I get huge gains in WAF
having discussed this with SWMBO I am probably going to go with the simplest layout of all, a shallow "U" frame maybe 100/150 deep.
AND just because I have everything I need to do it, it will be actively crossed to the sub at 40Hz and I'll actively cross to the Vifa mids at whatever frequency sounds best keeping it as suggested around 200Hz.
This way I can get a little more power handling from the 12's without blowing them out of the gap when I forgetmyself and turn the volume up to 8 on Carmina Burana.
I'd cross to the subs lower but 40 is as low as the CX units go.
I've had this sub sitting on the porch doing nada for over a year so it will be good to get that going again.
Will the woofer get any real benefit from offsetting from the baffle centre-line I could do 35mm easily enough and if I do does it matter if the mids are offset on the opposite side or should I keep the offsets the same??
That question has not arisen for me before as I've never played with a baffle wide enough to allow more than 10mm before, but in the past I have always offset to the same side of the centreline.
I know I'll be loosing something by not using a "H" frame but I get huge gains in WAF
Moondog55 said:
You could consider making it a bit deeper ((at the bottom anyway ) and narrower and mount the bass drivers on the 2 sides.
dave
About to start work on the woofers.
Are those self stick floor protectors that are made from what feels like stiff carpet good enough for basket damping on the inside of driver spokes or should I buy some better quality felt and cut it myself, I ask becuase they come in a shape and size that fits reasonably well and the glue isn't too bad.
Aussies will know the product, it's avaliable from "Bunnings" in packs of 8 pads, I need 6 pads per driver.
Regards
Ted
Are those self stick floor protectors that are made from what feels like stiff carpet good enough for basket damping on the inside of driver spokes or should I buy some better quality felt and cut it myself, I ask becuase they come in a shape and size that fits reasonably well and the glue isn't too bad.
Aussies will know the product, it's avaliable from "Bunnings" in packs of 8 pads, I need 6 pads per driver.
Regards
Ted
Question for Rudolf
Hi Rudolf, in a previous interchange you were letting me know of the advantages of the "H" baffle for bass in these types of speaker drivers, I decided on the simple "U" frame for WAF reasons, how-ever my beloved has said that I can build something a little bigger 'with-in reason' to make these acceptable they have to be nice furniture as well as sound good and I respect and understand her feelings here.
does it matter if I mix both a U & H baffles in the one speaker??
If I use an "H" baffle for the lower two woofers it will look better in the eyes of herself and I think myself that this wold also look better.
So here is second proposal,2 lower woofers H baffle 200mm either side of centre then a "U" frame for the mids, tweeter and top 2 woofers.
It would look like a flat board sitting on a box but I can pretty it up some, and similar in a lot of ways to OB mids sitting on a box the "Blackwoods" come to mind.
I have not yet discussed second iteration with Cecile.
Hi Rudolf, in a previous interchange you were letting me know of the advantages of the "H" baffle for bass in these types of speaker drivers, I decided on the simple "U" frame for WAF reasons, how-ever my beloved has said that I can build something a little bigger 'with-in reason' to make these acceptable they have to be nice furniture as well as sound good and I respect and understand her feelings here.
does it matter if I mix both a U & H baffles in the one speaker??
If I use an "H" baffle for the lower two woofers it will look better in the eyes of herself and I think myself that this wold also look better.
So here is second proposal,2 lower woofers H baffle 200mm either side of centre then a "U" frame for the mids, tweeter and top 2 woofers.
It would look like a flat board sitting on a box but I can pretty it up some, and similar in a lot of ways to OB mids sitting on a box the "Blackwoods" come to mind.
I have not yet discussed second iteration with Cecile.
I would try to avoid using "complex" solution. Simple baffle is always the best sounding and looking. So perhaps it doesn't have to be 4 woofers but 3. WWWMT. I think that would still put the mid & tweet at the correct height.
On experiental level perhaps try to arrange the Woofers like CS1? So 2 in front, 2 at the back. I'm not sure how they sound.
On experiental level perhaps try to arrange the Woofers like CS1? So 2 in front, 2 at the back. I'm not sure how they sound.
It's all a matter of perception, I don't feel that this is actally a "complex" speaker, really it is a clone of dozens of other designs and really the only difference between this and my last one is the number and size of the woofers.
While I agree that simplest is often the best I think this is pretty simple.
Chosen baffle size is luckily very close the one that modelled best, these woofers are very smooth and well behaved way up into the late teens, I used a first order XO on them in my second last practice baffle and no problem so I should have fewer problems using LR4 electronic, the Vifa P-13 is very well behaved and comparitively easy to work with and the change to a D27 has been documented my dozens of others in this forum and others.
I am lucky that I can stand on the shoulders of others.
As for using 3 woofers in parallel, I like the idea a lot, I've never made it sound good unless all the drivers were in parallel, which means rewinding the voicecoils.
I have 6 woofers here with 24Ohm voice coils for another project, one of thse days I'll build it.
My main concern with this project is the mods to the woofer baskets to make them as good as possible in keeping with the quality of the midrange.
Oh and trying tomake them look good,
my woodworking skills suck
While I agree that simplest is often the best I think this is pretty simple.
Chosen baffle size is luckily very close the one that modelled best, these woofers are very smooth and well behaved way up into the late teens, I used a first order XO on them in my second last practice baffle and no problem so I should have fewer problems using LR4 electronic, the Vifa P-13 is very well behaved and comparitively easy to work with and the change to a D27 has been documented my dozens of others in this forum and others.
I am lucky that I can stand on the shoulders of others.
As for using 3 woofers in parallel, I like the idea a lot, I've never made it sound good unless all the drivers were in parallel, which means rewinding the voicecoils.
I have 6 woofers here with 24Ohm voice coils for another project, one of thse days I'll build it.
My main concern with this project is the mods to the woofer baskets to make them as good as possible in keeping with the quality of the midrange.
Oh and trying tomake them look good,
my woodworking skills suck
With H-frame on the woofers I dont think you need U-frame fore the mid/tweet...actually I suppose it would be best with a plain ordinary OB baffle fore the mid/tweet
Moondog55 said:
I have a pair of P13 and not too sure about their sound on OB. Something is not right about these drivers even though they measure really well. Perhaps the basket is too big and blocking the rear radiation of sound? Or Qms too low - overdamped? I know they are much praised drivers but most usage are in box.
In fact my system now runs Alpha 15 full-range and it simply beats P13's resolution. Weird eh?
Hi Moondog,
since St. Cecile is the patron of all musicians we really have to give SWMBO some pretty speakers to rest her eyes on, don´t we?
I could not imagine how a symmetric WW MTM WW or anything else with such large woofers above the midrange could look good. But then I remembered some weird towers featured in those hifi mags of my youth:
You could build a 4-woofer line along a baffle of may be 140-150 cm heigth. Don´t space them too even (like on my sketch), but leave more space between two drivers where you want to put the MTM baffle. WWW MTM W would be fine too. Put all woofers to the outside edge of the baffle and the MTM on their own baffle to the inside edge. You could even let that sub-baffle protrude from the inside edge of the large baffle, perhaps in a bowlike shape.
It is paramount to have the MTM sub-baffle close to one side of the wide baffle and NOT in its center.
An U baffle could be made of two tapered wings. You may even fold them inwards up to 20° to keep them "out of sight". If the position of the MTM needs a cutout in the wing to clear the driver baskets - don´t hesitate.
It may look really freaky on my scribble, but I can imagine very beautiful ways to integrate the sub-baffle and let it really shine.
Let me know what you think about it.
Rudolf
since St. Cecile is the patron of all musicians we really have to give SWMBO some pretty speakers to rest her eyes on, don´t we?
I could not imagine how a symmetric WW MTM WW or anything else with such large woofers above the midrange could look good. But then I remembered some weird towers featured in those hifi mags of my youth:
An externally hosted image should be here but it was not working when we last tested it.
You could build a 4-woofer line along a baffle of may be 140-150 cm heigth. Don´t space them too even (like on my sketch), but leave more space between two drivers where you want to put the MTM baffle. WWW MTM W would be fine too. Put all woofers to the outside edge of the baffle and the MTM on their own baffle to the inside edge. You could even let that sub-baffle protrude from the inside edge of the large baffle, perhaps in a bowlike shape.
It is paramount to have the MTM sub-baffle close to one side of the wide baffle and NOT in its center.
An U baffle could be made of two tapered wings. You may even fold them inwards up to 20° to keep them "out of sight". If the position of the MTM needs a cutout in the wing to clear the driver baskets - don´t hesitate.
It may look really freaky on my scribble, but I can imagine very beautiful ways to integrate the sub-baffle and let it really shine.
Let me know what you think about it.
Rudolf
This effort was one of the inspirations.
Cecile looked at the photo and said
" I like those; those I could live with"
http://www.diyaudio.com/forums/showthread.php?s=&threadid=123512&perpage=25&pagenumber=5
post #119
Ok she likes Ikea; but when given a license to build big; you build big!!
Cecile looked at the photo and said
" I like those; those I could live with"
http://www.diyaudio.com/forums/showthread.php?s=&threadid=123512&perpage=25&pagenumber=5
post #119
Ok she likes Ikea; but when given a license to build big; you build big!!
- Status
- Not open for further replies.