I am in the search of the most musical bass section for my speakers (Flexunit 5H and SS9800). My listening room is rather small (5.5m x 3.5m). I have always been disappointing by traditionnal subs (tried 2 Rel subs). Now, I want to try a dipole bass with 2 Seas L26 aluminium woofers per side. The bass modules will be crossed, equalized and time aligned with the main speakers with the help of my Tact 2.2X to be able to choose the best location for the bass dipoles independently of the main speakers. I do not want the deepest and most powerful bass but something articulate and musical. If someone has an advice about this setup, it will be great. Other solutions are also welcome.
Thx, Christophe
Thx, Christophe
Member
Joined 2003
I think you'll really like Seas dipole bass. At least in my situation, it is very clean...very very well defined. They have virtually no "speaker" sound.
I use IB subs with mine, so you'll probably choose a wider/deeper baffle for lower response. If you use "wings", consider angles that minimize reflections between the wings. Test baffles with hinges convinced me to use at least 90 degrees between the wings...45/45, 60/30, 90/0 etc. Also, consider high mass baffles...they do have a tendancy to move at higher volume and that certainly can't help anything.
Enjoy!
W26 dipoles
I use IB subs with mine, so you'll probably choose a wider/deeper baffle for lower response. If you use "wings", consider angles that minimize reflections between the wings. Test baffles with hinges convinced me to use at least 90 degrees between the wings...45/45, 60/30, 90/0 etc. Also, consider high mass baffles...they do have a tendancy to move at higher volume and that certainly can't help anything.
Enjoy!
W26 dipoles
Thanks. I think I will make it as a push-pull H frame "à la" Linkwitz Orion. My main concern is about the crossover frequency (Tact advice is 325Hz 4th order) and the room placement (Tact recommend the corners).
The Seas L26 seems to be a good alternative to the W26 (expensive if you need 4).
Christophe
The Seas L26 seems to be a good alternative to the W26 (expensive if you need 4).
Christophe
Member
Joined 2003
The L26 drivers themselves should be fine at 325 but, I agree, it is a fairly high crossover for a push-pull H. Maybe simple test baffles before serious woodworking?
(I understand the benefit of the W26 motor is at higher frequency. I picked the W26 because I'm using 1st order xo to W22...and may eventually use the 26 in a different design with a higher crossover. Unfortunately, flexibility has a price.)
(I understand the benefit of the W26 motor is at higher frequency. I picked the W26 because I'm using 1st order xo to W22...and may eventually use the 26 in a different design with a higher crossover. Unfortunately, flexibility has a price.)
Have you already bought your drivers? For dipole bass, the TC Sounds TC2+ or the Peerless XLS 12" would be better (the TC2+ has more linear xmax than the XLS 12", which has more than the L26)
EDIT: Besides, the TC2+ and the XLS 12" are basically the cleanest not-too-expensive 12" bass drivers around.
EDIT: Besides, the TC2+ and the XLS 12" are basically the cleanest not-too-expensive 12" bass drivers around.
You're absolutly right. But I have 2 or 3 things that are in favor of the Seas L26: my listening room is small and I am not power hungry at all, I want to have the maximum flexibility to choose the Xover point with mid , and last, I need to be able to use these drivers in another way (perhaps a pair of sealed push-pull, no BR or PR) if I am not able to manage the dipoles in my room. The XLS 12" seems too oversized for me. My main problem is about the dipole placement in my room. Far from the back wall will be very difficult.
Christophe
Christophe
Try to read the articles on Siegfried Linkwitz's site about open baffle (bass) speakers. Many people visit his site and want to build something like it but noone seems to read the articles with the explination of the principle. Also read a lot of the open baffle topics on this site. He has a very good reson why he crosses his open baffle bass design at 100 or 120 Hz max.
I'm using open baffles for a long time now and can tell you a couple of things about your ideas.
A crossover frequency off 325 Hz with either a W-baffle or a H-baffle will not work. Cavity resonaces begin lower and you will have to stay out of that area. The H-baffle is not much better than the W-baffle in this case.
I don't kow if your mid/high system is also open baffle but open baffle bass combined with closed box midrange at a crossover frequency off 325Hz is very very hard to integrate, that simply doesn't work because off the totally different radiation paterns and character in sound.
By the way, why does TACT advise the 325Hz crossover point ? Probebly only to avoid the first floor reflection from the midrange unit ?
At this crossover point you can't seperate the low and mids too far. Open baffle bass is directive. I have tried putting my OB subs in the middle ones. Even at a crossover of 100 Hz with 60db/oct they could clearly be located and integration with mids was far gone.
If you really want to go the open baffle way at this crossover point maybe it's better to use a U-shape baffle with good damping at the back. This way you create a cadoid radation pattern wich also deals with room modes and can be placed much closer to the wall.
I'm using open baffles for a long time now and can tell you a couple of things about your ideas.
A crossover frequency off 325 Hz with either a W-baffle or a H-baffle will not work. Cavity resonaces begin lower and you will have to stay out of that area. The H-baffle is not much better than the W-baffle in this case.
I don't kow if your mid/high system is also open baffle but open baffle bass combined with closed box midrange at a crossover frequency off 325Hz is very very hard to integrate, that simply doesn't work because off the totally different radiation paterns and character in sound.
By the way, why does TACT advise the 325Hz crossover point ? Probebly only to avoid the first floor reflection from the midrange unit ?
At this crossover point you can't seperate the low and mids too far. Open baffle bass is directive. I have tried putting my OB subs in the middle ones. Even at a crossover of 100 Hz with 60db/oct they could clearly be located and integration with mids was far gone.
If you really want to go the open baffle way at this crossover point maybe it's better to use a U-shape baffle with good damping at the back. This way you create a cadoid radation pattern wich also deals with room modes and can be placed much closer to the wall.
It all depends on the volume levels you like to listen at. When I first built my dipoles I used a pair of Focal 10L6411 (10mm xmax) for the bass. They sounded very good, but loudish music below 40Hz could cause coniptions.
I switched to Adire DPL12s and the situation is much improved.
So the L26, which has a smaller xmax than my Focals will be correspondingly stressed. If you can't use a 12 incher, then the XLS10 as used in the Orion might be a better choice. Failing that, you could cross over to a monopole sub at 30-40Hz.
As for the top end, if you are using an H-Frame I'd also be leery about crossing over at 325Hz. Depending on the depth of the frame you would get odd resonances from 200Hz or so up. I think you'd be best not going any higher than 150Hz.
You could build the frame deeper to give you more bass, but this lowers the resonance point even further.
Another alternative would be to check out the NaO dipole woofer design at http://www.geocities.com/kreskovs/NaO.html
It is supposed to play 6dB louder than an equivalent woofer in an H-frame.
Cheers
Steve
I switched to Adire DPL12s and the situation is much improved.
So the L26, which has a smaller xmax than my Focals will be correspondingly stressed. If you can't use a 12 incher, then the XLS10 as used in the Orion might be a better choice. Failing that, you could cross over to a monopole sub at 30-40Hz.
As for the top end, if you are using an H-Frame I'd also be leery about crossing over at 325Hz. Depending on the depth of the frame you would get odd resonances from 200Hz or so up. I think you'd be best not going any higher than 150Hz.
You could build the frame deeper to give you more bass, but this lowers the resonance point even further.
Another alternative would be to check out the NaO dipole woofer design at http://www.geocities.com/kreskovs/NaO.html
It is supposed to play 6dB louder than an equivalent woofer in an H-frame.
Cheers
Steve
Thanks for the advices. I think that I will go for a pair of Seas L26 and try different test mules: sealed or U-frame dipole.
Christophe
Christophe
Paul,
have you considered running the W26/W22 as "2.5" way?
I mean like this; W22 in series, from sub (80Hz?) up to midrange and both W26 in parallel with with the W22´. W26 rolled of 1st order somewhere...
This would free you from one phase turn at the crossing 200Hz. The drawback off course more excursion from W22 but I wonder if that really would be any problem... depending on the crossing to sub.
(edit) I wouldn´t be surprised if removing of the caps to the W22 would clean up the midrange a bit, making up for slightly higher excursion.
/Peter
have you considered running the W26/W22 as "2.5" way?
I mean like this; W22 in series, from sub (80Hz?) up to midrange and both W26 in parallel with with the W22´. W26 rolled of 1st order somewhere...
This would free you from one phase turn at the crossing 200Hz. The drawback off course more excursion from W22 but I wonder if that really would be any problem... depending on the crossing to sub.
(edit) I wouldn´t be surprised if removing of the caps to the W22 would clean up the midrange a bit, making up for slightly higher excursion.
/Peter
Member
Joined 2003
Christophe,
Good luck with the L26. As long as you have enough Xmax, I think you'll like them better than nursing a subwoofer up to 325...some of the subs break-up just over 400.
Hi Peter,
I did consider a .5 with the 26/22 but, as you said, I wanted to limit 22 excursion. Lower crossover is around 50 so the 22s would work quite hard. I may try it sometime, but my current tweaking enjoyment is HF vertical radiation (tweeter is a little too strong on the vertical axis; so power response can be improved).
Paul
Good luck with the L26. As long as you have enough Xmax, I think you'll like them better than nursing a subwoofer up to 325...some of the subs break-up just over 400.
Hi Peter,
I did consider a .5 with the 26/22 but, as you said, I wanted to limit 22 excursion. Lower crossover is around 50 so the 22s would work quite hard. I may try it sometime, but my current tweaking enjoyment is HF vertical radiation (tweeter is a little too strong on the vertical axis; so power response can be improved).
Paul
Christophe,
I've had good results using a plain open baffle to cross over my front horns at 200hz see below:
With mine at 200hz I get no problems with reflections and you can see that I use them close to a rear wall. My room is the same size as yours.
In fact they are pretty insensitive to rear placement but more so with the "toe in" and "toe out" and the orientation of the drivers.
You could experiment with a similar baffle to see what happens at higher frequencies. Certainly there should be no baffle induced resonances as with the H or W frames, but reflections may be a problem at 325hz.
Good luck with yours and have fun!
Jonathan
I've had good results using a plain open baffle to cross over my front horns at 200hz see below:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
With mine at 200hz I get no problems with reflections and you can see that I use them close to a rear wall. My room is the same size as yours.
In fact they are pretty insensitive to rear placement but more so with the "toe in" and "toe out" and the orientation of the drivers.
You could experiment with a similar baffle to see what happens at higher frequencies. Certainly there should be no baffle induced resonances as with the H or W frames, but reflections may be a problem at 325hz.
Good luck with yours and have fun!
Jonathan
Thank you all, and for the pictures jonathan. The room dimensions are the same.I have just seen that at Linkwitz site: http://www.linkwitzlab.com/images/graphics/corner-dp.gif
I have ordered only 2 L26 for the moment to go sealed. I will do a test with something like jonathan or the corner config at Linkwitz.
If it seems promising, I will buy to other L26.
Christophe
I have ordered only 2 L26 for the moment to go sealed. I will do a test with something like jonathan or the corner config at Linkwitz.
If it seems promising, I will buy to other L26.
Christophe
Ah, thanks Peter. I need to learn to read more carefully. 🙂
Edit: actually, that's an amazingly low XO considering Paul's SPL preferences. In case you guys haven't seen what he's using for a sub -- an IB with 18 15" drivers. 😀
http://www.geocities.com/pnwright3/Gemini_subs.html
Paul, help us out here. What's the deal? Do the dipoles keep up with the IBs.
Edit: actually, that's an amazingly low XO considering Paul's SPL preferences. In case you guys haven't seen what he's using for a sub -- an IB with 18 15" drivers. 😀
http://www.geocities.com/pnwright3/Gemini_subs.html
Paul, help us out here. What's the deal? Do the dipoles keep up with the IBs.
Member
Joined 2003
Most people think "nitro" when they see the IBs, but the purpose is more subtle. IMO the importance of really clean bass is underestimated...and reducing driver excursion reduces distortion. With music, the IBs aren't noticed until you hear a note you realize can't come from a W26 dipole. So, from a distortion perspective, the big IBs are a good match.
For movies, everything above 30Hz is shelved down 8-10 db so you get the impact of big, deep, bass without everything else being so deafening. Helps keep family bliss and saves ears.
I have never bottomed the IBs or 26s but, of course, the IB would easily win a pure horsepower race. The 26s are pushed harder, so the next version (w/ribbons) will have a little wider baffle. I don't need them to play louder, just want to reduce excursion. 🙂
For movies, everything above 30Hz is shelved down 8-10 db so you get the impact of big, deep, bass without everything else being so deafening. Helps keep family bliss and saves ears.
I have never bottomed the IBs or 26s but, of course, the IB would easily win a pure horsepower race. The 26s are pushed harder, so the next version (w/ribbons) will have a little wider baffle. I don't need them to play louder, just want to reduce excursion. 🙂
- Status
- Not open for further replies.