I want to build some speakers and I would like to here what you guys have to say baout it. I want to build a 3 way fully active system with a vifa tweeter covering 10000-20khz, four or 6 tang band 3 or 4 inchers to cover 300-10000hz, and a pair of 8 inch tang band subwoofers for the bottom end. The drivers will be mounted on a baffle that is curved so that all the drivers are equidistant from the sweetspot. Im still not sure if I want to make the subs open baffle cause im not sure ill get all the output i desire. I chose such a high crossover frequency as i want to try something different, and many people argue that a xo at 2000hz is not good idea as our hearing is very sensitive in that range.
Any comments?
Thanks
Alex
Any comments?
Thanks
Alex
Hi Alex
Unless your room is small, a pair of 8 inch is too light for dipole bass, where the smaller SL dipole (Orion) bass uses a pair of 10 inch, with *12.5 mm Xmax for sufficent Vd.
Have you read www.linkwitzlab.com - allow a lot of time!
A curved baffle is quite a bit of work – may not be necessary. If listening distance is (guessing) more than 5-6 feet, benefit may be small.
Multiple drivers can cause lobing, but others know far more about that than me.
Cheers
Unless your room is small, a pair of 8 inch is too light for dipole bass, where the smaller SL dipole (Orion) bass uses a pair of 10 inch, with *12.5 mm Xmax for sufficent Vd.
Have you read www.linkwitzlab.com - allow a lot of time!
A curved baffle is quite a bit of work – may not be necessary. If listening distance is (guessing) more than 5-6 feet, benefit may be small.
Multiple drivers can cause lobing, but others know far more about that than me.
Cheers
If your baffle is quite large, a pair of high-excursion 8" drivers *might* get down to 50Hz at realistic levels, but with little/no headroom, IMO. Linkwitz recommends crossing his Phoenix dipole bass (2 x 12") steeply to a sealed sub at 40Hz, and I don't believe even that is a very high-output solution.
When it comes to bass driver displacement on OBs of reasonable size, I recommend figuring out how much sealed box displacement would meet your bass needs, then quadrupling it for an OB.
The dipole bass mantra: Displacement, displacement, displacement!
I have a smallish listening room, and I run a pair of 3' x 4' OBs down to 35Hz with 21" drivers (about 3-3.5 times the displacement of two eights per channel), and it's not hard to drive them into over-excursion. I am planning to add sealed subs in the future.
When it comes to bass driver displacement on OBs of reasonable size, I recommend figuring out how much sealed box displacement would meet your bass needs, then quadrupling it for an OB.
The dipole bass mantra: Displacement, displacement, displacement!
I have a smallish listening room, and I run a pair of 3' x 4' OBs down to 35Hz with 21" drivers (about 3-3.5 times the displacement of two eights per channel), and it's not hard to drive them into over-excursion. I am planning to add sealed subs in the future.
hi,
i have been experimenting with open baffles for a long time
and i can say that guys are right
for good open baffle bass, the bigger the baffle and larger the cone area the better
i have arrived at four 15" woofers total with intimidating size of baffle
and i love it
sound is free of boxiness if there is such word
i have been experimenting with open baffles for a long time
and i can say that guys are right
for good open baffle bass, the bigger the baffle and larger the cone area the better
i have arrived at four 15" woofers total with intimidating size of baffle
and i love it
sound is free of boxiness if there is such word
adason said:
Thats what mine is like.
I did post a response but for some reason it didnt get added to the thread?
DIY audio then went down so maybe it got lost in the wires getting to the DIY servers Anyway what I was asking was, with H baffles, if you have a baffle that is 12" wide with flaps that are 6" wide all over that means you have an overall 24" wide baffle right? the 12" from the main panel and 6+6=12 from the wings.
So then that gives you extension down to about 130hz, which is then about 10dB down at 40hz, this doesnt seem like a lot of EQ to get appreciable bass.
With all that in mind I tried it!
, thank god my brother got a big moniter for christmas, lots of cardboard. See pic.Now as you can see behind is the sealed box the XLS works in normally, this requiring EQ anyway. This is about 8dB per octave working from about 100hz, which is where my makeshift openbaffle starts to need EQ, so ive got about 2dB more per octave of EQ then is required.
Anyway to cut a long story short they sounded really good some of the most tuneful, and to my surprise, forceful bass I have ever heard.
Now I use the KX drivers on my computer which allow you to build digital xovers with the DSP so I added a 4th order highpass at 40hz to protect the driver from over excursion.
I dont really understand where you guys are coming from with the running out of excursion, this driver played just as loud in the open baffle as it did in the sealed box, OK it lost a little bit of SPL but nothing major. I also know that the sealed XLS with EQ is not designed for high bass SPL either, but if you are only interested in playing music you dont really miss the 20-40hz range, and in a small room you dont run out of level. This was a single pair of XLS playing in a 3*4 meter room and I certainly didnt require more level.
I will now be making Hbaffles and seeing how they perform.
Attachments
that bring us to the question what is the best material for making open baffles? should it be light and stiff or heavy and stiff? does it have to be one type of material only or the middle should be heavy and stiff and wing can be light and stiff? how stiff does it have to be? i have seen phy-hp mount their driver on small brass plate and this attach to a big wooden baffle
than other project, i lost the link, had ultralight balsa wood laminated....how about you guys, what do you use besides cardboard? /just kidding, i once mounted a fullrange on small board in the middle of the carpet and hang it from the ceiling in the middle of the room....impressive sound, very low gaf/
If its about displacement, then how about using something like:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-455
Models pretty well for OB and has a very large Xmax. Way out of my current price league (especially assuming I'd have to build some seriously sturdy now baffles to mount these suckers, too), but not all that pricy compared to drivers alot of folks are using in their subs or even as mids for pairs of speaks.
Or, how about even this:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=290-268
Cheaper, with nearly 3x the Vas. Slightly lighter weight driver, but even more surface area and baffle size needs.
Kensai
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-455
Models pretty well for OB and has a very large Xmax. Way out of my current price league (especially assuming I'd have to build some seriously sturdy now baffles to mount these suckers, too), but not all that pricy compared to drivers alot of folks are using in their subs or even as mids for pairs of speaks.
Or, how about even this:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=290-268
Cheaper, with nearly 3x the Vas. Slightly lighter weight driver, but even more surface area and baffle size needs.
Kensai
I think that accordion surrounds are not suitable for dipole (can’t recall why).
The Dayton would be good.
Remember that many otherwise very drivers make chuffing noise through the vent when used in dipole bass, and can’t be used eg the Adire Shiva.
The newish TC Sounds TC2+ 12 inch has knocked off the champ of 12 inch dipole, the XLS. With similar very low distortion, it’s Xmax is 56% higher then the XLS.
Richard
The Dayton would be good.
Remember that many otherwise very drivers make chuffing noise through the vent when used in dipole bass, and can’t be used eg the Adire Shiva.
The newish TC Sounds TC2+ 12 inch has knocked off the champ of 12 inch dipole, the XLS. With similar very low distortion, it’s Xmax is 56% higher then the XLS.
Richard
Chuffing will generally come in proportion to how much excursion you demand of your drivers. For this and other reasons, if you ever find yourself comparing two drivers of equal Vd, choose the one with larger Sd over the one with larger Xmax.
For example, though their Vd is about equal, a 15-incher with a 10mm Xmax will generally be less noisy and lower distortion than a 10-incher with a 20mm Xmax. You'll also likely gain efficiency in the bargain.
For example, though their Vd is about equal, a 15-incher with a 10mm Xmax will generally be less noisy and lower distortion than a 10-incher with a 20mm Xmax. You'll also likely gain efficiency in the bargain.
I was hoping to have a crossover point at about 250hz. I dont know that the subs mentioned would perform well at 250 hz. The 8 inch driver that i mentioned has extension to 1000hz, so i figure it would perform well. I want a high crossover frequency as i LOVE midbass punch, and i figure that the 2 8 inch drivers could punch pretty hard. Also note that i have a 12 inch sub (shiva) ported to handle movies below ~50hz.
Thanks
Alex
Thanks
Alex
Sealed or reflex, I imagine they might hit OK down to 50Hz, and a sub is prob. a great idea. But If you're still thinking dipole (and haven't bought the 8s yet), I'd consider supersizing. Response up to 1kHz isn't a problem for many larger drivers, up to and including some 15s.
Actually, if you've become used to an exagerated midbass (what most people describe as "punch") I would suggest that dipoles may not satisfy you. They tend to have a very neutral, even presentation, so some folks used to lumpy response think they sound lean.
Actually, if you've become used to an exagerated midbass (what most people describe as "punch") I would suggest that dipoles may not satisfy you. They tend to have a very neutral, even presentation, so some folks used to lumpy response think they sound lean.
> Response up to 1 kHz isn't a problem for many larger drivers, up to and including some 15s.
That seems an exaggeration. The XLS 12 enters breakup at 490 Hz. The TC2+ is kinda smooth to 800 Hz, but it’s efficiency is down c. 4 dB by 200 Hz.
A Lambda would be better, if they were still available. I think only some pro drivers might go flat 50 – 1000 Hz.
That seems an exaggeration. The XLS 12 enters breakup at 490 Hz. The TC2+ is kinda smooth to 800 Hz, but it’s efficiency is down c. 4 dB by 200 Hz.
A Lambda would be better, if they were still available. I think only some pro drivers might go flat 50 – 1000 Hz.
Yes, it's the prosound units I'm referring to--for example, those used in the wide variety of 2-way PA monitors.
The XLS and others of its ilk (the purpose-built subwoofers) are, of course, not going to deliver nearly as high. But if the goal is an open baffle from midbass down to 40-50Hz to cross to a sub, then you don't need the ~20Hz Fs of a sub driver.
The XLS and others of its ilk (the purpose-built subwoofers) are, of course, not going to deliver nearly as high. But if the goal is an open baffle from midbass down to 40-50Hz to cross to a sub, then you don't need the ~20Hz Fs of a sub driver.
Konnichiwa,
Don't give up so quick. If you have a Driver suitable for dipole operation the results may surprise you.
The Driver I use myself on baffles aroun 2' X 4' has a resonance at 55Hz, an X-Max of 12mm Peak-Peak and a Qts of 0.7. While the extremely low bass level is limited (due to the Fs of 50Hz) the overall sound is quite balanced and general levels achievable in playback are rather high.
I do use a sealed box subwoofer with a pair of 12" Drivers to support the system in the extremely low frequencies, but that one is optional with a lot of music.
If it still does not work out for you, then you can cut the baffle down in size and use the cutoffs for the sides/top/bottom of your sealed box and just add a rear wall... ;-)
Sayonara
akunec said:
Don't give up so quick. If you have a Driver suitable for dipole operation the results may surprise you.
The Driver I use myself on baffles aroun 2' X 4' has a resonance at 55Hz, an X-Max of 12mm Peak-Peak and a Qts of 0.7. While the extremely low bass level is limited (due to the Fs of 50Hz) the overall sound is quite balanced and general levels achievable in playback are rather high.
I do use a sealed box subwoofer with a pair of 12" Drivers to support the system in the extremely low frequencies, but that one is optional with a lot of music.
If it still does not work out for you, then you can cut the baffle down in size and use the cutoffs for the sides/top/bottom of your sealed box and just add a rear wall... ;-)
Sayonara
Konnichiwa,
No, the H-Baffle is not very ameanable to this type of "milkmaid" calculations. Actually, not even a simple rectangular baffle is, especially as you MUST include roll effects.
If you want to know how an H-Baffle works try simulating as short transmission line, then add room effects.
Sayonara
5th element said:
No, the H-Baffle is not very ameanable to this type of "milkmaid" calculations. Actually, not even a simple rectangular baffle is, especially as you MUST include roll effects.
If you want to know how an H-Baffle works try simulating as short transmission line, then add room effects.
Sayonara
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