I've tried baffle-less "midrange" of 12" driver, which could play down to about 300Hz with little EQ. For an 8"er, I guess you'll need some more EQ, or the lower range may suffer somewhat.
For temporary trial, I think it's quite easy to find out if it work for you. No wood work at all! Hahaha.... Just 2 poles and some string, you're good to go
Metal tube frame is a wonderful idea. I like that kind of functional beauty
For temporary trial, I think it's quite easy to find out if it work for you. No wood work at all! Hahaha.... Just 2 poles and some string, you're good to go
Metal tube frame is a wonderful idea. I like that kind of functional beauty
I've looked into the baffle-less mid in EDGE. I will roll off a lot earlier than the current baffle, but since I'm crossing over at 350 it should work with some EQ at the bottom end there. Without baffle, the dipole peak will come right up at the XO point - 1500 Hz, and the peak will be much smaller. The EDGE graphs below shows the difference between no baffle (green) and the current baffle (red).
An externally hosted image should be here but it was not working when we last tested it.
It can be, for mids-HF for sure.
I did think of the same idea, based on other projects (not OB) that i have studied in the past couple of months. For the low mids there is the issue of the baffle rolloff. With 350hz XO point as you have just a little EQ will be required. Bit more for me with 280-300hz
I wonder instead about the sound of the wingless woofers in your speakers. How much more EQ you had to put now? I think short wings are still the way to go, unless you have subs up to roughly 80hz.
After the woofer wings were gone I had to increase the compensation by approx 6 dB. I have more than +20 dB @ 35 Hz now.
I do prefer the sound without wings, no doubt. The lower midrange is much better, and I think the bass is better also. I have a very large bass driver (21"), so it can play down to 35-40 Hz even without a baffle.
I do prefer the sound without wings, no doubt. The lower midrange is much better, and I think the bass is better also. I have a very large bass driver (21"), so it can play down to 35-40 Hz even without a baffle.
(Ahhh, this is the third time trying to post - if it doesn't work, I'm quitting)
I currently operate each driver below its dipole peak. Each driver has its own baffle (or none at all).
My tweeter (a Neo3PDR) I operate without a baffle. My 8" mid doesn't use one either, because it has to run up to the XO of 1.5k. But my woofer is crossed around 200Hz, and has a baffle. I think I set the baffle peak at 400Hz, but could have gone lower. Obviously, I'm trying to get the most regular on and off axis response - which for dipoles, is ideally -1dB at 30deg, -3dB at 45deg, and -6dB at 60deg.
The situation for the mid is not ideal though. My 8" driver begins to beam at around 700Hz (measured), so its dipole response off axis is dropping quickly, which lead to a dip in the power response above 700Hz. But on the bottom end, I can't cross the woofer as low as I want because it is running out of power handling due to 18dB of EQ, AND contending with room issues between 100-300Hz. So the next step for me is to split the mid into a 4way. This way, the power response is regular at the upper end, while the lower end can have some baffle support and a larger size driver for more displacement. Each driver then has a smaller bandwidth, higher sensitivity, and lower non-linear distortion, higher power handling, and maintain a very nice off-axis response. There should be plenty of useful out of band response for smooth XO's - I'd consider 2nd order for their smooth power response and lower phase group delay distortion, but that is something I'd have to play with to see if it is important enough.
I would go with a 5.5" upper mid, and a 10" lower mid. One thing that may become possible is to shift the XO point between the woofer and lower mid down to around 100Hz (maybe), and then to totally separate the woofer from the rest of the system, by some distance. This would be good for both aesthetics, and to reduce baffle vibrations. Magnet mounting each driver, and things should be very solid. But one of the major advantages is being able to position the bass and mids separately for best in room response, which could be a very big deal.
Another possibility, especially for you Erik, is to cross your tweeter lower, say 700Hz? (I think this is only possible for the Beyma AMT and possibly the BG Neo8) This allows you to push all the other crossover points lower, larger baffles WRT each driver's bandwidth, and possibly use larger diameter drivers for the mid. It would allow a smoother power response and much less lobing between the mid and tweeter. This is something I may try in the near future, as a four way is both expensive and complicated.
I currently operate each driver below its dipole peak. Each driver has its own baffle (or none at all).
My tweeter (a Neo3PDR) I operate without a baffle. My 8" mid doesn't use one either, because it has to run up to the XO of 1.5k. But my woofer is crossed around 200Hz, and has a baffle. I think I set the baffle peak at 400Hz, but could have gone lower. Obviously, I'm trying to get the most regular on and off axis response - which for dipoles, is ideally -1dB at 30deg, -3dB at 45deg, and -6dB at 60deg.
The situation for the mid is not ideal though. My 8" driver begins to beam at around 700Hz (measured), so its dipole response off axis is dropping quickly, which lead to a dip in the power response above 700Hz. But on the bottom end, I can't cross the woofer as low as I want because it is running out of power handling due to 18dB of EQ, AND contending with room issues between 100-300Hz. So the next step for me is to split the mid into a 4way. This way, the power response is regular at the upper end, while the lower end can have some baffle support and a larger size driver for more displacement. Each driver then has a smaller bandwidth, higher sensitivity, and lower non-linear distortion, higher power handling, and maintain a very nice off-axis response. There should be plenty of useful out of band response for smooth XO's - I'd consider 2nd order for their smooth power response and lower phase group delay distortion, but that is something I'd have to play with to see if it is important enough.
I would go with a 5.5" upper mid, and a 10" lower mid. One thing that may become possible is to shift the XO point between the woofer and lower mid down to around 100Hz (maybe), and then to totally separate the woofer from the rest of the system, by some distance. This would be good for both aesthetics, and to reduce baffle vibrations. Magnet mounting each driver, and things should be very solid. But one of the major advantages is being able to position the bass and mids separately for best in room response, which could be a very big deal.
Another possibility, especially for you Erik, is to cross your tweeter lower, say 700Hz? (I think this is only possible for the Beyma AMT and possibly the BG Neo8) This allows you to push all the other crossover points lower, larger baffles WRT each driver's bandwidth, and possibly use larger diameter drivers for the mid. It would allow a smoother power response and much less lobing between the mid and tweeter. This is something I may try in the near future, as a four way is both expensive and complicated.
Unfortunately, I cannot cross the TPL below 1500 Hz in open baffle. It drops like a stone below 1500 Hz....
I just *had* to try it with no baffle. Below are pictures of the result! The tweeter is hung with rubber rings from a steel beam, and the mid is mounted the same way to the tweeter. It works quite well, and was easy to make.
The mid requires 6 dB/oct compensation below 1500 Hz in this setup, but its not a big problem, and it integrates well with the woofer, crossed over at 350 Hz.
I just *had* to try it with no baffle. Below are pictures of the result! The tweeter is hung with rubber rings from a steel beam, and the mid is mounted the same way to the tweeter. It works quite well, and was easy to make.
The mid requires 6 dB/oct compensation below 1500 Hz in this setup, but its not a big problem, and it integrates well with the woofer, crossed over at 350 Hz.
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.
An externally hosted image should be here but it was not working when we last tested it.
LOL
(you don't have to use rubber - no good!)
http://www.diyaudio.com/forums/mult...fle-dipole-beyma-tpl-150-a-3.html#post1857409
If you allow one further suggestion - make a small rectangular baffle (no much bigger then the outer diameter needed) for the mid - it helps with the directivity pattern.
As for your cables - try to wrap them around the horizontal bar before going to the amp to make them "kind of" flexible for horizontal spwaker movement.
Great look - to my taste!
Michael
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Another example of a stringed WOB (WithOut Baffle )
Xovers are at 100Hz and 1500Hz with 24dB/oct. Bass EQ is 20 dB total from 100-15 Hz. Mid EQ is 15 dB total from 450-100 Hz.
The builder reported that there is almost no movement of the Kilomax when hung from the ceiling.
)Xovers are at 100Hz and 1500Hz with 24dB/oct. Bass EQ is 20 dB total from 100-15 Hz. Mid EQ is 15 dB total from 450-100 Hz.
The builder reported that there is almost no movement of the Kilomax when hung from the ceiling.
Wow! that's a quick action, and wonderful, too!
In such 'suspension', I found the compliance in the tensional direction is not necessary. By the relatively low mass and low rigidity, the vibration energy can not pass through the suspension effectively. So any string/wire/cable can be used if only the tensional strength is enough. (I myself use stranded steel wire with clips for hanging my mid-high horns)
In such 'suspension', I found the compliance in the tensional direction is not necessary. By the relatively low mass and low rigidity, the vibration energy can not pass through the suspension effectively. So any string/wire/cable can be used if only the tensional strength is enough. (I myself use stranded steel wire with clips for hanging my mid-high horns)
Wow! that's a quick action, and wonderful, too!
...I myself use stranded steel wire ...
Me too - I found it the best sounding, cheap and most reliable solution.
I recommend to pay attention to some details - there is some reward of.
Make sure you have well defined points where the most part of movement (bending) occurs - meaning - avoid any rubbing there (the internal friction is already something we can not avoid).
Michael
I got a center OB sub which the construction is very shallow, accommondating 2 18" with 130g Mms (total 260g). When playing, its vibration is quite obvious by touch.
OTOH, my main baffle is more rigidly braced and with deeper base board. And with only one woofer (same as above), it's much calmer by comparison.
I think, baffle-less or not, these heavy woofers would better be braced/supported rigidly to obtain better dynamic and output. Suspended freely, there'd be inevitably opposite motion (or some forms of delayed and irregular motions... ) on the whole driver related to the cone.
OTOH, my main baffle is more rigidly braced and with deeper base board. And with only one woofer (same as above), it's much calmer by comparison.
I think, baffle-less or not, these heavy woofers would better be braced/supported rigidly to obtain better dynamic and output. Suspended freely, there'd be inevitably opposite motion (or some forms of delayed and irregular motions... ) on the whole driver related to the cone.
Regarding irregular motion - that's what I too thought before I dived into the topic – but actually quite the contrary is true. Try and you well see - aahhh - you will hear
If you read through my paper (math is pretty simple) you can see that "movement in disorder" only happens with the common approach eg. trying to keep speakers rigidly in place – whereas suspending a speaker freely results in absolute predictable movement of veeeeery low amount.
http://members.aon.at/kinotechnik/diyaudio/diy_audio/CIC/Introducing_CIC.htm
The net benefit is that there is *no* resonance whatsoever (except the veeeery low fundamental of the pendulum) when speakers are hung – well - for the overall movement we are talking of here.
Seen from a more philosophically point of view my arguments outlined in the paper directly relate on the concept of "local mass" – which can be seen as an equivalent to "acoustically small dimensions".
Michael
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Thats what the user of that Kilomax reported: There was NEVER a visible motion of the woofer basket and magnet.
Regardless it helps to make the pendulum as long as possible.
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