Hi all, it's been nearly 18 years since I've posted in here.
Nice to see how popular dipoles are now. I've built and sold systems sporadically over the years, and done some in wall infinite baffle installations, but was far too busy to put the time into the hobby I used to.
However, I'm an empty nester now and have built up quite a stash of new drivers to experiment with in my shop from all the sales over the past year.
This is an open baffle I did a few years back. Made from Maple, Pine and Cherry I logged and milled. Pine had some nice spalting in it.
Drivers are Scan 10F 4424 and 22W 4535 up top, and Dayton PA 380-8 on the bottom. The base of the speaker is a 1.5" thick slab of Maple, and there are 3 channels of amplification and a mini-dsp 2x4HD mounted on top of it behind each speaker.
Not sure how much they weigh, but I'm sure it's a lot. Had to use the tractor bucket to lift them up on a stand outside to measure them. I'll try to dig up the measurements and add them later. It was hard to let these go out the door, but there's always something else that needs to be tried.
Nice to see how popular dipoles are now. I've built and sold systems sporadically over the years, and done some in wall infinite baffle installations, but was far too busy to put the time into the hobby I used to.
However, I'm an empty nester now and have built up quite a stash of new drivers to experiment with in my shop from all the sales over the past year.
This is an open baffle I did a few years back. Made from Maple, Pine and Cherry I logged and milled. Pine had some nice spalting in it.
Drivers are Scan 10F 4424 and 22W 4535 up top, and Dayton PA 380-8 on the bottom. The base of the speaker is a 1.5" thick slab of Maple, and there are 3 channels of amplification and a mini-dsp 2x4HD mounted on top of it behind each speaker.
Not sure how much they weigh, but I'm sure it's a lot. Had to use the tractor bucket to lift them up on a stand outside to measure them. I'll try to dig up the measurements and add them later. It was hard to let these go out the door, but there's always something else that needs to be tried.
Last edited:
My OB journey began with a pair of Tekton OB4.5s that I still love.
Wanting a diy OB project, I started with a pair of Betsy 8" drivers and a 3/4 thick sheet of Plyboo cut to the Wild Burro specs. Augmented with a pair of subs, they sounded fine but completely owned our condo's living room.
I moved the Betsy drivers to the 18" wide baffle, added a pair of GRS 15PF-8 woofers and cut the wings down. (Admittedly they're still pretty large.)
A 200uf cap keeps the full-rangers from working too hard and the woofers are each driven by a 100w plate amp.
They don't pull off the disappearing act like the Tekton's, but I like what I'm hearing. What they give up on the top they make up for with the ability to rock a bit harder.
With no measuring equipment and not being blessed with golden ears, it's about what brings a smile to my face and has me listening to the music.
Wanting a diy OB project, I started with a pair of Betsy 8" drivers and a 3/4 thick sheet of Plyboo cut to the Wild Burro specs. Augmented with a pair of subs, they sounded fine but completely owned our condo's living room.
I moved the Betsy drivers to the 18" wide baffle, added a pair of GRS 15PF-8 woofers and cut the wings down. (Admittedly they're still pretty large.)
A 200uf cap keeps the full-rangers from working too hard and the woofers are each driven by a 100w plate amp.
They don't pull off the disappearing act like the Tekton's, but I like what I'm hearing. What they give up on the top they make up for with the ability to rock a bit harder.
With no measuring equipment and not being blessed with golden ears, it's about what brings a smile to my face and has me listening to the music.
Thank you for saving me the time of looking for that procedure when I got home Kjeldsen!
I managed to find a measurement I took inside the shop. My shop is 54' x 30' with just under 10' ceiling, so no room gain here.
1/3 octave smoothing with 500ms window, so all the room reflections are in there.
I managed to find a measurement I took inside the shop. My shop is 54' x 30' with just under 10' ceiling, so no room gain here.
1/3 octave smoothing with 500ms window, so all the room reflections are in there.
Attachments
Open Baffle AE15
6 years ago I had my first Open Baffle project with 2x Alpha15 + Supravox + Fostex. I was very impressed (especially the bass)
After that I left with the Troels Gravesen projects and now I have Jensen Accu (Jenzen-Accu)
But after buying an 8-channel DAC8PRo, I decided to go back to Open Baffle. I read a lot and in the end I decided to go for the AE and Beyma speakers: 2x AE15 Dipol + TD8M + TPL200 / H The speakers have been bought and the process has begun
My friend Gen is very helpful to me in this whole process. So far I have managed to cut the boards, the rest - follow
6 years ago I had my first Open Baffle project with 2x Alpha15 + Supravox + Fostex. I was very impressed (especially the bass)
After that I left with the Troels Gravesen projects and now I have Jensen Accu (Jenzen-Accu)
But after buying an 8-channel DAC8PRo, I decided to go back to Open Baffle. I read a lot and in the end I decided to go for the AE and Beyma speakers: 2x AE15 Dipol + TD8M + TPL200 / H The speakers have been bought and the process has begun
My friend Gen is very helpful to me in this whole process. So far I have managed to cut the boards, the rest - follow
Attachments
Last edited:
Very nice vitalica, I like the design. What method will you use to attach the frame to the magnets?
Agree with you on dipole bass, the absence of box resonance coming back through the cone, and/or port is very revealing of detail. 50hz to 200hz is where dipoles really shine in my opinion. Not just box resonance, but a third less power to the room activating modes in the most problematic range. You hear the bass strings groan and fingers sliding on the strings with a good recording.
Before the speakers I posted above left my shop, I had a couple friends over listening to them. One of them asked me to play Hells Bells by AC/DC, which is not the type of music I normally listen to and had not heard in many years, so I pulled it up and cranked it up for him.
The look on their faces was priceless, and no doubt I was making one too. The crystal clear sound and apparent size of that bell in such a large room was really something to hear.
It was one of those moments when, by the time the intro was done and both guitars came in, you realize you have never really heard the song before then.
Best of luck with the execution of your project, I look forward to following your progress!
Agree with you on dipole bass, the absence of box resonance coming back through the cone, and/or port is very revealing of detail. 50hz to 200hz is where dipoles really shine in my opinion. Not just box resonance, but a third less power to the room activating modes in the most problematic range. You hear the bass strings groan and fingers sliding on the strings with a good recording.
Before the speakers I posted above left my shop, I had a couple friends over listening to them. One of them asked me to play Hells Bells by AC/DC, which is not the type of music I normally listen to and had not heard in many years, so I pulled it up and cranked it up for him.
The look on their faces was priceless, and no doubt I was making one too. The crystal clear sound and apparent size of that bell in such a large room was really something to hear.
It was one of those moments when, by the time the intro was done and both guitars came in, you realize you have never really heard the song before then.
Best of luck with the execution of your project, I look forward to following your progress!
My OB is similar to yours ie near-circular baffle where your FR and Midwoofer are mounted on. Mind OB was built about 3-4 years ago now dismantled owing to lack of space, my built was Tweeter(one rear as well) and mid-range and mid-woofer all these are mounted on a circular baffle. Tweeter, midrange ad mid-woofer mounted on the U frame which houses twin 12" woofers. You will find your configuration will sound excellent, more importantly fairly flat response.
The AE speakers will be fixed to the rear frame through the existing thread through the AE15 and TD8M magnet.
6 years ago I had my first Open Baffle project with 2x Alpha15 + Supravox + Fostex. I was very impressed (especially the bass)
After that I left with the Troels Gravesen projects and now I have Jensen Accu (Jenzen-Accu)
But after buying an 8-channel DAC8PRo, I decided to go back to Open Baffle. I read a lot and in the end I decided to go for the AE and Beyma speakers: 2x AE15 Dipol + TD8M + TPL200 / H The speakers have been bought and the process has begun
My friend Gen is very helpful to me in this whole process. So far I have managed to cut the boards, the rest - follow
Looks great! Which part of Europe are you in, out of curiosity?
Up until fairly recently I too swore by the benefits of dipole bass.
It simply sounded better than boomy boxes.
However, as we all know, the cost, complexity and real estate required to do it properly is by far the trickiest part of open baffling.
Enter DSP and Room EQ. IMHO it was a game changer.
A while back I compared actively Room EQed sealed bass to my actively Room EQed dipole bass (Audio Excellence).
Each required slightly different Room EQ, but subjectively I'd be hard pressed to say which was 'better' until you go very low when sealed is obviously better. Higher up it was a wash.
Theoretically transitioning from sealed to dipole creates a cardio response around the crossover, which may even have advantages.
It takes four open baffle drivers to equal the output of one equivalent sealed driver.
Now that DSP is so easy to apply well, the hassle doesn't seem worth it.
The problem with this approach is that no amount of EQ can fix a null, for example. There is no perfect solution which just makes all of this more fun
The first dipole subs I built were 2 H-frames with 4 x 12" DVC woofers back around 2000 when SL first put up his website. The stereo subs from his Phoenix build.
I had Kef coincident monitors at the time, and obtained an active sub crossover with a mic, warble tone generator, level meter and several bands of eq. I crossed the Monitors to the subs at 100hz, measured them and adjusted the response down to 20hz.
I was blown away. A total newbie at the time, I messaged Siegfried to thank him for sharing the plans to build them. I had 3 young children and was working in a research lab at the time, and all this equipment was much more expensive and scarce than it is now. I was fortunate to use some of the lab equipment, as I had to be as frugal as possible.
Siegfried Linkwitz was such a nice person, so sad that he has passed. He told me to make sure that I plugged the ports on the Kefs, which I had not done.
I was hooked on building speakers after that day, and little did I know what a special time in speaker building the next 13 or so years would be, with John Kreskovsky joining in, the crew at the Madisound forum and here... and all the progress that was made with technology and understanding dipoles during that time.
Personally, for me it culminated when we finally had the computer power to run the sims on dipole baffles of different sizes with regards to the size of the driver. They were sent to SL and he posted them on his site. After that we understood that as little baffle as possible was best with regard to avoiding the sharp nulls and diffraction ripple above the dipole peak, where front and back waves come into phase and add together, before rolling off at 6db/oct
It was John K that first put the 4" between the tweeter and the 8", as that was the point where uniformity of polar response broke down and dispersion widened again until the tweeter eventually became directional once more. SL followed suite shortly after and joined the 4 way club, which he had been trying to avoid.
Not only did the 4" help maintain uniform directionality, but JohnK (what a mathematician and software wiz) had realized that with such tiny baffles, the 8" can be crossed right at the dipole peak and only used below it (run "off the baffle" so to speak) avoiding the nulls and ripples, while the peak and dip of the 4" could be dealt with in the crossover, as it was right in the perfect spot if you sized and shaped your baffle and picked your crossover point right.
I still like to experiment with baffle shapes, but aesthetics must play a part also. I try to ensure that the distances from driver to baffle edge are ever changing, but the baffle is small as possible. I try to avoid parallel walls and resonant effects designing the bass section. I like high sensitivity.
And always, like most I'm trying to make the compromises that give my clients the best bang for the buck. The scan 10f 4424 measures almost exactly the same from the front and the rear, has polar response better than some tweeters, and extends past 15khz. I leave the slight rise above 6khz. I cannot hear enough of a difference with a tweeter to justify using one. I remember JohnK saying that he wondered if he needed a tweeter when he first used it.
I enjoy research and experimentation and have built so many different kinds of speakers the last 20 years. I do not enjoy building the same thing twice and avoid it if at all possible.
I am sure your speakers sounded very nice and I appreciate your comments. I look forward to seeing what you build next!
Cheers sfdoddsy
Many good points. I use sealed under 50-60hz. Below that I cannot hear a difference and the benefits of trying to do dipole in that range are not worth it.
Likely more benefits from the cardioid response through the crossover to the dipole as you say.
Two 10" or a good 15" on a fairly small baffle can get me to the 50-60hz target, which is easy.
I can hear the box resonance in the 100-200hz range. It's just so loud inside the box and at those wavelengths nothing is going to swallow that, it's coming back through the cone. Not a big deal for my own listening though, I'm def not a speaker snob.
When I'm building speakers to sell it's a different story. No way I could compete with mass marketed box store speakers. It's got to look and sound worth the extra money and perform well in whatever room it finds itself in without the customer doing anything to it. I find the advantages of dipole work well and sound obvious to the listener in this regard.
But yes, nearly four times the displacement required and the drawbacks of that expense and size, which grows larger the lower you try and go with them. Plus, you need a room large enough to get them away from that back wall.
I prefer a good, small full range driver on the top and give up the tweeter, then go sealed below 50-60hz...unless someone has the space for a huge t-line hehe. Those are the cost vs performance compromises I choose.
I won't argue against any of your points and I'm sure your system sounds excellent. You're very knowledgeable from the posts of yours that I have read.
Many good points. I use sealed under 50-60hz. Below that I cannot hear a difference and the benefits of trying to do dipole in that range are not worth it.
Likely more benefits from the cardioid response through the crossover to the dipole as you say.
Two 10" or a good 15" on a fairly small baffle can get me to the 50-60hz target, which is easy.
I can hear the box resonance in the 100-200hz range. It's just so loud inside the box and at those wavelengths nothing is going to swallow that, it's coming back through the cone. Not a big deal for my own listening though, I'm def not a speaker snob.
When I'm building speakers to sell it's a different story. No way I could compete with mass marketed box store speakers. It's got to look and sound worth the extra money and perform well in whatever room it finds itself in without the customer doing anything to it. I find the advantages of dipole work well and sound obvious to the listener in this regard.
But yes, nearly four times the displacement required and the drawbacks of that expense and size, which grows larger the lower you try and go with them. Plus, you need a room large enough to get them away from that back wall.
I prefer a good, small full range driver on the top and give up the tweeter, then go sealed below 50-60hz...unless someone has the space for a huge t-line hehe. Those are the cost vs performance compromises I choose.
I won't argue against any of your points and I'm sure your system sounds excellent. You're very knowledgeable from the posts of yours that I have read.
So interesting to have your contributions here. I'm new to dipoles, just built my 2nd iteration and use 12" sealed subs below 70Hz and one naked (no baffle) 18" per side (it's an active 4-way system). Was wondering how small is the "fairly small baffle" you use with one 15" down to 50-60Hz and how high do you cross to the fullrange? I'm currently xo at 450Hz to an 8" mid. Tried 350Hz but the 8" wasn't liking it. Need to try 400Hz and see if I like it better than 450Hz. I've modelled in The Edge adding a baffle to the 18" to go lower, but seems I would need to cross to the midrange below 300Hz - hence my question.
see image of my OB implementation.
Attachments
Last edited by a moderator:
6 years ago I had my first Open Baffle project with 2x Alpha15 + Supravox + Fostex. I was very impressed (especially the bass)
After that I left with the Troels Gravesen projects and now I have Jensen Accu (Jenzen-Accu)
But after buying an 8-channel DAC8PRo, I decided to go back to Open Baffle. I read a lot and in the end I decided to go for the AE and Beyma speakers: 2x AE15 Dipol + TD8M + TPL200 / H The speakers have been bought and the process has begun
My friend Gen is very helpful to me in this whole process. So far I have managed to cut the boards, the rest - follow
Very nice!! Nice AE drivers!
Not sure what your plans are regarding the TPL-200, but would encourage you to try them open-back. I have TPL-150H and tried them in an dipole speaker with factory back cover, open back, and open and with a rough prototype of a waveguide in the back. Here's my thread with measurements done outside 180° with back waveguide: post #120.
It was explained to me dipole behavior up to about 6kHz is important. This approach achieves that and most importantly I like it better too. It's a cheap experiment with with a foam waveguide.
Another thought, since you will be grabbing the woofers from the thread in the back: consider having a 1-2mm gap between woofer frame and panel to avoid the woofer getting the panel to vibrate. Allows for a much simpler panel construction and avoids vibrations. It was suggested to me and thought it made sense, although for the time being I'm going baffleless.