I have been contemplating making my first pair of open baffle 2 way speakers, and have no experience in this endeavor.
So i would appreciate all the help and knowledge you guys are willing to share.
I would like to make something in the look of the pap15. I will be receiving 4 sb audience bianco-15ob350 woofers later today. Bought them firstly due to the fact that they are made for open baffle, and i like the look of the cones. I know that the qts is not higher than the 0.7 mark I have read people mentioning. But coming in at 0.6, with 11.02mm xmax they will do just fine.
At the momment I have a pair of fostex fe126 en lying around, but would like to try sonido sfr200a at a later time.
I have the minidsp shd and 2xclass D power amplifiers.
First question is where do I find the dimensions of the trio 15 baffles? Have looked so many places, and haven't found it yet? Hoping someone maybe has a nice drawing with measurements of the construction.
Can I use the fe126en as a mid/tweeter for the momment or will it be to shouty?
What would be a good crossover point for the sb audience drivers, and fe126?
These are the questions for now.
Regards Mick
So i would appreciate all the help and knowledge you guys are willing to share.
I would like to make something in the look of the pap15. I will be receiving 4 sb audience bianco-15ob350 woofers later today. Bought them firstly due to the fact that they are made for open baffle, and i like the look of the cones. I know that the qts is not higher than the 0.7 mark I have read people mentioning. But coming in at 0.6, with 11.02mm xmax they will do just fine.
At the momment I have a pair of fostex fe126 en lying around, but would like to try sonido sfr200a at a later time.
I have the minidsp shd and 2xclass D power amplifiers.
First question is where do I find the dimensions of the trio 15 baffles? Have looked so many places, and haven't found it yet? Hoping someone maybe has a nice drawing with measurements of the construction.
Can I use the fe126en as a mid/tweeter for the momment or will it be to shouty?
What would be a good crossover point for the sb audience drivers, and fe126?
These are the questions for now.
Regards Mick
Hmm, googling popped up this link, which lists: the smaller panel is 29.9cm tall, the larger 41.9cm tall, and both 53.8cm wide. The whole thing reaches 121.92cm off the ground.
Its published response is a bit 'shouty', but toeing them in to cross at/in front of you will solve the problem.
For me, a ~238 Hz XO to both keep the ctc spacing at ~1/4 WL and polar matched.
Its published response is a bit 'shouty', but toeing them in to cross at/in front of you will solve the problem.
For me, a ~238 Hz XO to both keep the ctc spacing at ~1/4 WL and polar matched.
I have those bass drivers in my OB and currently crossing to a 8" Betsy at ca 100Hz. Still working on XO. Active at the moment. The passive solution worked but had to pad down the Betsy ca 6dB to match the woofer. Now running 6Watt SE tube on the Betsy and 25W SS on the woofers.
The only thing I dont like about the bianco 15 is the very thin basket. It rings in free air (not mounted) when tapping the cone. I beefed up the basket so it's solid now. Probably not an issue when mounted tho. Fs seems to be just under 40Hz, not near the 25Hz or whatever they claim. But I like them, good bass.
The only thing I dont like about the bianco 15 is the very thin basket. It rings in free air (not mounted) when tapping the cone. I beefed up the basket so it's solid now. Probably not an issue when mounted tho. Fs seems to be just under 40Hz, not near the 25Hz or whatever they claim. But I like them, good bass.
Here are some more ideas for you to think about if you want
- two 15" OB per side is smart for better bass output
- The Fostex full range you already have has its own advantages over a horn and coax so no need to go looking for anything else now
- the digital XO will allow you try different XO configs
- try a steep filter under 40Hz to unload the woofers
- the Fostex may perhaps do better with the woofers assisting up to 500Hz so you get a good lower mid SPL , for a full sound signature ie an experimental very wide XO
- the modular OB from PAP is a smart concept allowing you to easily try different configurations
- Dont necessarily follow the PAP WMW - it may look nice but it could be better to have the woofers adjacent and low to prevent combing and slightly reduce torque on the baffle
- better to have the full ranger at the top for soundstage
- seal the bottom panel to the floor and just have a 1mm gap between modules for OB bass sealing
- with the miniDSP and EQ you may be able to minimise the Fostex shouting even with the OB toed in if you have one listening spot
You sould end up with a nice OB speaker. 
Here is a very important point.. Acoustical vs Electrical crossover point. A lot of people ignore this with a box speaker and the results aren't great. Ignore it with an OB speakers and the results will be awful. (been there, done that, have the scars).
The woofers on OB won't have a response like in a box, they will lose a lot of bass. That means that woofer top end has to be brought down to match the woofer low end. There are different ways to correct that, for example when usung a crossover from woofer to fullrange speaker in the 500-750 range, your woofer low pass might need to be set at 100Hz. Electrically. Why? Because that's what flattens the woofer response so that it blends with the fullrange. It will become a ~600Hz low pass acoustically. Box speakers rarely need that kind of massive EQ or crossover tricks. Open baffle does need it. I found this very difficult to understand at first, but it's key to getting the correct tonal balance.
Here is a very important point.. Acoustical vs Electrical crossover point. A lot of people ignore this with a box speaker and the results aren't great. Ignore it with an OB speakers and the results will be awful. (been there, done that, have the scars).The woofers on OB won't have a response like in a box, they will lose a lot of bass. That means that woofer top end has to be brought down to match the woofer low end. There are different ways to correct that, for example when usung a crossover from woofer to fullrange speaker in the 500-750 range, your woofer low pass might need to be set at 100Hz. Electrically. Why? Because that's what flattens the woofer response so that it blends with the fullrange. It will become a ~600Hz low pass acoustically. Box speakers rarely need that kind of massive EQ or crossover tricks. Open baffle does need it. I found this very difficult to understand at first, but it's key to getting the correct tonal balance.
I've used a type called golden walnut.
To make beautiful seams, you have to put the vinyl on the large surface, make sure you have enough to bend it all the way to reach the backside of the baffle.
2nd bend one of the longer sides, starting from the middle towards the corners(a heat gun is necessary to get a nice corner. Don't overheat it!) When you're about 10cm from the corner, you cut a 45 degree angle from the corner outwards. Fold the corner from the side of the baffle gently so that it can stick to the front, and make way for the long side. Now apply the last 10cm towards the corner, and let the vinyl go around the corner, forming a triangle 📐 on the side. Cut the triangle from the top towards the bottom in a straight line, so you have 5mm vinyl left.
Apply the same way in the other end of the long side. Then apply the short side, letting the vinyl follow the entirety of the side, don't bend the corner, just let the vinyl protrude over it. Cut of the excess that is protruding, and voila you have a beautiful corner. But I've made many things with vinyl, so practice with small pieces first to make sure you have the technique mastered, before wasting alot of vinyl.
Best of luck with the project.
Hi Mick.
Your speakers look great to my eyes and look pretty much what I have in mind to build myself. How do they sound?
My plan is to make them with two SB OB 15s and the new SB Acoustics 8 inch full range driver. If you don’t mind, could you answer the following questions please:
1) Do you apply any form of filtering to the full range driver? If so, what and at which frequency?
2) Regarding the woofers, do you apply an LP filter to them and again, at what frequency?
Regards
Alex
Thank you @Pano ! I was struggling to get my 2-way OB's (with Bianco-15OB350 and LiiAudio Fast-8) sound good, I have tried many different ways, played a lot in Basta! etc and this information got me out from the miseryYou sould end up with a nice OB speaker.
The woofers on OB won't have a response like in a box, they will lose a lot of bass. That means that woofer top end has to be brought down to match the woofer low end. There are different ways to correct that, for example when usung a crossover from woofer to fullrange speaker in the 500-750 range, your woofer low pass might need to be set at 100Hz. Electrically. Why? Because that's what flattens the woofer response so that it blends with the fullrange. It will become a ~600Hz low pass acoustically. Box speakers rarely need that kind of massive EQ or crossover tricks. Open baffle does need it. I found this very difficult to understand at first, but it's key to getting the correct tonal balance.
I was thinking these bass drivers are kind of shitty but yeah I was cutting them too high (electrically 200-250hz). Now I have just 10mH coil in front of Bianco and two resistors (L-pad) for Fast-8 and they sound golden with my Mastersound tube amp!Dear @ rekord, I 'm planninig buying the Bianco-15OB350 to much them with my Fast-8s but i was thinking in crossing them around 500Hz to be able to fill the missing low mid that the Fast 8s have and it makes me disatisfied with the "Betsys" I made with them. Now your are writting that they sound great with a 200-250hz cutting, so..? What should I do?
Where you XO a WAW OB (or woofer to mid) is very dependent on baffle width (shape). Martin King’s passive OB article clearly shows how to do this. http://www.quarter-wave.com/OBs/OB_Theory.html
If you want to push the XO up that high you wiull need a narrower OB, and will need to throw away more of the bass driver SPL.
dave
If you want to push the XO up that high you wiull need a narrower OB, and will need to throw away more of the bass driver SPL.
dave
Hi, these drivers have very annoying ringing sound between 200-500hz at least to my ears. They are decent when using only for lower part but yeah that is my experience with them and your baffle size and fullrange driver plays pivotal role here to match the woofer range nicely. One good tip for Fast-8 is that avoid L-pad/resistors in your crossover at all costs!
Yeah Martin King's articles are good but what have helped me the most and get your mindset correct is Lampizator approach to things, read this and maybe you find your path: http://lampizator.eu/SPEAKERS/Practical tips loudspeaker DIY.html
Yeah Martin King's articles are good but what have helped me the most and get your mindset correct is Lampizator approach to things, read this and maybe you find your path: http://lampizator.eu/SPEAKERS/Practical tips loudspeaker DIY.html
What is the point of the De Appolito style arrangement on the baffle?
Does it look magical.
Arrangement has long been since abandoned.
But depending on center to center spacing, which is miles apart.
Crossover be low, below 300 Hz
And any Shouty response be fixed not putting the mid in
the worst place possible on the baffle.
working against a dipole peak and baffle peak.
Offset the mid to one edge....top mounted
so its remotely close to a actual listening position
Does it look magical.
Arrangement has long been since abandoned.
But depending on center to center spacing, which is miles apart.
Crossover be low, below 300 Hz
And any Shouty response be fixed not putting the mid in
the worst place possible on the baffle.
working against a dipole peak and baffle peak.
Offset the mid to one edge....top mounted
so its remotely close to a actual listening position
The FR does not show any ringinf but that range is elevated 3-4 dB.
Has a to be a REALLY good 15” to get upthat high.
Paper cone: i’d puzzlekoat it by default.
dave
You have to have a really extended midTweeter to get teh spacing right in an MTM. XO at 250 Hz.
dave
Maybe the ringing is not the right word. Hard to describe (dunno the word in english for that). I only can compare it with the Eminence Alpha 15-A driver and as far as I remember it din't sound like that in this 200-300hz range. But yeah my experience says that these cheap 15" PA woofers are not good in hifi systems crossed above 200hz because let's not forget the natural rolloff too... If you cut them let say 200hz electrically then you hear them play also ~500hz range only with way lower volume and this range doesnt sound good.
The FR does not show any ringinf but that range is elevated 3-4 dB.
Has a to be a REALLY good 15” to get upthat high.
Paper cone: i’d puzzlekoat it by default.
dave