Nixxuz
Super Member
So many of you have seen my endless stream of questions about drivers, crossovers, OB in general, etc. Well most of that research has come to fruition with, what originally started out as a single full range driver OB project, but snowballed along the way into a 3 way OB project.
The initial idea was a decent FR OB project consisting of a single Tang Band W8-1808 on each side. The baffle was intended to be no more than 12" wide and 48" tall, as this would make for extremely simple baffles. Just a quick stop by Home Depot, or whatever your local lumber store is, and you'd have the baffles. The feet could be made from whatever you wanted. I eventually went with L brackets for shelving.
There was no inclination for an angle offset. I intended these to be straight up and down, and to point at the listener. Speaking of which, I suppose I should outline some of the other considerations that went into this project by talking about my room, and why some things might not work for some people.
First off, I have a sub. I like that little bit of low end. It's a DIY 18" Skar Audio EVL18 in a sealed box, and it only goes down to about 30hz. But since I have not gotten heavily into pipe organ music, it seems like it's enough for me. Part of the consideration in this project were that the FR driver need not do much in the way of LF. The sub would handle that. Or so I thought. And yes, I had thought about an Ultimax build, but PE cannot seem to keep the damn things in stock. I power this with a QSC ISA280 power amp bridged to 800w mono. It's probably overkill for a music only system, but I wanted effortless bass, as opposed to foundation shaking bass.
https://www.skaraudio.com/products/...LC03AINW8v1e-Mq328cTA4ov1z8hoiXMaAsl9EALw_wcB
I also run a Monoprice 31 band EQ in my system. It's never seen much use, outside of being a convenient way to feed the signal to the power amp for the sub. It's since become a very integral part of this project.
https://www.amazon.com/Monoprice-31-Band-Graphic-Equalizer-Subwoofer/dp/B00KLRP5CK
Eventually I decided that, while the TB W8's have a great reputation, I had read some good reviews on the Dayton Audio PS220-8. At less than half the price, and with glowing reviews from everyone who actually used them, they seemed like a fair bet. If they were terrible I'd just wait and get the TB instead, and use the the PS220's for something different.
https://www.parts-express.com/dayton-audio-ps220-8-8-point-source-full-range-neo-driver--295-346
The drivers arrived and I hooked them to a SS amp and just let them sit on their backs and play at low volume overnight. I've heard these particular drivers can take a bit of burn in, and that may be the case. They had not changed significantly in sound from the 1st day until now. Perhaps a touch smoother.
I got the 2'x4' panel, going with red oak faced plywood, (not gapless, this is a low cost low effort build!). Had it sawed in half and did the cutouts for the 220's at roughly 36", which is about head height for me in my listening position. Glued some angled supports and a base to each baffle and let it sit for 24 hours. I then gave them a quick coat of walnut stain and let them sit another day. They actually came out looking better than expected.
I secured the drivers with brass bolts. 8-32 and 1-1/2" They provided a bit of sparkle to the dour "woodiness".
(Note that this pic was originally using 1" galvanized construction screws, hence the torx heads!)
Now I fired them up with the sub pulling LF duty. Not bad, but there was something missing. I consulted my spectrum analyzer, which is an app called Spectroid running on my tablet used for digital music. I've got a Dayton iMM-6 calibrated mic hooked to it. Seems to give me accurate readings.
https://www.parts-express.com/dayto...wnMjZoqUNWlyBTWPVJf7EWOjJ3-ioazoaAkeQEALw_wcB
I had read about a 1-1.5khz spike that the 220's could exhibit, and boy howdy, it was there. Thankfully, I have the EQ to tame it! A 3-4dB cut to the affected region seemed to do the job, and I just did a lot of test listening and sweeps after that.
It became apparent very quickly that I'd have to cross the sub over at an unreasonable high frequency in order to fill in the LF that 220 could not. Close to 250-300hz. The 220's are supposedly alright in a sealed or ported cabinet when it comes to LF, but slapped on a plywood baffle, not so much. What to do? Perhaps another driver?
Our own OB master Poultrygeist came to the rescue by suggesting the Eminence Alpha 15A's as a good OB woofer. High Qts and not all that costly. (You can see the project scope start to creep at this point).
https://www.parts-express.com/emine...Z6VcQ-ZuN8_pHiHnppUZBm1075jNtHJcaAiGXEALw_wcB
Well I very well couldn't fit a 15" driver in a 12" wide baffle, so I figured, once again for the sake of simplicity, 2'x4' panels, this time of MDF. The idea being that there would either be paint, or veneer work, to give these speakers a little class down the road. I got the drivers and went back to HD to get the MDF.
I also have cats, so some grills were needed for paper drivers close to the floor.
Since I'm youthfully impatient and wanted to actually hear what the 2 drivers sounded like together, I just went with a parallel 4 ohm wiring scheme and some of the aforementioned L brackets to keep them upright.
Now some of you might ask; Why are the 220's set so low on the baffle? Well by this time another AK'er and audio enthusiast I had connected with on FB through the Yaqin group, had advanced the idea that perhaps a tweeter of some sort could elevate these to REALLY good sounding speakers. I agreed. The PS220's have some top end, but seem to lack that "sparkle" that a dedicated tweeter can provide. I like that sound, although it may be fatiguing to some. I've always said I'd rather have a "hot" tweeter I can tame, than a driver that mechanically has no room to get more detailed. So I started looking. The beautiful Fostex T90A was a brief consideration, but it's crazy efficiency and high cost quickly ruled it out. I perused some car audio supertweeters as well that still hold promise for future projects. The Skar Audio VX1-ST seem to hold an attraction for me...
https://www.skaraudio.com/products/...zg0pFRFTp2FI5p_4HEnVBK-61CVz5H5UaAovEEALw_wcB
But I digress! I finally settled on the HiVi RT2C planar's. It would be a wait as funding was limited, but the fellow enthusiast was interested enough in the outcome of my project to just donate a pair found on eBay for a significant discount from the Parts Express price, for which I am grateful.
Now that I had all these drivers floating around I knew I'd need to learn a little something about crossovers. I was trying to avoid this, because the project started out so much simpler. But, needs must and I jumped in.
I knew the drivers all had a fair amount of overlap, so I figured KISS and go for first order components. I got a pair of 9.0mH ferrite core inductors for the Eminence 15A's,
A pair of 150uF electrolytics for the high pass on the PS220's,
And a pair of cheap Audyn 3.9uF for the RT2C's, which I didn't take a pic of...
https://www.amazon.com/Audyn-Metalized-Polypropylene-Crossover-Capacitor/dp/B00AEBEMFO
I ran these components solo, in the proper areas of the signal path. This is all a learning experience for me so the concept of a crossover board with everything mounted nice and neat floated by, and was promptly ignored. I wanted to HEAR these things! Tightening everything up was secondary to actually finding out how it sounded. I went with a series/parallel scheme for simplicity and ran it to 6 ohms, which could be solved with resistors or another driver.
Here is my EXTREMELY amatuer "schematic" of the crossover;
And, with the 220's set low enough off axis for the "spike" to be smoothed out, the addition of the HiVi's to bring that "sizzle" and the Alpha's functioning as very good LF into the 40hz range, I can say these OB's are by far the best speakers I have personally heard. This comes with the caveat that IN MY SPACE they sound exceptional. YMMV dependant on where you have to place them. Mine are almost "corner loaded" as they are about 1 meter from the back wall, but only about 6-8" from the sidewall of my listening room.
Additionally, I must add that, while these would be just fine for most listeners, you are going to get fairly accurate, but not DEEP bass from the single set of Alpha's. I have a monster of a sub to back everything up if I feel the need, but it may not be enough for some on their own.
The focus of the project broadened from it's initial idea, but I think I've built a very capable set of speakers for just around $500, that will allow the use of a relatively low powered SET amp, or something similar, to get excellent, and also quite loud, sound. At this point all the EQ is doing is a very slight rise around 100-150hz, but that's just personal preference. Everything else is running flat, and they are detailed and full bodied.
Anyway, thanks for reading. I found it a rewarding, sometimes frustrating, and extremely instructional experience. While I am eager as ever to do more experimentation, these are staying as my main speakers for the conceivable future. Immense thanks to the AK community for all the help. I would have been lost without you. And extra thanks to the benefactor who donated the RT2C's. I hope his project goes as well as mine!
Edit: per mjw21a's request, I had forgot to put down the offset of drivers in the baffle. Alpha's are 6" from the bottom. The PS220's are 4" above the Alpha's. The RT2C's are 6" above the PS220's, and about 3.75" from the top of the baffle.
The initial idea was a decent FR OB project consisting of a single Tang Band W8-1808 on each side. The baffle was intended to be no more than 12" wide and 48" tall, as this would make for extremely simple baffles. Just a quick stop by Home Depot, or whatever your local lumber store is, and you'd have the baffles. The feet could be made from whatever you wanted. I eventually went with L brackets for shelving.
There was no inclination for an angle offset. I intended these to be straight up and down, and to point at the listener. Speaking of which, I suppose I should outline some of the other considerations that went into this project by talking about my room, and why some things might not work for some people.
First off, I have a sub. I like that little bit of low end. It's a DIY 18" Skar Audio EVL18 in a sealed box, and it only goes down to about 30hz. But since I have not gotten heavily into pipe organ music, it seems like it's enough for me. Part of the consideration in this project were that the FR driver need not do much in the way of LF. The sub would handle that. Or so I thought. And yes, I had thought about an Ultimax build, but PE cannot seem to keep the damn things in stock. I power this with a QSC ISA280 power amp bridged to 800w mono. It's probably overkill for a music only system, but I wanted effortless bass, as opposed to foundation shaking bass.
https://www.skaraudio.com/products/...LC03AINW8v1e-Mq328cTA4ov1z8hoiXMaAsl9EALw_wcB
I also run a Monoprice 31 band EQ in my system. It's never seen much use, outside of being a convenient way to feed the signal to the power amp for the sub. It's since become a very integral part of this project.
https://www.amazon.com/Monoprice-31-Band-Graphic-Equalizer-Subwoofer/dp/B00KLRP5CK
Eventually I decided that, while the TB W8's have a great reputation, I had read some good reviews on the Dayton Audio PS220-8. At less than half the price, and with glowing reviews from everyone who actually used them, they seemed like a fair bet. If they were terrible I'd just wait and get the TB instead, and use the the PS220's for something different.
https://www.parts-express.com/dayton-audio-ps220-8-8-point-source-full-range-neo-driver--295-346
The drivers arrived and I hooked them to a SS amp and just let them sit on their backs and play at low volume overnight. I've heard these particular drivers can take a bit of burn in, and that may be the case. They had not changed significantly in sound from the 1st day until now. Perhaps a touch smoother.
I got the 2'x4' panel, going with red oak faced plywood, (not gapless, this is a low cost low effort build!). Had it sawed in half and did the cutouts for the 220's at roughly 36", which is about head height for me in my listening position. Glued some angled supports and a base to each baffle and let it sit for 24 hours. I then gave them a quick coat of walnut stain and let them sit another day. They actually came out looking better than expected.
I secured the drivers with brass bolts. 8-32 and 1-1/2" They provided a bit of sparkle to the dour "woodiness".
(Note that this pic was originally using 1" galvanized construction screws, hence the torx heads!)
Now I fired them up with the sub pulling LF duty. Not bad, but there was something missing. I consulted my spectrum analyzer, which is an app called Spectroid running on my tablet used for digital music. I've got a Dayton iMM-6 calibrated mic hooked to it. Seems to give me accurate readings.
https://www.parts-express.com/dayto...wnMjZoqUNWlyBTWPVJf7EWOjJ3-ioazoaAkeQEALw_wcB
I had read about a 1-1.5khz spike that the 220's could exhibit, and boy howdy, it was there. Thankfully, I have the EQ to tame it! A 3-4dB cut to the affected region seemed to do the job, and I just did a lot of test listening and sweeps after that.
It became apparent very quickly that I'd have to cross the sub over at an unreasonable high frequency in order to fill in the LF that 220 could not. Close to 250-300hz. The 220's are supposedly alright in a sealed or ported cabinet when it comes to LF, but slapped on a plywood baffle, not so much. What to do? Perhaps another driver?
Our own OB master Poultrygeist came to the rescue by suggesting the Eminence Alpha 15A's as a good OB woofer. High Qts and not all that costly. (You can see the project scope start to creep at this point).
https://www.parts-express.com/emine...Z6VcQ-ZuN8_pHiHnppUZBm1075jNtHJcaAiGXEALw_wcB
Well I very well couldn't fit a 15" driver in a 12" wide baffle, so I figured, once again for the sake of simplicity, 2'x4' panels, this time of MDF. The idea being that there would either be paint, or veneer work, to give these speakers a little class down the road. I got the drivers and went back to HD to get the MDF.
I also have cats, so some grills were needed for paper drivers close to the floor.
Since I'm youthfully impatient and wanted to actually hear what the 2 drivers sounded like together, I just went with a parallel 4 ohm wiring scheme and some of the aforementioned L brackets to keep them upright.
Now some of you might ask; Why are the 220's set so low on the baffle? Well by this time another AK'er and audio enthusiast I had connected with on FB through the Yaqin group, had advanced the idea that perhaps a tweeter of some sort could elevate these to REALLY good sounding speakers. I agreed. The PS220's have some top end, but seem to lack that "sparkle" that a dedicated tweeter can provide. I like that sound, although it may be fatiguing to some. I've always said I'd rather have a "hot" tweeter I can tame, than a driver that mechanically has no room to get more detailed. So I started looking. The beautiful Fostex T90A was a brief consideration, but it's crazy efficiency and high cost quickly ruled it out. I perused some car audio supertweeters as well that still hold promise for future projects. The Skar Audio VX1-ST seem to hold an attraction for me...
https://www.skaraudio.com/products/...zg0pFRFTp2FI5p_4HEnVBK-61CVz5H5UaAovEEALw_wcB
But I digress! I finally settled on the HiVi RT2C planar's. It would be a wait as funding was limited, but the fellow enthusiast was interested enough in the outcome of my project to just donate a pair found on eBay for a significant discount from the Parts Express price, for which I am grateful.
Now that I had all these drivers floating around I knew I'd need to learn a little something about crossovers. I was trying to avoid this, because the project started out so much simpler. But, needs must and I jumped in.
I knew the drivers all had a fair amount of overlap, so I figured KISS and go for first order components. I got a pair of 9.0mH ferrite core inductors for the Eminence 15A's,
A pair of 150uF electrolytics for the high pass on the PS220's,
And a pair of cheap Audyn 3.9uF for the RT2C's, which I didn't take a pic of...
https://www.amazon.com/Audyn-Metalized-Polypropylene-Crossover-Capacitor/dp/B00AEBEMFO
I ran these components solo, in the proper areas of the signal path. This is all a learning experience for me so the concept of a crossover board with everything mounted nice and neat floated by, and was promptly ignored. I wanted to HEAR these things! Tightening everything up was secondary to actually finding out how it sounded. I went with a series/parallel scheme for simplicity and ran it to 6 ohms, which could be solved with resistors or another driver.
Here is my EXTREMELY amatuer "schematic" of the crossover;
And, with the 220's set low enough off axis for the "spike" to be smoothed out, the addition of the HiVi's to bring that "sizzle" and the Alpha's functioning as very good LF into the 40hz range, I can say these OB's are by far the best speakers I have personally heard. This comes with the caveat that IN MY SPACE they sound exceptional. YMMV dependant on where you have to place them. Mine are almost "corner loaded" as they are about 1 meter from the back wall, but only about 6-8" from the sidewall of my listening room.
Additionally, I must add that, while these would be just fine for most listeners, you are going to get fairly accurate, but not DEEP bass from the single set of Alpha's. I have a monster of a sub to back everything up if I feel the need, but it may not be enough for some on their own.
The focus of the project broadened from it's initial idea, but I think I've built a very capable set of speakers for just around $500, that will allow the use of a relatively low powered SET amp, or something similar, to get excellent, and also quite loud, sound. At this point all the EQ is doing is a very slight rise around 100-150hz, but that's just personal preference. Everything else is running flat, and they are detailed and full bodied.
Anyway, thanks for reading. I found it a rewarding, sometimes frustrating, and extremely instructional experience. While I am eager as ever to do more experimentation, these are staying as my main speakers for the conceivable future. Immense thanks to the AK community for all the help. I would have been lost without you. And extra thanks to the benefactor who donated the RT2C's. I hope his project goes as well as mine!
Edit: per mjw21a's request, I had forgot to put down the offset of drivers in the baffle. Alpha's are 6" from the bottom. The PS220's are 4" above the Alpha's. The RT2C's are 6" above the PS220's, and about 3.75" from the top of the baffle.
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