So I've been searching for an inexpensive and simple way to get into this hobby from the bottom.
I don't have a large budget, but would like to create a nice stereo that I can learn from.
Interested in the WildBurroLabs "Betsy" driver paired with the Altair 15 in the Burro/Boomer combination.
http://www.zillaaudio.com/betsy-boomer.htm
However, a friend told me that I would have issues running them in where they would currently reside, my bedroom. It's 16' by 12'. Would dampening behind the OB's, placed along the walls help?
Or would these perform just fine in a bedroom with no assistance? I can place them some distance from the walls, that is not an issue.
Any help would be appreciated.
I plan on powering the "Betsy" portion of the stero with this amplifier:
http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=300-380
I am hoping to build a more-than-decent stereo for nominal cost and am hoping for a significant upgrade from the near field PC speakers I am currently using.
I don't have a large budget, but would like to create a nice stereo that I can learn from.
Interested in the WildBurroLabs "Betsy" driver paired with the Altair 15 in the Burro/Boomer combination.
http://www.zillaaudio.com/betsy-boomer.htm
However, a friend told me that I would have issues running them in where they would currently reside, my bedroom. It's 16' by 12'. Would dampening behind the OB's, placed along the walls help?
Or would these perform just fine in a bedroom with no assistance? I can place them some distance from the walls, that is not an issue.
Any help would be appreciated.
I plan on powering the "Betsy" portion of the stero with this amplifier:
http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=300-380
I am hoping to build a more-than-decent stereo for nominal cost and am hoping for a significant upgrade from the near field PC speakers I am currently using.
I think the room you describe is at least half the square area required for an OB of these dimensions to deliver their full potential.
For a "toe-dip" in the very large pool of DIY speaker designs, and most particularly for this room, I'd suggest you start with something smaller. Since to a lot of us in this particular forum "Full Range" is virtually synonymous with single driver, perhaps a 4-6" would be worth considering.
There will be no dearth of personal favorites offered as examples, and the number / size / cost of drivers and complexity of enclosure does not necessarily bear any relationship to real-world performance.
For a "toe-dip" in the very large pool of DIY speaker designs, and most particularly for this room, I'd suggest you start with something smaller. Since to a lot of us in this particular forum "Full Range" is virtually synonymous with single driver, perhaps a 4-6" would be worth considering.
There will be no dearth of personal favorites offered as examples, and the number / size / cost of drivers and complexity of enclosure does not necessarily bear any relationship to real-world performance.
Well, it wouldn't be their permanent home.
But perhaps if I just kept it to the original WildBurro design, with the single Betsy on OB? And then add a subwoofer?
http://www.wildburroaudio.com/projects.php
Would the above solution be more appropriate for the given room?
Really I'd prefer to build the Burro/Boomer combo. If by loss of potential due to room size you merely mean loudness, then that's not an issue.
But perhaps if I just kept it to the original WildBurro design, with the single Betsy on OB? And then add a subwoofer?
http://www.wildburroaudio.com/projects.php
Would the above solution be more appropriate for the given room?
Really I'd prefer to build the Burro/Boomer combo. If by loss of potential due to room size you merely mean loudness, then that's not an issue.
I do love open baffles, but they like a lot of room. Ideally the speakers are going to be placed at least 3 feet from the back and side walls.
Damping behind the speakers would be a bad idea. That reflection off the back wall is part of the sound of open baffles. You don't want to absorb it.
Open baffles are a fun way to get into diy speakers. They are super easy to experiment with. You can even make baffles out of cardboard to try out different configurations.
I'd start with the Betsys and just fool around with them. $75 is a pretty cheap investment. Try mocking up some simple baffles of different sizes and shapes. Try different positioning in your room. When you find something you like, make the real baffles. If you make them big enough, you can always cut a hole for the big speakers later on.
Damping behind the speakers would be a bad idea. That reflection off the back wall is part of the sound of open baffles. You don't want to absorb it.
Open baffles are a fun way to get into diy speakers. They are super easy to experiment with. You can even make baffles out of cardboard to try out different configurations.
I'd start with the Betsys and just fool around with them. $75 is a pretty cheap investment. Try mocking up some simple baffles of different sizes and shapes. Try different positioning in your room. When you find something you like, make the real baffles. If you make them big enough, you can always cut a hole for the big speakers later on.
I'm still working on a reply to your email. This will mirror some of what I planned to say. It's true that OB's like space. However, one of my college friends had a pair of Magnepans in his tiny dorm room, and they were great fun. There are some upsides to the Betsy/Boomer system in your situation, namely that the required baffle is smaller and the bass is adjustable. I think there are a few mods you could pursue to make them work decently in your situation. The Betsy-Ks in a small sealed box are probably most ideal for your little room, but where is the fun in that? I'll send you a complete reply in the morning.
pj
www.wildburroaudio.com
pj
www.wildburroaudio.com
..of_letters said:
Well, no - not just loudness, but bass extension (or more precisely, even distribution throughout the room), sound stage dimensionality, and location/size of listening window would be at the top of my list of concerns for a 2-way OB in a room this size.
However, you'll no doubt receive lots of advice either way, and as always your mileage may vary .
I think your room will work OK. A bigger room would be better, but your room size will work. My room is a similar size at 14' x 14' and I have used all kinds and sizes of boxed speakers with different diameter drivers and a few different OB speakers with multiple 15" drivers, even an 18" driver, and while I would love a bigger room I have not received any complaints about the room size limiting speaker performance. A smaller room is not optimal but an OB can still sound great if it is positioned a few feet from the rear wall.
I'm sure he wouldn't mind.
Here's what I asked (posted this at WildBurroaudio.com under Contact)
> I'm interested in building a set of the Burro/Boomer's as my first > diy set.>> Apparently the Burro/Boomer kit comes with an amp for the large > drivers, so I would use this for the Betsy's:>>
http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=300-380>>
I have two questions: I'll be using these in my bedroom. A friend > suggested that this would be a bad idea as the room is only 16' by > 12' or so. I was wondering if I could deaden the walls behind the > speakers by placing dynamat over plywood and then also covering the > dynamat with an additional accoustic foam or goop or some other > dampening material to really stomp out the backwave. Would using > the Burro/Boomer in my bedroom be a problem and if so would my > solution suffice?>>
Also, would finishing the OB in something odd like a faceted stone > veneer or .... tree bark or something of this sort ruin the > accoustic properties of the OB? Would I want to keep the surface > smooth?>> Thank you!
Here's what Mr. Janda responded with:
You ask a bunch of good questions. Bear with me here; I'll try and answer the most simple first. Amp: I like that little amplifier a great deal. It sounds amazing for the price. There is a potential complication for the Betsy/ Boomer setup: it rolls off below 60hz because of it's small input capacitor. That's a great thing for the Betsy on an OB, as it eliminates excess excursion and lowers distortion. It isn't such a great thing for the "boomer" amp, as it is meant to be crossed over at speaker level, and it can't amplify low frequencies it doesn't get. Now, if you've got a source with a volume control (computer, Ipod or some CD players), it isn't a problem, as you can just use a Y cable and feed the Boomer amp using the preamp inputs. Similarly, you could also build a passive preamp to get a volume control into the system. If neither of those things is possible, there are two potential solutions. First, given the adjustability of the boomer amp, it is quite possible that with the right combination of crossover, volume level and room gain (which will be considerable in a small room), it won't be a problem. If you try it and wish for more bass, you could also change the input caps (it is a tough PCB to solder on, so only try it if you know what you are doing or are willing to buy another amp. I've ruined one myself).
OB finish: Fullrange drivers get more directional at higher frequencies (referred to as "beaming"). That means the frequencies that are bothered by things that might cause diffraction (edges on an unusual finish for example) aren't going to be anywhere near high frequencies that might be affected by them. Such a baffle could be an issue with a small tweeter, but never with a fullrange. The OB does get more vibrational energy than you'd think, so something like stone may cause an unpleasant coloration. Think of how the baffle will sound if you tap it. You want it to sound nice, not bright, sharp or ring-y. Now, it is quite possible that depending on the adhesive you used, it wouldn't be an issue. If you attach stone tiles down with something that doesn't dry super hard (I'd consider PL 400 subfloor adhesive), then I can't imagine it will ring badly. Go nuts.
And finally: OB's in a little room As I mentioned in the thread, I've heard Magnepans in a dorm room. And MJK (high priest of speaker design) says it could work. He's always right. The biggest potential issue is distance to the rear wall. If you can get them out in the room, you'll be fine. If you can't, there are some tweaks that could help. I don't think attaching stuff to the wall will do much. Let's think about the Betsy and the Boomer separately. For the Betsy, the potential issue is funny sounding midrange reflections. You could attenuate the rear wave right at the back of the driver. It could be as simple as fixing a couple of layers of polyester batting over the backs. If that isn't enough, you could cram more poly fibers of some sort over the back of the driver. You could take boxes (like those the drivers come in), and cut them full of holes, stuff them full of stuff, and then tape them over the back of the speakers. You could, of course, build something nice looking, but you'd want to get a quick mock-up sounding right before you spent any time fixing the cosmetics. You could even build a frame over the backs and cover whatever you've got with grill cloth. A fancy version might include some batting sandwiched between a couple of layers of fence wire, all covered in grill cloth. There are many ways you could address this problem. I haven't done it myself, but I'm sure you could find a decent solution by playing around with it. The great thing about building an active two way (boomer has it's own amp), is that it is completely adjustable. So, if you've got too much bass, you can just turn it down! If it isn't quite flat, you can play with the crossover setting. But, if you can't get the bass as tight as you like, some treatments may be necessary. Keep in mind that absorbing bass takes something big. A layer of egg crate foam won't do anything. You need a bunch of fiber, and it needs to be compressed. The simplest potential solution I can think of is to buy a few really cheap polyfill filled pillows (I've heard that you can get polyfill cheaper in pillows at Walmart than you can in bulk at a fabric store) and wrap two or three together with some string or twine to achieve some compression. Place each bunch where the floor and wall meet behind the speaker, or ideally in the room corners. It might help, but it is still a little undersized. There are big plastic wrapped bunches of fiberglass insulation at home depot (I'd have to look up the specific ones, don't just buy something random) for about $15 each. If you had the space, a pair of those would be even better. Finally, if you are planning on the boomer setup, you might consider the Betsy-K. You can't use it by itself on an OB, but it should get down low enough to play nice with the woofers. And, you'll get a couple more DB of efficiency. I don't have any in stock right now, but I should in a couple of weeks. I do have some brand new Betsy's that have slightly different specs than advertised, so I'm selling them at a $10 discount. They'll be slightly less sensitive (1 db less or so), but it should be enough for a small room, and $65 is a steal! (They sound great). Let me know if you've got more questions, and I'll see if I've got more answers. I think you'd have a bunch of fun with the Betsy +Boomer. pjwww.wildburroaudio.com
Here's what I asked (posted this at WildBurroaudio.com under Contact)
> I'm interested in building a set of the Burro/Boomer's as my first > diy set.>> Apparently the Burro/Boomer kit comes with an amp for the large > drivers, so I would use this for the Betsy's:>>
http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=300-380>>
I have two questions: I'll be using these in my bedroom. A friend > suggested that this would be a bad idea as the room is only 16' by > 12' or so. I was wondering if I could deaden the walls behind the > speakers by placing dynamat over plywood and then also covering the > dynamat with an additional accoustic foam or goop or some other > dampening material to really stomp out the backwave. Would using > the Burro/Boomer in my bedroom be a problem and if so would my > solution suffice?>>
Also, would finishing the OB in something odd like a faceted stone > veneer or .... tree bark or something of this sort ruin the > accoustic properties of the OB? Would I want to keep the surface > smooth?>> Thank you!
Here's what Mr. Janda responded with:
You ask a bunch of good questions. Bear with me here; I'll try and answer the most simple first. Amp: I like that little amplifier a great deal. It sounds amazing for the price. There is a potential complication for the Betsy/ Boomer setup: it rolls off below 60hz because of it's small input capacitor. That's a great thing for the Betsy on an OB, as it eliminates excess excursion and lowers distortion. It isn't such a great thing for the "boomer" amp, as it is meant to be crossed over at speaker level, and it can't amplify low frequencies it doesn't get. Now, if you've got a source with a volume control (computer, Ipod or some CD players), it isn't a problem, as you can just use a Y cable and feed the Boomer amp using the preamp inputs. Similarly, you could also build a passive preamp to get a volume control into the system. If neither of those things is possible, there are two potential solutions. First, given the adjustability of the boomer amp, it is quite possible that with the right combination of crossover, volume level and room gain (which will be considerable in a small room), it won't be a problem. If you try it and wish for more bass, you could also change the input caps (it is a tough PCB to solder on, so only try it if you know what you are doing or are willing to buy another amp. I've ruined one myself).
OB finish: Fullrange drivers get more directional at higher frequencies (referred to as "beaming"). That means the frequencies that are bothered by things that might cause diffraction (edges on an unusual finish for example) aren't going to be anywhere near high frequencies that might be affected by them. Such a baffle could be an issue with a small tweeter, but never with a fullrange. The OB does get more vibrational energy than you'd think, so something like stone may cause an unpleasant coloration. Think of how the baffle will sound if you tap it. You want it to sound nice, not bright, sharp or ring-y. Now, it is quite possible that depending on the adhesive you used, it wouldn't be an issue. If you attach stone tiles down with something that doesn't dry super hard (I'd consider PL 400 subfloor adhesive), then I can't imagine it will ring badly. Go nuts.
And finally: OB's in a little room As I mentioned in the thread, I've heard Magnepans in a dorm room. And MJK (high priest of speaker design) says it could work. He's always right. The biggest potential issue is distance to the rear wall. If you can get them out in the room, you'll be fine. If you can't, there are some tweaks that could help. I don't think attaching stuff to the wall will do much. Let's think about the Betsy and the Boomer separately. For the Betsy, the potential issue is funny sounding midrange reflections. You could attenuate the rear wave right at the back of the driver. It could be as simple as fixing a couple of layers of polyester batting over the backs. If that isn't enough, you could cram more poly fibers of some sort over the back of the driver. You could take boxes (like those the drivers come in), and cut them full of holes, stuff them full of stuff, and then tape them over the back of the speakers. You could, of course, build something nice looking, but you'd want to get a quick mock-up sounding right before you spent any time fixing the cosmetics. You could even build a frame over the backs and cover whatever you've got with grill cloth. A fancy version might include some batting sandwiched between a couple of layers of fence wire, all covered in grill cloth. There are many ways you could address this problem. I haven't done it myself, but I'm sure you could find a decent solution by playing around with it. The great thing about building an active two way (boomer has it's own amp), is that it is completely adjustable. So, if you've got too much bass, you can just turn it down! If it isn't quite flat, you can play with the crossover setting. But, if you can't get the bass as tight as you like, some treatments may be necessary. Keep in mind that absorbing bass takes something big. A layer of egg crate foam won't do anything. You need a bunch of fiber, and it needs to be compressed. The simplest potential solution I can think of is to buy a few really cheap polyfill filled pillows (I've heard that you can get polyfill cheaper in pillows at Walmart than you can in bulk at a fabric store) and wrap two or three together with some string or twine to achieve some compression. Place each bunch where the floor and wall meet behind the speaker, or ideally in the room corners. It might help, but it is still a little undersized. There are big plastic wrapped bunches of fiberglass insulation at home depot (I'd have to look up the specific ones, don't just buy something random) for about $15 each. If you had the space, a pair of those would be even better. Finally, if you are planning on the boomer setup, you might consider the Betsy-K. You can't use it by itself on an OB, but it should get down low enough to play nice with the woofers. And, you'll get a couple more DB of efficiency. I don't have any in stock right now, but I should in a couple of weeks. I do have some brand new Betsy's that have slightly different specs than advertised, so I'm selling them at a $10 discount. They'll be slightly less sensitive (1 db less or so), but it should be enough for a small room, and $65 is a steal! (They sound great). Let me know if you've got more questions, and I'll see if I've got more answers. I think you'd have a bunch of fun with the Betsy +Boomer. pjwww.wildburroaudio.com
..of_letters said:
Given you are in Redmond you should consider coming to VI diyFEST thus summer..
http://www.diyaudio.com/forums/showthread.php?s=&threadid=139005
... we should have a set of Betsys with the works playing in the "big room".
dave
..of_letters said:
My room is 17'x11', so basically the same as yours. And the speakers are on the narrower wall (which sounds better). There's a thread about my progresses here:
thread
A 8" FR will sound fine in your room, and I'm thinking that even a 10" can do well. A smaller size is still a no-no for me for open baffle.
Bass (under 150hz) and room modes can be a bigger problem and in the end i would EQ.
About dampening/reflections, I did some research and it seems that wood felts to be put around the back of the drivers in the baffle are the best solution. I have exchanged a couple of emails with John K. These felts are not cheap, so, on the test baffles I will try with some synthetic material that can be had for the pennies. If it works well, I'll order the felts.
Despite what other people said, I would also try some absorbing material on the back walls, if it's WAFfable, because theoretically absorbing some of the back wave at the reflection point (where would come too soon reflected to the listener) would be ideal. But I got to try
and stuff on the walls besides paintings are out of the question for WAF reasons.I think the most problems will be with the woofers. You wont be able to absorb much of the LF with even the most dense felt. Personally, I'm looking for alternatives to the classic dipole configuration for the woofers (a 12" or 15" per side, prolly i'll go with the smaller one, but who knows). Alternative means, side firing or Ripole. The latter is more inviting because of better boost in the LF.
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