chops Posted November 12, 2006 Share Posted November 12, 2006 Well since the "alternative designs" thread is getting a little jumbled (lol), I have decided to start a new thread. Just wanted to show everyone what my plans are. I may just get started on this little project within a week or so, maybe sooner. BTW, this is my first time ever using AutoCAD. The last CAD program I ever used was Generic CAD in DOS when I was about 13. I'm now 31! And yes, I realise that I forgot a couple of bolt heads on the bottom angle brace and center back brace. hehe I'm going to start this project off by using the Pyle Pro PPA15 drivers. Why? Well, because I have them and I know they performed superbly in my last dipole project. Also, I want to see how everything's going to sound first off before I go out shelling $$$ for new drivers. I will also be building these out of 0.75" MDF. Being that these baffles are going to be considerably smaller than the H-frames I built before, I am expecting to use some EQ'ing on the bottom end due to the earlier bass roll-off. The only thing that really concerns me with this is that I have never run those PPA15 drivers past 100Hz, so I have no idea how they're going to sound up around 600hz. I guess I'll find out soon enough though. At any rate, I'm looking forward to starting this project soon. I just need to find a room to stuff these Cornwalls into so I can get the OB's up and running in my music room. Anyway, let me know what you guys/gals think... Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted November 12, 2006 Share Posted November 12, 2006 interesting. very cool Quote Link to comment Share on other sites More sharing options...
darkside Posted November 12, 2006 Share Posted November 12, 2006 What kind of horn you gonna use? Looks like an Altec in the drawing... Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted November 12, 2006 Share Posted November 12, 2006 Intteresting .. could ge a good project do you anticipate using EQ below, say, 60 hz ..?? what is the Xmax on those drivers ..?? Quote Link to comment Share on other sites More sharing options...
darkside Posted November 12, 2006 Share Posted November 12, 2006 I believe the xmax is 6mm, according to the PE listing Quote Link to comment Share on other sites More sharing options...
chops Posted November 12, 2006 Author Share Posted November 12, 2006 Intteresting .. could ge a good project do you anticipate using EQ below, say, 60 hz ..?? what is the Xmax on those drivers ..?? Once I build them and see what they can do buy themselves, then I'll know where I have to boost. I honestly can't guess where I'll have to start. When I had those drivers in the H-frame subs, I used the EQ to ONLY cut from 63Hz up to 125Hz a little as they seemed to put out a little too much around that range. As far as from 60Hz down, they needed NO help at all, no EQ, no tone controls, no loudness, nothing. The Xmax is 6mm. I'm not going to be concerned with that. It will be plenty. Don't ask me why or how, but these drivers just simply do not move in OB's. However, there are other people that say the same of the drivers they use as well. I honestly think the ones that need a large Xmax are the ones that have no right being on OB's like the Peerless drivers that Mr Linkwitz likes using. They are small drivers (12"), have a low Qts in the 20's I believe, and are inefficient, somewhere around the 87- 89dB 1w/1m mark. Of course those drivers need a lot of Xmax because they need crap-loads of bass boost and power to get anything usable out of them below 100Hz. Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted November 12, 2006 Share Posted November 12, 2006 I honestly think the ones that need a large Xmax are the ones that have no right being on OB's like the Peerless drivers that Mr Linkwitz likes using. . Hmmmmnnnnnn ....... it had never occurred to me that LInkwitz didn't know what he was doing ..[:^)] Quote Link to comment Share on other sites More sharing options...
chops Posted November 12, 2006 Author Share Posted November 12, 2006 I honestly think the ones that need a large Xmax are the ones that have no right being on OB's like the Peerless drivers that Mr Linkwitz likes using. . Hmmmmnnnnnn ....... it had never occurred to me that LInkwitz didn't know what he was doing ..[:^)] Nooo... I didn't say he didn't know what he was doing. The reason he chooses to use those drivers instead of the ones more desirable for OB is to make the entire loudspeaker look more pleasing and have a better WAF and to take up a lot less floor space. And in doing so, his designs need a lot more equalization and amplifier power to get decent output. And while there's 12+dB of boost in the bass region along with 5 times the needed power, the drivers need to be able to handle all of that with higher power handling and much higher Xmax. I'm just going "by the book" and sticking with the original design criteria because 1) I don't have to worry about any WAF, 2) I have the room to go with full-sized baffles to get decent output with a lot less EQ'ing and amp power, and 3) The drivers I use are less expensive and the overall design is much simpler. It's just a little harder for me to find decent drivers with a high enough Qts and low enough frequency response and Fs to get the same amount of bass while keeping costs down. And just an FYI, IF you stick by the "rules" of open baffles, everything the Peerless drivers are is exactly what NOT to look for in a driver more suited for OB's. Anywho... [] Quote Link to comment Share on other sites More sharing options...
DrWho Posted November 13, 2006 Share Posted November 13, 2006 Just curious...how much sound do these drivers make without any baffle whatsoever? (basically just plugging in the driver and holding it in your hand...) Quote Link to comment Share on other sites More sharing options...
ben. Posted November 13, 2006 Share Posted November 13, 2006 I'd play with side wings to achieve better bass, too. A piece along the side of each woofer might help out. I'm toying with the idea of cobbling up some OBs for the 605B I've got sitting around just to hear what they'd do. I'd love to find some super cheap local Regencies or Altec 620 cabs, but not counting on it. Quote Link to comment Share on other sites More sharing options...
chops Posted November 13, 2006 Author Share Posted November 13, 2006 Just curious...how much sound do these drivers make without any baffle whatsoever? (basically just plugging in the driver and holding it in your hand...) I don't exactly know how to answer that, Mike. I've never tried them that way. I'm assuming they would make "some" bass if you're standing far enough away from the walls and holding it. Quote Link to comment Share on other sites More sharing options...
chops Posted November 13, 2006 Author Share Posted November 13, 2006 I'd play with side wings to achieve better bass, too. A piece along the side of each woofer might help out. I'm toying with the idea of cobbling up some OBs for the 605B I've got sitting around just to hear what they'd do. I'd love to find some super cheap local Regencies or Altec 620 cabs, but not counting on it. I can't. I have a limited amount of space I'm working with. If I were to do wings on the baffles, I'd start getting in the way of the projection screen. Besides, you can start getting some of that "box" sound in the midrange if the wings are big enough to effect the backwave of the drivers. Quote Link to comment Share on other sites More sharing options...
DrWho Posted November 13, 2006 Share Posted November 13, 2006 Just curious...how much sound do these drivers make without any baffle whatsoever? (basically just plugging in the driver and holding it in your hand...)I don't exactly know how to answer that, Mike. I've never tried them that way. I'm assuming they would make "some" bass if you're standing far enough away from the walls and holding it. Let's just say a low distortion driver is going to make absolutely no sound whatsoever...and there is effectively no difference between holding the driver in the air with your hand and putting the driver on a small open baffle. Quote Link to comment Share on other sites More sharing options...
ben. Posted November 13, 2006 Share Posted November 13, 2006 I'd play with side wings to achieve better bass, too. A piece along the side of each woofer might help out. I'm toying with the idea of cobbling up some OBs for the 605B I've got sitting around just to hear what they'd do. I'd love to find some super cheap local Regencies or Altec 620 cabs, but not counting on it. I can't. I have a limited amount of space I'm working with. If I were to do wings on the baffles, I'd start getting in the way of the projection screen. Besides, you can start getting some of that "box" sound in the midrange if the wings are big enough to effect the backwave of the drivers. I meant wings extending back from the baffle - towards the back. It would take some experimentation but a combination of that and maybe alittle less EQ might be worthwile. Shouldn't be too tiresome to mount them temporarily and play around with things. They'd increase the effective baffle size without increasing the width. Quote Link to comment Share on other sites More sharing options...
chops Posted November 13, 2006 Author Share Posted November 13, 2006 Just curious...how much sound do these drivers make without any baffle whatsoever? (basically just plugging in the driver and holding it in your hand...)I don't exactly know how to answer that, Mike. I've never tried them that way. I'm assuming they would make "some" bass if you're standing far enough away from the walls and holding it. Let's just say a low distortion driver is going to make absolutely no sound whatsoever...and there is effectively no difference between holding the driver in the air with your hand and putting the driver on a small open baffle. Huh?!?! What are you getting at? Quote Link to comment Share on other sites More sharing options...
chops Posted November 13, 2006 Author Share Posted November 13, 2006 I'd play with side wings to achieve better bass, too. A piece along the side of each woofer might help out. I'm toying with the idea of cobbling up some OBs for the 605B I've got sitting around just to hear what they'd do. I'd love to find some super cheap local Regencies or Altec 620 cabs, but not counting on it. I can't. I have a limited amount of space I'm working with. If I were to do wings on the baffles, I'd start getting in the way of the projection screen. Besides, you can start getting some of that "box" sound in the midrange if the wings are big enough to effect the backwave of the drivers. I meant wings extending back from the baffle - towards the back. It would take some experimentation but a combination of that and maybe alittle less EQ might be worthwile. Shouldn't be too tiresome to mount them temporarily and play around with things. They'd increase the effective baffle size without increasing the width. Yes, I realise that, but like I said before, the wings can "box in" the sound, especially in the midrange, and that's something I don't want. Quote Link to comment Share on other sites More sharing options...
DrWho Posted November 13, 2006 Share Posted November 13, 2006 Just curious...how much sound do these drivers make without any baffle whatsoever? (basically just plugging in the driver and holding it in your hand...)I don't exactly know how to answer that, Mike. I've never tried them that way. I'm assuming they would make "some" bass if you're standing far enough away from the walls and holding it. Let's just say a low distortion driver is going to make absolutely no sound whatsoever...and there is effectively no difference between holding the driver in the air with your hand and putting the driver on a small open baffle. Huh?!?! What are you getting at? Physics... When I had those drivers in the H-frame subs, I used the EQ to ONLY cut from 63Hz up to 125Hz a little as they seemed to put out a little too much around that range....As far as from 60Hz down, they needed NO help at all, no EQ, no tone controls, no loudness, nothing. Quote Link to comment Share on other sites More sharing options...
DrWho Posted November 13, 2006 Share Posted November 13, 2006 Yes, I realise that, but like I said before, the wings can "box in" the sound, especially in the midrange, and that's something I don't want. are you sure you're just no hearing the acoustical summing the 150Hz region? When mics sound "boxy" this is the first thing that would be turned down on a mixing console. Sombined with a lack of low frequency extension things are going to sound even worse. What you want to do is get the rear wave in phase with the front wave at the point where the driver is 3dB down in free space. Quote Link to comment Share on other sites More sharing options...
ben. Posted November 13, 2006 Share Posted November 13, 2006 What's typically described as "boxy" is 3-400Hz. Quote Link to comment Share on other sites More sharing options...
ben. Posted November 13, 2006 Share Posted November 13, 2006 Yes, I realise that, but like I said before, the wings can "box in" the sound, especially in the midrange, and that's something I don't want. Gotya. I just though it would be something relatively easy to play with - nothing ventured, nothing learned, right? Quote Link to comment Share on other sites More sharing options...
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