| chops |
I know this isn't really a "Full Range" setup as in single driver, but it's the only place where OB talk seems appropriate, so...
I'm pretty sure I want to go with an OB (dipole) setup again, but this time as the main channels. The reason I say "again" is because I have done this before, but it was a pair of dual 15" dipole subs... Some of you will remember me!
That entire system is long gone now since those subs took up way too much room and I couldn't get any decent placement for my Maggies.
Now I am back to a "monopole" sub using dual 15" Dayton DVC drivers in a push/pull configuration which has decent output down to 10Hz. It's crossed over at 50Hz.
Here's a more current view of my system...
So what I'm wanting to do now is build an OB using dual 15" again, but they need to reach up to 600Hz to meet the Altecs. I want to go OB because of the near perfect bass speed and attack, and also because of no coloration in the excellent midrange.
To get any kind of decent bass out of them (if I decide to play them fullrange from time to time) I'm going to have to build them tall and somewhat deep, not low and wide. As you can see, I'm limited in space due largely to the projection screen. And I think I would like to have both 15's up towards the top of the baffle to get them as clsoe as possible to the horn.
So what do you guys think of the design and do you think this driver would be up to the task?
http://www.partsexpress.com/pe/show...tnumber=264-338
Thanks a bunch in advance! :) |
|
|
| chops |
| Gee, no response yet? ;) |
|
|
| panomaniac |
Hey Chops(rr)
I remember you!
Cool idea. I had been planning something like it on paper, but was going to use the Eminence Alpha 15 because of the high Q and because Martin J King uses 2 in OB and really likes them. It's the "Big Butt" response of the high Q driver that looks good on paper. A little bass boost to counter the OB roll off, if you see what I mean.
But then I got to talking with friends who have done a lot of OB stuff, and was told that a more mid Q, like 0.6 usually works better, sounds better, has better control. The Eminence Beta 15 was suggested instead.
So from what I've learned, that Selenium 15 would make a very good choice. The Beta 15 has a little more x-max. |
|
|
| MJK |
| quote: | | But then I got to talking with friends who have done a lot of OB stuff, and was told that a more mid Q, like 0.6 usually works better, sounds better, has better control. The Eminence Beta 15 was suggested instead. |
I sumulated both the Beta and the Alpha and the responses were very similar in my OB design. However, the Alpha did extend a little lower and was flatter between 50 and 100 Hz. The Beta looked alot like my original Dayton response with a rounded low end but did extend a little lower then the Dayton. So I selected the Alpha and do not regret the decision. I think both driver would work really well and the differences would be very small, so it becomes a matter of personal preference. |
|
|
| panomaniac |
Thanks Martin! That's good to know.
So Alpha, Beta or Selenium should sound a lot alike. There you go Chops.
I am torn between doing an OB with the above drivers, or a sideways BIB. I know the OB is going to have a sound I will love, but a sideways BIB (flat side to the wall) is a verified High WAF design. Takes up so little floor space, you know. |
|
|
| chops |
| quote: | Originally posted by panomaniac
Thanks Martin! That's good to know.
So Alpha, Beta or Selenium should sound a lot alike. There you go Chops.
I am torn between doing an OB with the above drivers, or a sideways BIB. I know the OB is going to have a sound I will love, but a sideways BIB (flat side to the wall) is a verified High WAF design. Takes up so little floor space, you know. |
Yeah, thanks Martin!
Ok, so call me stupid, but what does "BIB" stand for?!
So say I go with the Selenium drivers, how big should I go with the baffles to get decent output down to at least 40Hz. I don't need super low performance since I am crossing over to my sub at 50Hz.
And I imagine that it would be fine to run both top and bottom drivers up to 600Hz where it crosses over to the horn?
BTW, the WAF doesn't "factor" into anything with me since I have no wife... yet! :D |
|
|
| chops |
| Boy, I was expecting there to be a little more action on this thread than this. Oh well, I guess it doesn't interest too many folks. :rolleyes: |
|
|
| moray james |
| also looks very good for dipole bass gets low and has enough xmax. Are those Altec horns the 500's? My very first audio "to die for" was hearing a set of Altec Valencia's with the 500 Hz sectral horn (after first falling in love with the A7 which were too big for fit into my bedroom at the time). Regards Moray James. |
|
|
| chops |
Hi Moray,
Yes, the horns I have are the 511B's and 902 drivers that come stock on the A7's. They ARE great sounding horns, that's for sure.
I've been eye-balling that Delta driver as well. We'll see what happens. ;) |
|
|
| moray james |
| Chops damp those horns. I think that a pair of Delta's in a "W" style dipole with an Alpha or Beta on top OB for mid bass running up to the 511B might be the ticket. The design at the Herritagre site that talks about matching mid/bass driver dispersion to the horn is I think a key to making it all work. Believe that fellow used a ten inch unit below the horn. Have seen the same idea used with a 5 inch mid crossing to a 5 inch ribbon to achieve similar dispersion at crossover point. Looking forward to seeing your new design grow. Regards Moray James. |
|
|
| panomaniac |
Hey Chops
The BIB is HERE.
But beware! The thread is over 1660 posts long.
So to sum up, the BIB stands for Bigger Is Better. It's a sort of back loaded horn or Voigt pipe with the top end open. One fold inside. Line length is usually 1/2 wavelength of driver FS. The box couples to the room to complete the horn. Should be placed against the wall and/or in a corner. Said to really get things shaking!
Moslty used with small drivers, like Fostex 6.5" full range to augment the bass. Some plans are in the works for larger drivers, some have been built. But a BIB for large drivers will get really huge, so no one has done it yet. Might take up the whole room. Not that you would mind. ;)
My plan was to turn the broad side to the wall to make it blend into the wall. Maybe only 8 to 12" deep, but plenty wide.
Keep us informed on your OB project! Gotta have another look at the Deltas. |
|
|
| chops |
| Well I guess this thread is dead. :whazzat: |
|
|
| Kensai |
What kind of action are you looking for, Chops? Looked like your questions had been answered. You got something else you want to know about or gather opinions on?
The drivers are fine, and 4 in stereo dipole are going to be pleanty for that room of yourse, but you know that already from your Pyle H-frames. Of course, you're not going to get flat to 16Hz or even 20Hz without EQ, and maybe not even then (or at least not while keeping the sound as clear as you may want), but that's the nature of the dipole bass beast.
You might look into ripole config for this. Take up less space, create lower FS, should couple to the room similarly as OB. moray james had a couple threads going on that a couple weeks back. Lots of driver discussion.
The BiBs are a great thing, and have a lot in common, listening wise with OB, but they're going in a different direction (less driver, more cabinet).
Kensai |
|
|
| chops |
You know what, I'm totally sorry about that. I've been discussing this subject on several different forums and I thought I had posted the link below on this thread as well. Obviously, I didn't! :ashamed:
http://www.partsexpress.com/pe/psho...r=264-347&DID=7
Anyway, I wantd to get some input from you guys about using this Selenium 18" driver for the dipoles instead of the many different 15" drivers. All of the specs are slightly better, Freq Resp: 35-3000Hz, Fs: 33Hz, Xmax: 3.75. The only thing that's down a little is the Qts, which is 0.45.
I figured since I have all of those specs working for me except the Qts, with a little bit of EQ'ing, I could possibly get better results, especially in the bass (between 30-50Hz) and even a little more kick in the upper bass.
So, what do you all think? |
|
|
| chops |
The Qts on all those drivers are way too low. |
|
|
| moray james |
| The dual coil versions can be run with a single coil to approx. double the Qts. The single coil 18 inch run in a Ripole or "W" frame dipole would be fine as is OB would require some EQ. 9mm xmax on a couple of 18's is a lot if air my friend. Regards Moray James. |
|
|
| chops |
| quote: | Originally posted by moray james
The dual coil versions can be run with a single coil to approx. double the Qts. The single coil 18 inch run in a Ripole or "W" frame dipole would be fine as is OB would require some EQ. 9mm xmax on a couple of 18's is a lot if air my friend. Regards Moray James. |
How do you mean that about the DVC ran as a SVC? As in wiring them together in series? If that's the case, were would that put the Qts?
You are right, those prices are very good, though.
But remember, I'm going to be using these all the way up to 600Hz. If these drivers are in fact "subwoofers", then they are probably rolled off below 500Hz. Unfortunately, the site doesn't give the freq resp of those drivers at all, so I have no idea what top end they are capable of. |
|
|
| panomaniac |
I have a buddy in California how has build a lot of OB stuff. He has a pair of OBs with 2 Eminence 18s (going opposite directions) a Beta 12LTA for the mid and a big dome tweeter. That's a lot of speaker!
You could skip the 12" and dome and use your 511 horn instead. I'll see if I can dig up a photo of his dipoles. |
|
|
| chops |
| quote: | Originally posted by panomaniac
I have a buddy in California how has build a lot of OB stuff. He has a pair of OBs with 2 Eminence 18s (going opposite directions) a Beta 12LTA for the mid and a big dome tweeter. That's a lot of speaker!
You could skip the 12" and dome and use your 511 horn instead. I'll see if I can dig up a photo of his dipoles. |
Cool. Sounds good!
I'd be interested in see a pic of that. ;) |
|
|
| panomaniac |
Here is a photo.
Very bad photo, but it's all I have. You get the idea, anyway. |
|
|
| Kensai |
Those 18"ers would be about perfect for a ripole (might even give you an Fs as low as say 18Hz in that config). Of course since you want them to run up so high, ripole won't work for you (even small drivers in ripole really won't sound good or even respond audibly above say 200Hz). In OB, yeah, they'll need EQ, or possibly you could use some resistance in series with them to raise their Qts a bit to help out.
Kensai |
|
|
| panomaniac |
That 2x18 - 1x12 + tweeter shown above is all passive filtered.
EQ is part of the crossover. Basically the hi/mid of the 18s is attenuated to bring it into line with the resulting low end.
I have not heard them - I'm 4000Km away and they aren't that loud! But they've been around to a number of DIY meets and the bass is said to be "heart rending." Driven off about a 100 watt, amp I think. |
|
|
| Cal Weldon |
| quote: | Originally posted by moray james
Chops damp those horns. |
Do you do this? I found that all you have to do is to damp one of the two "lips" to deaden the horn. No need to coat it, there's no ringing other than at the lips. |
|
|
| chops |
| quote: | Originally posted by Cal Weldon
Do you do this? I found that all you have to do is to damp one of the two "lips" to deaden the horn. No need to coat it, there's no ringing other than at the lips. |
Ahh, stop givin' me lip! LOL :clown:
No, I never did anything to the horns except give them a really good bath after I got them...
BEFORE:
AFTER:
The music has to be pretty loud to get any audible ringing out of the horn, and at that point, the music is a heck of a lot louder than any ringing coming from the horn. IOW, I'm not too concerned about it. ;) |
|
|
| chops |
| quote: | Originally posted by panomaniac
Here is a photo.
Very bad photo, but it's all I have. You get the idea, anyway. |
Say panomaniac,
I know those 18's are Eminence that your buddy is using, but do you know which series they are? From Eminence's current series, the Selenium one that I'm looking at seems to be a better choice (for OB that is). |
|
|
| panomaniac |
| quote: | Originally posted by chops
I know those 18's are Eminence that your buddy is using, but do you know which series they are? |
I don't remember, but think they are no longer made. I will ask. I know he likes mid-Q divers for OB, somehwere around 0.6 Qts, but these may not be. |
|
|
| Cal Weldon |
Hey no lip from you either ;)
If you want to do a little testing use a stick of wood to tap on the horn at different locations. You'll find that only the lips ring and that putting your finger on it will damp it very quickly. If you want to be silly like me, just put some water in the upper lip when listening and see if you can get it to dance with a little volume. :D
OMG, I spend too much time in the garage. I have to go out more often.
And yes, the horns need a pressure washing about once a year. Helps to remove the dirt and what's left of the paint. |
|
|
| chops |
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 when I was about 13. I'm now 31!
Anyway, let me know what you guys think...
 |
|
|
| freddi |
| hey Chops - kinda OT - what size was your PPA-15 H-baffle? - got sketch with diomenions? did you try a W-baffle? Freddy |
|
|
| Cal Weldon |
Hi Chops,
Where are you planning to XO this? |
|
|
|
