Hi guys,
so I'm building a PA system. Thanks to this forum I successfully built my first one and this is my second. The first one was smaller and thanks to the multitude of answers on this forum I didn't even have to ask a single question, but we all know not asking questions is no good, so here we go.
Now the second one is going to be a bit more complex and is partially in the works in the woodshop, but I'm still trying to figure out what do to for upper bass+mid bass (UB+MB). The subs are 4x tapped 18" horns 30-70/80Hz. Then I have mid/high horns: 4x Altec Lansing 1005B loaded with B&C DCX464 each. This driver should work a bit better than for example famed BMS's 4594He coax, since it seems to go down to 300Hz more effortlessly, which I still have to verify. I'm aware that the Altec Lansing horns are tuned to 500Hz, but let me just say here that I talked to fans that happily drive it lower. But let's just say I'm going to cross over at 400/500Hz. At this point I'm planning to also drive all HF with them.
The listener will be (hopefully) dancing in a 30ftx40ft area and the four satellite speakers will be arranged in the corners of that rectangle. I'm not so much worried about the pattern control with potential lobing, but more so excited about the timbery sound of the 1005Bs. But I do wonder if I should investigate potential phase issues having them arranged like that.
Anyway, I still need to cover frequencies 70/80-400/500Hz, depending on crossover, with appropriate SPL. I really like the PM90 design, but Peter recommends to cross them over at 100Hz...I will need them to play a little lower than that I think.
I'm playing with the idea of altering the PM90 design and swap the horn there with the 1005Bs in some sort of insert fashion with a fancy latching mechanism. I could also just forget about the 1005Bs at this point, since the PM90's got everything needed, but I really want the looks of the Altec Lansings in the system. On the other hand I don't want to reinvent the wheel if I don't have to. But I wonder if this fusion design would play low enough after all.
Simply resting the 1005Bs onto separate UB+MB enclosures would also do.
What are your thoughts on this? I'm also curious to hear your opinions on using e.g. 15" front loaded ported enclosures for UB+MB since I think it would throw bass nicely. But then again: minimal weight/size are high priorities, because it won't be a stationary system. Some say that just getting 4x D&B Y10Ps would be easier, but where is the fun in that?
Thanks guys!
Al
so I'm building a PA system. Thanks to this forum I successfully built my first one and this is my second. The first one was smaller and thanks to the multitude of answers on this forum I didn't even have to ask a single question, but we all know not asking questions is no good, so here we go.
Now the second one is going to be a bit more complex and is partially in the works in the woodshop, but I'm still trying to figure out what do to for upper bass+mid bass (UB+MB). The subs are 4x tapped 18" horns 30-70/80Hz. Then I have mid/high horns: 4x Altec Lansing 1005B loaded with B&C DCX464 each. This driver should work a bit better than for example famed BMS's 4594He coax, since it seems to go down to 300Hz more effortlessly, which I still have to verify. I'm aware that the Altec Lansing horns are tuned to 500Hz, but let me just say here that I talked to fans that happily drive it lower. But let's just say I'm going to cross over at 400/500Hz. At this point I'm planning to also drive all HF with them.
The listener will be (hopefully) dancing in a 30ftx40ft area and the four satellite speakers will be arranged in the corners of that rectangle. I'm not so much worried about the pattern control with potential lobing, but more so excited about the timbery sound of the 1005Bs. But I do wonder if I should investigate potential phase issues having them arranged like that.
Anyway, I still need to cover frequencies 70/80-400/500Hz, depending on crossover, with appropriate SPL. I really like the PM90 design, but Peter recommends to cross them over at 100Hz...I will need them to play a little lower than that I think.
I'm playing with the idea of altering the PM90 design and swap the horn there with the 1005Bs in some sort of insert fashion with a fancy latching mechanism. I could also just forget about the 1005Bs at this point, since the PM90's got everything needed, but I really want the looks of the Altec Lansings in the system. On the other hand I don't want to reinvent the wheel if I don't have to. But I wonder if this fusion design would play low enough after all.
Simply resting the 1005Bs onto separate UB+MB enclosures would also do.
What are your thoughts on this? I'm also curious to hear your opinions on using e.g. 15" front loaded ported enclosures for UB+MB since I think it would throw bass nicely. But then again: minimal weight/size are high priorities, because it won't be a stationary system. Some say that just getting 4x D&B Y10Ps would be easier, but where is the fun in that?
Thanks guys!
Al
Al,
Peter's PM60 appears to be good to 80 Hz, and still capable of 135 dB (half space) at 70 Hz. I have not looked at the PM90 all that closely, but if it's dimensions are closer to what you are looking for than the PM60, you could simply lower it's bass reflex tuning to be slightly below the crossover point you want for your subs.
Art
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Thanks for your response, Art!
Isn't the bass path not more like a horn rather than bass reflex for the PM90? I suppose I could make the enclosures a bit deeper to widen their mouths. It seems that the PM60 is the same as the PM90 for the bass section, just the mid/high horn differs. This might be a silly question, but how about building half a PM90, just one 12" driver section?
By the way, your SyntripP design is one of my favorite option on this topic, only my obsession with the Altec horn look ruled them out...
Isn't the bass path not more like a horn rather than bass reflex for the PM90? I suppose I could make the enclosures a bit deeper to widen their mouths. It seems that the PM60 is the same as the PM90 for the bass section, just the mid/high horn differs. This might be a silly question, but how about building half a PM90, just one 12" driver section?
By the way, your SyntripP design is one of my favorite option on this topic, only my obsession with the Altec horn look ruled them out...
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1)The PM90/60 horn is augmented by it's bass reflex ports in the low frequency.
2) Not silly, though the Altec Lansing 1005B loaded with B&C DCX464 would have more output capability than a single 12 could produce in that general size range. Using the DCX464 drivers, you have the equivalent of more than 25% of Hanley's 1969 Woodstock PA system!
3) Considering your obsession with the multi-cell look, a low-mid design to compliment the look may be in order, using the PM90/60 as a template for the horn expansion and porting, but shaped to fit your aesthetic.
Art
Thanks Art!
1) is that something Hornresp can do? I know what horns are and bass reflex but port-augmented horns?! - do you happen to know a good read on that one? I'm really curious about starting to use Hornresp to simulate all that.
2) How about using the B&C 12NDL88, which seem similar to the RCF MB12N351, a little more powerful with 700W Prms, and even cheaper. It's probably still not enough SPL then since it's still 100W Prms below the 12NDL76 combo. But imagine using two 12NDL88 in a PM60 box...then we're talking 50% Woodstock! :-D
3) Yeah that's what I'm going for now, some kind of removable baffle with my horns.
I'll post some pictures of progress here, probably at around the end of January 🙂. Until then, I'm sure questions will arise.
1) is that something Hornresp can do? I know what horns are and bass reflex but port-augmented horns?! - do you happen to know a good read on that one? I'm really curious about starting to use Hornresp to simulate all that.
2) How about using the B&C 12NDL88, which seem similar to the RCF MB12N351, a little more powerful with 700W Prms, and even cheaper. It's probably still not enough SPL then since it's still 100W Prms below the 12NDL76 combo. But imagine using two 12NDL88 in a PM60 box...then we're talking 50% Woodstock! :-D
3) Yeah that's what I'm going for now, some kind of removable baffle with my horns.
I'll post some pictures of progress here, probably at around the end of January 🙂. Until then, I'm sure questions will arise.
1) Yes, Hornresp can simulate horns with bass reflex ports, as PM did in his designs, or my SynTripP design, or countless others. Hornresp allows you to look at the horn and port contributions both separately and combined. Freddi has posted loads of Hornresp simulations of various horn/br combos, searching his posts could give you basic starter parameters.
2) Once you arrive at a basic design, you can plug in the various drivers under consideration to see how well they will work. With as low as you want the mid section to go, excursion is probably more a consideration than power handling.