I've done enough searching and reading to know that if I choose to build a tapped horn subwoofer, I should use some kind of high pass filter to keep away the frequencies lower than the capability of my system. If I don't, I should learn to enjoy frequent replacement of the damaged driver.
What do most people use for a crossover? I'd like something with adjustable frequency points as well as some kind of level control for matching the gain of the amps and sensitivity of the speaker systems. If there are other features (phase?) that you think I need, please feel free to suggest them as well. I'd prefer to have something dedicated and self contained. I don't want to keep a PC around running some software package to do my filtering.
All my signal connects are simple unbalanced RCA types. It'd be nice if they were all balanced, but alas they are not. I intend to run one modestly powered vacuum tube amplifier for the left and right channels, which will run primarily full range. A high pass (~100 Hz) filter would be most helpful here, I think. I've got two channels of modestly powered (150 watt/ch) solid state amplifier for the subwoofer(s). I can bridge the amp mono and will most likely do so until I can build the second sub. (note - the first sub is not yet built either). I'm guessing the sub ought to be some kind of band pass from ~30 Hz to ~100 Hz, or wherever the filters for the mains are set.
Any recommendations? I'm also interested in ideas for the subwoofer driver and specific box plans. I think I want something about 12" for the driver, and 6' to 8' long for the box. William Cowan's "30 Hz Tapped Horn" is pretty much what I have in mind, though perhaps with a different woofer? I want to learn how to use hornresp, but that will take a little time and experimentation.
(note: crossover points shown in the diagram are too high for my purposes.)
What do most people use for a crossover? I'd like something with adjustable frequency points as well as some kind of level control for matching the gain of the amps and sensitivity of the speaker systems. If there are other features (phase?) that you think I need, please feel free to suggest them as well. I'd prefer to have something dedicated and self contained. I don't want to keep a PC around running some software package to do my filtering.
All my signal connects are simple unbalanced RCA types. It'd be nice if they were all balanced, but alas they are not. I intend to run one modestly powered vacuum tube amplifier for the left and right channels, which will run primarily full range. A high pass (~100 Hz) filter would be most helpful here, I think. I've got two channels of modestly powered (150 watt/ch) solid state amplifier for the subwoofer(s). I can bridge the amp mono and will most likely do so until I can build the second sub. (note - the first sub is not yet built either). I'm guessing the sub ought to be some kind of band pass from ~30 Hz to ~100 Hz, or wherever the filters for the mains are set.
Any recommendations? I'm also interested in ideas for the subwoofer driver and specific box plans. I think I want something about 12" for the driver, and 6' to 8' long for the box. William Cowan's "30 Hz Tapped Horn" is pretty much what I have in mind, though perhaps with a different woofer? I want to learn how to use hornresp, but that will take a little time and experimentation.
(note: crossover points shown in the diagram are too high for my purposes.)
Ty, for a TH I'd suggest a higher order filter for the HP, and they are very difficult to make adjustable due to the amount of values that need to change in perfect synchrony. I'd have a look at Bob Ellis's Active Filter PCB GB. Though the frequencies are fixed, it's well documented and will give you all the facilities you need to build an excellent crossover.
A DSP (digital signal processor) is the best way to go for tapped horns. As well as HP and LP, you will need to delay the top cabinets to time align the output, the time delay roughly equates to the path length of the horn. Many TH designs have large out of band peaks, the parametric EQ available in DSP allows those to be tamed so the acoustical crossover ends up being correct.
DSPs come in a wide price range and feature set, many use Behringer units which tend to have reliability issues but a great feature set for the cost.
I use the DBX DriveRack PA, which is quite reliable and reasonably priced.
DSPs come in a wide price range and feature set, many use Behringer units which tend to have reliability issues but a great feature set for the cost.
I use the DBX DriveRack PA, which is quite reliable and reasonably priced.
I noted one mention for the Behringer DCX2496. I admit I didn't read the feature specifications too closely, but it seemed like maybe it did approximately what I might want. After I saw all the balanced connectors on the back, I quickly lost interest in that unit. I'll go look up the DBX DriveRack PA and see if that looks like a closer fit more me. Thanks!
edit: Hmm, all balanced connectors again. Is there an easy way to deal with that?
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Either, but more than a slight nod to "ready to buy". Price will quickly make the decision. I'm happy enough to sling solder. I did see the Elliott Sound Products P09, which was interesting. I wish it had some accommodations to adjust the frequency points and levels of the outputs.
I might have some p-cad files for crossover with fixed frequency....
Did you see that mini dsp units?
It looks promising.
Well if you decide to build it diy i can search for files...
I would recommend you something really sharp if you want to avoid that annoying bass over 100Hz....muuuuuup...muuuup....
Regards, Taj
Did you see that mini dsp units?
It looks promising.
Well if you decide to build it diy i can search for files...
I would recommend you something really sharp if you want to avoid that annoying bass over 100Hz....muuuuuup...muuuup....
Regards, Taj
So, what is a MiniDSP? How do I set one up? Are there different versions, and if so which do I need?
I see... miniDSP in a BOX looks a lot like what I want. But how do the plug-ins work? So many choices, a good thing, but which one?
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Yes, make adapters to whatever input you are driving.
The balanced Pin 1 and 3 tied together for -, pin 2 +. If ground loops (hum noise) develop, lift (disconnect) pin 1.
The DCX2496 and DRPA are rack mountable, and relatively easy to adjust, with dozens of presets available for recall.
If for home use, the minidsp sounds cheap and viable, though I personally don't like having to connect stuff to a computer to adjust parameters.
And test equipment to arrive at the proper time alignment, and...Thanks for all the suggestions. I've gone ahead and placed an order for a MiniDSP with the 2way Crossover ADV 2.1. It looks like exactly what I want. Now all I need is a good driver and plans for a box.
Have fun, building, and there are ways to do the time alignment with just a dB meter if you are clever and patient.
You'll be pleased. The miniDSP is a great product. I'm using one to crossover and EQ both my OB woofers and a TH sub. The software is simple, yet plenty flexible. If you are tube user, the 10K input impedance can be a little challenging. My unit was a prototype, and its been running flawlessly.
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
I am pleased. The miniDSP showed up over the weekend, and I finally got the chance to play with it tonight. If your mind is even slightly oriented towards audio concepts, the thing practically sets itself up. The software is so easy to use. And gosh darn it, so effective too! I haven't built my sub yet, but I hooked up an old junk Radio Shack garbage Optimus "Pro" SW12. It's a nasty 12 inch woofer in an undersized ported box, passively crossed over at a uselessly high 250 Hz or so. With the miniDSP and some minor surgical removal of the SW12's passive x-over, I can almost find some useful band from the retched thing. I've got the rest of the spectrum covered with some wideband Fostex FF85K in back loaded horn enclosures. The Fostex sound OK in their own right, but have one or two odd resonance peaks in their response. I have no idea how I survived this long without a parametric EQ. It just makes so much sense and makes it so easy to dial a peak or valley in or out.
Good deal!
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