I've enjoyed the flexibility of the miniDSP so I decided to try something pretty crazy.
I connected a Line out converter (PAC SNI-35) to the front left and right speaker outputs of my Denon 591 Receiver. I also connected to the speaker outputs of those channels to a pair of Polk PSW 10 sub woofers and set their built in crossovers to 80hz (LR 2nd Order).
I configured the MiniDSP so that my speakers (Alpair 10.2 Pensils) have an 80hz high pass to match the subs and I added some extra stuffing since I don't need the LF extension on them anymore. They are being powered by a Audiosource amp100.
This leaves me with a set of unused outputs on the miniDSP for a set of tweeters. I plan on using the new Dayton AMT mini-8's because they will fit very nicely in the space above the drivers in my Pensil Cabinets. They will be powered by a Topping TP22. I don't have the tweeters yet so the Alpair drivers are running without a low pass filter.
The reason I'm doing this is that I wanted to evaluate the signal degradation I would get by converting the high level output of a receiver to RCA and if the results are good enjoy the benefits of a miniDSP 2x4 on my mains with all of the preamp functions of the receiver. I also need better off axis performance from my speakers! These Alpair 10.2's sound great but they have a very narrow sweet spot. Perhaps I can retain the full-range goodness with a high crossover point.
The results so far:
I thought that Line out converter would be terrible but there's really no problem with noise or other perceivable signal degradation. I'm really impressed with the PAC SNI-35 unit. I had to adjust it's output down a little bit to keep the RCA voltage within the miniDSP's input range and there's a little more background hiss compared to my receiver (not audible from listening position) but I think the Audiosource amp actually sounds a bit better than my receiver's built in amp at higher levels. The ability to play around with the crossover in real time is wonderful. Overall, I wish I had tried this earlier.
By the way, to get the noise down on my miniDSP I am powering it with a 60W 12V 5A Adapter for an LCD monitor. It's ridiculously overkill but has enough capacitance for low noise.
Once I get it all set up I'll post my measurements from REW as well as share my crossover recommendations for this speaker combination.
I connected a Line out converter (PAC SNI-35) to the front left and right speaker outputs of my Denon 591 Receiver. I also connected to the speaker outputs of those channels to a pair of Polk PSW 10 sub woofers and set their built in crossovers to 80hz (LR 2nd Order).
I configured the MiniDSP so that my speakers (Alpair 10.2 Pensils) have an 80hz high pass to match the subs and I added some extra stuffing since I don't need the LF extension on them anymore. They are being powered by a Audiosource amp100.
This leaves me with a set of unused outputs on the miniDSP for a set of tweeters. I plan on using the new Dayton AMT mini-8's because they will fit very nicely in the space above the drivers in my Pensil Cabinets. They will be powered by a Topping TP22. I don't have the tweeters yet so the Alpair drivers are running without a low pass filter.
The reason I'm doing this is that I wanted to evaluate the signal degradation I would get by converting the high level output of a receiver to RCA and if the results are good enjoy the benefits of a miniDSP 2x4 on my mains with all of the preamp functions of the receiver. I also need better off axis performance from my speakers! These Alpair 10.2's sound great but they have a very narrow sweet spot. Perhaps I can retain the full-range goodness with a high crossover point.
The results so far:
I thought that Line out converter would be terrible but there's really no problem with noise or other perceivable signal degradation. I'm really impressed with the PAC SNI-35 unit. I had to adjust it's output down a little bit to keep the RCA voltage within the miniDSP's input range and there's a little more background hiss compared to my receiver (not audible from listening position) but I think the Audiosource amp actually sounds a bit better than my receiver's built in amp at higher levels. The ability to play around with the crossover in real time is wonderful. Overall, I wish I had tried this earlier.
By the way, to get the noise down on my miniDSP I am powering it with a 60W 12V 5A Adapter for an LCD monitor. It's ridiculously overkill but has enough capacitance for low noise.
Once I get it all set up I'll post my measurements from REW as well as share my crossover recommendations for this speaker combination.
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Since I'm converting to RCA after the amp, I'm retaining all of the preamp functions including the Audyssey setup. I ran through the calibration and it worked just fine. All of the miniDSP stuff is another layer after that.
You really don't need the miniDSP to take advantage of this. Perhaps you have an excellent component amp that you would like to use with a receiver. Depending on the power requirements of your speakers, that could really be worth it.
Quote: These Alpair 10.2's sound great but they have a very narrow sweet spot. Perhaps I can retain the full-range goodness with a high crossover point.
End quote.
I've verb playing with miniDSP too, and very novice I am. I came across Charlie Laub's software page. He has some Excell sheets available for download called Active Crossover Designer. At first glance it looks more complicated than it is, but the instructions are very good, and I was able to muddle my way through it.
My point, I didn't realize how important the "time alignment" part of it is. I've been able to see some graphs with minimum phase. In my case, setting a delay on my tweeter of .03 milliseconds makes the phase of mid and tweet align more closely in the crossover region, and the perceived change in sound seems indescribable by my. Perhaps looking into this could broaden your sweet spot. Be prepared for a learning curve, but if excel makes sense to you, and you don't give up; I think it will be worth your effort.
Ciao
End quote.
I've verb playing with miniDSP too, and very novice I am. I came across Charlie Laub's software page. He has some Excell sheets available for download called Active Crossover Designer. At first glance it looks more complicated than it is, but the instructions are very good, and I was able to muddle my way through it.
My point, I didn't realize how important the "time alignment" part of it is. I've been able to see some graphs with minimum phase. In my case, setting a delay on my tweeter of .03 milliseconds makes the phase of mid and tweet align more closely in the crossover region, and the perceived change in sound seems indescribable by my. Perhaps looking into this could broaden your sweet spot. Be prepared for a learning curve, but if excel makes sense to you, and you don't give up; I think it will be worth your effort.
Ciao
Hey Alex,
Thankfully, I've spent a heap of time learning to use the miniDSP. There is a really cool piece of software called REW available free from hometheatershack. Combined with a calibrated measurement microphone you can use it to get some amazing results. One of the coolest things you can do, is set a target response curve that matches the crossover slope you are going for, then set that same crossover in miniDSP. After that, you can measure the response in REW for each driver and create a filter that will be applied to each driver in miniDSP so that the crossover works the way it's supposed to. Then you can measure the summed response and create a filter to adjust that. REW creates biquad filters and outputs them to a file that can be imported in the miniDSP interface. It's pretty insane. I cant tell you how many hours I've spent measureing, applying filters, measuring again, trying new settings over and over again. It can really get out of hand, but not any more than some of the video games. My wife just spent over 200 hours playing fallout 4. Now that's a lot of time.
I'm looking forward to trying your delay trick on my tweeter when I get them installed.
Thankfully, I've spent a heap of time learning to use the miniDSP. There is a really cool piece of software called REW available free from hometheatershack. Combined with a calibrated measurement microphone you can use it to get some amazing results. One of the coolest things you can do, is set a target response curve that matches the crossover slope you are going for, then set that same crossover in miniDSP. After that, you can measure the response in REW for each driver and create a filter that will be applied to each driver in miniDSP so that the crossover works the way it's supposed to. Then you can measure the summed response and create a filter to adjust that. REW creates biquad filters and outputs them to a file that can be imported in the miniDSP interface. It's pretty insane. I cant tell you how many hours I've spent measureing, applying filters, measuring again, trying new settings over and over again. It can really get out of hand, but not any more than some of the video games. My wife just spent over 200 hours playing fallout 4. Now that's a lot of time.
I'm looking forward to trying your delay trick on my tweeter when I get them installed.
Yes, I used REW and measure mic to create the .frd files which I used with the ACD excel sheets. I've been using excel at work for years, so it's a familiar interface for me. REW on it's own has so many capabilities and options, I get lost. Seems like I've spent many hours too measuring and listening; but I'm really happy with the XO I'm currently listening to.
I built just one loud speaker first (to keep costs down). It was a success to my ears, so I bought the drivers to build the other one. Need wood, but I'm working on amplifiers now.
I'm really interested in full range (I bet your Alpairs are awesome). After I finish my current pair of speakers, and amps, I'm going to build Vulcans (Woden design) with Fostex full range driver.
Glad your having fun and success.
I built just one loud speaker first (to keep costs down). It was a success to my ears, so I bought the drivers to build the other one. Need wood, but I'm working on amplifiers now.
I'm really interested in full range (I bet your Alpairs are awesome). After I finish my current pair of speakers, and amps, I'm going to build Vulcans (Woden design) with Fostex full range driver.
Glad your having fun and success.
Do you plan to use your miniDSP with the Vulcans? If so, will you be using a tweeter or subwoofer on the other set of outputs on the miniDSP?
Not sure yet. Probably build and listen to them solo first. I think subs are more likely to be the add on if needed. I have nanoDIGI 2x8, so technically I could do both. It may be fun to do neither, perhaps build a tube amp and have "pure and simple" be the goal of the vulcans
With the nanoDIGI you could build some subwoofer speaker stands and put the full range in its own sealed cabinet on the subwoofer stand. Then you would have a modular system that would outperform any single driver solution (in my opinion). A setup like that would be really fun because it keeps your options open and it allows for tube and solid state hybrid amplification. If you have a nanoDIGI I can only assume you like to change things up, and that will not change no matter what you build.
Check out this guy's system.
No Audiophile's Reference system review / Selah Mejor Supreme
He's not messing around!
Check out this guy's system.
No Audiophile's Reference system review / Selah Mejor Supreme
He's not messing around!
So here's the plan.
The major Frequency response shaping is happening in the overlap region of the crossover in an attempt to get the crossover to work the way it's supposed to. It's kind of experimental but we'll see. If it doesn't work out I'll just shift the crossover to a higher frequency or something.
After all of this, I'll apply the Audyssey calibration which uses much better FIR filters that will not affect the phase / timing as much as the miniDSP's IIR filters.
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An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The major Frequency response shaping is happening in the overlap region of the crossover in an attempt to get the crossover to work the way it's supposed to. It's kind of experimental but we'll see. If it doesn't work out I'll just shift the crossover to a higher frequency or something.
After all of this, I'll apply the Audyssey calibration which uses much better FIR filters that will not affect the phase / timing as much as the miniDSP's IIR filters.
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