THE Crossover Thread

mr_rye89

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I put win10 on that ancient Thinkpad R60 and lol its slow. I did put a 64 bit Core2Duo in it but the ram maxes at 3gb due to the 32 bit Northbridge/BIOS limitations. I also put a less ancient wifi card in it that supports 802.11N/WPA2 and a 256gb SSD. It does sport a high-ish resolution 4:3 display, weighs 6 lbs and is over an inch thick. I got some weird looks using it in back in my college classes. No one would steal a laptop that looks 20 years old (and now it is almost 20 years old!) I was gonna put a 1tb m2 SSD in the T480 and just put windows on the existing 256GB SATA and dual boot but I'm too cheap! And Ive had bad luck with Virtualbox and USB ports working......
 

George S.

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A R60? Ancient and painfully slow.
Even a much newer T410 with a spinning HD is very slow. A SSD makes a T410 responsive and usable.
Time to look for a more modern machine.
I run cheap used ex corporate Samsung or Liteon SSD's from the companies that resell after data wiping. The cheaper the better.
Same with Lenovo desktops. Lenovo S30 Series 2 or D30 ex corporate desktops. Workstations. I go into Bios and select boot from internal HD (SSD) rather than default network.
Old but still very powerful machines for Streaming and Home Theater.
 

Bob Boyer

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So a quick question for you miniDSP users while the grill heats up so I can cook a steak...

Once you have things set as you like with the crossover points and any room correction adjustments, is it plug and play or do you still need to have the computer turned on and talking to the box when your stereo is on?

Louis and I were just talking and I think the less expensive experiment for these little single driver speakers is to add bass by just using an active crossover (the 2x4 miniDSP is what I'm thinking) to funnel the sub-100Hz signals to my Parasound and use the 6" mid-woofs in my LSAs to provide bass augmentation. Right now, I think we're just gonna experiment with an old Dahlquist active crossover he has stashed away but if that works, I may want a more permanent solution and the miniDSP appeals to me.

Not sure if I can utilize the DIRAC software with the Exposure or not, but it appears the 2x4 without DIRAC would work. Maybe I ruled out a miniDSP earlier because I didn't have the Parasound in the system and you can't split the Exposure's amp from the preamp section.

Thanks in advance for your experience.
 

George S.

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Bob, you program the MiniDsp with a computer attached via USB by entering data and changing settings via virtual sliders in the MiniDsp software.
That software is called the "plug in".
You can then detach the computer and the settings are saved in the MiniDsp.
You can also save those settings as a file on your computer.
So you can have multiple files on the computer and easily swap completed setup files into the MiniDsp that may have different crossover frequencies, gain structures, crossover slopes, etc.
Or, simply move a virtual slider or change a crossover frequency or slope while connected in real time while playing music or frequencies.
Easy enough to simply add a 2x4 and a sub or two for a biamped system. The crossovers are easily set.
But, the subs won't be properly integrated until you add a Umik1 measurement mike and room measurement software like Dirac Live or REW.
I suggest researching room measurement software before pulling the trigger on subs. It's a deep subject with a emphasis on multi channel Home Theater.
 

Bob Boyer

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Thanks, George. I wondered about the need for DIRAC. Good to know the miniDSPs have enough ROM in them they don't have to be connected to a computer once the curves and crossover points are set.

I think now that I'm back to using my Exposure in its bi-amp mode where it drives the tweeters and the single preamp out goes to the Parasound to drive the mid-bass drivers in the LSAs, I can insert the 2x4 between the two amps and it will work fine. At $470, a 2x4 miniDSP with DIRAC from Parts Express is about the same as an 8" active sub of decent quality and might have more applications. The trouble with running a sub off of the Exposure is that it absorbs the single set of preamp outputs so it's an either/or situation. Sub or active crossover.
 

George S.

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Here's a very interesting video about audio above 20 KHz.
I tried this before and results were disappointing with the PL2000 preamp.
Now that Joe has solved the PL2000 preamp frequency limitation with cap value changes, effectively extending frequency response out beyond 30 KHz, limiting tweeter frequently response in the active crossover is no longer necessary to eliminate the very high frequency distortion or hash I could identify from time to time.
I put the video's info to work by removing the MiniDsp's tweeter high frequency filter that was set to limit response to a maximum of 20 KHz.
The active crossovers frequency response now extends from DC to approximately 30-35 KHz which I think is the limitation of the modded preamp and MiniDsp. I'll verify this with frequency sweeps as I do need to generate new room correction filters.
Weird thing is this.
I'm older and really can't hear high frequencies well, but, I can hear a definite improvement in high frequency response with that 20 KHz filter removed.
 

gene french

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Here's a very interesting video about audio above 20 KHz.
I tried this before and results were disappointing with the PL2000 preamp.
Now that Joe has solved the PL2000 preamp frequency limitation with cap value changes, effectively extending frequency response out beyond 30 KHz, limiting tweeter frequently response in the active crossover is no longer necessary to eliminate the very high frequency distortion or hash I could identify from time to time.
I put the video's info to work by removing the MiniDsp's tweeter high frequency filter that was set to limit response to a maximum of 20 KHz.
The active crossovers frequency response now extends from DC to approximately 30-35 KHz which I think is the limitation of the modded preamp and MiniDsp. I'll verify this with frequency sweeps as I do need to generate new room correction filters.
Weird thing is this.
I'm older and really can't hear high frequencies well, but, I can hear a definite improvement in high frequency response with that 20 KHz filter removed.
harmonics...
 
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