THE Crossover Thread

Gibsonian

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Yes. Total recap but did some opamp swapping and that seemed to be biggest contributor. Working on a 1001 now. I forgot how wimpy these boards are. Thin wimpy traces. Have you started on yours?
 

laatsch55

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No...just getting information right now. Had an XR2000 in rotation for about 5 minutes and there were some pretty strange noises coming out of it. Swapped in an XR4000 that I'm running now. The xr2000 was replacing an XR 2001 that was getting weak in the right channel.So...i've got 2 to work on. And 2-XR 1001's waiting in the wings...
 

Gibsonian

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How bout now Lee, any progress? I started depopulating my spare XR1001 but I don't really enjoy it. The boards are so fragile. I need to get it going, really best chance to improve soundsystem left for me is ugrading one of these.
 

laatsch55

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Haven't started on any of em Scott. Need to get off my dead ass and order some stuff. Are you using sockets with the SOIC's and adapters?
 

laatsch55

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George S.

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Dayam George.... that's some heavy shit...
Yeah, I had to compromise because I don't have a purpose built "listening" room.
I was able to:
1. Run frequency sweeps of each individual driver and precisely calculate the crossover points. These points were way different from the original points and what I thought they would be. The measurement graphs don't lie.
2. Precisely time align each individual driver to each other. Can't stress enough how important this is. The ability to set the delays digitally is a powerful tool Using the Deer Creek Audio method of time alignment that's aimed at Home Theater, my subs time aligned easily. Surprising, they were very close in time alignment to the drivers in the JBL boxes. Reason being, they're front and center, and not in a corner, beside, or behind my listening position. I got best results running the subs as individual drivers in "stereo" mode and not summed.
3. The final measurement was the "room correction" filter. This is where room sweeps for each channel are taken. Getting the crossovers and timing set precisely beforehand must be done. Calculating it for a flat response and not using a room curve worked best for me. Others state the same in some YouTube videos showing advanced use of REW and DSP.
There were additional setup considerations prior to taking benchmark measurements, such as checking individual driver, speaker cable, interconnect, and amp channel polarity, and running amp gain sweeps to balance the gain.
Right channel and left channel must be consistent through all the components to each driver.
Haven't touched a setting in a long time.
And, it sounds great at very low volumes as well as high. Sometimes I really like those low volumes and ability to hear dialogue for home theater.
 

Gibsonian

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George S.

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Once you get it, register with MiniDsp and send tech support a email with the model and serial #, explaining you just bought it used. asking them to activate the plugin download on the download page.
You'll need to be logged in to download the software.
Hopefully they'll let you download it free, as they allowed me.
They're great people. They immediately respond to my emails during Taiwan business hours.
Latest plugin came bundled with a newer firmware than was installed on my used 4X10HD.
Flashing it was kinda convoluted, but the how to is out there on the MiniDsp forums.
Mine had a random USB connectivity issue I solved by resoldering the USB jack.
That fixed it and it's been rock solid. I see no reason to upgrade to a newer unit.
 

mr_rye89

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Are you using REW and the MiniDSP plugin or the MiniDSP Console software or both? Curious as REW works in Linux, and if I don't need a Windows PC/MiniDSP Console that would be okay......

EDIT: You need MiniDSP Console to control the MiniDSP, it only runs in Windows/Mac. Sorry Freetards:confused:
 
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George S.

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Kyle, the 4X10HD requires the specific plugin software for that model. This resides on a PC, and controls the unit via USB.
This plugin is available for download on the site.
Once the 4X10HD is configured and saved, the PC can be unplugged from the 4X10HD. The settings are saved internally in the 4X10HD, and as a file on the PC.
In addition there is a firmware update for the unit.
REW is a different animal all together.
REW is room measurement software among many other uses for audio, and it is arguably the premier software for measurements, driver integration, and room correction.
The issue with REW is it's deep and comprehensive, made for audio pros. Took me a long time to learn enough to use it competently to set up my system.
Lots of bad or out of date videos out there on how to use it, and so complicated that leaving one setting unchecked or with wrong value will give poor results.
But, it was worth it.
REW will do individual driver frequency sweeps to find your optimum crossover points for the drivers
These crossovers points are entered into the MiniDsp plugin.
REW will do driver timing tests for each individual driver and calculate each driver delay in milliseconds.
The delays are entered into the MiniDsp plugin.
REW will do channel sweeps and gains can be adjustedl in the plugin.
Once each channel is configured for gain, crossover frequency, filter slope and DB, then the room correction EQ sweeps can be run on REW that generate the Biquad Filters.
These can be exported from REW directly into the MiniDsp plugin. This equalizes the system to the room.
Channel gains can work as a balance control, and the 4X10 does have a master volume control in the multifunction knob on the front.
My understanding is a remote also controls the master volume.
So you really have a built in preamp. But I don't use mine this way, I use the PL preamp.
You'll need a measurement microphone.
I use the MiniDsp Umik1.
So, yes, it's a ton of work and learning to get it right.
But it's SO worthwhile.
My crossover points are far from JBLs published crossover points for the drivers and the stock crossovers
My sub crossovers are at 50 Hz, lower than I expected. They're set at DC to 50 Hz, with a steep 48 dB filter just above DC.
The measurements when done with precision don't lie.
The problem is learning the software.
That's why Dirac Live is now offered on the newer MiniDsp units. Easy to use with a Umik1.
But, the Audio Pros say better results can be had with REW. So I studied it and learned it.
Haven't touched the settings in months, no need to.
Hope this helps.
If you want links to what helped me learn it, I'll post.
And Windows 10 is easy to download and get validated as genuine on any Windows 7 or newer PC.
Just due a search for Windows 10 Download Tool. Put it right on a USB flash drive. Windows 7, 8, or 10 key will validate it.I put a fresh copy of 10 on the garage PC last week.
For the main system, I use a huge dual CPU Lenovo D30 Workstation converted for PC use. Fast dual Xenon processors, lots of ram, 4K video card for the flat screen. Long USB, HDMI cables. Runs all the software including REW and the 4X10HD plugin.
And, a long USB cable for the Umik1 that sits at the sweet spot facing the ceiling when needed.
Cables cheap from Monoprice.
 
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