MiniDSP Sub Setup

[BigDan79]

Hello,

I just purchased a Rythmik FV18 for Christmas and have been trying to integrate it into my system. I purchased a MiniDSP 2x4 HD and mic and have been making adjustments. I was curious if just purchasing the DIRAC software would be and easier solution. Is the DIRAC software on the MiniDSP HD more for speakers and subs or will it work for 3 subs? Does it have bass management?

 

[JStewart]

Welcome BigDan79!

I was curious if just purchasing the DIRAC software would be and easier solution. Is the DIRAC software on the MiniDSP HD more for speakers and subs or will it work for 3 subs?

There’s only 2 channels of Dirac correction on that unit so it’s a no go for 3 subs.
Have you considered @andyc56 MSO (multi sub optimizer) freeware? A bit of a software learning curve but works really well.

Multiple Subwoofers: Optimize Them With Multi-Sub Optimizer Software

The benefits of multiple subwoofers are maximized using Multi-Sub Optimizer software for lowest seat-to-seat frequency response variation and highest SPL.

www.andyc.diy-audio-engineering.org

 

[BigDan79]

Thanks for the reply. Yes I have started using MSO but it seemed pretty complicated that why I was willing to pay for the Dirac upgrade. If Dirac can only do 2 of the 4 channels I will have to learn MSO. Are there any good MSO youtube walk though videos? I couldn’t seem to find any similar to the REW videos.

 

[JStewart]

Don't know about the youtube videos but I'd be happy to answer any questions I can.

 

[BigDan79]

Thanks! I was able to get my REW seat measurements imported into MSO and that’s where I stopped. I will mess with it some more and ask questions in this thread as I hit road blocks.

 

[JStewart]

Nice.

Even though you're past this point I'll throw in a couple things I found helpful for measurements.

- To get as much measurement range as possible for the subs either a) if you have an LPF for LFE setting available either set it as high as possible and measure using the LFE channel or b) set the XO for a speaker pair that's set to small as high as possible, disconnect one of the speakers in that pair, and use that disconnected speaker channel for measurements.

- Have a system to number subs and measurement positions. It makes it much easier to keep from making a mistake as far as what's what in MSO. So example measurement names become S1 P1, S2 P1, S3 P2, etc. where S=Sub and P=Position.

- Have the sub numbers correspond to the output numbers on the MiniDSP

 

[BigDan79]

I don't completely understand what you are saying for setting the LFE channel as high as possible. When I took the measurements I would turn off the subs that were not being used in MiniDSP. See the attached REW measurements and DSP screen. Hopefully I did these correctly. I just started taking measurements a few days ago and I have a lot to learn. Please let me know if I have anything screwed up.

 

[JStewart]

- To get as much measurement range as possible for the subs either a) if you have an LPF for LFE setting available either set it as high as possible and measure using the LFE channel or b) set the XO for a speaker pair that's set to small as high as possible, disconnect one of the speakers in that pair, and use that disconnected speaker channel for measurements.

I don't completely understand what you are saying for setting the LFE channel as high as possible

What I meant was we want to measure the sub up to 250Hz (or higher) if possible AND if we are using the LFE channel to take measurements with REW there is typically a low pass filter (LPF) of 120Hz on that channel. So my recommendation would be to raise it if this applies and your equipment allows a LPF for LFE adjustment.

Second option was "b) set the XO for a speaker pair that's set to small as high as possible, disconnect one of the speakers in that pair, and use that disconnected speaker channel for measurements." So for example, set the Fronts to small. Set the Front XO to 250Hz. Disconnect the front left speaker wires (with proper precautions to prevent a short from live wires touching). Send the Sweep measurements to the front left speaker.

A third option I didn't mention to get a wider range for your measurements is to just plug the minidsp into a left or right pre-out on your equipment if you have one and set that speaker to "Large". Run your sweep to the channel you've plugged the MiniDSP into.

Looking at your jpeg the sub measurements are cut off at about 120Hz or so. So, we'd like that to be up to 250Hz if we can. That way the corrected range will not include the effects of any XOs in place. (or at least minimize them, depending on the range we choose to correct.)
Recall that crossover filters are slopes and not brick walls. Here's a picture from MiniDSPs website as an example.


When you took the measurements did you set REW to use a timing reference? There will usually be some data that REW puts in the text box for each measurement and I don't see it in the text box for the measurement that's visible at the bottom left of the jpeg that's posted.

Example with the REW notes I'm referring to.:



Hope this is more understandable and not TMI

 

[BigDan79]

Ok. I can run the subs off the left or right channel pre out with it set to large. I will set REW to 250 and make sure the MiniDSP is set right too. I can check the timing reference when I am home tomorrow. I just used whatever the standard settings were so I will make sure it set to use it. I will try to rerun the measurements tomorrow if I can escape the wife and kids for an hour.

 

[mata7]

hi bigdan i am also contemplating the dirac live software with the minidsp, if you buy it can you please post your result if you like or not and how easy was the setup

thanks in advanced

 

[JStewart]

Ok. I can run the subs off the left or right channel pre out with it set to large. I will set REW to 250 and make sure the MiniDSP is set right too. I can check the timing reference when I am home tomorrow. I just used whatever the standard settings were so I will make sure it set to use it. I will try to rerun the measurements tomorrow if I can escape the wife and kids for an hour.

MiniDSP pre-mso measurement check
- remove any crossovers set for each output channel of the pre-set bing used (by default or after resetting a pre-set or factory reset some may be active). (Appears from earlier measurements this had been done )
- remove any gains, delays, and filters that may have been set by user previously for the pre-set OUTPUT being used.
- remove any gains and filters that may have been set by the user previously for the pre-set INPUT being used.

Using UMIK usb mic will require use of REW acoustic timing reference during measurements.
See @andyc56 REW measurement advice here https://www.andyc.diy-audio-engineering.org/mso/html/measuring.html
Follow Andy’s link to the REW documentation where John M will explain the concept.

The timing reference used to be and still can be set in REW’s preferences.
It can now also be set when on the measurement screen.

 

[BigDan79]

What I meant was we want to measure the sub up to 250Hz (or higher) if possible AND if we are using the LFE channel to take measurements with REW there is typically a low pass filter (LPF) of 120Hz on that channel. So my recommendation would be to raise it if this applies and your equipment allows a LPF for LFE adjustment.

So I was looking at my Paradigm subs and their crossover only goes as high as 150. I am not sure how high of a signal the Rythmik will accept. So how should we handle this situation?

hi bigdan i am also contemplating the dirac live software with the minidsp, if you buy it can you please post your result if you like or not and how easy was the setup

thanks in advanced

--- I do not plan on buying the Dirac software because it can only do 2 sub channels. I need 3.

 

[BigDan79]

I also wanted to include a picture of my space so you can see what I am working with. This was taken prior to adding the Rythmik sub.

 

[BigDan79]

Does this look better?

 

[BigDan79]

Also

 

[JStewart]

Very Nice Room!!

So I was looking at my Paradigm subs and their crossover only goes as high as 150. I am not sure how high of a signal the Rythmik will accept. So how should we handle this situation?

Normally when you use the LFE input on a sub the subs crossover control on the sub is bypassed. This is a definite on the Rythmik but I'm not familiar with the Paradigms. The owners manual would need to be checked.
Either way I'd connect up as you said and run the sweep to 250 (or 300Hz even) and see what happens. If the XO is in effect and not bypassed on the Paridigms then you'll limit the correction range on MSO to 120Hz or so.

I didn't mention earlier when you run the measurements, set the phase on each sub to 0 and I assumed you already set the volume of the 3 subs so the combined response is about right to match your mains. MSO will make adjustments if you ask it to, but its better, though not absolutely necessary, to get them close with the volume controls on the subs and make smaller adjustments on the minidsp with MSO.

 

[JStewart]

Does this look better?

Looks like we were posting at the same time.
The responses look very good, but I hope they're not really that loud. I doubt they are because the signal would compress at those levels. Have a smart phone you can download an SPL Meter app to? So can see what each sub is really doing at the MLP?
Was the UMIK selected as the input device in REW? Normally when it is it will calculate the SPL correctly, but I've seen this before. If we have a rough idea what the real SPL is we just change the measurements you've taken without having to re-do them. If you attach your REW mdat file I can do it for you or try to explain with pics when I'm back at the house. It's not hard at all.

EDIT: The SPL levels on the jpeg are loud enough to cause hearing loss. But again, I'm guessing they are not correct.

 

[JStewart]

Also

This pic shows a high pass filter in place on this channel. We want all crossovers bypassed in the minidsp for each output channel so they're not affecting the measurements. The one in the pic is cutting off pretty low frequencies from about 25hz and lower so up to you if you want to remeasure based on just this one in the pic, but if it were me, I would.

 

[BigDan79]

I think something is wrong with the levels. It wasn't that loud. I do have an SPL meter and will check it.

I will fix the Minidsp crossover settings. Looks like I got a lot of bad info from YouTube videos on setting it up.

I will also make sure all of the phases are set to zero and they have the same output to match my mains. I did this initially but have been playing with settings and may have changed things.

I will rerun everything and post again.

 

[Epoxy1]

I suggest watching this video:

He does an excellent job of explaining how to integrate multiple subs into a room. A lot of us had to learn this through trial and error

 

[BigDan79]

I figured out why my levels were so high. I used the front speaker output that had a higher gain output that what was on the sub output.

I also removed the MiniDSP crossover and measured everything again.

Does this look better?

 

[JStewart]

So far as I can tell the measurements are ready to export from REW and import to MSO.

 

[BigDan79]

Woohoo!!! I will try that next.

 

[JStewart]

I suggest watching this video:

He does an excellent job of explaining how to integrate multiple subs into a room. A lot of us had to learn this through trial and error

Good video. Too bad this was done with REW before John M added the alignment tool. Using a timing reference with the alignment tool eliminates the trial and error measuring to find the best (phase) alignment he does in the video and I suspect most of us will have a lot more trial and error than the video does.

 

[BigDan79]

I am unable to export frd files from REW. I was able to import the text files into MSO. Is this ok? The directions so far say to use the frd files.