Ok that issue was sorted, reset everything again and now it’s back up and working.
So, I'm trying to keep this simple as possible and only setup the subs from one listening position and am not worried about the mains. My biggest issue is that I have an open plan room, so I am trying to even out the response at low frequencies. (My wife couldn't tell the difference so I’m only running one measurement per channel.)
I've ran three acoustic timing sweeps in REW, from 10-200hz (512kb at 48kHz), preferences set for MiniDSP 2x4, from my laptop with HDMI and USB Umik-1. I can only sweep to 200hz as this is the highest value on my cross over on my AVR.
The three sweeps were:
- LHS sub
- RHS sub
- Mains only with no subs and no crossover
Frequency range to optimise set to 20-100hz (gave myself a little play here for cross over in AVR which is set to 80hz) and the Frequency range to compute reference is on auto (99.8-199.6), which I still don't understand.
I have 5 PEQ filters, gain and delay, on both channels and polarity inversion and all pass filter on the second channel.
I've been getting predictions around ¬1.5 db error, however the example below I ran the optimisation short as didn't want to keep waiting for 30 minutes for testing.
I'm using the Biquad text export set for MiniDSP 2x4 (48kHz with 5 PEQ Channels, max gain at 12db, max delay 7.2)
I've imported the left and right hand sub biquad data to channels 1 and 2 in the MiniDSP, manually set the required delay for channel 2 and synced.
It's definitely changing the sub outputs but nowhere near what is expected so something is amiss. I just can't work out what.
I'm getting significantly different results compared to expectation.
Black and Red = individual subs before optimisation
Blue = MSO prediction
Green = After MSO settings applied in MiniDSP
View attachment 44463
Hello again,
Glad the unit is working again.
At first glance it looks to me like your GREEN line is just showing the measured response from your MAIN Speakers WITHOUT the SUBS. Which means that you might be taking your final measurements with the MAINS set to LARGE, and this is in effect leaving the SUBS out for those measurements. Go back into the AVR settings and make sure that the Speakers are set to SMALL and the Crossover is set to 80Hz or 100Hz.
Having said that, I will try to lay out some steps for you to take to hopefully help you (and anyone else reading this) nail this. As Tony mentioned above. MSO was mainly designed with the purpose of achieving a better seat to seat consistency from your multiple subs. Andy mentions this in his posts on AVS. So at minimum, you will want to take measurements at 2 different seats.
So here is a summary of steps that I recommend:
First:
At the Subwoofers:
1. Set the Phase knob or switch to 0 (ZERO). Don't worry, MSO will figure out the proper distance needed to properly align the subs without needing to manually adjust the phase.
2. Set the Crossover knob to its highest setting to avoid the frequencies from being filtered at the sub. The AVR will take care of setting the crossover later. For now you want to run the sub crossover fully open and sweep at least 100Hz past the highest point on that Crossover. This will allow you to see where the subs cap out on the higher frequencies. You can run the sweeps from about 10hz to 300Hz and then later tell MSO which range to optimize for.
3. Make sure that you gain match your subs so that they are working at the same efficiency. This is different then level matching. Here is the difference...
With Gain Matching you are going to measure each sub under the same condition as the next. This means finding a "neutral spot" in the room away from walls (such as the middle of the room), and placing the first sub there. Then you place the measuring microphone at a fixed distance close enough from the sub to minimize the influence of the room on that measurement.
So let's say you place the mic at 8 inches from the center cone of the sub and play some pink noise at a set volume through the sub using the generator in REW. Use the SPL meter to see what the output level is from the sub (with the gain knob on the sub set to 0db). Since the mic will be close to the sub, the output reading is going to be very high, much higher then that same output reading would be if measured from the listening position. But that is not the important part. The goal is to take note of that output level reading, and then remove that first subwoofer from that measuring location, and place the next subwoofer in that same spot. Now you will measure the next sub the same way and adjust the gain knob on that sub until its output measures/matches the same as the previous one.
If you have two or more of the same subs, the gain knob position should be close on each after matching the output, but if you are using different subs, the gain knob could end up at different positions for each sub, but at least now the gain and output from each is closely matched (with minimum affect from the room, difference in location or difference in distance from the mic).
If you were to Level match instead, and you had the subs located at different locations while take the measurements, you would run the risk of over driving the subs since the location and distance from the measuring mic would be different for each, and thus affect the measured output.
4. After gain matching the subs, mark or take a picture of where the gain knob setting is on each (in case it is accidentally moved), and then move the subs back to their final location. If possible, find and place each sub in a location where each one gives you the best output and frequency response on its own. This will give you a better starting point.
Next:
At the AVR:
1. clear out the auto calibration software memory. This includes all EQ settings, distances, channel levels, etc. Since you are going to do a SUB ONLY Configuration in MSO you don't need nor do you want anything affecting the raw output from your subs.
***Also make sure that you indicate on the AVR that there is only 1 (one) Subwoofer in use.
You will send only 1 sub-out signal from the AVR to the MiniDSP, and the split that signal via the MiniDSP into the corresponding number of Subs. When this is all said and done, your AVR will read the combined subs as ONE LARGE EFFICIENT UNIT regardless of how many subs you actually have. That way, later on (post MSO) when the AVR Auto-Calibration makes adjustments to the Gain or Distance for the sub, it will be acting as if only one sub is in use, and the adjustments will affect the UNIT as a whole as opposed to each subwoofer individually.
2. Make sure that your channel level (gain) in the AVR is set to 0dB. This will also ensure that the subs are getting a clean and full signal.
3. Again, make sure you've turned off any EQ that the AVR may have... you want a clean unedited signal to pass through the AVR when you use REW to send the signal through.
4. Set your AVR to STEREO. Make sure that no other DSP mode is on such as Dolby Surround, etc.
5. Manually set the Speaker Sizes to Small and set Subwoofer to YES (or whatever your AVR displays to indicate that you are using a SUBWOOFER).
*** Also make sure that the AVR Crossover is set to its Highest setting to ensure that the subwoofers gets a full signal.
So with the Speakers set to Small, set the Crossover for the Speakers to the highest setting allowed in the AVR.
6. Now, connect your laptop via HDMI to your AVR and again make sure that the EQ and DSP mode for that input is set to STEREO per the instructions above. You also want to make sure that REW is properly set.
7. Place the UMIK-1 at the MLP (main listening position) and use the Generator in REW to send a pink noise signal to one of your Mains. Use the SPL meter to read the output level of that Main speaker at the MLP, and adjust the Volume Knob on the AVR to a level where the output of that Main is roughly 75dB. Take note of that volume setting for future reference, so that any subsequent measurements you take are under the same conditions. So if your AVR volume knob is say at -21dB for that measurement, you want to make sure that you use the same -21dB for the rest of the measurements.
Next:
At your MiniDSP:
1. Make sure that all levels are at 0 (ZERO). This includes delays, channel gains, EQ, etc.
2. Make sure all of the Polarity settings are also OFF.
3. Make sure that All Crossover Settings are Bypassed. You should see nothing but a straight line going across the graph to indicate that it is inactive.
Next: REW and MSO
Now you are ready to begin taking Measurements using REW.
1. Set your Preferences correctly with the ASIO4ALL installed.
Make sure that in the SOUND settings on the Laptop, the Playback settings are showing your AVR as your DEFAULT device. Then, under the Recording tab, Make sure that the Default Device is set to your UMIK-1 (per the MiniDSP instructions)
2. If all of the above is set properly, you can now choose your LEFT or RIGHT Main Speaker as the Timing Reference Speaker. If you choose the Left Main for the Timing Reference, then use the Right Main speaker as the channel to send the sweep through. When you send the sweep to the Right Main you will want to make sure that this speaker is disconnected so it doesn't affect the output, and also confirm that the AVR has that speaker as SMALL with a Subwoofer ON.
3. Now that you are ready to run the sweeps, you will want to run a sweep of EACH Subwoofer at the same listening location before proceeding to the next listening location. For this, you can use the MiniDSP to Mute all the subs EXCEPT for the one being measured at that time. So if you have 2 subs and 3 seats, you will set the MIC at the first listening location and take 2 measurements (one for each sub). Then you will move the MIC to the next location and do the same.
*** If you want to compare how well MSO performed, you can also take a measurement of all of the Subs combined (unmuted) at each listening location. Just make sure that you don't use those combined measurement to feed MSO data to configure. You can instead import those for PLOTTING ONLY so you can compare before and after.
4. Make sure that in REW you indicate which Equalizer you are using (MiniDSP 2x4, MiniDSP2x4HD, etc.) before you EXPORT your measurement from REW to MSO.
5. Follow the instructions for a SUB ONLY Configuration in MSO. This includes CREATING a new SUB ONLY Configuration.
6. Once setup, you can run MSO for 2 minutes just to make sure that you've set things up properly. Once confirmed, allow MSO to run for 30 minutes so it can work its magic!
7. You can import the combined raw measurements you took earlier at each listening position, and create a plot only graph with them. After MSO is done making its calculations, you can create a graph that compares the raw measurements to the MSO results. If the results are to your satisfaction, you can proceed to export the MSO results by saving the biquads for each sub and importing them to the MiniDSP, and then notating the delay and gain adjustments that MSO recommends for each sub channel, and then manually inputting them into the MiniDSP sub channels.
8. If you have successfully transferred/inputted the MSO results into your MiniDSP, you can now retake the combined measurements at each listening location using REW, and confirm that the new measured result (after configuring the MiniDSP) match the predicted results from MSO. If they do, CONGRATS!! you now have all of your subs working together as one Large and Efficient unit that provides good seat to seat consistency in the Bass Frequencies!
Final Steps:
1. Now that you have created the effect of having one large and efficient subwoofer (after properly combining them all via MSO), you can now set up your AVR properly.
*** Make sure that you reconnect the Main speaker that you disconnected earlier while taking measurements.
2. Start by placing the AVR supplied Microphone at same MLP location that you placed your UMIK-1 when using REW.
3. Run the AVR Auto-Calibration. This will allow the AVR to use the new "sub" and the rest of the speakers for its calibration.
Once the Auto calibration is completed, you may need to manually change 2 key settings. The first will be the Speaker Size that the Auto-Calibration set. Make sure you set the speakers back to Small (if the Auto-calibration set them to LARGE) so that the new Sub is allowed to work as intended.
The second change will be adjusting the Crossover setting set by the AVR Auto-Calibration. Again, manually change the Crossover in the AVR to 80hz or something close. Assuming that your speakers can all be crossed-over at the same frequency, I would set them all the same. This will again allow for the the new sub (combined subs)to work as intended across a larger frequency range.
4. Once you have made those changes, you can re-measure the MLP using REW to confirm that the bass frequencies (at least up to the Crossover point that you set) remain unchanged. If so, sit back and enjoy some music or a movie with your newly tuned setup!
Good luck!
P.S. If I missed anything, feel free to point it out, and I will edit this write up.