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NanoAVR Summary
I have recently spent a great deal of time using the new nanoAVR product and wanted to share my learnings and experience with you. My primary interest in this product and one of its big advantages is that it provides a comprehensive set of EQ and crossover tools to shape any home theater while keeping all channel content in the digital domain. Traditional digital EQs /crossovers have A/D and D/A stages and require the user to manage both input and output levels carefully to maximize the useable bits in these conversion stages. However, the nanoAVR eliminates this need to manage the input/output leveling and eliminating possible noise and distortion from the conversion process.





First I would like to point out some set up tips that may save you some time. Perhaps if I would have read the instructions more carefully I might have avoided a few time consuming issues myself The first major activity was to use the nanoAVR to EQ my home theater 7.1 channels. To do this, I connected the HDMI output on my PC to one of the nanoAVR inputs and the output HDMI to my Denon receiver.

The first tip to note is that when you connect your PC or Laptop HDMI to the nanoAVR, the PC graphics will also be routed to the nanoAVR and to your receiver. My PC was hooked up to a monitor that I was using to run the nanoAVR utility... but after connecting the HDMI port, my monitor went blank. It is very difficult to control anything using a blank screen. You will either have to control the nanoAVR software via your TV or projector connected to your receiver or you will have to switch the display on your PC using the "Windows key" while pressing the "P" key.

The second tip involves the setup for the calibration and equalization. I used the REW software to perform both of these functions. In order to calibrate the sound card internal to my PC, I had to somehow loopback the sound output back into my PC. I did this by feeding the calibration signal through the nanoAVR into my Denon receiver and then used one of my front channel RCA outputs to feed back into the computer's microphone input. I just needed a RCA to 3.5mm cable to do this. In this way I was able to calibrate out both the PC sound card and any possible effects of my receiver.
There is another important tip to note before doing the calibration. Make sure you turn off any equalization in your receiver such as Audyssey. It is easy to forget. If you don't, it will throw off you calibration.
After calibration, you are ready for the equalization process. Here is the big tip to make this work. The REW output is on a single channel, typically either front right or left. It is very difficult to equalize the center and surround channels without a input sweep signal. Thus you must use the routing matrix to make this work. I used the front left input and simply routed this same signal for all channels. (basically just enable all the channels on the horizontal bar for front right output). It's easy enough... it just took me awhile to figure it out. Hopefully this will save you some time. Again, before you equalize your channels, make sure you turn OFF any EQ functions in your receiver. I then proceeded to equalize one channel at a time by muting all other channels except the one I was calibrating. If you use REW, you can do this using two different methods: manual EQ or use the room calibration feature. If you use the automated room calibration feature built into REW, use the "Generic" EQ when selecting the EQ type. This is recommended because it has 10 PEQ settings that match the 10 PEQ spots in the nanoAVR. If you select the miniDSP EQ, it will only give you 6 PEQ settings which is standard for many of the other miniDSP products. I chose to do it the hard way and used the manual EQ method. The results EQ results show are via this method. I will say that the automated Room EQ built into the REW software does an amazing job of producing a flat response. I will likely go back and redo my EQ using this method on one of the other 3 config memory settings in the nanoAVR.

If you calibrate your subs (the LFE channel) using the nanoAVR, don't forget that you can use the sub-EQ filter instead of the "peak" filter for frequencies below 50 Hz.

One important tip I found during calibration is that you can cause the output channel level to clip by adding to much compensation for a particular frequency... especially low frequency adjustments. You will know the signal is clipping as the sweep will have a distorted rattling type sound at the frequencies that are clipping. If this happened, I just lowered the channel gain a bit until the clipping was gone.

I have one final tip for you that may save you some time and unneeded distress. I am feeding my nanoAVR with an Oppo Blueray player. Once the channel content passes through the nanoAVR, the particular sound encoding (Dolby or DTS) will not be recognizable by the time it gets to your receiver. Your receiver will always display something like "Multi Chan 7.1" instead of the typical Dolby or DTS encoding type. This means you MUST set your DVD or Blueray player to "LPCM" output. If your output is set on "bitstream", there will be some content that your receiver will not know what to do with. Set it to LPCM and you will have in issues.
Enough of the tips and onto the results.... I have provided you with 3 different sets of data to compare for all channels: (1) The sweep results with no equalization. Just the straight room response. (2) The sweep results using the built in Audyssee Multi EQ. I used 5 listening tests all close the main listening position to eliminate the room averaging, and (3) the sweep results using just the nanoAVR equalization.









As you can see, the Audyssee did a pretty decent job, especially since they usually give you a cheap microphone to use. However, the nanoAVR provide a much superior tool to equalize your home theater. I'm sure I can get the response to be even flatter if I use the built-in room EQ feature in REW.
My conclusion (after I got past the initial learning curve) is that the nanoAVR is an amazing box for the amount of power and features you get for the price. I don't think there is another product like on the market today. Hats off to mini-DSP for coming up with such a great idea. If you want total control over all 7.1 channels ( especially the surround channels) while keeping your audio clean, then this box is for you.

Hi Ken, nice report

On the REW routing to center and surrounds, just wondering if you looked into the ASIO4ALL method to route REW output to individual HDMI channel - www.minidsp.com/applications/acoustic-me...ik-1-hdmi-on-windows

I had not realized this functionality existed. Thanks for the tip and the link.

In using your NanoAVR what are the details of your cut and boosts for the center channel ie frequency, Q and amount of cut/boost?

Since I have written this article, I have built a custom center channel speaker and have redone the EQ. I could provide you with the frequency, gain, and Q settings for the new center channel, but they would not be usable for you. The settings only apply to a particular set of speakers, their placement in the room, the room acoustics, and where the EQ mic is placed. Thus your settings would be completely different from mine.

I still use the automated EQ function in REW to get the best EQ settings quickly. I would recommend it if you don't want to spend the time to manually set the EQ parameters.