Originally Posted by craig john
I have a Yamaha RX-V4600 and here is the progression I use to incorporate both the SMS-1 and the YPAO:
First, I ignore self-EQ and Auto-EQ; I go straight to "Manual". I start with the SMS-1 at the factory default settings and in the "setup" mode. I then go back to the receiver and set the bass management, (all speakers "small" and LFE/subwoofer output to subwoofer.) Remember that the SMS-1 can only EQ the sub, so sending LF bass to all speakers will make the EQ much less effective. There are several other advantages to this setup, even if you have nearly full-range speakers. The key is the crossover point. My mains extend into the mid-40's, so I use an 80 Hz crossover. If your mains extend lower than that, use a lower crossover. Just remember that any bass produced by speakers other than the sub can't be EQ'd with the SMS-1. Also, the SMS-1 has a fixed 80 Hz high pass crossover, so it's output drops dramatically above this.
The next thing I do is set up the subwoofer. I set the volume control to approximately 10:00 (or whatever is reasonable on your sub). I turn the sub's internal crossover all the way up to it's highest point. If it can be disengaged, I do that. I'm using bass management in the receiver and it set's the crossover point. Using another one in the sub is not only redundant, it can be detrimental. I set the phase control to "zero" or "+".
The next thing I do is run the the YPAO, but I disengage the EQ's. I just have it set speaker levels and distance. If it selects the wrong crossover or speaker size setting, (which it always does), I change it. Now I'm ready to start EQ'ing because I'm using the correct size, level and distance settings that I will eventually be using when I'm finished. If you do the entire EQ first and then change something later by running the YPAO, you will affect the EQ.
BTW, the receiver should be in stereo mode at this point. The SMS-1 outputs a stereo signal and the receiver's bass management re-directs the the bass to the subwoofer output. Putting the system in a multichannel mode won't help, at least not at this point.
Before I start EQ-ing, I disconnect the mains. With the speakers disconnected, I'm only looking at the response of the subwoofer without any influence of the speakers. I also reset some of the factory defaults on Page 2. I defeat the low-pass crossover, (once again because I'm using the receiver's crossover and redundant crossovers can be detrimental.) I also reset the subsonic filter to it's lowest point (5 Hz with the new software) and the slope to 6 dB/octave. (When I'm finished I will reset these to 10 Hz and 24 dB/octave for safety purposes, but for EQ-ing, the levels are not high enough to be of concern.)
Now, after I've done all this, it's finally time to EQ the sub. This is the fun part! I use the manual mode and the "Setup" preset, as this will set the default EQ for all other presets. I look for the biggest peaks in my response. I ignore nulls as EQ can't do much to fix them anyway. (I used to use a lot of boost to augment the VLF response, but I've gotten away from that.) I move my sliders to points underneath the peaks and bring them down. I can also change the "Q" to widen or narrow the effect of each slider. As I reduce the peaks, I will also increase the overall volume to maintain the same average or total volume.
Once I've gotten the sub EQ'd to my liking, I reconnect the mains and evaluate the response. What usually happens is that the response changes most at and around the crossover. These response changes are caused by multiple speakers reproducing the same frequencies. At some frequencies they are out of phase with each other (causing cancelations). At other frequencies they are in phase with each other, (causing augmentation). Therefore, if the response with the stereo speakers engaged is not what I want, I will first try to improve it with the phase control on Page 2. I try not to change the EQ of the sub because I know it is correct by itself.
(You can also use the speaker distance control in the receiver to adjust phase. This control is actually a delay in the signal sent to the speakers which are "closer" than the furthest away speaker to bring them into time alignment. You can do this, but it's more complicated and I prefer to use the SMS-1 phase control and leave the speaker distances at the YPAO settings.)
Then I put the receiver in one of the multichannel modes, (PLIIx, etc.). This engages the rest of the speakers and shows how they interact with the sub. I usually don't change anything here, I'm just looking to ensure it doesn't induce any significant problems.
When I've finished with the SMS-1, I go back and re-check the levels of the speakers and sub manually with the receiver, (or with Avia and an SPL meter.) If the sub level is off, I don't reset it in the receiver, I use the volume control on the SMS-1. I never re-engage the YPAO's EQ's. I don't like what any of them do to the imaging so I don't use them.
Although my technique is a little different than what Velodyne recommends, I have used it with success. I have a reason for every choice I make and the end result works. I arrived at it through a lot of experimentation. I'm sure you will want to experiment with yours also. You'll find that all these controls in the receiver, the SMS-1 and the subwoofer interact and you'll want to set things appropriately for your system before you begin the EQ process.
Edit. I forgot one very important step. Before you begin EQ-ing, you need to move your sub into all the possible locations in your room to find the best baseline response. Most rooms only have a few possible locations from an aesthetics POV. Try the sub in each location, and even in a few variations within each location, i.e., move it a little left, right, front and back, turn it so the driver faces different directions, etc. This is really easy to do with the SMS-1 because the sweeps are so quick. Once you've found the best location, you can proceed with the rest of the EQ process.