Folks,

In the other thread titled "Auto-EQ Question(s)" you can read about how it looked like my new SMS-1 was not working.

I spent the entire weekend agonizing over it. Reading the manual. Searching online forums. I exchanged email messages with Gonk (thanks again Gonk) and even Steve at Outlaw jumped in with a help message of his own (on a Sunday to boot!). But I just couldn't figure out how to get the most basic of SMS-1 operations to work: namely the auto-EQ.

Basically it was drawing a perfectly flat response curve fom 15-100 Hz from the get-go. No slider action. Nothing.

This morning I re-read all of my correspondence and the proverbial light bulb went off over my head. The "solution" was there all along. And you are not going to believe it!

My SMS-1 actually does work. It works exactly as described on page 8 of the owner's manual. It works with the way I set it up. The problem was....my three sub configuration works even better than it does!

This morning I remembered that when I took one sub offline I got a small change in the response from 20 Hz down. The engineer in me says that this is a good thing; it's an indication that something is happening. It got me thinking. What happens if I take two subs out of the equation and go with one?

Huge difference!

First, here's my sub location / configuration.

Back left corner: B&W ASW-1000. Call it sub 1.

Front wall: two Velodyne Servo 1200 subs - placed at "prime number" coordinates from each side wall (not in the corner). Call the one on the left sub 2 and the one on the right sub 3.

I've connected my subs direct to one of the SMS-1 LFE outputs. I've connected the mic to its input - and placed the mic at my seating position. I've connected my Model 950's LFE output to the SMS-1 LFE input - but for the purpose of the auto-EQ routine, that's not needed since the "loop" is formed only between the SMS-1, subs, and mic.

I pressed 8-9-0 on the SMS-1's remote to reset it to its default settings.

Then I ran the auto-EQ (3-2-1) with just sub 1 on. The response was pretty flat from 50-100 Hz so nothing happened with the sliders there. But it fell off (unevenly) below that. The SMS-1 applied (step by step, as each sweep happened) a max boost at 20 Hz. This left a pretty flat curve from 20 Hz down, and the remaining droop between 25-50Hz was within 2-3 dB. I guess I could have then used the SMS-1 manual mode to fix it.

Then I did 8-9-0 again (to reset the SMS-1 to default) and this time engaged only sub 3. Ugly curve this time to begin with and this time the SMS-1 used every slider available, (some max boost, some max cut - mostly a big cut with the lower sliders, big boost with the upper ones) to get a pretty flat response curve - that again was good enough for "auto" and which could have been touched up manually.

But it was back to 8-9-0 again with only sub 2 in the picture and...similar results to what happened with sub 3 (as you would expect for identical subs placed in mirror positions to one another). Lots of cut with the bottom three sliders. The mid stayed the same, and lots of boost on the upper sliders. Similar curve to sub 3's in the end. Some unevenness at all frequencies - but easily within 2-3 dB of flat.

So then I do 8-9-0 and turn all three subs on and...I get a perfectly flat line from 15Hz to 100Hz - right from the get go! Dang. The three sub configuration IS giving me perfectly flat response without the SMS-1's help! Actually there is a 1 dB dip, 2-3 Hz wide, centered at 42Hz, and the same thing at 100Hz. After that the response falls off above 100Hz - which is apparently the upper limit of the auto-EQ function.

So the SMS-1 was working as designed. It had to work very hard to equalize just one sub. And not at all to do all three.

I never ever would have thought this possible. I knew that I had worked hard to find ideal placements for the three subs and to level balance them perfectly with respect to each other. But perfectly flat response from 15-100 Hz? Never in a million.

So now I'm left with a real problem. Why keep the SMS-1 when it's working perfectly - but not doing anything? As I said, the trace is perfectly flat for all three subs. If I were just running one sub, it would be a great help. But I'm there already. I might try manual mode, with my mains and the 950 in the loop. My mains are themselves huge and flat down to 28 Hz and I've crossed them over at 40Hz. I know now that if I want to bump that up to 80 or even 100 Hz that the subs will give perfectly flat response below that.

I also have a much more modest home theatre in my family room that everyone else uses. It only has one sub. I might move the SMS-1 there to see what it can do.

Regardless, this has got to be one for the SMS-1 record books! A customer who thought his SMS-1 was not working - because it did not have to work!

Finally, I should add that I recently (ie. in the last two weeks) re-did my main HT. It's laid-out different. I've added acoustic treatments. I put a lot of thought into the sub placements. I guess it paid off.

This is also a testament to the benefit of using multiple subs to smooth out room response. So get out those chequebooks folks and start ordering that extra LFM-1 or two!

Jeff Mackwood