Axiom Home Page
Since I've upgraded from my old speakers that had a built in parametric equalizer for bass management to the EP500s, I have extended my bass range down into the low 20Hz range. The problem I'm facing now is my room itself. My room has a natural resonance at 63Hz, and I had adjusted my old speakers to attenuate that frequency -6db. The EP500 of course does not have that capability, and my measurements are showing that same enforcement.

I have read some reviews of the Velodyne SMS-1 parametric equalizer as well as the Behringer FBQ2496, and they both seem like they would do the job. The SMS-1 is quite expensive ($599), but the FBQ2496 seems more reasonable at $149 (it of course lacks the ability to show the measurements real time on your screen, which I would really like).

Does anyone here have any experience with these items?
I have the SMS-1 along with the EP-500; they work quite well together. SMS-1 will help you find the best placement for your subs. Once, you have the optimum location(s), you can either do auto-EQ or manual EQ and see the FR in your room. Auto-EQ is not that great as SMS-1 will make adjustments in large steps. if you have the patience for manual tweaking, then this is the way to go, and results could be quite rewarding. Also, once you are done with the SMS-1, it just does its job and you don't have to worry about it. I think $599 is well justified for its capabilities. The mic is a rebadged Behringer ECM8000 that is of very high quality. Of course, sub placement and bass traps should ideally come before something like the SMS-1. I bought the SMS-1 after getting positive feedback from dllewel and jakeman. I think few others, like sirquack,Tharkun, and craigsub also had experience with the SMS-1 and can provide valuable feedback to your inquiry. Good luck.

John
I have no doubt that the SMS-1 is the premier solution.

I bought the BFD and used the Room Equalization Wizard (REW) software available (free) through hometheatershack.com. I also ended up getting an external Creative sound card. I use my Radio Shack SPL meter as the mic.

The setup does some pretty cool stuff, including allowing you to tame nasty peaks and make uber groovy graphs. I also invested in the M-Audio MIDI interface that allows me to download the settings directly from REW to the BFD. I think you can get a new BFD on fleabay for closer to $100.

So - by the time I bought the BFD, the sound card and the MIDI thing, I was probably out $200-250. But the geek factor is huge.

The Home Theater Shack has good resources on the BFD/REW setup.
I have tried both. If budget is a factor then the Behringer FBQ2496 or BFD with REW software is the way to go. It will take a bit longer to organize yourself and learn the software but once you do you will have a program with display capabilities and higher resolution than the 1/3rd octave of SMS.

On the other hand, the SMS is easier to setup and use and its constant sweeps and real time display makes it easier to set up manual filters. The one thing I appreciated in the SMS was the flexibiltiy to move filters to whatever frequency needed adjustment whereas with the Behringers you are restricted to filters fixed at 20, 25, 32, 40, 50, 62, 80 100hz etc.
I downloaded REW yesterday (right after I posted), and took some measurements with my Radio Shack SPL meter attached to the PC. I also downloaded the .cal file for the meter.

My initial measurements were pretty bad. It seems I peak at about 70Hz (88db), and the low point is about 35Hz (72db), for a 16 db difference. I do have bass traps set up in the back corners.

After this initial reading, I tried different curve settings on the subs, but the thing that seemed to help the most was different crossover settings on the subs. I set one crossover at 80 Hz, the other at 40 Hz. The one at 80 Hz has the level set at about 7pm, while the one at 40 Hz is set at about 9pm. When set this way, the difference between the high and low point is only about 9 db. Not great, but still much better.

Does anyone else here set their subs at different crossover points?

After playing around with REW, and looking at the prices of the SMS-1 and the FBQ2496, I think I like the features that the REW software and the FBQ2496 can provide (more control), and I definitely like the price! I already have the Radio Shack SPL meter, so it would only be around $100-$120 for the missing piece.
Are you talking about the crossover settings on the receiver? Normally, you want to use bypass or max out the sub crossover settings on the subs to let the receiver handle the bass management.

Now, phase will help a lot as well, which is a nice thing with the SMS-1 as you can adjust phase in increments, not just "0" or "180" on the subs. You can also control polarity.
I mean different settings on the subs. I have the receiver set at 80 Hz, one sub at 80Hz, and the other at 40Hz. This way, I don't have 2 subs outputting between 40 and 80 Hz, only 1. This helped me reduce the peak at 70hz, and also allowed me to increase the low end by increasing the level on the sub set at 40Hz crossover.
I tried individual crossovers on multiple subs a couple of years ago. It can work depending on your room acoustics and phase settings. The only question concerns the cascading crossovers. Some say you can get away with it on the EP subs because of the brick wall filters. The 40hz crossover on one sub is far enough away from the receiver crossover, that its OK. Have you tried setting the other sub to bypass instead of 80hz and is there any difference?
© Axiom Message Boards