Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems G68 multiple subs setup w Velodyne sms-1

Hi there Halej,

IMO, MRC can be improved upon at subwoofer frequencies. MRC is effective but fairly subtle. Accurately applied parametric EQ can really step-up the performance of your subwoofer system. That being said, the SMS-1 is a great little device but its handy on-screen measurement system is its weakest point and it has other shortcomings when it comes to owners of multi-sub systems.

The SMS-1 only displays frequency response and that display has been 1/3 octave smoothed. This makes it difficult to determine which peaks n' valleys are due to your room's low frequency modal behavior (sharply defined peaks and nulls), which are due to shortcomings in your loudspeaker and subwoofer placement, and which are due to phase and delay/distance differences between all the sources of bass within your room. Affordable software-based acoustic measurement tools such as REW or the Dayton Omnimic are inexpensive and offer far more detail in their frequency vs time waterfall displays. With this additional info and some knowledge of the subject, you can set the SMS-1 much more precisely than is possible with the built-in facility. Coincidentally Meridian's MRC used the same sort of frequency vs time waterfall display to go about doing its thing.


So that brings us to another potential shortcoming of the SMS-1 as applied to your system. It doesn't offer separately adjustable delay on each of it's subwoofer outputs. If you use a single subwoofer or a pair of subs located equidistant from the listening position, then the delay setting in your pre-pro (adjusted to account for the SMS-1's latency) and the SMS-1's phase control will get the job done. However if you are using multiple subs at varying distances from the listening position, you need an EQ processor box that:

• #1)Allows you to perform multiple bands of global parametric EQ on your mono subwoofer channel.
  
  #2)Splits that EQed mono signal into sufficient channels to support each subwoofer which is located at a significantly different sub-to-listening-position distance.
  
  #3)Permits separate delay adjustment of each of those individual subwoofer outputs.

At the moment I'm unaware of any manually adjusted all-in-one consumer product we can add to our M pre-pros and that can accommodate all these requirements. The SVS and Audyssey stand alone automated sub EQ boxes offer two separately adjusted sub outs but personally, I prefer the control of doing the adjustments myself. So if you want to ideally setup your subs you need to resort to a loudspeaker controller/processor from the pro audio world. There you can find a myriad of DSP based all-in one boxes which can be configured to achieve our needs. Checkout the QSC DSP-30, DBX Driverack 260, and any of the Xilica processors. You will still need that software based measurement system like REW or the Omnimic, but with these tools, you can really do justice to your high-end setup.

Happy Trails!
MTB Vince