SMS-1 Questions

I just purchased 2 Rythmik F12 subs to integrate into my MO system. My speakers are full range. If I purchase an SMS-1 for DRC, what would be the most effective way to use it. Do I need a TV in the room for it to be effective, or will it display to a laptop?
You need something that will display composite or s-video video. That is usually a TV.

What is DRC?

I've always assumed DRC stands for Digital Room Correction.

it's been some time since I set up my SMS-1, but I think you can just let it run if you don't care to see what it's doing. Although I may have the display turned off, IIRC it does have a display that shows what state it's in. Still, it's fun to watch the changes in correction as it makes its passes, so hook it up to a monitor or TV.


Do you run your mains through it as well or just the subs?
Digital Room Correction. OK. I do not think it is a common abbreviation.

As for letting it do its thing without a display, that is a real problem since the autoEQ function is woefully inferior to the manual EQ with the SMS-1. IIRC, the autoEQ will not change the default F or Q of the filters, only the amplitude, making it no more effective than a graphic EQ.

Kal is dead right.
Manual operation is a MUST with the SMS-1.
It will take some time to get the hang of it (this is work), but after a while it's fairly painless. The payoff is absolutely worth the effort.

BTW, I use a Sony wireless TV - S video connection - which means that only a microphone cable must be strung across the room and pluged/unplugged for calibration. I do kill the TV transmitter when I'm done calibrating.

It's kind of embarassing, but I do get a bit of a kick from the measuring/calibrating process. The inner geek can be a hard thing to control.


I should add one thing: You have to want to do this.

There are a bunch of parameters that can (and - for optimal results - must) be varied for the sub's high cut function, while the trial/error process with parametric EQ is (almost) infinitely variable and extremely time consuming. There are LOTS of combinations to try and many, many test runs will be checked and rejected before you find a satisfying mix. Then you can start tweaking.

Being the somewhat compulsive type, I actually developed a taste for the process. (I'm pretty sure that there is treatment available for this.) If this doesn't sound appealling, I'd say that the SMS isn't for you.

If you follow through, it is rewarding. OTOH, the SVS/Audyssey box (more sophisticated auto calibration) probably gets you to substantially the same place with a LOT less work (although it costs a fair bit more). Different courses...

Good Luck

Thanks Marty,

Does the Audyssey provide stereo bass or would I need 2 as well (like the SMS-1)
In looking at the options it appears that the biggest drawback to the SMS-1 is that it does not truly process stereo subs. It nulls them to one signal. Thus for true stereo bass you would need 2 units. The SVS AS-EQ1 does allow for stereo, but also has a 7.5 ms electrical latency which requires either placing your subs 8.4 feet closer to the listening position than the mains, or purchasing a digital cross-over to compensate for the delay. There does not seem to be a single solution for DREQ of the subs. Is any one aware of any others? I have truly full range speakers with their own powered Low frequency Modules.
The need for stereo subs is greatly overrated considering the wavelengths involved.


I'm sure you and Marty are correct, but when I installed mine I just let it do what it did automatically. My plan was to get back and tweak it, but I have yet to do so, and my Velodyne HGS-15 sounds pretty good and seems to blend seamlessly with my KEF 104/2s with the 80 Hz crossover.

There are many routes to satisfaction and some appeal to different people differently. Still, in this day and age of sophisticated bass management and roomEQ/subEQ, some traditional configurations might be reconsidered. In fact, one can probably get better, more integrated, more even and more convincing bass from 2 mono-signal subs, placed carefully and balanced/EQ-ed properly, than from stereo subs whose placement is constrained by the placement of the main L/R speakers.

There are a few relevant "white papers" from Harman on this.


So it sounds like you are saying the SMS-1 with a mono signal to both might be the way to go rather than getting the Auddysey and having to add some sort of cross-over to compensate for the latend delay?
If I were to use the SMS-1 and wanted to let my mains run full, what would be the best way to hook-up the SMS-1?
Use a pair of Y cables from the preamp to split off the L/R signals for the SMS-1. (I cannot remember if one can use the SMS-1 to do this but that might be possible.) There is a small delay introduced by the SMS-1 but that is folded in with the rest of the adjustment you will do to integrate the subs with the main speakers. However, you should also use the SMS-1 display to assist you in placing the subs as optimally as possible before invoking the EQ.

Frankly, I would prefer real bass management with delay/level/crossover including a HP filter for the main speakers but that does not seem to be where you are going.

If you were going to go the way you suggest (full bass management) how would you proceed with true full range speakers?
Full range is, already, contentious since there are different definitions for it. In addition, without measurements, there's no assurance that they will perform as "full range" in any particular setup.

With the B&W 802Ds in my city system, I use them as full-range, no sub, for casual stereo listening. Sometimes, I invoke bass management (40 or 80Hz) but I always do it for multichannel.

With Paradigm Studio/60s in the country system, I always bass manage at around 40-50Hz (varies per speaker).

All that said, I am unfamiliar with almost all the equipment you have in your main system.

The only point I'd add to the discussion is that the concern with latency may be more theoretical that real with regard to subs. I have done a physical A/B test on this one. With a pair of Verity P/E's I bi-amped and EQ'd (woofers only) via the SMS with the monitor in its usual position on top of the woofer box (time aligned), then moved the woofer cabs to the corners, put the monitors on stands, and compared.

I really did this to see whether I could improve some behavior in the woofer boxes by moving them to the corners, so the latency issue wasn't my primary focus. However, I did a fair bit of focused listening and can say that no imging/smearing artifacts were audible to me until I adjusted the x-over point way up to 150hz (Verity's choice for the on-board passive).

I don't compensate for delay and don't hear a need to.

Of course, you might.


If one did not consider latency to be an issue, why would one need to introduce a cross-over in front of the Audessey unit?

Eric, you need an x-over in front of the SVS/Audyssey box because it doesn't include a x-over function. I'm pretty sure it was designed with the (non-Audyssey equipped) HT market in mind, so - since pre-pros and HTRs have the x-over built in - it was omitted.

As far as the SMS-1, I just don't like the sound or the limited flexibility, (fixed frequency, fixed slope) of the built-in high cut function.