Room correcting subwoofer for music?

Is it worth buying a sub with room correction such as velodyne dd or can you make a non room correcting such a mj acoustics or others sound and blend well? Thanks, Scott
You can add room correction to any sub by using products such as the AntiMode 8033, Velodyne SMS-1, SVS AS-EQ1, etc. You can also buy a sub with it built in, such as those offered by Velodyne or Paradigm (with their PerfectBass kits).

So what's recommended?
Many. What's your room, system and budget?

To answer the 2nd part of your question, yes you can integrate a subwoofer without digital PEQ. Bass management is another aspect to consider. The nice thing about the external room mode correction devices, is that you can buy one later. Pick a good sub, maybe with bass management builtin, and if necessary (or you just want) buy an RMC device later.
Depending on your budget, you might want to try the following approach:

App. $1500 buys a pair of 12" Rythmik or SVS subs. I know the Rythmiks are awfully good for music (I use 'em) and suspect that the SVS are, as well (feedback from apparently reliable sources and great test results).

$450 buys a Velodyne SMS-1 controller. Use the RTA function on the SMS-1 to optimize placement of the 2 subs. Then, A-B the DRC function to see/hear the difference in bass response between straight subs and DRC subs. If you're impressed, stick with the DRC unit. If not, it's returnable (if you buy it from, anyway). Even if you end up returning the SMS (and IME, I tend to doubt that) you'll have had the aid of the RTA in optimizing subwoofer placement.

I believe that the SVS subs, the Rythmik subs, the Velo SMS-1 and the SVS/Audyssey DRC units are all available direct with a money back policy. You get to learn with the house's money - except for return shipping.

I'd only add that you need an x-over ahead of the SVS/Audyssey unit. The NHT x-2 x-over is $300, and you should note that the SVS/Audyssey is a greater initial layout ($700 or $800 IIRC).

I'd add that you might want an external x-over with the Velo unit, too (the internal low pass on the SMS-1 isn't my cup of tea), so you might budget accordingly.

Bottom line: $1500 buys a pair of excellent subs. Using 2 allows for optimizing placement to smooth bass response. An SMS-1 (on money back terms) at $450, will allow you to:

A) Optimize placement of the subs for non-DRC use and
B) Compare optimized non-DRC subs with optmized DRC subs

with no additional dollars at risk (besides shipping).

You might end up spending another $300 - $700, if you want an external x-over or the SVS/Audyssey unit with an external crossover.

You're in the $2k to $2.7K range, so it's definitely not spare change, but IMHO you're talking about pretty extraodinary bass performance options here.

Good Luck

One quick correction:

I said that the low pass function on the SMS-1 isn't my cup of tea. The low pass (or highcut) for the woofer is actually great. It's the low cut for the mains that doesn't sound great to me (it's also kinda bare-bones with no adjustability).

My budget is no more than 700 so I am going to just buy larger floor stNding speakers, thanks
Forget all that nonsense..REL or JL audio
Velodyne DD series subs are better than REL.

In retrospect, I guess Toetapfactor is right.

You asked about the difference between room corrected vs non-room corrected subs for a music and (after mentioning budget issues as a "heads up"), I foolishly outlined a way to directly compare the 2 approaches in your home with a choice of components all offered on a money back basis. What was I thinking?

Just forget all that "nonsense"...and go with REL or JL.

Just for the record, all the JLs feature their proprietary "ARO" DRC system. To my knowledge, REL doesn't offer any DRC type subwoofers. So, suggesting that you pick one or the other without further explanation doesn't really address your question about the differences between the approaches. Unless, of course, the implication is that they sound the same...which is very, very bad advice, indeed.

Good luck with the floorstanders.

Marty, I appreciate you taking the time to give me your suggestion, I am just not that familiar with smaller speakers and subwoofer or subwoofers. Like everyone else here I am just trying to acheive a great sounding stereo. So in your opinion subs is better than sub? thanks,Scott


Unless you use DRC, in which case the answer is "maybe".

One sub, properly placed will usually produce much smoother bass response than a full range speaker in free space. There may be other issues with this approach(integration, for one) that, for some people, impose too steep a price to pay for this benefit.

Two (or more) properly placed subs will virtually always produce much smoother bass response than a single sub. The integration issues with your main speakers may well still exist.

OTOH, properly implemented DRC will address both FR and integration. It very effectively smooths the response of a single sub at your listening position, so a single sub w/DRC may be enough to address the FR smoothing issues. And....

My Velo SMS-1 sub controller includes RTA which displays the on-axis FR at the listening position on a video monitor. This has 2 benefits. It makes placing sub(s) much easier. That is, you can use the SMS-1 just as a set-up aid to determine optimum position for your sub(s) by looking at the FR readout. Trust me, this is easier and faster that testing trial and error by ear. If you must, you can even use the RTA to "put you in the ballpark" and then further tweak by ear.

And, the bonus...

The flexible low pass x-over in the SMS-1, coupled with the RTA readout and Parametric EQ allows for a lot of flexibility in fine tuning the "hand-off" at the x-over frequency. (IMHO) This can allow for a seamless, inaudible (again, IMHO) x-over from subs to mains. It's quite a bit of work, but (yet again, IMHO) definitely worth it.

The more expensive SVS/Audyssey unit is automatic (easier), but I'm not sure that you can use it as a placement aid and then remove it. To do that, you need a visual display of the uncorrected FR and I'm not sure that this unit has that capability. Perhaps someone else out there knows for sure.

I use both 2 subs and the SMS-1 and get great results. This approach is not necessarily for everybody, but EVERYBODY (hearing impaired excepted, I suppose) will instantly hear the difference between an uncorrected sub and a DRC sub in almost any room (anechoic chamber excepted). I wouldn't live without it. YMMV.

Marty, is fr frequency range? I was talking back and forth with Bob, he has been a great help. He told me that a properly placed sub will almost always be better than floor standing speakers because of the flexibility to be able to move your bass around to the proper spot. makes sense to me. It also amazes me how much room acoustics effect overall sound. thanks again,Scott
Ok another question ,really since bass is the foundation of all music, how much of your speaker budget should be put towards that? I have been looking at this being a add on to make the main speakers sound better but maybe it should be the other way around?

1) FR = frequency response.

2) Can't answer the budget question (it's personal taste), but I will say that a 12" Rythmik or SVS sub with SMS-1 will run $1200, and I think that's money well spent. Some, like Bob, might point out that the full range Audyssey found on many pre-pros and HTRs is a better value. I wouldn't argue, but I chose a different route.

3) Continue to take advice from Bob, he is among the most informed contributers here. My current system was largely constructed around his input.

Scott, listen to Marty -- he always provides great reasoned advice. He has real world experience with multiple subs and room mode correction products.


There's a statement by Dr. Floyd Toole in one of his papers that can be paraphrased like this: Below 350Hz we hear the room, above we hear the speakers. The room is so important and until recently electronic technology was not readily available to address it.

If you've never visited Robert E. Greene's web site: I highly recommend it.
Check out the KRK Ergo. This unit incorporates the Lyngdorf "room perfect" correction system all the way up to 500hz.

It uses the same DAC chip as the Logitec Transporter and is even better implemented. It accepts a coax input or firewire. It also has a top notch ADC built into it with a single analog input. It can support 2 pairs of speakers or a pair of speakers and a sub utilizing its own internal active crossover. It does 24/96 conversion both ways.

All of this for $499 at your nearest guitar center-which includes a very high quality calibration mic too. It is an absolute hidden gem (in the audiophile world) and one of the best deals out there. It sounds exceptionally good with room correction bypassed and with it enabled it is down right awesome in my room. We are not talking small differences here- major, major, major.

When you take all the audiophile faceplates and jewelry out of the package it is amazing what $500 can get you.

Thanks for the link to Greene's web site.

I've found the Velodyne SMS-1 to be very effective with my HGS-15. I cross at 80 Hz to KEF Reference 104/2s; the result is sufficiently seamless experienced listeners cannot identify the sub as a separate sound source. I also highly recommend setting subs on an Auralex SubDude for isolation.
Has anyone tried an ERGO? I've looked at it for almost a year (I use KRK VXT6 in my office system), but never pulled the trigger.

JBL has recently released a competing product based on their room mode correction system: MSC1. I use JBL LSR4300 speakers in my main system, so I will probably try the MSC1 in my office system.
Dbphd, you're welcome. REG publishes addendums to his Absolute Sound reviews that include measurements -- always interesting to me. He was the first author I read that was promoting digital room correction.

There seems to be plenty of happy SMS-1 customers. Since my speakers do RMC, I sold my SMS-1 to a buddy and he loves it with his Martin Logans.
Bob- the MCS1 looks very similiar to the Ergo but I am not familiar with their room correction software. The thing about the Ergo and it's Lyngdorf system is that TacT and a few other well known "audiophile" brands have adopted it already and there is a lot to be read.

The only thing I could see being an issue with the Ergo is the fact that firewire is required for setup. You don't need it after you calibrate but there is no way around it initially. I use a MAC mini and prefer firewire as the dac interface so this isn't a problem for me but firewire does seem to be getting a little less commmon these days.

Robr45, agree about Lyngdorf being a known item -- it's what attracted me to the Ergo originally. Also, agree regarding firewire losing favor to USB.
Based on a conversation some time ago with the tech guys at Lyngdorf, the TacT and Lyngdorf systems differ significantly from each other:

TacT is a more traditional DRC that measures output with a mic and EQs the input to produce a corrected flat (or a "target" curve) result. Speaker FR deviations and room FR deviations are both EQ'd.

Lyngdorf is designed to look for room induced anaomalies only. I never got a specific explanation of how the algorythms make the determination, but Lyndorf is supposed to correct to the speaker's "native response" rather than flat or targeted.

Since Tact sells direct and Lygdorf has only a handful of dealers, it's hard to hear either, much less compare the two. But it would be great to get some feedback on these two DRC systems.

There are three reasons why rooms have so much more impact on the sound in the bass region than elsewhere in the room. The first is acoustic, and the second two are psychoacoustic.

Normal home listening room dimensions tend to be "small" relative to the wavelengths in the bass region, and so room interaction results in large peaks and dips, which are usually spaced fairly far apart.

The ear-brain system tends to average out the sound energy across ballpark one-third octave wide bands, such that narrow-band peaks and dips get psychoacoustically smoothed. But if the peaks and dips are large and far apart - as they typically are in the bass region - the ear's averaging mechanism doesn't help much.

Finally, the ear is literaly slow to register bass energy. It takes at least one full cycle for the ear/brain system to even register the presence of bass energy, and much more than that to discern pitch. So by the time the ear is detecting a bass note, the room's effect is in full swing. In other words, the ear cannot separate the room from the woofer in the bass region; they are a system.

Equalization/room correction systems can greatly improve the bass at a single location and the better systems use multiple microphone positions and can make an improvement over a reasonable area. But they are limited in their ability to effect an improvememt throughout the room because the room-interaction peak and dip pattern changes so drastically from one location to another within the room. Using EQ to tame a peak or fill a dip in one location will likely result in deepening a dip or heighteing a peak in another location.

There is an acoustic technique for smoothing the room-induce peak-and-dip pattern throughout the room. It calls for using multiple distributed bass sources; in other words, multiple subs (and they can be smaller since there are several of them). Each will produce a unique peak-and-dip pattern at any given listening location within the room, and the sum of these dissimilar peak-and-dip patterns will be significantly smoother than any one of them would have been. Any significant remaining trends in the bass region are more likely to be global (throughout the room) and thus more practical to address with equalization.

Multiple subs (even small ones) may not be practical in many situations, but in my opinion it's the front-runner if sound quality is the top priority. This opinion is shared by Todd Welti, Floyd Toole, and Earl Geddes (though there is some differene of opinion on the details).