Dumb question about AntiMode 8033 & Speakers with Powered Subs...

Well, I can maybe offer some advice - but keep in mind I do not own an Antimode:

From what I understand, the 8033 will only correct one sub output, correct? Your friend would have to run all 3 subs from a single output. If you ask me, trying to use the Antimode to EQ multiple mismatched subs is most likely a bad idea. If I was him, I would use the Antimode with the SVS and leave the internal subs on the DTs for Audyssey to figure out.

As far as hooking it all up, it seems pretty straightforward to me - sub out from AVR > Antimode > 3 way RCA spltter > subs

WRONG - I have used a single Anti Mode 8033 to EQ 4 subs in one room. Just "Y" split them off the Anti Mode.

Mis-matched subs though?

The confusion with Anti-Mode and the OP's setup are the "built-in" subwoofers in the mains. In my opinion, built-in subwoofers are a bad idea as you can't locate the subs to where they'll do their best. As we pretty much have all learned, know or whatever, subwoofer placement isn't a one size fits all proposition.

Again in my opinion, one has to use the built-in subwoofers for nothing more then a full range speaker system and one still needs to use the LPF to port the <80Hz (or where ever one wants to set the crossovers) over to the "real" subwoofer in the bunch. I hate to say this, although what I consider to be expensive mains and I'm not knocking these speakers, I think that even for music, these are a bad choice in main speakers. All in my opinion, building the subwoofers into the mains is a convenient idea with high WAF but low approval on technical issues regarding the integration of <80Hz reproduced sound into a room's acoustics.

Sorry.

The Definitive Technology Mythos STS speakers, mess everything up royally. I don't know if the Def Tech speakers have a separate subwoofer hookup. If they do, it simplifies things a lot. If separate subwoofer connections, then connect everything as if three separate subwoofers, run Anti-Mode and pray as the Anti-Mode microphone will pick up the sound as if one unit is reproducing the bass, based on what the microphone picks up at the main listening position/microphone location.

A final thought, do you have a room analyzing program. If not, you'll need to get one as you won't be able to get the best out of this classic "Ménage à trois."

Good luck with helping your buddy with this issue.

I have a remarkably similar system: Def Tech Mythos STS mains, CS8060-HD center, Gem XL surrounds, and Dual SVS PB13-Ultra's. I currently use Audyssey MultEQXT32 in my AVR for all the room correction, but I used to use (and still own) an Antimode 8033-C. I've played around with various bass configurations, including running the STS's as large and LFE+Main, STS as Large but not running LFE+Main (I'm blanking on what to call this, basically not double bass), STS's as small with the crossover set at (at various times), 40, 60, 80, 90, and 100 hz, running the Anti-Mode on all four subs simultaneously via y-splitters (multiple splitters, obviously), and just running the Ultra's off the Antimode with the STS's set as small.

Here are a couple of my thoughts (take them with a grain of salt as room acoustics and preferences are going to be highly individualized):

I was able to achieve the best (smoothest) bass response with all four "subs" running off of a single LFE out and split between the 4 speakers, but this had the least amount of extension. My guess was/is the extension was being effected due to phase cancellations under the STS's tuning point. In my case, per REW (sorry, I no longer have the graphs, so this is off of memory), bass started rolling off rapidly in the low 30hz range. Until that, the Antimode was able to give me a very flat frequency response and it sounded great. But I missed the extension I paid for with my subs.

I was/am able to get the best extension when running the STS's as small and having all the LFE routed to the subs, which were EQ'd by the Antimode. In my room, running the Ultra's in 15hz tuning, I am pretty flat to ~13hz up until about 105-106db, at which point compression starts kicking in on the lowest frequencies, but I am still pretty flat to 16hz up above 110-111 db, and flat to 22hz up to 115-116db. My room provides some gain, but is very leaky, about 4,300 cubic feet, and very awkwardly shaped, all of which impact my results. DB readings were/are via REW ("Room EQ Wizard", a freeware program available from Home Theater Shack) and a Ratshack meter with the appropriate calibration files loaded. When I tried running all 4 "subs" these figures were very different. I had much less extension, and was not able to get anywhere near these max numbers before I heard the STS's crying for mercy.

For me, in my room and to my tastes, the best deep bass and midbass came about when crossing over the STS's (and the 8060HD) to the Ultra's at 100hz. A lot of people are now going to state that the STS's bass sections are useless, they're wrong. I've heard the Mythos One's, and I've tried my Gem XL's as mains, and even crossed over they do not have the same sound stage, impact, or scale as the STS's. My tastes are based off of my room, and my placement, and these resulted in a best crossover point of 100hz. I suggest people try out various frequencies as 80hz is not the best setting for everyone's room and/or equipment.

Setting the bass knobs and getting the transition between the passive and active sections of the Def Tech's took me the longest amount of time during setup and tweaking. Def Tech normally advises people to set the knob at around the 12 o'clock settings and adjust from there. This may work for some, but I ended up using the RTA function of REW to tweak the knob until I got the smoothest transition. Others may not be as OCD as me about this. If looking at REW, which I highly recommend even when using auto eq's such as Audyssey and/or the Antimode, there is a new option to use a USB mic from MiniDSP called the UMIK-1, which is a calibrated mic and REW now has some neat features to support it. I have not tried the UMIK-1 yet, (need to find the time to play around), but there are threads on it here and at Home Theater Shack. It looks promising, easy, and cheaper than previous/alternate setups.

The owners threads for SVS, Def Tech Mythos, and the Antimode all have good information in them and are great resources for specific issues. Your friend may want to peruse them.

If (S)he has an AVR or pre/pro with room EQ software, run the Antimode first, then the room EQ with the Antimode on and in the system. The Antimode adds a bit of delay to the signal, which shows up as increased distance for the LFE channel, and should be compensated for via the distance setting in the bass management settings (speaker config/distance). Do not worry/and or "adjust" the distance to the sub based off of a tape measure, as this will effect phase and cause problems. Sometimes, with some room eq's, adjusting the distance can be useful for smoothing out the frequency range around the crossover (especially with Audyssey based systems), but this is best determined and adjusted using a program such as REW.

The STS's are very good speakers, but can be more challenging to set up due to the active bass sections. There is no reason though that using them and the SVS would prevent or limit the need for using sub EQ. I'd suggest to your friend the usual pieces of advice: placement and set up are going to be key to getting the best out of his system, room acoustics are a major factor, and room treatments/bass traps/EQ can go a long way towards making a room have less impact on the system.

Cheers.

I disagree. The STS's, which do have separate LFE inputs FYI, don't "mess everything up" any more than any other full range speaker. Granted, a little more care is needed during set up to get them to sound there best, but unlike some full range towers, these come with a volume knob. If placement is near a wall/corner, they are adjustable, something many passive full range speakers are not. The powered bass sections are not as powerful as separate subs, but for many non-AVSer's are probably more than sufficient for bass playback. In the end though, no "praying" is needed, just a little time and effort.

Based on your above, placement of these speakers becomes conflicted as on one hand you're describing placement as if they're separate subwoofers and OTOH, one normally places their mains with the intent of creating a convenient sitting position sound field, dissimilar to that created by subwoofers. I can move our subs anywhere the wife allows (WAF) but the mains are stuck in the middle of the room with the intent of creating a frontal sound field surrounding the up front action next to the television. I'm sure we'd both agree that it's hard to create a sound field for the television if the mains were in their very own corner.

And yes, I agree, two Def Techs with two separate subs, does make the task much easier as opposed to a single subwoofer. Currently I'm using an Anti-ModeS II, which in it's own way is severely limited in design; 16Hz - 250Hz with only thirty-six filters. Next time I get an AVR box with MultEQ XT32 and stereo sub pre-outs installed and be done with it.

My point (not argument), Def Tech speakers, with built in subwoofers make the placement of their built in subwoofers, that much more difficult to integrate into the acoustics of one's listening venue when dealing with but a single additional separate subwoofer.

You're more than welcome. One other item I forgot to mention. I used RCA's from my AVR to the LFE to help send test tones during setup, but once that was done I just went back to speaker cable only.

IMHO, a splitter is a splitter. Monoprice has pretty decent ones for a very reasonable cost. Here is a link to the ones I used, and they work fine.

I looked at the website for that integrated amp. http://www.rega.co.uk/html/Elicit.htm I don't see Bass Management capability in it. How will you derive the signal for the sub without some Bass Management capability? You don't mention which SVS sub your friend is using. Does it have speaker level connections? Do you plan to use the Bass Management in the sub? That can work, but it's generally not as flexible or robust as the Bass Management built into the DSP of the pre/pro.
The reason your system rolled off at 30 Hz is because the Mythos rolled off at 30 Hz. When you calibrate the *combined* response of all 4 subs, you end up turning down all 4 of the subs. By turning down the only subs in your system capable of <30 Hz response, you turned down the <30 Hz output... no way around it with that type of setup. I can absolutely understand why you found it wanting. As I have said MANY times on these fora, when you try to integrate dissimilar subs, the limiting factor will always be the lesser subs. Most times you will find that the best "final" result will be to eliminate or sharply curtail the output of the lesser sub(s) so they don't hold back the better subs.
BINGO!!! This is exactly right. Don't even think of the Mythos "powered woofers" as "SUBwoofers." Think of them as speakers with pretty good LF extension. Run the Mythos at speaker level. Set crossovers in the pre/pro/receiver at the frequency that best blends the Mythos with the sub AND provides the most undistorted output from the speakers. That frequency can be anywhere from 40 Hz to 100 Hz, depending on placement and room acoustics. Experimentation and measurements will provide the optimal result.

Craig

Beware that the Radio Shack sound meters have a high sound pressure noise floor level that's higher then your room's noise floor. If you can. see about getting a sound meter which has a noise floor threshold of about 30db to 35dB with +/-1.5dB accuracy. More then the above and you're going pay some major dollars. I currently have two sound meters and I'm looking to acquire a third meter in this upgrade path.

This is the least expensive sound meter I've found that meets the above standard, The low limit is limited to 30db to 00dB and high limit is 60dB to 130dB.

This was the best I could find for a manufacture spec sheet on the above recommendation.

I went ahead and ordered one so I can play with it and see if it's worth a Tinker's Damn.

I do recommend getting a calibrator and for what ever reason, in my opinion, sound meter calibrators are very expensive. This is the lease expensive calibrator that I've found and is the one I use.

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Edited by BeeMan458 - 2/3/13 at 10:46am