Seaton Sound SubMersive1 - Page 260

Well, you could probably just do what you're suggesting and it will "work", but it's not likely to be the most "optimal" setup for your room.

Mark is only about 90 miles from you. Can you get him to come help you with setup. I know he used to do this for a modest fee. Maybe he still does if it fits his schedule. If you can get him, I'm positive he could tweak a lot more performance out of the subs.

Craig

You will get more spl with them in the front corners.

lol!!!!!!! get your mind out of the gutter.

Not sure i'm going to try it in the rear... lol. Sicko's


I was more asking about setup procedures, then location of the subs.

I just want to make sure my steps seem like the correct ones to take and if there was anything else missing left to do?

Steps again:

*Leaving the SubMersive amp gain at default on both... Use Program 2 designed for larger rooms and lower htz +/-3db... And just run Audyssey MultEQ XT32...*

Anything else I'm missing or should do first?


I know to check Audyssey after and make sure it's not -15db on the sub, I will play with the volume controls on the HP after temp calibration and try to get the receiver to 0db after calibration..*






Out of curiosity Craig John... what leads you to beleive the front corners would not be the best location?

It very well might not be. Have you seen a setup similar or heard one like this and was it drastically different?




***Now jumping into positioning a little... Would the HP's work just as good at the same 45 degree angle like in the pics or should I just face them straight out?

As you guys/gals can see I have lots of room behind my screen to move the subs around...

I got one vote for the corners from bsoko2.






Is placing the sub in the main seat and walking around your room for most output still a good way of checking? I haven't done it as I would need a super long cable for the sub...
Edited by SOWK - 2/9/13 at 11:53pm

Lol. Ok gotcha now. I don't use audissey, but I believe a few people posted in this thread that they ran audyssey with the subM in program 1 and then switched to program 2 after the sub was calibrated with audyssey. I could be wrong. You can go back a few pages or wait a few hours and I'm sure a few more people will provide more details. And I believe you mean crawling around the room, yes that's still done.

Yup, the sub crawl is done by placing the sub so the drivers are about where your head would be in the MLP, then crawling around the room with your head at the driver height (if the sub was on the floor) to hear the optimal locations.

And yes, running Audyssey with the sub in Prgm 1 then switching to Prgm 2 after is a 'house curve' tweak that creates a slight boost in the under 40Hz region only.


Max

^^^^Much easier (and I believe far more accurate for most) to do with a mic and some software that measures frequency response. Given the SUBSTANTIAL investment you have already in your room (even before the dual HPs) a $100 USB mic and REW (plus a laptop or PC nearby) would go a long way towards optimizing your sound quality.  Check out the USB mic and HDMI setup thread here on AVS for using REW as there's a wealth of knowledge about calculating your room modes to better understand how placement is affecting your sound quality and plenty of great people willing to help. It might sound intimidating at first, but I just started measuring a few months ago with Omnimic and switched to REW so I could get some more advanced help with the placement of room treatments.

REW is not always that easy to set up, even with the USB mic. It is far from plug-n-play. While some have had success getting it to work fairly quickly, that has not bee the case for MANY --- GREAT program by the way. For under $300 (still a small investment compared to the total room cost) their is XTZ and OmniMic -- which are both plug-n-play (I have owned both).

That said any of those 3, knowing what I now now, should be considered mandatory for a room a spectacular as yours.

And I would also be surprised if the front of the room was the best spot for both of your subs. That is where mine started out and it was far from ideal. I now have one near the front and one near the rear. I agree with Craig --- see if you can get Mark to come by. Whatever he charges is worth the effort and expense.

 

I am gasping in amazement and admiration of your HT. I make no apology for reposting the pictures as they will surely be inspirational to everyone. WRT to the sub placement, I have nothing to add to what has already been posted - all I can say is that the Submersives really reward the effort involved in optimising their performance in-room. Good luck with it all - the results are going to be breathtaking.

You are correct. Many of us run Audyssey with Pgm1 engaged and then, after Audyssey, switch the SubMs to Pgm2. Extra oomph where you want it ensues.

I'm not sure what you mean by "leaving the Submersive amp gain to default on both." There is no "default" setting on the Submersive HP amp. There is a continuum of detented positions from -36 to 0.

Depending on which version of Audyssey XT32 you have, the first step is always to set the subwoofer gains. Audyssey plays a noise signal and the user sets the gains so they measure 75 dB at the LP. If you do that, you'll definitely end up with a trim setting that is within the subwoofer trim range, (i.e., not -15), which is the only really important thing to achieve. If your version of Audyssey XT32 has Sub EQ2, you'll set the gain on each sub so they read 75 dB at the LP. If your version of XT32 does not have Sub EQ2, you'll want to Y the subs off the one subwoofer output and set both sub gains so they are the SAME, then set the combined response so it measures 75 dB at the LP. What receiver or pre/pro are you using?

If you change the sub amps' gain settings after you run Audyssey, you should re-run Audyssey. You are much better off getting the gain settings right before you run Audyssey than try to adjust them afterwards.

Todd Welti of Harman published a paper that evaluates optimal placements of subwoofers: http://www.harman.com/EN-US/OurCompany/Innovation/Documents/White%20Papers/multsubs.pdf He found that opposing midwall placements were optimal, (front and rear midwalls, or left and right midwalls.) Of course, his conclusions are based on the room being sealed, symmetrical and rectangular. I can't tell from your pictures if your room fits those criteria. If it does, midwalls is where I would start.

There is another "philosophy" for subwoofer placement, one that I currently use; that is asymmetric placement after Earl Geddes: http://mehlau.net/audio/multisub_geddes/ Basically, he recommends placements that are statistically likely to provide different, and off-setting responses, where peaks from one sub are off-set by dips from the other sub(s), where the final frequency response is a cumulative of all the responses, and is flatter than any one response. I posted my technique for using this philosophy here: http://www.avsforum.com/t/759877/seaton-sound-submersive1/4500#post_19446901 and in the following posts.

Bottom line, I think it is unlikely that your current symmetrical sub placements are the most optimal placements for your room. They'll work, and XT32 will make them better. However, the more you can do to give XT32 a better starting point, the better the final result will be. You'll need measurement capability to really optimize your system. Without that, you're just guessing. (In the video arena, I know you're aware of the value of measurements and calibration; it's no different in the audio arena.)
The way you "face" the subs wil have virtually no impact on their room transfer function.
Bill's comment was based on maximizing output, and in that respect, he is correct. If you need output, corner loading will provide it. Corner loading will maximally excite all room modes. Depending on the distribution of room modes in your room, it may provide provide good FR; but more likely it will provide significant peaks and nulls. With your corner bass traps it will be somewhat difficult to get the subs fully into the corners anyway.

The only way to know the best placements for your subs in your room is to measure the response of different placements, both individually and combined. No one on this forum can predict with any accuracy what the best placements will be, and anyone who tries is just guessing. If you are going to spend close to $5K on subs, it would behoove you to spend another 5% on measurement gear. There are a few P 'n P systems available: http://www.acousticfrontiers.com/XTZ-Room-Analyzer-II-Standard.html or http://www.parts-express.com/pe/showdetl.cfm?partnumber=390-790 or you can get into REW: http://www.avsforum.com/t/1449924/simplified-rew-setup-and-use-usb-mic-hdmi-connection-including-measurement-techniques-and-how-to-interpret-graphs/270#post_22823228

With dual subs, using the "sub crawl" technique is infinitely more difficult. You can spend hours moving subs around and never be *certain* you've achieved the optimal result. Measuring your response will be much faster and more reliable.

Craig
Edited by craig john - 2/10/13 at 6:13am

Where is this pivot point measured? One point in space? How about 4" away from that? How about 24"?

 

I didn’t see that in my measurements when I took 'before' and 'after' measurements of the difference Pgm2 vs Pgm1 made. 

 

Can you please post your own measurements showing this 'pivot' phenomenon you describe?

 

Here is mine showing the effect of engaging Pgm2: (Edit - blue line is, obviously, Pgm 2, red line Pgm1)

 

 

I can’t find right now the graph showing the entire range up to 20KHz, but you will see from the one above that there is zero effect on the FR above about 45Hz and you can trust me that this zero effect continued all the way to 20KHz (as I would have expected).

 

I'd be interested to see your own graphs along with any explanation for the phenomenon you are describing. Thanks.

Edited by kbarnes701 - 2/10/13 at 6:50am

Pgm1:


Pgm2:


The only "pivot point" I see is the lift below 40 Hz.

Craig

Do you have to totally remove the screen to get behind it or is it on some kind of pivot?

 

Not to go too far OT here but FWIW (and audioguy your trials and tribulations from the USB mic and HDMI thread are duly noted), I think it's worth mentioning for anyone here considering new measuring equipment that the USB mic portion of the setup is relatively plug-n-play wrt to the previous setup of REW.  I think based on the evolution of the new thread, it's pretty clear that using HDMI is a subset (that may or may not make setup easier!) of the new setup and is not required to start measuring with REW.  I may be oversimplifying a bit but imho the major hassle in the past with REW was having to use an external sound card (with a calibration) and a device to provide phantom power while the USB mic (and most notably here not the use of HDMI) resolves this issue completely.  I believe getting REW running with a USB mic and RCA connections simplifies the setup for those less savvy Windows OS users (although the latest beta purports to run on Mac OS as well now).

I think something is wrong in that case. Moving from Pgm1 to Pgm 2 should not cause this effect. Absent your graphs, there seems little point in continuing the conversation though.

 

Same for me. On my superimposed graphs the plot lines merge perfectly from about 75Hz upwards, and almost perfectly from 45Hz upwards. This is what I would expect from a modification in the DSP that is designed to give a small boost only to the very bottom end.

I don't have them superimposed, but I've highlighted the specific differences:

Pgm1:



Pgm2:


Above 40 Hz, the graphs are virtually identical. Below 40 Hz, you can see the "lift."

Remember that BeeMan doesn't have Submersives. Therefore, he doesn't have Pgm1 and Pgm2 to switch between. I don't know how he is raising the LF output, but it's probably something in his AntiMode. That effect would be different than the effect provided by Pgm1/Pgm2.

Craig

 

Ah - right. That would explain it. Thanks, Craig. As he was replying to a specific post about Pgm1 and Pgm 2, and in the Submersive thread, I ASS-U-MED that he was using PGM1 and 2. 

 

In my defence, he does seem to suggest in his post to Max that the 'pivot' he is experiencing is fairly commonplace or normal - "experience has shown me that when a boost is implemented the room's acoustics pivot" and "with a boost it is not just the left end of the graph that is affected" and "there's no free lunch" and "when [not if] it happens" are all fairly definitive remarks. Although, to be fair, he does say that his "experience will not be everybody's experience". I would go a step further and suggest that it will be NOBODY's experience if using Pgm1 and Pgm2 on the SubMs. 

 

Your graphs and mine both show pretty conclusively, I feel, that using Mark's Pgm1 and Pgm2 settings do exactly what they are intended to do, without causing additional problems further up the FR.

Edited by kbarnes701 - 2/10/13 at 9:57am

Denon AVR-4311CI

I did match the initial 75db on my current subs, but when Audyssey finished it was at -10db...

I just want something that isn't near the receivers limits.

-10 is no problem. You're well within range and that is ALL that matters. If you're really concerned, set them to 72 to 73 on the initial setup. That way Audyssey will "see" their levels as lower and raise the post-Audyssey levels.

Bottom line, it doesn't matter AT ALL where you are in the range, as long as you are *within* the range.

Craig

I had to lower the gain 3 clicks from off to get 75db... Does that sound right? Seems like I am taking to much of the amp power away from the SubMersives...

After a quick dirty calibration, I'm not sure how much "better" they are then my previous subs...

I won't provide a final thought till I get the chance to fully calibrate at 6 positions and calibrate it well. I will probably try the submersives in two locations as well. Second location will be just to the right and left of the center channel in front of the sound panels.



Some pics...

Old sub vs Seaton SubMersive...




Seaton Subs new home...


Edited by SOWK - 2/10/13 at 7:47pm

Audyssey always killed my SubMersive. I'm not sure what it does to it but it basically kills it's out put. It works well with my old Polk and SvS Ultra but does something strange to the SubM. I run Audyssey with my Ultra then do a clean swap to the SubM and then WaM, the SubM comes alive. I tried finding answers but could never come up with a good fix.

If you feel the bass is lacking try running Audyssey with your old sub then switch it out for the SubM.....just a thought.

I have a pair of SubM's and using XT32/SubEQ(Denon 4311) my bass output was low after calibration. I tried adjusting both of them via channel levels but that adjustment would reset sometimes between AVR power cycling from standby to on. So what I did was to raise the SubM "volume" knob by 1 click on each sub and all my bass was back where I wanted it. It may be a little hot but I like the effect.

For conversation sake each volume knob click was worth about 3db during audyessy sub calibration so it works for me since I can't get the receiver setting to stick.

As a side note you are not limiting the SubM amp by such a low setting on the "volume" knob. You just have more headroom than other in your space. My set-up only called for 2 clicks from the lowest and they now sit at 3 clicks.

Travis