Seaton Sound SubMersive1 - Page 151

AWESOME!! Are you running the 2nd DSP or 1st?

Do yourself a favor and check out the blu-ray of How to Train Your Dragon.

^^^^^

You'll laugh, but, I'm not sure which program it's in! I was so excited to get it running and work the other two subs into the mix with all the cord-swapping and moving them around, I never got to that part yet! I had this "window" of time to take advantage of when everyone was out of the house, so I was trying to cram it all in...

So, I have some exciting testing yet to do!

I'll report back with the difference soon.

I love getting to do this in the name of science!

Wow, that must mean you run your Submersive super hot!

+4 - +5dB (80db vs. 75-76dB for the 5.0), but, that particular scene is pretty insane on that part. Transformers for example hits about 113db.

No one, including me, has ever felt it was "hot" however. My room is well-treated and the SubMersive has this uncanny ability to outright disappear when nothing is happening. It also starts and stops on a dime, so with no overhang and no echo/bass build-up in my room the +4 - +5dB seems just right. Believe me, my wife would be complaining if she thought it was too much!

Looking forward to more movies, etc., with the new HP. So far, so incredible....

you got that right, on both counts!!

I know exactly the part you mean. When that part hits there seems like there is very little bass but my door shakes like mad. Pretty cool. It just is just a pressure wave in the room.

Part I

I received my Seaton Sound Submersive HP amps, (3 of them), a week ago. At the same time, I also upgraded my pre/pro from an Onkyo PR-SC885 to an Integra DHC-80.2, which upgrades from Audyssey MultEQ XT to MultEQ XT32, which has 32 times the resolution of XT for the main channels. I have spent the last week playing around with configurations of the system and placements of the subs to find the optimum setup. A week later, a half dozen configurations, about 6 or 7 Audyssey MultEQ XT32 runs, and probably 100 xtz measurements, and I think I've come up with the best setup.

My current system consists of:
Atlantic Technology 8200e THX Ultra2 LCR's, (3 identical speakers with the CC placed behind the screen)
Atlantic Technology 8200e SR THX Ultra2, (L & R Surrounds, bipole and at 90 degrees to the LP)
Klipsch AW-650's Rear L & R Surrounds, (mounted horizontal at 135 degrees to the LP)
3 Seaton Sound Submersive HP's, (dual-opposed 15" drivers with 2,400 watt amps, placed asymmetrically to the LP
Integra DHC-80.2 Pre/Pro, (Audyssey MultEQ XT32)
Earthquake Cinenova Grande 5, (300 wpc x 5 into 8 ohms for LCR and L/R Surrounds)
Emotiva RPA-1, (200 wpc into 8 ohms for Rear Surrounds)
Oppo BDP-83
BenQ W10000 projector
SeymourAV 128" electric drop-down AT screen
Crowson Tech Tactile Transducer powered by Buttkicker BKA1000 amp.

My room is in the basement, carpet over concrete, about 3,800 cubic ft., with bass traps in the front corners and the ceiling. It is *not* a sealed room; it is open to a stairwell, a hallway to a bathroom, and it has a large, double sliding glass door in the back as well as 2 windows. Also, it is not rectangular; it has a pool, table/bar area in the back and a walkway on the right side. The room does not do a great job of reinforcing the bass; it does not provide a lot of room gain, and it has a lot of modes, as you will see below.

One comment about the new Submersive amps... with the previous amps, I needed to use cheater plugs to eliminate the hum from the subs. With the new amps, the cheater plugs are removed and the subs are dead silent with no signal applied. The system is wired using balanced interconnects and there is no hum whatsoever!

My previous system with the 1,000 watt Submersive amps, EQ'd with MultEQ XT was the best system I had ever experienced in my HT. I knew it was going to take some work to exceed what I had before. I think I've done it, but read on...

1 Output or 2, Gain-Match vs. Level-Match. My first consideration was how to connect 3 Submersives to the 2 subwoofer outputs of the Integra. My subs are placed asymmetrically to the LP, (non-equidistant), with one on the left side at ~ 1/5 wall, one up front between the CC and the R speakers, and one in the left, rear at ~ 2/3 wall. I had previously been advised by several members to connect 2 of the subs to one output, (preferably the 2 that were closest to being equidistant to the LP), then connect the 3rd to the other output, and then level-match them. The logic was that Audyssey could then set the Distance controls independently to better time-align the subs... well, at least the 2 subs with the one sub.

So I tried this approach. In every combination I tried, (and I tried them all), the gain setting on the lone sub ended up being set 6 to 8 dB higher than the gain settings on the 2 subs ganged together. Considering that a 6 dB difference is equivalent to 4X the amplifier power and excursion, I felt this 6 to 8 dB of gain setting difference was excessive. I didn't want one sub to be working 4X as hard as the other two. Consequently, I abandoned this approach.

Next I tried gain-matching. I moved each sub to the middle of the room, then, playing the subwoofer test tone from the pre/pro, I measured the SPL with my RS meter from 3" away from the "front" of the box, (the front being the side with no driver or amp.) I set all 3 subs to the same nearfield SPL of 85 dB. Then I moved each sub back into it's place, and mesured each one's SPL at the LP. Theoretically, his should yield different SPL's for each sub based on their in-room FR and the distance from the LP. Surprisingly, they were very similar, (70, 70 and 68 dB's.) In this configuration, all 3 subs were Y'd together off one subwoofer output. Since the Submersives have no Phase Control, and there is only one Distance Setting in this configuration, I have no way to control the individual sub's timing, and there is the potential for the subs to be mis-timed. Nonetheless, I felt that gain-matching was the superior approach, and I moved forward to taking some measurements.

Submersive Placements The 2 front placements yielded very different FR graphs, but they both re-inforced the bass well and had good SPL's. The right rear 2/3 sub had lower average SPL, which would explain it's lower measurement when measured at the LP. I moved that sub all over the back of the room and measured it in every conceivable location. It didn't measure any better anywhere else, and it measured worse in most other locations. I left it where it was, but I am open to suggestion about other placements in the front of the room.

First, I measured each sub individually. The following 3 graphs are the subs with the speakers, and with an 80 Hz crossover. I included the speakers so you can see that the levels were the same for all measurements, and the only variable was the sub being measured. Note that from about 100 Hz up, the speakers measure exactly the same in each of the 3 graphs:

Left 1/5 wall:



Front:



Right Rear 2/3 wall:



Obviously, each sub is interacting quite differently with the room and listening position. However, once they are combined, the summed response looks better than any of the individual responses:

All 3 subs together. (This graph is the subs alone, without the speakers, but with the 80 Hz crossover set. As you will see, there is some interactivity of the FR once the speakers are added back into the mix, so here I am showing the subs isolated from the speakers):



Using this combined response, I finally ran Audyssey MultEQ XT32. Here is the result:



This graph is self-explanatory. Plus 1.5 dB/ Minus 0 dB from 16 Hz to just below 80, with the expected tapering to allow a -3 dB point at 80 Hz. This is as perfect a result as I have ever seen. After seeing this, I am convinced that there is no benefit to going back and re-configuring the system to set it up as 2 and 1 with level-matching. The technique of gain-matching works so well that I can't see that there would be any improvement.

In the next post, I show the speakers and sub re-combined.

Part II The System

The following graph is the composite of the speakers and subs, with an 80 Hz crossover, but with Audyssey turned OFF. This shows the native response of the system with no EQ:



The next graph is just the speakers playing, with the subs turned off. Audyssey is turned back on. This shows the response of the speakers as they are impacted by the 80 Hz crossover and Audyssey EQ:



(I was surprised at this graph as it shows a more shallow roll-off than I expected to see. My speakers are sealed and THX certified, so they are designed to work with the THX crossover of 80 Hz and 12 dB/Octave High Pass. The combination of the 12 dB/Octave slope of sealed speakers with the 12 dB/Octave High Pass of the crossover should yield the 24 dB/Octave slope needed for the L/R (4th/4th) crossover. Yet the in-room roll-off of the speakers doesn't provide that. Hmmm...???)

Finally, this graph shows the speakers and subs combined:



Comparing the subs alone without the speakers, (see above post), to the combined speakers and subs, it is apparent that there is some interplay between the speakers and subs in the ranges they share. I tried different crossover points, both above and below 80 Hz to see what looked better, but the best looking graph was the 80 Hz crossover. Nonetheless, the response is +/- 3 dB from 16 Hz to 300 Hz.

I should also mention that the Distance setting was consistently wrong after every Audyssey run. There was a consistently huge 25 dB trough from about 65 Hz to about 90 Hz, (i.e., through the crossover point.) This trough was measurable all over the listening area. The subs and speakers were clearly out of phase with each other. The system found the subs at 10.4 ft every time. I had to reset the Distance to 13.8 ft. in order to eliminate this trough. Once I did that, it resulted in the response you see above. I suspect the system found the distance of the closest sub, which is right at 10 ft. However, the best integration of the 3 subs was realized with a Distance setting closer to the average distance of all 3 subs. (I did not save the graphs with the trough and the incorrect Distance setting, but I can re-run it if anyone is interested.)

This was likely an anomaly of my system, and in a system with just 2 subs, and having them set up in the conventional configuration with 2 subs connected to 2 outputs, I would expect the system to find the distances more appropriately. Nonetheless, with a system like mine, (3 subs all connected to one output), the system was fooled into an incorrect Distance setting. The only way to know this, and the *only* way to optimize such a system, or any other multi-sub system, is to be able to measure the response with a program like xtz, REW or some other measurement system.

I should mention that the above measurements were taken with the Submersive HP amps in DSP Prog 1, which is designed to be flat to 19 Hz. I subsequently measured them with Prog 2, designed to be flat to 16 Hz. I measured the nearfield response with Programs 1 and 2 and the difference started about 40 Hz, with the 2 graphs slowly separating to yield 1 dB at 30 Hz, 2 Db at 20 Hz and 3 dB of additional output at 16 Hz, just as predicted. Setting the subs to Prog 2 yielded the following graph:



I played around with Dynamic EQ and it provided a similar kind of uptick in the bass as Prog 2, but I liked the sound of the system with Prog2 over the sound with Dynamic EQ. It's hard to describe the difference, but DEQ sounded somewhat artificial and "hollow" whereas Prog2 sounded "right", and very similar to Prog 1, just with more impact, concussiveness and DEEP, DEEP bass.

Next, listening impressions...

Part III Listening Impressions

Stay tuned...

Craig John: For some reason, none of your graphs are visible! (On a Mac with Firefox)

No graphs for me either....

Thanks for the write up though CJ....

I'm really enjoying my HP as well, haven't really pushed the limits, though I know for a fact its overkill for my small bedroom... In fact I get better down low from it then all my subs in my great room...

Same for me; and would surely like to see them.

I have a few pics of the HP integration.....
I have to say, I'm thrilled with the performance, and I think it blends extremely well in the looks dept for my setup...

My plan is to upgrade to the 80.2. I am currently using the Onkyo 885 PLUS the Audyssey SubEQ. I have 4 subs. The front two are equidistant from the LP and the back two are as well but the back two are not the same distance as the front two.

My sub locations were initially chosen to optimize the FR when I had just two subs (one was on the side wall near the front and the other was in the back corner). So the way I have them now running under the Audyssey SubEQ is that the left two subs are on one connection and the right two are on the other. So while a front and rear sub (which Audyssey sees as one sub) are not the same distance, it does look at the combined response. My LFE output is amazing.

Prior to this configuration, I had the front two as one output and the rear two as the other so that Audyssey could time correct the rears to the fronts. The quality of my LFE now is at least as good as it was when I used the previous configuration.

As an aside, I have the gain position on all four subs set the same even though, using the RS meter, the rear subs measure louder than the fronts.

The distance difference of the fronts to the rears is maybe a foot or so. Given the wave length of an 80hz cycle is about 14 feet, I would be hard pressed to believe I am able to hear less than 10% phase shift at those frequencies.

Earl Geddes has written extensively about sub positioning and he likes the approach you have taken.

Try out Trent reznors new album "the social network" if u want some good submersive pounding music.

Very nice write up Craig , but like other folks, I can't see any of the graphs. I am in IE. On Nov 20th Craig and Dennis will help me with setting up my "new" setup. I am replacing my Halo C2 and Esoteric DV50s with an Integra 80.2 and the OPPO 83. I have one sub and a pretty good starting point so I hopefull that we can get great results without to much effort. I hope that with room correction, my entire system will be taken up a few levels .

Craig, out of curiosity...were any of your HP's set to a different volume level on the amp? I have two HP's and simply set them to the same volume level on the amp without measuring. I assumed that this effectively gain matched them as they use the same amplifier. Is this a bad assumption?

thanks,
Martin

I have re-attached the graphs above. They seem to be working now. I'm still working on the Listening Impressions.


Martin,

One of the subs was one-tick lower than the other 2. It changed about 2 dB with one tick of the volume control. It's probably not a big deal, but it doesn't hurt to measure them if you have an SPL meter.

To do this, move one of the subs out to the middle of the room, place the SPL meter 3" from the middle of the "front" side, and play the subwoofer noise tone from your pre/pro. Record the SPL, then switch that sub with the other one, place it in exactly the same spot, (I use duct tape on the floor around the first sub to ensure I get the second and third in exactly the same spot), and measure it. With the SPL meter in the same position, set the Volume Control so it measures exactly the same SPL as the first one. They are now exactly gain-matched.

Craig

Very nice work on your part Craig. Now that I can see your graphs. Truly a flat reponse. Would love to come by sometime and give it a listen.

Thanks for your efforts, Craig; the pics now come through perfectly, and they do show quite impressive results. Are these XTZ measurements? And if so, are you using its mike in one position, or more?

So you are now using only Audyssey for eq, correct? Nothing (Antimode 8033, SMS-1, etc.) else? Do you know whether or not the '32' enhancement to the 'XT' version of Aud made a major improvement in your results?

Thanks again, and congrats! (Will you be using Prg2, or staying with Prg1?)

That looks great Craig. I can only imagine how it might sound. If it sounds much better then what I heae before, then it should really be outstanding. But, I will say that I am very anxious to see what you can do with my system . Hopefully we can take some more measurments of my system as well.

If you're ever in the area, give me a shout. You're always welcome.


These xtz measurements are all at the primary LP.


I took the SMS-1 out of the system when I got the 3rd Submersive. I no longer needed it. It's assign the improvement in the bass to XT32 or to the new amps. I suspect the improvement in the articulation, clarity and detail is due to XT32, especially in the mid-bass were XT32 has so much more correction capability in the man channels. The DEEPER response is certainly due to the new amps.


Program 2.


We'll get you setup and I am now sure it will make a big difference in your system. We can certainly do some measurements.

Craig

Cool. I am glad that you got to hear my setup before. So now you can also make a comparison as well. Looking forward to this.

There is little doubt Room EQ can be trusted to provide tremendous benefit. However measurements after the fact is quite a slippery slope as Audyssey has mentioned in many posts such as this one -

While I agree that Audyssey is a great system, I believe in Ronald Reagan's philosophy... "Trust, but verify."

Here is the graph of the response with Audyssey/Integra's recommended Distance setting of 10.4 ft:



Lest you think this is due to a single position measurement, I took one that is a weighted average of 3 positions:



The trough is worse than I described previously. It starts at 50 Hz and goes to well above 100 Hz. The subs and speakers are *clearly* out of phase. Setting the Distance to 13.8 ft. resulted in the flat response I showed above in Post #4508 & 4509:



I never would have known this, or been able to correct it without measurements. One can certainly blindly accept the response provided by Audyssey and your receiver or pre/pro. Myself, I'll verify it, and correct it when necessary.

Craig

You missed the point of Audyssey's post. Verifying is only possible with the most sophisticated equipment and technique. $300 XTZ does not rise to that standard.

You're funny.

Thanks! That's the counterpoint?

I would agree that there may be some value to pre-calibration measurements for such things as finding room modes, speaker placement, etc. After Audyssey I make no changes based on measurements or anything else. In fact quite the opposite - I if change something I run Audyssey.

But have fun in any case.

Yeah, if those graphs are not conclusive enough evidence, then any more discussion is pointless.
Craig