Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Interesting Discussion 861v6 v ADA

George,
You have no subs? Do you use your system for movies as well as music? It we be pure luck if your main speakers ended up being in the correct spot for you to get the optimum bass for your seating position.

If you took a sub, an SPL meter, and a test tone disk and measured the db at the various freq between 15 and 80 hz, you will see (hear) what I mean. Move the sub from spot to spot and here the differences.

No matter how big you get the speaker, its not going to take the place of a sub(s).

With the QSC, it does room correction as well as does equilibration for 80 hz and below.

When I used MRC on the 861, I was not able to achieve the sound quality I was able to get with the QSC.

By the way, If you ever get a chance to look into the control room of a movie theater, you will see QSC.
Ken

I'm well aware of what you're talking about. If it were so simple your 861v6 would have worked just fine.

I have no urge to add more bass. It's not a large room. Only thing I may consider is an LFE sub for more accurate bass.

You have a "QSC System" (as far as I'm concerned) just like the movie theaters.

I also understand perfectly why MRC would fall flat on it's face. You tried to make it do what it was never designed to do.

You talk about "luck" I think it's just plain luck the ADA is working better for you.

I run all the non sub channels through a heavily modified Balanced Audyssey Pro. That does introduce an incremental A/D and D/A after the Meridian's volume control. Meridian's 861v6 sonic signature shines through anyway; it's far more transparent than the crossovers in my high end speakers.

I'd like to clear up some misconceptions I've seen in this thread. Each of these are topics for which volumes of research data is available and getting into the details behind the physics, psychoacoustics, and basic concepts of digital signal processing would take more time (and space) then I have at the moment so I apologize in advance for being brief. Each of these are expressed in the context of small room acoustics.

Multiple Subwoofers:
The primary purpose of multiple subwoofers in a residental room is most certainly not to increase SPL or low frequency energy in the room. Indeed if there is a lack of performance in this area, one is well advised to get better subwoofers. As shown in the research by Floyd Toole, Sean Olive, Todd Welti and Alan Devantier, the result of multiple subwoofers in a space is providing consistent bass response in the seating positions ... noting we don't give a hoot about bass response where people do not sit and listen. The key word here is "consistent". This work also dovetails into the work by Gerry Lemay in which he presents the concept of the "virtual subwoofer". This work predates the publication of Mr. Welti's 5000 subwoofer document. When two subwoofers are placed in a space, they do not behave as to independent subwoofers but rather mimic the performance of a single subwoofer placed midway between the two. Largely due to the wavelengths involved, multiple subwoofers do not exhibit the audible problems associated with a dual-mono configuration (example: two center channel speakers playing exactly the same signal). Without getting into the details of diferential EQ of multiple subs, the first step in calibrating a multiple subwoofer configuration is to make certain all subs are set to exactly the same phase and SPL. Any suggestion the purpose of multiple subwoofers is to increase SPL is misguided to the extent such use is contrary to the intent of such configurations.

Multiple Subwoofers and Automagic Room Correction Systems:
At the current time, automagic room correction schemes with exception of the more recent Audyssey products, do not deal well with multiple subwoofers. It may be more appropriate to say "inconsistent" rather than "not deal well". This is not a fault of the correction schemes but rather a design constraint. One can get lucky but traditionally if everytime you push the automatic button you get a different result that is a symptom. At present only Audyssey has developed a room correction system designed specifically to address (I believe the upward limit is four) multiple subwoofers (for example Denon has four sub outs in some of their newer products). Note, I am not making any implied statement pro or con about the Audyssey implementation. I have not had a dialog with Chris in the past year and if we had discussed this it would have likely been under NDA in any case. In order to perform a right proper job, the room correction system would need to individually adjust the parameters and PEQ each sub individually. Where only a single sub out is available, such would not be possible. (Potentially, Meridian could do this in the digital domain once they could individually address multiple digital subs in a configuration.)

Full Range Speakers:
I don't care to debate an individuals preference for full range speakers or full range speaker configurations rather in two-channel or multi-channel environments. None-the-less, the physics behind the behavior of sound in small rooms makes it very clear that it is virtually impossible to configure speakers in such a manner as to provide excellent sound staging concurrently with smooth bass response in the seating locations. It is, of course, less difficult to accomplish with only one seating location in the room. Just to avoid notches would require such a speaker to be approximately 15' from any room boundary.

Equalization Systems:
It is clearly more convenient to have all the PEQ capability resident in the surround processor. Currently, we see more, and more of this being introduced into the market place. I advocate this if only because it sends a message to the consumer that audio needs to be calibrated. On the other hand, the vast majority of these imbedded systems do not currently contain the full set of tools required (or perhaps access to those tools) to provide a truly excellent calibration. (Note: calibration is to deal with speaker/room interaction and not to compensate for speaker performance or lack thereof.) In the context of Meridian specifically there currently does not exist a product to provide that level of calibration in a full digital environment. I had a SigTech unit for a brief period of time in my Meridian system but SigTech is no longer with us. QSC does provide a DSP with digital in/out but that protocol is propriety to QSCs playback chain ... it would be great if Meridian and QSC got together to provide a Meridian branded tool. None-the-less, there is nothing inherently wrong with using a high quality DSP between the surround processor and the amplifier(s). There can be a lot of arm waving about A-D/D-A conversion steps; but it is generally just that. In any case, the proper calibration process (using QSC for example) is to utilize the interior test signals generated by the QSC such that from the QSC, through remaining playback chain, to the seating positions, the adverse impacts of speaker room interaction are resolved. At that point, the surround processor can be brought into the mix followed by each individual source.

To suggest that Meridian (or any other processor) is inappropriate to use in an environment utilizing various PEQ or equalization tools is incorrect. The fact Meridian, ADA, or any other surround processor does not have multiple subwoofer outputs disqualifies that processor from PEQ would not be correct. Indeed, in the absence of multiple subwoofer outputs suggests a greater requirement for third party intervention. Meridian's full digital playback chain does, however, limit ones ability to perform calibrations. None-the-less, I am convinced that over time Meridian, or another vendor, will provide a solution.

Happy Holidays to all...

George, it's really not that hard to comprehend. How do you keep missing the mark??

Thje 861 was setup using their MRC the way it was intended to. There was no QSC in the picture at that point. It wasn't for months later that after being dissapointed with the 861 that I looked for alternatives.

With regards to the ADA working, it's not luck. I can see how you may wonder since you have no knowledge on the equipment mentioned previously, nor do you seem intent on learning.
Ken

Ken,

I've just checked back through your posts because I had missed this point. Your post no #131550 on 11th December is the first time you mention it (to my reading, I'm not a denizen of AVS). You state you added the QSC to the 861v4 after six months.

May I ask did you ever try the 861v6 without the QSC?

Hi Gianni,
I had not tried the V6 without the QSC. I had seen no reason to as I was more than happy with what the QSC does and so there wasn't a thought to try the V6 without it.

I know quite a few people using the QSC as well who all feel the same way.
Ken

First, I never said multiple subs can't be done.

Second, I wonder what Mr. DErskin has to say with Ken's Meridian system sounding inferior to ADA (in the Bass tightness and slam department) when both "properly" calibrated with the QSC. Make no sense to me. This is my biggest issue on the whole topic. Not that can't have multiple subs or what you prefer. But's total B.S. ADA has more slam tightness than ADA. Especially when you farmed 99% of that OFF the freaken processor.

Third, I think we all agree more bass drivers is a good thing. Because it smooths the bass out. Some folks do want more bass (Slam and Shaking house). That's fine I don't have an issue with someone wanting that.

Fourth, I think we can agree MRC/Meridian alone can't calibrate multiple subs.

Fifth, Large speakers vs Subs...

Meridian themselves have hinted on more than one occasion they prefer full range over subs. I learned that long ago I prefer not have them and I'll explain some reasons. I really don't care if folks prefer them. And I understand their advantage. But I think it's dumb some length people go in compromising other parts of the system.

a) One correction I'd like to make is, adding more subs is not all about solving room nodes. Bigger rooms need to move more air. Moving more air is SPL. Moving smaller amounts from more locations than moving a lot in one location is a good thing.

b) One huge problem I have with subs is matching volume of the sub to volume of the high frequencies of the channel it came from. I WANT IT RIGHT. It's extremely difficult to measure. When a speaker is designed it's calibrated in a chamber. You'll never achieve that balance (highs and lows) at home. Every speaker has it's own custom crossover for those drivers. Again all done in a chamber. It's designed to be FULL RANGE which is exactly what's on the Bluray disk.

c) People assume anything below 80hz is the same exact content on every channel as well as LFE. Lumping it all onto one channel loses content (that's MY OPINION). The argument is bass below 80hz has no direction. There are quite a few folks that think otherwise. It may be higher freq harmonics generated or what ever. But true stereo subs sound better than two mono subs.

d) Having multiple bass drivers is good. Which do think would sound better? Five DSP8000's directly connected to a 861v6 or Five 3200's (or 8K heads) with Five great subs "optimally" placed and calibrated with everything running through something like a QSC. I know which I would prefer sound wise. Not mention looks and ease of setup.

e) In my case. I would not have the room to have 5 subs ANYWHERE if I had small speakers. Except perhaps under the small speakers. Large speakers give me PLENTY of air moving nicely distributed around the room. I have 12 woofers. All on seperate channels. All calibrated level to their high frequency drivers. All calibrated individual cross overs and maintain all the channel seperation. Are they perfectly placed in the room, NO. But I basically have a "Woofer" (something moving air) almost everywhere I can. Do I get down to 15hz. No.

f) Are most subs PERFECTLY placed. NO. They may sound good to one sweet spot but not another. Usually the best you can do with a sub is not place it in the worst spots (WAF, Room looks, Cabling, Space, Seating etc.). If your main speakers (running as large) are in the worst spots of the room, move them.

Here I'm in agreement with George. It's very hard to get rid of sub localization, perhaps even more so with multiple subs.

Early into my calibration, despite having both subs time and phase aligned at the crossover point, and despite close to perfect measured combined response at the listening position, I could still hear the bass "swimming" around the room with frequency. It wasn't until I first equalized each sub independently, and then equalized the combined pair, that the localization went away and a stable sound stage returned.

After spending lots of time finding a successful integration of Two large Digital Subs into my room and arriving at a 7.2 system.......I then went backwards and forwards between a 7.0 and 7.2 system

Listening (video off) to a few challenging movie clips, I reasonably quickly arrived at the conclusion that I preferred the In Room Performance offered by the 7.0 system. I tried multiple cross-over points

When using 5.1 Music DVD-A's discs, and again comparing 7.0 versus 7.2, I found that the difference with Music was even more pronounced...........resulting in a STRONG personal preference for 7.0

Summary: I could probably live with a 7.2 system for Movies, but would prefer a 7.0 system........For Music, I don't think I could have lived with the 7.2 system........7.0 sounded far more natural and musical to my ears

All of which has led me to the conclusion (and there's lot of supporting evidence out there) that Bass IS Directional............We may not necessarily HEAR all those Low Frequencies coming from a particular location.............but our Senses can FEEL the Energy created, as coming from a particular location.........

Having spent the time necessary to get the Two Subs successfully integrated, I feel I can say that if I ever wanted to give myself a reason to commit suicide, I would try and integrate Four Subs........

YMMV.........

How do you mean this? Did you just run automatic mode in the Meridian config app? That is known to do close to nothing. Or did you follow the instructions from the wiki on this forum? That will give much more effect. Unfortunately in my experience that is even not enough. If you have serious room modes and lower the decay too much trying to cope with them, you will loose a lot of bass (and slam). I spend much time on this, experimenting a lot with my own system and other peoples systems, but eventually found out how to fine tune the MRC manually without losing the bass and get a consistent bass response both on different locations in the room as on the frequency range, removing the room modes almost completely.

How did you go about the placement of the subs?
Btw, I have 4 subs in my room which is 19x16 and I defy anyone to come and listen and say that you can here where the bass is coming from.
Ken