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

That's alright dear you don't have to eat the nasty brussel sprouts!

I think we can discuss the technical merits of adding analog Equalization after a Meridian 861, can't we? Independent of your ADA Preference. Meridian isn't really designed for 4 subs either.

It would be totally silly to try an ADA with Meridian DSP Speakers. Don't ya think. And it would probably take me a year to truely evaluate it. Took me years to really understand Meridian and years to understand Lexicon (yeah I'm a bit slow). I really have little doubt an ADA is a fine machine. But I'm completely satisfied with Meridian performance and have not had the urge to look beyond Meridian, just higher up the Meridian food chain. I have 13 DSP Speakers. And I love them all. And the 6K's can rock the house (as much as I would expect or want) with a CD hooked direct, with no other help.

Try bringing home a pair of 8K's some time.

I agree and I won't.

I got better things to do.




Damn ... did I really forget to put in smileys?

I am aware of Mr. Erskine's work, had the pleasure of looking into one of his projects, and let's say that I was not impressed by his work. With the MRC disabled and the QSCs only equalizing the subs (which were driven by the single .1 output of the 861), the main speakers are not tuned at all. The result was less than optimal ...

He's running FIVE subs?? If they're hooked up in mono he could get by with one QSC I suppose but his system is, to paraphrase Bobby Jones, a system with which I am unfamiliar.

Ken

Perfect, this is exactly the type of discussion that I am interested inenegaging in...




Fair enough but, to be just to both sides, this is no different that what ken is adviocating...

Almost. He could test drive DSP Speakers with any digital source (and the 861 in the box for that matter). I can't test drive an ADA with my speakers.

By the way there is another huge problem with running the QSC Split like that. PM me if your interested.

George, to be clear, I was commenting on the fact that each of you has your opinion and believes it to be true [i.e. rather than, the ability to test] sohopefully we can agree on this one...




George, I am most appreciative and most interested on anything that you could add on on this subject and, because I believe that others would be as well, ask that you respond within this thread but, should you prefer to do otherwise, please respond via PM...

Thanks so much...

I�m 100% sure an 861 is as tight and has as much slam as any preamp. It's what you do with the signals after it that defines what you hear. So I�m speculating what on earth went wrong. This is my hunch.

First 861 can only properly handle 1 sub with 7 channels (he runs 7 channels).

So MRC cannot not tune each sub and more importantly, you can't set the distance to each sub.

Now you can cheat and make sure all the subs (all 4) are the same distance from sweet the spot (did he or installer do that, I don�t know). Still weird stuff can happen with the same signal driving to 4 different places in a room (no matter what you do).

MRC will still run poorly even with that cheat. If any single sub has too much decay at a particular frequency, MRC will attenuate that peak for ALL the subs (since they are jammed on one signal). And if the distances don't match it will be confused. You won't get the benefit of multiple subs filling in problem frequencies because to MRC they are all "OR'd" together.

So to "solve" the problem he adds a QSC-322ua.

There is a major feature this box describes. That it has 2.354 ms of latency on ALL channels. This is fast and insignificant for lip sync issues. But it's not insignificant as far as relative timing (phase). If he ran all channels through QSC then this is not a problem. But he ran only his subs through it. That puts them 2.5 ft out of phase. That's not huge but fairly significant. The way to fix this is to subtract 2.5 ft on the Meridian sub channel to keep them in phase with the speakers.

Now the QSC box (I believe) can account for the subs being different distances, by adding delays to closer ones. Making all the subs appear the same distance to the Meridian. But you still have subtract the right distance in the Meridian to keep it in phase with the rest of the system. Again, did he do that, I don�t know.

And as EvdBerg said you�re not applying any room correction above 80hz. Lots of low freq issues can occur above 80hz.

The best way to handle multiple subs (IMHO) is to run a bunch of channels as LARGE. And only run an LFE only sub.

In DSP land you can seamlessly add a sub to any channel. And the beauty is the latency (phase) is NOT changed at all and MRC will continue to work 100%. Because both speaker and sub get the same signal at the same time and each apply their respective filter (same latency). I love DSP speakers. You can even add multiple subs per channel (I never would though). Again you must keep sub right at speaker to keep distances right. Basically that�s what the big DSP speakers are, a sub and a small speaker in phase at the same distance. You also get better imaging doing it this way.

You can do the same in analog. But to keep latency/phase issues right (and not lose quality of Meridian DACs) I would use an analog crossover for each speaker/sub.

Another option is to find a preamp that truly handles 4 subs. Maybe ADA does, then there would be no need for a QSC.

Now did he or his installer account for all this, I have no idea. But based on his questions on the forum (and lack of questions) and speed of which he had 861v4, added QSC, upgraded 861v6, Upgraded ADA I believe something like this was going on.

I suspect once he added a 3rd and 4th sub he was in trouble.

And I still believe it's much better to process Fixed Signals (even if just subs) than Variable ones.

Again maybe he did everything right, but I want folks to realize how complex stuff gets and how you can get yourself in trouble.

Evdberg:

Out of curiosity I woudl be interested which speciifc work you are referring to...

Thanks...

George:

Although I appreciate the response I do not know where to take this thread but do note the following:


1. I am complete agreement that this issue is extremely complex.

2. I am still curious as to your comment that it is *wrong* to apply EQ to the signal that has / is exiting the processor for a number of reaons...and in thinking about, this would suggest that all the very smart people at Audyssey, Dirac. QSC, Trinnov, etc. are all wrong...and, a related point and as you note, because there are either few / no pre/pros that can account for multiple subwoofers how would one calibrate mltiple subwoofers and their differential EQ.

3. There is a counter arguement to that you present here that I have received from a knowledgeable source but do not want to misrepresent or post his thinking without him being present....I will therefore attempt to get him to jump in and join this most interesting discussion.


Over to you with much thanks for continuing the dialog..

A lot of the devices you mention can work inserted before volume on systems that permit it. It does not mean they won't work at all on variable outputs. I can assure you MRC runs on Fixed level inputs internally then applies volume. And they may well be aware of different volumes. But how does an eq know if you're playing softly with loud passage or playing loud with a soft passage. It makes the problem much harder. And I like I said earlier Meridian does some tweaking based on volume and that will throw off any equalizer inserted after.

EQ Loop goes before volume, it's been done that way for eons.

A lot of what I throw out is THEORY. In practice is another story. How much effect in practice for each thing I'm not sure. And I don't know what was accounted for.

Multiple subs are extremely complex. And my opening statement stands. It's what you do with the signal after it leaves the Meridian box will dominate what you hear.