Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Digital EQ, Why the Digital Room Correction Is The Most Important Issue in the 861

I just wanted to write a quick note regarding the importance of digital room correction and digital equalization in terms of priority of the 800 series offerings. IMO upsampling, DVD-Audio with an all digital pathway (vs analog) are no comparison to digital equalization. There is just magnitudes of order of benficial difference provided with digital Equalization. In actuality, I doubt any of us would pass double blind listening tests between upsampled vs not upsampled, analog out DVD-A vs all digital DVD-A, etc... Of course I am all for improvements, but ultimately we must put in perspective what will bring us closest to 'perfection'.

In the heirarchy of importance, there is no question, IMO, that room response is the weakest link in all of our systems, even the very few of us who have dedicated rooms that were new construction, optimized by acoustical engineers. Even in the best case scenerio with new contruction acoustically engineered dedicated rooms, there is still a need for digital room correction. While almost none of us would want to entertain putting our pure digital signal through an analog EQ, there is really no detriment if maintained and processed in the digital domain. There are still many arguments that the benefit of analog EQ, still easily outweighs any disadvantage such as group delay, phase, and additional potential noise introduced by an analog EQ. In the order of importance we should not be concerning ourselves with trivialitles and little upgrades that for all intensive purposes will not make an 'audible' difference, or at least very minute that you might have to spend three hours trying to detect any difference whatsoever (and if under a DBT, would almost defintely fail to do do so in any significantly significant manner).

In the grand scheme of things, the digital room correction card from Meridian, is what *ALL* of us should be desiring, ASAP.

Here is some good reading, although anybody should contribute to this thread.

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What Software/Hardware Do You Use to Measure Your Listening Room?

Use both LAud & the Behringer Ultracurve 8024 RTA & graphic EQ.

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I was just wondering what software and hardware people here use to measure the acoustics of their listening room and if somebody could sum up the advantages/disadvantages of what is all available...

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The advantages of the Behringer is that it works in real-time, and the
measurement microphone can be any high quality condenser as the XLR mic
input is phantom powered. The disadvantage is that it will not graphically represent waterfall, but only one-third octave. For more info see this Behringer review by Thorsten Loesch.
http://enjoythemusic.com/magazine/equipment/0101/behringer8024.htm

LAUD advantage is that it is a defacto standard with many many uses, but is difficult to set up as the Fiji cards are hard to find, it only runs well on Windows 95, and if you are not a computer genius (Windows) as well as an electrical engineer, the instruction manual can be quite incomprehensible.

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How many people here use devices like RPG diffusers and Helmoholtz resonators to achieve good room response?

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I use eight home brew Helmoholtz resonators, built into and behind the
walls & corners and ceiling of my small listening room. Bass in my room
is NOT boomy... <grin>

BTW, I use Strike's BassZone test CD as a signal source for above. I literally wore out my first copy using it to EQ my listening room.

Paul B

--
Paul Butterfield
Squeaky Chair Recording Studio
Central Florida Audio Society


In any case, feel free to contribute, and please read the link above, as it contains some useful info.


[This message has been edited by Health Nut (edited 12-23-2001).]

Chris,

I've often heard the need for the Room Eq card from members of this forum, but my complet lack of understanding of what it's supposed to do means I have not a clue what it's supposed to do, except of course improve the sound of whatever it is your listening to(-:

Are there any links that anyone can provide that talk about this in idiot terms.

Everything I have ever read tends to suggest that the room design and treatment are the most important considerations and most of us do not have dedicate cinema rooms.

Recently I was at a private viewing of Monster's Inc at Disney's offices in Hammersmith in London, this cinema could hold I would say about a 100 people. I was of course very interested in how it sounded, well it was amazing (good film too), it proved to me that the design of this cinema was spot on. I wanted to go ask what kit was being used.

Getting back to room eq, I hear that one of the main reasons such a card is not available is becuase of the user interface is so complicated (you have to be a sound engineer to use the thing). Given the potential market of 861 users it does not look like a business case can be made to produce such a card. How would such a card work? Once the system has been set up properly would the card be needed? Is there an external device that can be hired?

Have a good Christmas everyone and I certainly look forward to the release of Fellowship of the Ring, what a fantastic film!!!

Martin.

HealthNut,
Is the type of 861 Digital EQ which you are requesting, analogous to that which Z-systems offers in their digital equalisers? e.g: rdq-1 & rdq-6.

If you are unfamiliar with the Z-systems gear cf.: http://www.z-sys.com/cp_rdq6m.html

Z-systems brought these devices to market in late '98.

Has been a point of my own interest as to whether Meridian would develop equivalent capability for room correction. To a degree elements of such correction are already on board the DSP speakers (e.g: Axis, Phase, Bass, Treble, Positioning(Boundary/Corner)adjustments are achieved through Digital EQ). The Z-devices take it further offering rather more extensive room correction capabilities. Incorporating such capability into the 861,and/or the DSP speakers, seems a logical and at least already to market (if not market proven) concept.

i think the UI argument, while rational on the surface, is a specious one.

there are two types of Meridian installations (even more so with 800 series equipment).

1) professionals install the whole thing or
2) ultra-geeky consumers install the whole thing

in either case the UI is not an issue. the "average consumer" isn't buying 861s.

i'm a happy 500 series owner but bemoan the insane redundancy between my 500 series units and the lack of configurability of I/O. since i use DSP speakers, all the analog out stages are nearly worthless. the duplication of functionality b/w the 568 and 562V.2 is excessive.

but i can't justify the substantial cost for the 861.

HOWEVER with a room correction card (and boy does my room need correcting - the LCR speakers are one on a floor one foot higher than the listeners; the center of the ceiling is open to the floor above; wall of stone; wall of glass; you get the idea) i'd be all over it. it'd be worth the entry price.

i've looked at the z-sys stuff, but i'd rather Meridian just did it right, fully integrated and pc controlled.

i agree with healthnut that we'd all probably fail double-blinds on most of the stuff, but room correction we'd know spot on.

so, what's the story, Meridian?

sab

Their room correction card deals with 20Hz to 200Hz only and this is all you need to fix electronically. Above 200 Hz is easy enough to fix with room treatment.

I am looking forward to the room correction card as I need it to fix some peaks in my room. I have positioned the speakers in the best possible location to get the flattest response with little to no dips, just a couple of peaks.

I doubt we will see any such card until 500 series is doing DVD-A, which of course comes after the 800 series doing DVD-A.

The Meridian EQ card was done a couple of years ago. Be thankful it was not released. Why? First, you would have paid a lot of money only to find out it did not have the DSP to do 96/24. That would mean re-purchasing a new card.

I am confident it will come when it is ready. If not, we will just have to make post after post until it does come.

Thier UI for the room eq is pretty easy to use once you understand what is going on. The UI is in the software today, just add an 861, then add the room correction card and go back to the top level and you will see the EQ UI.

You simply notch out the peaks that exist between 20 Hz and 200Hz for global and each of the 8 speakers.

ETF for Windows works great just for setting this. You use the tones built into ETF by feeding them into the multichannel input. Simply plug into the channel you want to EQ and ETF will generate teh tone. It will show you the peaks, you then add a notch to that freq and re-run to see how it works.

I use the Z-sys with Meridian DSP5500 speakers , and invaluable tool BUT.............. there are issues
Digital EQ has to be done in the time and freq domain (Like TACT or Sigtech) NOT like the z-sys which is just a glorified (and very expensive) digital partametric.

Read my review of the unit , specifically with Meridian speakers at http://www.tnt-audio.com/ampli/rdp1e.html

I will say this, the Z-sys is the most valuable component in my system.

The problem with a third party eq is that it will be of no use with DVD-A because DVD-A will require MHR to be on.

Stacy and Chris,
Might it be possible for Meridian to have a new card featuring digital loops for either the main right and left channels or all channels so after the DSP circuits have done their processing, like DD or whatever, the digital data can then be sent to an external digital device like a z-system, and then sent back into the Meridian for D to A conversion? Kind of what accuphase does with it's CD player DP-75v.

[This message has been edited by mburnstein (edited 12-24-2001).]

The is subject to the same issue as just using the digital outputs and passing through a digital EQ, MHR. If it is a high speed source like DVD-A, Meridian will either encrypt or downsample.

The other issue is can these thirdy party EQs run at 96 kHz?

Stacey, the TACT RCS 2.0 can handle 24/96, however & as you point out, this is moot since Meridian will only output 24/96 MHR encoded...

We obviously need an industry standard high-rez interface with encryption...Although I'm sure we'll see a Meridian RC solution sooner

I've got to agree though that digital room correction should be a priority - I currently use the TACT product & I've got to say that the improvements it provides, in my less than ideal (typical?) listening space, dwarfs those I (sometimes )hear when comparing 16/44 to 24/96 source material.

Paul.

I agree with Chris and other 861 owners that room correction is a very important feature. Meridian promoted this capability when the 861 was introduced and has shown it. I, and I am sure others, purchased the 861 partially based on the anticipated availability of room correction. This was four years ago!

No doubt, there are installation issues. However, high quality room measurement systems are now available at a relatively low cost. The Smaart software from SIA is a good example: www.siasoft.com . If you already have a suitable PC, the cost of the software, high quality measurement microphone, and preamp is about $1,250. This provides very sophisticated transfer function measurement capability that cost more than $50,000 only a few years ago. Further, SIA can do a driver to interface with the 861, as they have done with several brands of pro EQ units: http://www.siasoft.com/links.html . It would be reasonable to require Meridian dealers that sell room correction to purchase a reasonably priced measurement system and to have some training.

Given the very long delays in introducing new products and features and the seeming orphan status of 861 room correction, I don't think that we will ever see this. It is really a shame because it is needed and Meridian has an obligation to do it.