Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems +3dB "LevelPerfect" Tweak Performance Improvement Poll

Width setting doesn't work is the problem. HQ suggested last year it was a simple fix as it's a modular design.

The Width function doesn't work.

Well,

I've been vacillating for some time - possibly because I have a couple of systems and did an upgrade in the interim. I tried again the tweak again today - I believe that I hear some improvement on my 861/DSP system (5200, 5200HC, 2* DSP1500, 2* 24/96 5000) and a greater improvement on my 861/analogue system. I know this flies somewhat in the face of others' experiences - but this is what I find (today at least).

I could only vote once - but have two opinions (typical, 'Dither' is my middle name - possibly... ) and have only recorded one (the first, DSP ). I also note that I said yes to all three letters as I think that we should all be advised against speaking nonsense... not that this is... I'll get my coat...

I hope someday to understand this fully.

Liam

Well, re-reading this thread (or at least the key posts), I have to confess that my understanding of 518 resolution enhancement - specifically the word length aspects of resolution enhancement - was mistaken. In part, I think this is because the otherwise excellent 518 manual doesn't explain how DAC word-length matching is actually achieved.

I had assumed that the top 16-bits would be stretched to 24-bits, filling the (previously zero) least significant 8-bits with extrapolated signal. This is wrong and, as I now realise from George's excellent posts and diagram, the top 16-bits must remain where they are.

However, I didn't understand George's diagram, until I read this very good paper by Wadia. When I did, the penny dropped and everything fell into place.

http://www.wadia.com/technology/technicalpapers/Resolution_Enhancement.pdf

The Wadia paper is entirely consistent with what Bob Stuart has written on resolution enhancement in the 518 manual (page 49ff); that section now makes a lot more sense to me, particularly how the different dithers are applied and how the benefits of resolution enhancement to the DAC - namely increasing effective DAC resolution and linearity - are achieved. In short, the bottom 8-bits are filled with jitter de-correlating dither.

As an aside, I'm not sure whether digital gain is applied to the top-most bits (I.e. the original signal) before adding the LSBs, or to the 24-bit signal afterwards. It doesn't really matter though.

Has anybody tried getting a comment from Meridian on the +3dB "LevelPerfect" Tweak via the official route? i.e. through a dealer? Have any dealers on this board talked to Meridian on this subject?

Cheers
Tom

If folks have been evaluating this for a while I think it may be time to cast your vote.

By the way I did get a itty, bitty bit of info from Meridian on this.

All they could say is "No Comment". And the reason for no comment has something to do with Patents. I have no idea if that means pending or existing or basically a blanket statement that they would have to go into too much technical detail that they prefer not share with their competitor of why +3dB should help or not help. They didn't have a problem with it, but they neither recommend using or not using it. Nor did they comment if they plan to do anything about it. I personally have no problem with this position.

And for the record (Purhasing Poll), it has no effect my future purchasing.

And for the record (Listening Poll), I think it sounds better even when I'm not in the same room.

P.S. I'm unstickying this. I added a link to this poll in the HT18 program thread which is still sticky.

https://www.meridianunplugged.com/u...bb=showflat&Number=116105#Post116105

I want to add a positive endorsement of this brilliant work by George Mills. Sadly, I have waited a long time to take advantage of what turns out to be a very easy mod to apply to Meridian`s configuration. After uploading the modified .msl, I thought music was plenty loud, very good on top end, and more engaging. After a while, I noticed I was paying more attention to the music. Something had changed for the really good. The 5500hc center in my 5.0 is better tamed and better handles complex music forms. Some screeching in both pop and classical music is gone. That is, female voices, violins, and similar are warmed a little…all by the db boost! I had thought, with a new 808.2i in play that the DSPs were the limiting factor in my system; not so. The extra boost from George`s mod was a BIG step forward.
Before and after settings (in case someone cares):
Left front from 0 to +3.0 db
Center from -.5 to 3.0 db
Right from -.5 to 3.0 DB
RS from -2.0 to 1.5db
LS from -1.5 to 2.0db
Should also mention that what George has done is not only technically brilliant (discovering SQ Meridian have chosen to leave on the table) but he has designed a very easy interface to make the change. If you are a fence sitter, get off, it`s very easy to get this BIG SQ improvement.

I'm sure it was mentioned a while back, but can anyone point me to the instructions on how to do this with a 568.2mm please? I know the tool won't work, but there was another way outlined...

Cheers

George

Hi George,
I'll email you some notes.

Cheers

N

Question to George:

I want to adjust the rears more then +3B but ONLY for natural (not decoded like AC3,DTS)
2 channel sources-CD ONLY.
The rears have a very low volume when you play a Trifield or music preset.
I only want to play these presets-not interested on other presets.

So the idea to use the advantage of your +3dB "trick" and gain of the rears with (for example) +10dB or more.
To get the same SPL ratio front to back as without doing this,
I want to change the (Trifield & music) preset for the rear and turn down it the same amount(10dB).
Then the same front back SPL ratio should be reached.
It should make sense in my understanding as it is using the same idea with you with the +3dB.

Of coarse, its only for that CD-sources and when I use other sources like DVD�s or user other presets (ambisonic,Party &...) I have to use the standard gain or better your +3dB.

What do you mean, I will try it.
Or dit you allready make that?

Thanks

Robert

Robert,

The tool already tries to maintain the ratio you have now front to the rears and will set them to what ever they have to be. Mine are +5dB.

You can have some differences in what you want to do by playing with levels on the rears within the preset.

Hi Gents

Brief experience with 568.2mm:

I must admit to being late to the party on this one, but it's been very interesting. Changing the parameters by opening your .msf config file in Wordpad on Notepad is easier than I expected, and it's not in hex code either, just plain decimal; a level of -2.5dB will read as "-20", so adding 3dB means that the figure would be changed to "05".

The system is 8k mains, 6k centre and 5k rears. I changed the dB calibration levels as follows:

L -2.5 > +0.5
C 0.0 > +3.0
R -3.5 > -0.5
RR -2.5 > +0.5
RL -2.5 > +0.5

Listening in Trifield, first impressions were very positive, it definitely has the same effect I enjoyed with the 518 and it's digital gain feature. You can hear more detail, enjoy an improved soundstage, and everything sounds more engaging. However, a few tracks in and clipping occurred. The CD was Stacey Kent's "Breakfast on the morning tram", second track. Her voice clipped a few times on the centre channel with audible distortion. I changed the centre Eq from 1 to Flat as suggested previously, but the problem persisted. The same album also sounded a little forced on sibilants, but pretty much everything else I listened to sounded better.

I've now reduced the calibration settings by 1dB and the clipping on that CD is less pronounced, but still there to an extent. Of course, losing that dB means slighly less of all the other improvements, so I'll need to do some further tweaking, but Trifield seems to be the preset which exhibits this overload, as neither Direct nor Music seemed to suffer.

I'll post back more info when I get things sorted completely, but I'm struck again George, this is a cracking piece of work, and hats off to you for having the tenacity to track down those missing 3dB!

Cheers

George