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

fwiw - My understanding has always been LFE goes to all speakers set to LARGE.

Nick,

could you flesh out that understanding (noting that it appears to be at variance with George's findings) a little please?

Does all the LFE get sent (i.e. down to 20Hz) and is it unattenuated (other than managing the +10db) and is it sent equally to all speakers.

For the sake of argument, let's assume that the pre-processor speaker settings are all Max.

My concern around your understanding is the idea of sub 30Hz signals at full (relative) volume hitting my speakers at a loud (absolute) volume. Do I really need a subwoofer with five very capable large speakers at FL/C/FR/RL/RR?

OK everyone, I ran a little test this morning. A note about my setup, all my speakers are set to large and I have no sub.

Video Essentials, the original one, played back via my Kaleidescape where I use the coax digital audio out and that is run into my Radiance XE and then HDMI over to the HD621 and smartlink to the 861. Calibration noise tests, sub channel = all speaker set to large get a signal

Digital Video Essentials, DVD, again via Kaleidescape, same result: LFE signal going to all speakers set as large

DVE Basics Bluray via my Dune, which converts internally to PCM and then HDMI out to the HD621, etc. Same result. All speakers set to large play LFE

DVE Basics Bluray via Oppo, which converts internally to PCM and then to HDMI, etc. Same result. All speaker set to large plays LFE.

What does that mean? I think when you set speakers to large, and there is no sub present, then they will all share in the LFE

Accoording to that link I sent DTS from DVD's doesn't have an LFE and if your rears are set as large all the effect bass goes to the rear channels. So in this case with a Bluray player and Meridian setup you don't want to not select LFE in the player. All the DTS bass will go to the rear channels or does it still go to the rears even with a sub and rears set to large? I am setup for small rears so I can't test easily. Rear bass will get redirected to the LFE sub as stated in that link when the rears are set as small. You would need a DVD with DTS test tones to test this. I don't even know if I have such a test DVD for DTS.

Everything I read said the LFE if not selected goes to the front speakers not the rears when it comes to DD. So I was surprised you guys were measuring bass from all channels. If only two channel setup the LFE is thrown away or at least its supposed to. Meridian has screwed up bassmanagement in the past. Like they did with the 568.2mm before beta 2.5.

George, can you shrink your pictures in the thread as I'm scrolling across 2 screens to read the comments ?

Cheers

No need, we are on the next page now

Good point on DTS- its all being tested via DD.

I've been trying to convince SqueezeBox folks to not use digital attenuation and ironically, in defense that it's ok to attenuate digitally someone pointed out this old test that proves digital attenuation is very costly.

They seem have difficult time over there interpreting test results. Or even reading the designers comments they keep referring to on the topic. Which he sums up in 1 sentence. "it does NOT mean that those first 8 bits of attenuation are "free"".

Any way this test is on the SqueezeBox's DAC itself. It's supposed to have a "24Bit DAC".

The Volume scale at the time of this test is 1.25dB per step.

So

Volume 40 is 00.0dB attenuation. About 0-Bits. Close to 96dB Dynamic Range no loss.
Volume 30 is 12.5dB attenuation. About 2-Bits. Drops to 88dB Dynamic Range 1.25 bits lost
Volume 20 is 25.0dB attenuation. About 4-Bits. Drops to 75dB Dynamic Range almost 4 bits lost

If the DAC was Perfect for even for 20Bits. Those should all read close to 96dB.

http://mysite.verizon.net/forumwebspace/RightMark/Test%20Reports/Volume.htm

Here is great example of why all your dynamic range is so prescious.

It's fun looking at tunes I have used for years for reference. No wonder I picked it. Basically swings between very loud and soft many times.

I'm not 100% sure the Meta data is correct it was one of the tough classical ones.

Jacques Offenbach,Jacques Ibert\Gaite Parisienne,Divertissement for Small Orchestra - Track 04 - Poco Allegro

George,
I've screwed up, sorry.

After finally sorting out my system and giving the +3dB a go, it was time to vote in the poll.

I scrolled down to 861v4 (made sure it was not v3 or v6) checked it and hit confirm.

861V4 Alg Improvement LARGE x

Doh! It should have been

861V4 DSP Improvement LARGE x

I don't know if you can correct my error, if so please do so.

Again Sorry

Carl.

has anybody tried this tweak with the older 568.1

Look at the Poll in the first post. 2 568.1 DSP owners say yes.

But always do your own diligence (i.e. check with an SPL meter).

Given how Trifield EQ, Center Boost and LFE bass management works basically the same on 568 - 861 running with the same DSP speakers it should exist. The bigger question is can you get that +3dB to take effect, but you can confirm that easy with an SPL meter yourself.

If you were calibrate at 75dB say with an offset of -3dB and after +3dB tweak it measures 81dB you are all set.