Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Sub woofers, Sub Bass Systems and Crossovers....

Andy,

That is excellent. Thanks. Can anyone verify Andy's experiences?

Another question. If I have a hypothetical Redbook CD recording (thus, no LFE) that features 20-20,000Hz signals in each channel using Direct with Large speakers, will the Large center channel speaker produce a 20-20KHz signal? Is there any bass management going on in Trifield? I guess I am asking indirectly how Trifield works.

Damon

From my experience it is totally superior having 2 subs.
More even room resonances and a better stereoimage.
Yes, you can hear the direction of the sub if you compare one to two. Maybe not playing a 80Hz tone but certainly on music and movies.
Myself I'm running 2 Paradigm Servo-15 as the lowbass speaker, and no sub.

I just spoke with Meridian UK. They said that the LFE signal in a no sub speaker layout is equally divided among all large speakers.

They also confirmed that the mono sub does receive the same bass below the crossover point as do the large speakers.

Also, in a three large speaker L-C-R arrangement using Trifield, the center speaker does receive a full 20-20,000Hz signal. In other words, Trifield isn't rolling off any bass for the center speaker.

Hope that helps.

Damon

AndyS, in regard to this comment:

"My understanding of the M bass management is that Mono does give bass duplication below the Xover point with other speakers set to Large - in the G68 literature, M indicates this is not optimum"

I'm curious to know why this setup is considered "not optimum". Which G68 literature says this?


[This message has been edited by xrayyou (edited 08-13-2004).]

Damon/xrayyou,

Firstly, thanks Damon for the clarification from M. - this is a help to me! not sure where I got my version/interpretation, but, as always, there is some room for interpretation in the M. literature (well that's my excuse).

xrayyou - In the Config program, going through 3 alternative bass settings shows that Bass Neutral = 'Centre' and Bass Heavy = 'Mono' (and that with either, the Centre speaker is treated as Small). To go with this, quote from p. 19 of the G Configuration program Guide: "... If the main speakers are Large, the Front subwoofer option allows you to choose whether the subwoofer handles just the LFE, all the bass (Bass-neutral) or the bass together with the Main Speakers (Bass-heavy)". Then quote from p28 of the G series digital surround controller installation guide (speaker options table): "the bass balance is: neutral, heavy. Whether the bass is distributed to all the large speakers and the subwoofer (heavy) or just the subwoofer (neutral - recommended). Only available if there is only one subwoofer and it handles all the bass, not just the LFE".

It was the 'recommended' bit that I had picked-up on. My reading of 'Mono' sub is that it's primary use is in a THX-type all Small speaker set-up, as going Bass Heavy with any/all Large speakers would not give an 'accurate' representation of the bass signal below the Xover point.

Andy

AndyS,

I understand your point now about not "optimal". Going with a mono sub when one has large main speakers would indeed accentuate/duplicate the bass information, hence the name "bass-heavy".

Unfortunately, I can think of no ideal setup for integrating a sub with large, i.e. full range, main speakers.

The options with respective drawbacks:

1. Mono sub - accenuation/duplication of bass information below the crossover point. Probably acceptable for movies but would cause bloated bass for music. Not available as an option when using more than one sub.

2. Centre sub - main left and right speakers are left full range but no bass information from the front channels is sent to the sub. May be acceptable for music. But, most large "full range" speakers like mine still only go to 30hz, so very low bass in the 20 - 30hz range in the front channels will be lost.

3. All "small" speakers with mono sub - could set full range main speakers to small and cross over into the sub thus keeping the very low bass and avoiding accentuation/duplication of bass. But, the full range main speakers would be crossed over at the same 80hz level as my small centre and surround speakers and therefore not used to full advantage.

These issues are simple software fixes and need to be addressed by Meridian in a timely fashion. I have already written to them about the lack of a mono sub option when also using a surround sub and am waiting for a reply. The "3." entry above is probably the most viable option for a system of this type but would require separate, individually adjustable crossovers for the large main speakers and small centre and surround speakers. I hope M is reading this.

Any thoughts from the forum?

Xrayyou

Although option 3 is not ideal, you are not losing any bass as it's being directed to the sub. I use this X-over in my movie set-up even though my mains are capable of much lower Hz (I want to protect them from potential damage). As a compromise you could reduce the X-over as far as your centre will allow (or get a bigger speaker of course).

Cliff

Xrayyou,

These sub options have been just as you say for years in Meridian equipment. I doubt they will change them now. However you do bring up a good point. I wish I had that option to set the crossovers differently for the fronts using Mono sub. Someone told me that the 861 does have that option. Is this true? Anyone! Actually I can check this myself be creating an 861 setup on the PC!

Might I suggest a sub with built in crossovers! You could set the Meridian to center sub, adjust the crossover to 80hz or where ever your center rolls off. Now take your preamp outs for your main left and right channel and feed them into your sub. Then set the sub crossover to 30Hz or where ever your main left and right speakers roll off. The high frequency outputs from the sub will go to your main left and right channel amplifier. The only problem with this setup is you need two subs just for the front. What you could do is buy an external crossover for your main left and right that sums the lower bass after the crossover. Then you could feed one sub your LFE channel into one input on your sub and feed the output of your external crossover into the other input. They will sum in the sub. Or you could sum the two channels with a y adapter before it inputs the sub.

Just a thought!

Ron

Update! I just thought another option. just use the external crossover to extract the low bass info and sum it with the LFE channel directly into the sub. Just run your main left and right full range. this would be the most transparant of sound quality. Some crossovers don't sound so good up high and through the mids.

[This message has been edited by Ronomy (edited 08-13-2004).]

Thanks for the suggestions. I still feel, however, that all of these options involve compromises on some level. We shouldn't have to add an external crossover to a $9000 processor with ample horsepower for individual channel crossovers. Anyway, I'm still enjoying my music and movies but am always lokking to tweak an extra ounce of performance out of my system. I have written Meridian about this and will post an update when I hear back.

This is not true. 1 frequency for all the speakers set to small. This is commmon for all the Meridian units.

Perhaps we one day will get advanced bass management. Other brands like lexicon and theta have more flexible bass management.

I would like to have the LFE channel seperated from the bass management.
In that case stereo subs would be nice too.
Perhaps different crossovers for main, center, side and rear.

The G68 and the 861 have enough output channels for that it seems.

All this will make it much harder to configure right i think. But of you know what you are doing you can perhaps get better results.

Jaco


[This message has been edited by jaco (edited 08-15-2004).]

I think M might argue that having a centre speaker of different size to the front mains is a compromise in itself. I tried out this option once and found it to give an unbalanced soundstage.

Cliff

Why is there not a DPS8000C and a DPS7000C than ?

I agree all the same speakers around would properbly be best, and you than end up with one crossover most likely.
In the real world not every one has the same speakers all around.

But to split the LFE away from the channel the bass management low part ends up would be a good start for me.
Divide up the bass management into all info from the left to a left woofer, and all info from the right to a righ woofer (perhaps slit op the Center ?) and i could live with one crossover.
My speakers have roughly all the same -3dB point (within 5 Hz i think) so it works OK for me the way it is now.

But we might get nice new goodies, see this comment from Mr Stuart:
from this document: Meridian is moving.pdf

Jaco

[This message has been edited by jaco (edited 08-15-2004).]