Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Meridian 861 Bass Management issues

It didn't do anything. Still the same exact output from both of the subs and the speakers.

I had the LFE and crossover both at the same frequency because the person at Meridian USA tech support said they are the same thing, but one is for material without an LFE Channel header, and the other is for surround material that is for an LFE channel. So, he said, they both do the same thing for different formats.

I ideally want my crossover at 80Hz. I only lowered it to 35Hz as an extreme for testing purposes. I have tried it with all those settings 'on' as well as 'off' already, unfortunately, still no change.

How long should the slope be after the crossover for these? My sub is playing output all the way to the 100 Hz where the disc stops, and my speakers start playing output at around 30Hz (I think this is because of the small setting, not because of the crossover, as the crossover appears not to work on my setup so far). At 100Hz the sub is no less loud than it is at 50 Hz, I would think the slope wouldn't be that long...

Thanks,

- Jeff

I had a "similar" problem a few months back, with slightly different symptoms. In my case bass management was applied inconsistently and incorrectly across various DSP settings

My unit had to be sent back to M for repair. Not sure what they did, but it works now.

They aren't the same thing. One governs the high pass filter for the main speakers, the other governs the low-pass filter knee point. You want the knee point to extend out past the crossover point.

I have always set the LFE crossover to 150Hz.

Technically speaking, the LFE crossover should only be valid on LFE content, otherwise, it's a subwoofer crossover.

What are you using to measure the differences? Any knid of SPL meter or just your ear?

Then something is wrong, as the slope is 24dB / octave above the High-pass point. So it if was set at 35Hz, but 100Hz it should be very low in comparison.

Also, what disc / test tracks are you using?

I'm using an SPL meter to measure everything.

I'm using the Revel B-15a sub parametric EQ setup disc. The sin waves are 3 Hz bandwidth warble tones. Also, using the Meridian built in sin waves the crossover isn't taking effect eitherr though the US Tech dept. said that it doesn't work like that, but I get the distinct feeling that they have no idea how it really works when talking to them and asking them... They are reading what it says in the manual and very liberally translating it to their benefit, not mine.

I'm using tracks 4 through 32. These are tones ranging from 20Hz to 100Hz.

I don't have that disc, but I do have similar discs.

I'm set at 80 Hz High-pass, 150Hz low-pass on all speakers. I'll do some testing and see what I get.

A friendly reminder -- crossovers aren't brick walls and for 1-2 octaves past the crossover you could get measurable output that is psychoacoustically masked.

Let's say for example you're playing tones @ a 90dB target spl at all frequencies. At the crossover frequency would be getting 87dB from each loudspeaker. This crossover is asymetrically implemented with the High-pass side @ 12dB/octave and the low-pass side at 24dB/octave. It is important to note that this ignores any room effects completely and it assumes only 1 loudspeaker plus subwoofer. I know, it's not the real world but we're looking at the crossover's effect on either side so cut me a little slack

So let's go two octaves above and below to look at our output:

I hope this helps you out some

Cheers,

What disc do you recommend I use for testing? Does your built in sine wave generator on the Meridian work for the crossover filter? Or does it not work through it?

I have my 861 set to the settings you gave me (was it 65Hz or so?) and the volume set to 70dB. I have my test tone at 100 Hz giving a sub output of ~70dB.

The reason why I am worried and trying to figure out the issue is because I want to use EQ on the sub. Right now it is turned off. When I play the speaker tones on the CD and set the volume so the speakers are at 80Hz, and then switch to the sub tones, the sub is measuring ~5 dB lower in volume. This shouldn't be the case, because in the 861 setup I set the sub levels to be at 80Hz compared to the main speakers. No matter what source I use, there is a discrepency in the dB levels between the speakers and the subs. I called Revel and they said that both tracks have the same level settings, so they should both be measuring the same when the volume is raised and I have the crossover set to the value that Revel recommended (80Hz), but they don't measure the same.

With a crossover set at 65 the sub should be reading less than the mains by (give or take) 5dB.

Leep in mind that most SPL meters (I have no idea what you're using) are off on the low-end due to A vs. C weighting. For kicks and grins, check to make sure it's C weighted instead of A weighted.

The chart above was illustrative. Just work with 1/2s and 1/4s, 2x and 4x the crossover frequency to get an idea of what the "textbook" measurements will be, keeping in mind that the room affects measurements to some extent.

Cheers,

With the crossovers set to 80Hz, the sub was reading 5dB (75dB) less on an 80Hz pink noise burst (the same type of signal sound used by Meridian for their system setup function I think), while both had the same measured dB levels using the Meridian setup software (both 80dB).

So according to the Meridian unit, I would think they should both be measuring 80Hz?

If anything, I need a recommendation for a Test CD that has a larger range of frequencies to use so I can figure out if the crossover is actually working. If it is, then there may be another issue (either in the Meridian, or not) that is the problem. First I need to establish that it definitely isn't the crossover. Does anyone know a good downloadable Test CD that goes up to say 300 Hz (or something equivalent that is good enough for this purpose)?

BTW, the SPL is set to C weighted.

Thanks,

- Jeff

Jeff:

If it's the Radio Shack SPL, it's notoriously low on subwoofers....

I'm not sure that's particularly relevant here, as it doesn't know whether the sound is coming from a subwoofer or a regular speaker, but they are in different physical locations.

Can you move to another spot and remeasure? The sub could be in a null.

Cheers,

I'm not explaining this well, or I'm not understanding something in the bigger picture.

When I do the Meridian setup in the configuration program, the program where you set the levels for all the speakers and subs, I set all the speakers and the subs to the same dB level using the Radio Shack SPL (I set them to 80 dB). They are all set to the same volume and all are at 80 dB in the Meridian configuration program. I download the settings that make all of them equalized at 80dB into the 861 (the crossover set to 80Hz). Then I go to measure the speaker with pink noise meant for the speaker measurement off that disc (Bandpass filtered pink noise from 500Hz to 2kHz, -20dB RMS average) and set the 861's volume so the speakers are at 80dB on the SPL meter. Then when I measure the sub with the Test CD track for the sub (bandpass filtered pink noise from 20Hz to 80Hz, -20dB RMS average) it is ~5dB lower in volume.

I guess what is confusing me is the difference between equalizing their levels on the 861 vs using the supplied revel disc to equalize their volume levels. Is it possible that there could be such a discrepency between them?

In any case, despite whether that may be the actual issue, in order to test out whether the crossovers are working correctly (or at all), I still need a suggestion on what test discs to use, or some freeware that will allow me to make my own test tones and burn them to CD. That way I can test for the rolloff (if there is any) on the sub through the Merdian software. I want to determine for certain if the crossover is working correctly. So far it doesn't appear to be and the only way to figure out if that is incorrect is to get a long enough FR reading off the sub to see when it eventually rolls off and if that falls in-line with what should be happening for those crossover settings (or if it is falling off simply because it is reaching the limits of the subwoofers FR range).

Thanks,

- Jeff

If the 861 sine generator does work with the crossover, instead of bypassing it, I could use that instead, but the tech support at Meridian USA said it bypasses the crossover settings and bass management in general.

Thanks again,

- Jeff

Jeff:

To be honest, I don't use the internal sine generator.

Please, move to another location and see if your meter is in a null.

Cheers,