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Author Topic: A question about JRSS and Subclarity behaviour  (Read 7894 times)

Gedeon

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A question about JRSS and Subclarity behaviour
« on: November 05, 2012, 12:45:24 pm »




I just read the wiki article on how to set JRSS and Room Correction. However I still have some doubts and I wish someone would kindly clarify me this.

I have connected the 5.1 analog outputs of my sound card (Auzen Prelude) to the 5.1 inputs of my amp that doesn't perform any signal processing.

I have defined two zones with the same ASIO device as output (checked the swapping for Center/LFE channel)

   The number 1: "Music Only"
      Channels: 2.1 (music never will be upmixed to 5.1 output)
      Mix: JRSS 2.0
      Only 2.1 mix for stereo:enabled
      Subwoofer: JRSS Subwoofer (70 Hz lowpass) (my front speakers are medium sized, no bass below 55-60hz)
      Subclarity: enabled

      Room correction: disabled


   The number 2: "Video"
      Channels: 5.1
      Mix: JRSS 2.0
      Only 2.1 mix for stereo: disabled (stereo tv shows and movies will be always up-mixed and 5.1 sources remain untouched)
      Subwoofer: silence

      Room correction: enabled (to substract and redirect bass to the subwoofer channel)


Subclarity should be used only for Music in 2.1 setups?

If i've understood well Subclarity doesn't substract low frequencies from source. Is this correct ?. In that case, should I enable room correction for Zone 1?.

Could anyone suggest me a better/simplier configuration to get the same behaviour ?

Perhaps I've missunderstood something.... :-\

Any help will be appreciated.

Thank you.

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Matt

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Re: A question about JRSS and Subclarity behaviour
« Reply #1 on: November 05, 2012, 12:50:25 pm »

Subclarity should be used only for Music in 2.1 setups?

Subclarity reduces drone / rumble while preserving bass hits.

Subclarity only applies to building a subwoofer channel for a source that has no subwoofer.  

It does nothing for a movie with a 5.1 soundtrack since that has a subwoofer channel (hopefully well crafted by a mastering engineer).

So it's safe to leave it enabled always.  That's what I do.
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Gedeon

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Re: A question about JRSS and Subclarity behaviour
« Reply #2 on: November 05, 2012, 01:14:13 pm »

Thank you for such a fast reply !!!

So should I enable Room Corrrection with bass redirection for my "Music" Zone ? In that case "Music" will have the same behavior that "Video" Zone...

In other words ... Is compatible "Bass Redirection of Room Correction" with "JRSS Bass Redirection and Subclarity" ?


Thank you

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InflatableMouse

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Re: A question about JRSS and Subclarity behaviour
« Reply #3 on: November 05, 2012, 01:17:37 pm »

Question about that too ...

I was under the impression Subclarity was meant for "cheaper" subwoofers, ie those that rumble and drone as you put it. Cool for movies, uncool for music.

Isn't it true that a "good" subwoofer shouldn't be doing that and Subclarity shouldn't need to be enabled?
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mojave

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Re: A question about JRSS and Subclarity behaviour
« Reply #4 on: November 05, 2012, 01:35:34 pm »

So should I enable Room Correction with bass redirection for my "Music" Zone ? In that case "Music" will have the same behavior that "Video" Zone...

In other words ... Is compatible "Bass Redirection of Room Correction" with "JRSS Bass Redirection and Subclarity" ?


Thank you
If you don't use Room Correction, the mains will still be full range.

If you want to use Subclarity but have bass removed from the mains, you need to specify the crossover in Output Mode and also in Room Correction. Then in Room Correction you select "Remove bass below crossover." This way JRiver will create the subwoofer channel in Output Format and allow the bass to be removed below the crossover from the mains. If "Remove bass below crossover" is selected and you are also creating a subwoofer in Output Format, you won't get duplicate bass sent to the subwoofer. JRiver (actually Matt) is smart enough to only do it once.

Quote
I was under the impression Subclarity was meant for "cheaper" subwoofers, ie those that rumble and drone as you put it. Cool for movies, uncool for music.

Isn't it true that a "good" subwoofer shouldn't be doing that and Subclarity shouldn't need to be enabled?

I've never found any "rumble and drone" in any of my subwoofer systems and haven't used Subclarity except to just try it. There shouldn't be anything in the source that is unintended if you can produce it so it seems to me that it must try to remove frequencies or something that subs are having difficulty in producing. There are subs that sound like a muddy mess due to long decay. Shortening bass notes or reducing sequential bass notes of the same frequency could actually help them sound better.
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Matt

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Re: A question about JRSS and Subclarity behaviour
« Reply #5 on: November 05, 2012, 01:50:06 pm »

I was under the impression Subclarity was meant for "cheaper" subwoofers, ie those that rumble and drone as you put it. Cool for movies, uncool for music.

Isn't it true that a "good" subwoofer shouldn't be doing that and Subclarity shouldn't need to be enabled?

If you go to a concert, you'll hear the bass drum on big subwoofers and the bass guitar separate.  It'll give you really clean bass hits.

But a CD has all the tracks mixed together into two channels, making it difficult to get those clean bass hits with a simple energy preserving cross-over.

Subclarity gives you the clean hits when building a subwoofer from a 2.0 source (like a CD).
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Gedeon

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Re: A question about JRSS and Subclarity behaviour
« Reply #6 on: November 05, 2012, 01:57:09 pm »

So, If I understand well:
  • JRSS Low Pass Filter creates a standard subwoofer channel from sources without LFE channel.
  • If I choose the correct low pass frequency (the lower reasonable limit of my front speakers) I don't need bass redirection in room correction because my front speakers actually can't perform frequencies below that limit.
  • Subclarity enabled substracts some "bad patterns" of the sub channel to avoid undesired rumbling as a result of simplests low pass filter from stereo sources
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mojave

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Re: A question about JRSS and Subclarity behaviour
« Reply #7 on: November 05, 2012, 03:14:41 pm »

  • If I choose the correct low pass frequency (the lower reasonable limit of my front speakers) I don't need bass redirection in room correction because my front speakers actually can't perform frequencies below that limit.
Bass management is complicated and difficult if you don't have a way to measure the frequency response. If your speakers are ported and roll of at 55 Hz, then there is a 180 degree phase change at around 60 Hz vs 100 Hz due to the port producing the output. By not removing the bass from the mains, this phase change can interfere with the output from the subwoofer and cause reduction in output around that frequency.

The typical solution is to remove the bass from the mains at a higher frequency with a crossover that matches for both the subs and mains. This is done with Room Correction and by removing bass from the mains (as I mentioned before) using the same crossover you set in Output Format. I would consider this to be a better practice than keeping the mains fullrange. However, there can also be instances where keeping the mains fullrange is beneficial. If you can't measure the frequency response, then I would suggest trying it both ways and deciding which you like better.

There are actually 3 main things you can try:

1.  Set the JRSS Subwoofer to the crossover of choice and keep the mains fullrange.
2.  Set the JRSS Subwoofer to the crossover of choice and remove bass from mains in Room Correction.
3.  Set the JRSS Subwoofer to silent and use Room Correction to move bass to the subs using the low pass/high slope of your choice.

There are several of other ways to route bass for 2 channel for 2 channel, but these should get you started.

 [/list]
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Gedeon

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Re: A question about JRSS and Subclarity behaviour
« Reply #8 on: November 05, 2012, 04:14:06 pm »

I'd already made all measures some years ago, first with sweep tones and a sound level meter and later with a microphone an REW to obtain a 44Khz fir filter to be used with the convolver plugin of foobar and a 48khz for MPC-HC convolver direct show filter.

Since convolver works in time domain, has latency and the output needs to be normalized and free VST parametric equalizer plug-ins didn't work as I expected well a few years ago when I checked I'm looking for other solutions. I'm just reinstalled and rebuilt my 4 years old HTPC 3 weeks ago and now I'm testing  parametric filters of MC to obtain a flat response without attenuation and latency (I think is good enough for my setup) but I've to test MC convolver too. I need these corrections mainly for low frequencies. I've applied the parametric equalizer settings that REW calculated 4 years ago.

AFAIK my speakers still are in "phase" (I think that) and I know relatively well how they behave.

But certainly you're right and I need to take some time to test each combination with sweeps, test tones, music and movies. I'll get the time in few days...

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Gedeon

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Re: A question about JRSS and Subclarity behaviour
« Reply #9 on: November 08, 2012, 02:37:08 am »

After some additional tests, I think that to get a more receiver-like behaviour of JRSS (and more unattended), should be really useful a checkbox to enable the up-mix, only for sources with video content  (mkv, avi, DVD, etc...).

So, when enabled, no multichannel up-mix will be applied to music files and you'll still get JRSS surround mix when playing AC3 2.0 and mp3 video sources.

I'm almost sure that many users will enable this option.
What do you think? Any opinion could be useful...

PD: Thank you for the DVD playback improvment.
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mojave

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Re: A question about JRSS and Subclarity behaviour
« Reply #10 on: November 08, 2012, 09:13:47 am »

The new features thread for MC18 mentions a zone settings presets feature. This will allow you to create zones based on your criteria and have your media automatically use the zone you desire. You could have a zone for stereo music, a zone for multi-channel music, and a zone for movies. Playback of each type would automatically use the correct zone.

Quote
18.0.33 (8/23/2012)
6. Changed: Revised how zone-specific settings are stored (groundwork for the coming zone setting presets feature)
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Gedeon

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Re: A question about JRSS and Subclarity behaviour
« Reply #11 on: November 08, 2012, 01:06:20 pm »

That's true, should be great. Sure will solve my question and other ones.

Will be a really good feature. Its time to wait for it. ::)


Thank you.
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