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Author Topic: Upmixing to 5.1 adds a lot of Bass  (Read 2915 times)

flac.rules

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Upmixing to 5.1 adds a lot of Bass
« on: June 20, 2010, 06:58:51 am »

It seems like using upmixing in MC (upmixing 2-channel music) to 5.1 adds quite å lot of bass in my case (the sub is in use in both instances, and i run the sound over hdmi), it sounds quite unatural. Could it be that MC does have the right level on the LFE-track? Or that MC in the combination with the receiver does not handle the LFE-track the right way? Another explanation?

On a related note, the "sub-clarity"-function, is it possible to get som rough technical detalis of what it actually does? No need for "industry secrets", but just a few words about what kind of filtering is done.
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Matt

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Re: Upmixing to 5.1 adds a lot of Bass
« Reply #1 on: June 20, 2010, 08:13:26 am »

It seems like using upmixing in MC (upmixing 2-channel music) to 5.1 adds quite å lot of bass in my case (the sub is in use in both instances, and i run the sound over hdmi), it sounds quite unatural. Could it be that MC does have the right level on the LFE-track? Or that MC in the combination with the receiver does not handle the LFE-track the right way? Another explanation?

Do you have a calibrated system with the LFE channel +10dB louder than the other channels?  Regardless, bass levels are a personal thing.  Some people want a perfectly flat frequency curve and others want exaggerated lows (and often highs).

For now, you can turn down the subwoofer channel in DSP Studio > Room Correction.  If others also want more control over the level during JRSS mixing to create a LFE channel, we could consider an option.


Quote
On a related note, the "sub-clarity"-function, is it possible to get som rough technical detalis of what it actually does? No need for "industry secrets", but just a few words about what kind of filtering is done.

It allows quick impacts like thumps and hits to pass through, but filters out long rumbles.  The goal is to remove drone from bass guitars, etc. from the subwoofer line while keeping tight hits from bass drums and other low bass.  

Subclarity is one of my favorite recent improvements to the audio engine.  I had always wanted something that did this, but wasn't sure it was possible.  In my opinion, it works and sounds really good.
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Matt Ashland, JRiver Media Center

flac.rules

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Re: Upmixing to 5.1 adds a lot of Bass
« Reply #2 on: June 20, 2010, 10:16:00 am »

My system is calibrated, I would guess the LFE-channel is +10db louder, as it should be, but the menues on my receiver aren't exactly the most intuitive :) Bass levels is a personal thing, but the problem is that the bass level is much higher than if i just output to stereo (or movies), the bass sounds about right for me in stereo or film, but it very noticably increses in 5.1-upsampling, calibrating it to be good while upsampling would just cause the bass to be too low in other circumstances. I have access too good sound-measuring equipment if some measurements would be helpful to pinpoint the problem.

Thanks for the feedback on the sub-clarity-options. A second more or less unrealted question; setting the crossover in MC, what is the practical consequence when crossover is already set on the receiver (and receiver is set to feed non LFE-track bass to the sub-line)
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mojave

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Re: Upmixing to 5.1 adds a lot of Bass
« Reply #3 on: June 22, 2010, 08:56:15 am »

Elvis133,

The JRSS upmixing to 5.1 does not remove the bass from your mains below the crossover point. Therefore, you are getting bass not only out of the LFE channel, but it is combining with the bass in your mains.

If you have a receiver, you could use Dolby ProLogic II to upmix. You should also only set the crossover on either the receiver or Media Center. Using both crossovers will create a cascading effect and you will get reduced output around the crossover frequency.

If you use JRSS and set the crossover to none, instead of no information going to the LFE channel, you now get all frequencies going to the LFE channel. It basically duplicates the main channels into the LFE channel. Therefore, you can't use JRSS with a receiver's crossover.
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Matt

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Re: Upmixing to 5.1 adds a lot of Bass
« Reply #4 on: June 22, 2010, 09:55:03 am »

This is sort of off-topic in this thread, but more sophisticated bass management is on the to-do list.  We're taking requests now.

We're not sure if the system belongs in the 'Output Format' DSP, in 'Room Correction', or in a new DSP 'Bass Management'.
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Matt Ashland, JRiver Media Center

sunfire7

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Re: Upmixing to 5.1 adds a lot of Bass
« Reply #5 on: June 22, 2010, 11:06:47 am »

New DSP !
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flac.rules

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Re: Upmixing to 5.1 adds a lot of Bass
« Reply #6 on: June 22, 2010, 04:05:36 pm »

Elvis133,

The JRSS upmixing to 5.1 does not remove the bass from your mains below the crossover point. Therefore, you are getting bass not only out of the LFE channel, but it is combining with the bass in your mains.

If you have a receiver, you could use Dolby ProLogic II to upmix. You should also only set the crossover on either the receiver or Media Center. Using both crossovers will create a cascading effect and you will get reduced output around the crossover frequency.

If you use JRSS and set the crossover to none, instead of no information going to the LFE channel, you now get all frequencies going to the LFE channel. It basically duplicates the main channels into the LFE channel. Therefore, you can't use JRSS with a receiver's crossover.

Yeah, i understand that, my understanding is that so does most receivers. (add info that are below crossover in mains to the sub-channel), however, this should be the case with stereo too. Rember, my problem is that bass is much higher on upmixing than on stereo alone. Thanks for the tip on the dolby-thing, I am actually already using my receiver for upmixing at the moment.

I don't quite undersant your first statement about the crossover in conjunction with the second, your first stement seems to indicate that i should se the crossover to "none" in MC if i set it in the receiver, but the second seems to indicate that i should not set it to none? Would it be possible to clarify abit?
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mojave

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Re: Upmixing to 5.1 adds a lot of Bass
« Reply #7 on: June 23, 2010, 09:20:32 am »

Yeah, i understand that, my understanding is that so does most receivers. (add info that are below crossover in mains to the sub-channel), however, this should be the case with stereo too.
The receivers always start to rolloff the frequencies a little above the crossover frequency. You usually lose 12 dB per octave so a crossover set at 80 Hz would be down 12dB by 40 Hz. With JRSS, at 40 Hz you are still receiving the full signal in your mains.

Quote
Rember, my problem is that bass is much higher on upmixing than on stereo alone. Thanks for the tip on the dolby-thing, I am actually already using my receiver for upmixing at the moment.
This is be related to how you have your system calibrated. You might have the gain on the subwoofer turned up too high and your receiver is compensating by lowering the level on that channel (if you have Audyssey or some other room correction in your receiver). You could lower the gain on the sub so that the redirected bass is at the same level as when you just play in stereo. You could also just use the Room Correction DSP in MC to lower the volume level of the sub channel. Then you would probably need to increase the gain in the receiver for that channel. The main point to consider is that currently your subwoofer is playing too loud in relation to your mains when using MC.

Quote
I don't quite undersant your first statement about the crossover in conjunction with the second, your first stement seems to indicate that i should se the crossover to "none" in MC if i set it in the receiver, but the second seems to indicate that i should not set it to none? Would it be possible to clarify abit?
I was trying to clarify that if you use the receiver for bass management, you also must use it to upmix. This is because if you upmix to 5.1 in MC and even with the crossover set to None, the full range signal is still sent to the subwoofer. This prevents you from doing any bass management with the receiver. Does this make sense?
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flac.rules

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Re: Upmixing to 5.1 adds a lot of Bass
« Reply #8 on: July 06, 2010, 02:46:07 am »

The receivers always start to rolloff the frequencies a little above the crossover frequency. You usually lose 12 dB per octave so a crossover set at 80 Hz would be down 12dB by 40 Hz. With JRSS, at 40 Hz you are still receiving the full signal in your mains.
This is be related to how you have your system calibrated. You might have the gain on the subwoofer turned up too high and your receiver is compensating by lowering the level on that channel (if you have Audyssey or some other room correction in your receiver). You could lower the gain on the sub so that the redirected bass is at the same level as when you just play in stereo. You could also just use the Room Correction DSP in MC to lower the volume level of the sub channel. Then you would probably need to increase the gain in the receiver for that channel. The main point to consider is that currently your subwoofer is playing too loud in relation to your mains when using MC.
I was trying to clarify that if you use the receiver for bass management, you also must use it to upmix. This is because if you upmix to 5.1 in MC and even with the crossover set to None, the full range signal is still sent to the subwoofer. This prevents you from doing any bass management with the receiver. Does this make sense?


Hello, sorry for the extremly late reply, i have been busy getting married.

To clarify, the problemm isn't simply one of the sub gain beeing wrong, the problem is that the relative level of the usb is different in MC in upmixing mode than in stereo-mode, if its perfectly calibrated in stereo, the sub will be to high in upmixing, or the other way around, if i lower the gain, it will be to low in stereo, this is the case no matter what is actually setting the gain (the sub itself, audessey and so on)

I can't see how setting no crossover prevents the receiver from doing managment? First of all, the LFE-track is only up to 120 Hz(?), so MC should only send up to 120 Hz on that track. Secondly, if the receiver has the crossover at for instance 80 Hz, it will only send info that are from 80 Hz and below from the LFE-track, even though it has inof up to 120 Hz, shouldn't this be the case also when MC outputs the 5.1-signal?
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flac.rules

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Re: Upmixing to 5.1 adds a lot of Bass
« Reply #9 on: July 06, 2010, 02:50:27 am »

I have read the changelog, and see som extremly interesting updates concerning the bass-managment, I will check out the new version. Very good work guys!
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JimH

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Re: Upmixing to 5.1 adds a lot of Bass
« Reply #10 on: July 06, 2010, 06:30:13 am »

Hello, sorry for the extremly late reply, i have been busy getting married.
On behalf of the forum, congratulations!   :) :D 8)
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