# Bass Management - Need Help!



## vann_d (Apr 7, 2009)

Analog audio out to 3.2 system
M-Audio Revo 7.1 sound card
Win7 64-bit

My problems are these:



Must set configure speakers in Win7 Sounds and Devices to 5.1 audio. If I set as 3.1, MC7 tells me video codec not found or not installed. I think this means surround content is lost.
Also, in M-Audio control panel if I do not enable bass management I do not get bass below crossover frequency directed to the subwoofer. This means 2 channel sounds terrible. If I enable bass management, when playing 5.1 content the subwoofer signal clips terribly unless I set LFE to -10dB. This did not happen when I had a 2.1 setup. With 2.1, I set windows to 2.0 stereo and used M-Audio bass management. Now, the combo of speaker channel re-directed bass plus LFE gives me clipping.
Any ideas? My speakers are configured in windows as small. In M-Audio, they are medium with crossover at 100Hz. Again, if I don't set LFE to -10dB, I get bad clipping on sub channel with bass management engaged (5.1 tracks). If I uncheck bass management, I still get LFE on 5.1 tracks but with stereo I get no bass redirected to sub. Not sure what I should do. Windows works in mysterious ways so maybe I'm missing something there.

Need Help! :hissyfit:


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## nova (Apr 30, 2006)

An interesting dilemma, first thing I'd do is check for driver updates. Does not sound like you're missing anything, sounds like a software issue to me.


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## Gregr (Nov 2, 2010)

Input..., need more input???.
There are a min of three sources you will need to consider right? The first two the sound card and the computer. What type of connection are you using? a 75ohm digital I believe is best..., direct from the sound card. In this case the the computer will simply have to be out of the way of the sound file in play. 

Now the card input from the computer is only 2 channel except for DVD and other known multichannel media. You can still play multichannel media with 2 channel input setting. However you cannot play 4,6 or 8 channel input to the sound card. Anything more than 2 channel input to the sound card for stereo music will cause an error.

What your M-Audio card outputs must now be read by your AVR Pre-Amp and your AVR has lots of preferences to consider..., right. 

Does your Pre/Pro have a low level LFE out?


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## vann_d (Apr 7, 2009)

HTPC is the pre/pro. There is no AVR. I'm using analog out from soundcard directly to a multi-channel amp then speakers.

Drivers are the newest available. Unfortunately, M-Audio is not really supporting this product anymore (or for some time) .

The bass management problem only seems to occur with movies on DVD or Video_TS. I haven't tried blu-ray yet. Doesn't seem to have a problem on broadcast TV.

My temporary solution is to leave bass management turned on except when watching a movie. This is far less than ideal because I'm not the only user of this system. I almost blew my woofer cones right out of their baskets today during the DVD menu for Startrek because bass management was enabled.


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## Gregr (Nov 2, 2010)

Ya know, I do not mean to be over-simplistic but lets not overlook the first step. Your MOBO sound codec must be disabled. 
I am using Win7-64bit. So, right click on "'My Computer" then click "Properties" then click "Device Manager" click "Sound" and now right click then click "Disable" each sound device except for M-Audio. While you are here check to see if M-Audio has updates and is set up properly.

Now that the computer is out of the way you can focus your attention on the M_Audio driver/program. Make sure the input is only 2 channel sound for music. There should be a "Main Settings" or "Overview" page.

I wrote this two hours ago. 

I am writing now to respond to newest post.


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## vann_d (Apr 7, 2009)

Thanks I'm interested to hear your ideas.


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## Gregr (Nov 2, 2010)

What Amp is it? Which Model ?
Is there a sub out on the amp?
Is your sub Passive or Active..., Powered or Not Powered?
Are you using a Digital or analog connection to your sub"
Does M-Audio offer a Center Channel/Subwoofer swap option in your driver software package?
What model M-Audio sound card?
Is there a direct sub-out on the M-Audio Card?

I use an HT Omega Claro+ sound card..., this is an amazing card.

I need all of the info you've got..., what are the specifics.

When you go into the sound card driver software does it offer PCM (Pulse Code Mod)
DTS Interactive (Digital Theater Sys) or Dolby Live? Try PCM this is probably the simplest codec with a high degree of compatibility and most likely to work without issue. 

Let me know


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## Gregr (Nov 2, 2010)

If your sub is powered..., pull the speaker cables and use your sound card sub low level out to the sub.


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## Gregr (Nov 2, 2010)

One more thought. To my knowledge there is no 3.1 channel codec. Manufacturers offer a 3.1 channel Sound Bar and with the added 2 Television speaker channels you can use the 5.1 protocol. Any two speakers will do to make up the five.


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## vann_d (Apr 7, 2009)

Thanks for your thoughts Gregr.

The amp and subwoofer are really kind of irrelevant as this is a problem that is occuring before audio leaves the computer. Anyhow, it is a DIY 6-channel amp based on 3 Shure 2 x 300W chip amp boards. Each channel accepts an RCA line level input. I am taking line level analog audio out from the soundcard. 4 channels: FR FL Center and Sub. I do not have surround speakers in this system. I'm splitting the sub channel into two of the amplifier channels that power two passive DIY subwoofers.

The soundcard is M-Audio Revolution 7.1. The only surround processing it has is Circle Surround which I am choosing not to use. The on-board audio is still enabled because I use it for headphones. I don't think my revo card has front panel audio. I will try disabling anyhow to see if that fixes it.

Playback software is MC7, Pandora, or PowereDVD11.


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## vann_d (Apr 7, 2009)

The reason I mentioned the 3.1 audio setup is that it shows up as an available option in win7 sounds when I have speakers connected this way. MC7 does not like it however and will not play video with this setting. Leaving win7 sounds speaker config on stereo prevents 5.1 playback in MC7.

I'm dreading the uninstall/reboot/install cycle I see in my future.


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## Gregr (Nov 2, 2010)

Let me just say this..., I am not sure you can do any of this with the amp you have. It sounds like a nice amp. If I remember correctly it is recommended you only power up when all speakers are connected or all amp channels connected. Any amp channel not connected to a speaker but receiving a signal could overheat and/or incur some form of damage.


What I have for thoughts at this point is about connections: first a low level out for front L/R that is a 3.5mm out to two RCA's and into two amp channels. Next is Center/Subwoofer..., this is not Center Channel or Subwoofer. This is Center Channel and Sub. So the output is again a 3.5mm out to two RCA's. From one channel of the power amp you can split to power the two subs. Next you need two additional speakers to make up the 5.1. 

I am thinking with the M-Audio card you can adjust output to the two additional speakers to a minimum output, so that your 200w output doesn't blow them up. Keep your volume low until you get this all settled. 

I believe there are others here at HTS with specific experience with Sure chips/boards and your sound card. M-Audio makes a nice card and the 24/192 tells me it is a few years old and I wonder about auto switching, sound steering. I just do not know. With some of the newer Amps with various logic boards you may try splitting from the sound card to the seperate amp channels but again..., I do not know what will happen. The fact you have not blown anything up says at the very least, you have a tough amp.

What I have given you is the safe choice that will work if all else is working.


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## vann_d (Apr 7, 2009)

Thanks for your concern Gregr but I'm confident that I'm not endangering the amp. I do, in fact, have the channels connected as you suggest. (3.5mm to stereo RCA -> RCA line level in to amp channel(s) -> amp channel high level out to speakers)

I've tried disabling the on-board audio. It makes no difference. Whenever there is a significant LFE signal present in the material and bass management is enabled on the speakers, the sub channel will clip. I can see it clipping in the M-Audio output mixer. It makes no difference if I turn down the sub channel in the output mix. It will still clip signal, just at lower output level. Disabling bass management is not a good option with my small bookshelf speakers.

I've tried all the available drivers from M-Audio. The best functioning are the Vista 64-bit ones but all that I've managed to make function with Win7 have the bass management issue. My conclusion is that, while this was a nice card for XP, the Revo 7.1 does not function with Win7.

I'm going to try and live with on-board audio for the time being if I can get its bass management figured out. I'll post an update.

Looks like I'm in the market for a new soundcard with modern drivers compatible with Windows7. Any suggestions (sub $200). I was looking at HT|Omega Striker and ASUS Xonar D1


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## vann_d (Apr 7, 2009)

K, I made the switch to on-board audio analog out and everything is working as it should. Sounds good so far. I haven't been able to do any critical listening yet to compare sq to the M-Audio card but it definitely gets a lot of points for functionality!

Thanks Gregr for all your suggestions. I think it's just a device driver problem that is never gonna get solved for this piece of hardware.

BTW, the DIY amp thing is still very much a work in progress...as in no enclosure yet . Attached are a couple pics. Specs from TI on the chip are 300W at 4ohm an 10% THD+N. At a more reasonable 1% THD+N, its more like 200W at 4ohm and 100W at 8ohm (per channel). You can see I'm using 5 of the 6 channels (L,R,C,Sub x 2).


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## Gregr (Nov 2, 2010)

Nice kit! 200w is the sweet spot for me. I wish I had never sold my PS Audio. 

Looks like channel #6 has direct cooling, prob don't need to worry about overheating. You've got an impressive PS. Does the PS detect the empty channel.

Looks like a nice start on some good listening. May the Gods be with you.


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## vann_d (Apr 7, 2009)

Thanks! The amp has self-protection built in the circuitry so no problems. Also, channel 6 will just be in idle mode so will not draw much power from supply.


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## Gregr (Nov 2, 2010)

Nice!

I cannot be careful enough when I'm the first responding to a thread. I do not want to end up buying somebody's experiment. You know what I mean.


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## RTS100x5 (Sep 12, 2009)

Try this....Using FOOBAR 2000 with WASAPI add on as a source.....youll have to setup FB propeties w WASAPI. This setup will bypass Win7 audio properties and give a better understanding of the problem... If I may ask,, Ive always understood that a soundcard is a line voltage output and therefore not capable of driving an Amplifier input stage sufficiently ..... thats why we dont have CD players et all connected directly to amps thus the necessity for Preamps..... lddude:


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## vann_d (Apr 7, 2009)

Preamps can be used to provide gain for mics and turntables but with sources such as CD players they just provide input switching and volume control. A computer soundcard should be able to output 2V or so which is plenty to drive most amplifiers.

I like the Foobar idea. Will help me understand the problem. Unfortunately, it doesn't help resolve the issue with MC7. I need to try JRiver again because I think that software will bypass windows settings as well. Unfortunately, I've tried it twice already and haven't successfully been able to setup the tv tuner (or at least gotten it to work the way I want).


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