Unwanted frequencies on LFE output

svenjohan · Nov 24, 2007, 11:33 AM

I'm trying to set up a 2.1 DSP.

Thing is, the full range of sounds still come trough to the subwoofer output. At a low volume level but they are there. If I disconnect the Front (i.e. rear) outputs from k2lt only the freq's that are supposed to end up on the subwoofer outputs does.

Results are the same if I use epilog instead of the profx thingy, also the same if I use the front or rear outputs.

This is my setup:
HIDEBEHIND.COM - free anonymous image & movie host - kx2.1.JPG

The amp for the subwoofer is a normal amp so it only amplifies what it gets on its inputs, and the subwoofer doesn't have any filters in it so this is not such a good thing.

I get the feeling that this is a hardware related problem..

The card I use is a Audigy 2 ZS. Would it be possible to get around this problem if I added yet another card (I have a Live 5.1 lying around somewhere) and somehow used outputs of that card instead? Without adding a delay o the sub ofcourse..

Russ · Nov 24, 2007, 01:25 PM

Quote:

Originally Posted by svenjohan

The amp for the subwoofer is a normal amp so it only amplifies what it gets on its inputs, and the subwoofer doesn't have any filters in it so this is not such a good thing.

Are you absolutely sure of the above? It really sounds like it is an issue with the speaker system.

What happens if you disconnect the sub connection in the DSP, is the sub completely silent?

What happens if you connect the front speakers to a separate audio source (i.e. portable CD or mp3 player, etc), with the sub still connected to the computer, with audio playing on both sources?

svenjohan · Nov 24, 2007, 02:57 PM

Thank you for replying.

Quote:

Originally Posted by Russ

What happens if you disconnect the sub connection in the DSP, is the sub completely silent?

With the sub disconnected and the fronts connected to k2lt the full range of the source I'm playing ends up at the sub at very low level. When I disconnect everything from k2lt everything goes silent.

I've currently disconnected all wires between computer and amps (at both ends) except the one for the sub amp and the problem persists.

Quote:

What happens if you connect the front speakers to a separate audio source (i.e. portable CD or mp3 player, etc), with the sub still connected to the computer, with audio playing on both sources?

Works as it should, no trace of external source in sub, or vice versa.

As stated before, with only the sub connected in the DSP it works as it should but when I connect the high outs from the 4th order crossover to left and right outputs on k2lt a tiny bit of this sound also ends up at the sub.

Some more info on my setup:
Driver:
Version: 5, 10, 00, 3539 - debug
Kompilerad: Aug 24 2007 17:27:48

Amplifiers are seperate NAD power amplifiers. (no pre-amp involved between soundcard and power amps).

But other people using similar setup does not have this problem so it's not an issue with the design of the soundcard, right? If so I'll have to dig deeper into my cables and such.

Russ · Nov 24, 2007, 04:58 PM

Quote:

Originally Posted by svenjohan

With the sub disconnected and the fronts connected to k2lt the full range of the source I'm playing ends up at the sub at very low level. When I disconnect everything from k2lt everything goes silent.

I've currently disconnected all wires between computer and amps (at both ends) except the one for the sub amp and the problem persists.

Hmm, thats strange. I do not have an SB0350, but with my card (Live! 5.1) I get no such bleeding. From your above info, it does seem to be an issue with the card or something with kX...

Try resetting AC97 (button on AC97 page) in case something is screwy there.

With an older version of kX (one that did not fully support my card) I would get some such bleeding when the SEND levels were set to anything over 0. Just for the heck of it, open up kX Router and set the SEND levels (for Wave 0/1, Synth1, and Synth2) to 0 (make sure no audio is playing when making the changes, as it may not take effect immediately otherwise), and see if it makes any difference.

svenjohan · Nov 25, 2007, 08:14 AM

I've now tried resetting AC97 and setting send levels to 0, no change in results.

Also downgraded to 3538m, still no luck.

Russ · Nov 25, 2007, 11:43 AM

Yeah, I did not think it would make a difference, but I figured that it could not hurt to try...

Assuming your above info is accurate (i.e. only the sub is connected to the sound card (connected to LFE out), with only the fronts connected in the DSP, you still get audio in the sub) I do not know, I cannot think of anything else at the moment. Again, this does not happen with my card, but it would be good if someone else with a SB0350 could verify that they do not have the same issue. If others with the same model do not have this problem, then I can only conclude that there is something wrong with the sound card itself.

If you do have another kX compatible card lying around as you stated, then you might want to test that card as well (just to help rule out other possible causes).

BTW: Since you are not using the rear output anyway (2.1 setup), have you tried using the rear output for LFE (that would be the best workaround... assuming that it does not exhibit the same behavior)?

Max M. · Nov 25, 2007, 12:36 PM

by the way, i'm not sure - but could not it be a kind of "mis-jacking"?
AFAIR, A2ZS has no dedicated "subwoofer output" - its "LineOut3" is a combined "center/sub/side/whatever-else" output... So, maybe it has something to do with just an incompatible jack? (Although it does not explain why _frînt_ is bleeding)

Russ · Nov 25, 2007, 01:05 PM

I wondered that too, but (as you said) I could not think of any reason for the front to bleed into any of those channels (but if it is somehow bleeding into both side channels, then the rear jack (Line Out 2) may have similar problem).

svenjohan · Nov 25, 2007, 01:31 PM

Quote:

Originally Posted by Russ

BTW: Since you are not using the rear output anyway (2.1 setup), have you tried using the rear output for LFE (that would be the best workaround... assuming that it does not exhibit the same behavior)?

Actually it is a 5.1 setup but with separate DSP for 2.1 and 5.1. I tried the above and now it works. Of course now there's some bleeding in the surrounds when that amp's turned on but that does not really matter to me.

Thanks!

It now appears that this thread was posted in the wrong fora, sorry about that.

Russ · Nov 25, 2007, 01:41 PM

If you get some cables with 4 pole connectors, you could utilize the other outputs in both jacks and *maybe* you can find 4 channels (out of the 6) that will work for 5.1 (together with the fronts) without the bleeding.

BTW: (out of curiosity) Does the swap front and rear option make any difference (with the original problem)?

svenjohan · Nov 25, 2007, 02:04 PM

Quote:

Originally Posted by Russ

If you get some cables with 4 pole connectors, you could utilize the other outputs in both jacks and *maybe* you can find 4 channels (out of the 6) that will work for 5.1 (together with the fronts) without the bleeding.

I'll look into that, it would be nice to have two separate subwoofer outputs. However I have the feeling that this is some sort of proprietary connector of creative's which would make it a bit hard to come by. I suppose it's included with the card reatil but I bought this of ebay..

Quote:

BTW: (out of curiosity) Does the swap front and rear option make any difference (with the original problem)?

Nope. Bleeding on what used to be my LFE (and now is my right surround) out occours whenever I connect something to any of the analouge outputs on k2lt, connecting to the SPDIF pin does not cause problems though.

And further investigation has shown that it only occours on what now is my right surround, the left one is silent. So swapping center/lfe would also have helped.

Russ · Nov 25, 2007, 02:32 PM

You should be able to get the cable from Creative, and IIRC, the iBook A/V cable has the correct pinout for most of the 4 pole jacks used on these cards:

The thing to look for is the location of the ground (it is different from most camcorder cables).
i.e.
Line Out 3 pinout

As for the bleeding, check the card to make sure something is not shorting out some of the connections (circuit board traces or header pins, etc)

i.e. A loose wire in the PC, some small metal object, or bent pins (touching each other) on one of the headers, etc.

Quote:

Originally Posted by svenjohan

So swapping center/lfe would also have helped.

Ok, so that is probably a better option for you as it should allow for both 2.1 and 5.1 without any bleeding.

Nov 24, 2007, 11:33 AM	#1
svenjohan DriverHeaven Newbie Join Date: Nov 2007 Posts: 7 Rep Power: 0	Unwanted frequencies on LFE output I'm trying to set up a 2.1 DSP. Thing is, the full range of sounds still come trough to the subwoofer output. At a low volume level but they are there. If I disconnect the Front (i.e. rear) outputs from k2lt only the freq's that are supposed to end up on the subwoofer outputs does. Results are the same if I use epilog instead of the profx thingy, also the same if I use the front or rear outputs. This is my setup: HIDEBEHIND.COM - free anonymous image & movie host - kx2.1.JPG The amp for the subwoofer is a normal amp so it only amplifies what it gets on its inputs, and the subwoofer doesn't have any filters in it so this is not such a good thing. I get the feeling that this is a hardware related problem.. The card I use is a Audigy 2 ZS. Would it be possible to get around this problem if I added yet another card (I have a Live 5.1 lying around somewhere) and somehow used outputs of that card instead? Without adding a delay o the sub ofcourse..

Nov 25, 2007, 11:43 AM	#6
Russ HardwareHeaven Extreme Member Join Date: Jan 2005 Posts: 5,561 Rep Power: 62	Yeah, I did not think it would make a difference, but I figured that it could not hurt to try... Assuming your above info is accurate (i.e. only the sub is connected to the sound card (connected to LFE out), with only the fronts connected in the DSP, you still get audio in the sub) I do not know, I cannot think of anything else at the moment. Again, this does not happen with my card, but it would be good if someone else with a SB0350 could verify that they do not have the same issue. If others with the same model do not have this problem, then I can only conclude that there is something wrong with the sound card itself. If you do have another kX compatible card lying around as you stated, then you might want to test that card as well (just to help rule out other possible causes). BTW: Since you are not using the rear output anyway (2.1 setup), have you tried using the rear output for LFE (that would be the best workaround... assuming that it does not exhibit the same behavior)? Last edited by Russ; Nov 25, 2007 at 12:10 PM.

Nov 25, 2007, 12:36 PM	#7
Max M. h/h member-shmember Join Date: Dec 2002 Location: Evil Empire Posts: 2,639 Rep Power: 69	by the way, i'm not sure - but could not it be a kind of "mis-jacking"? AFAIR, A2ZS has no dedicated "subwoofer output" - its "LineOut3" is a combined "center/sub/side/whatever-else" output... So, maybe it has something to do with just an incompatible jack? (Although it does not explain why _frînt_ is bleeding) Last edited by Max M.; Nov 25, 2007 at 12:44 PM.

Nov 25, 2007, 01:05 PM	#8
Russ HardwareHeaven Extreme Member Join Date: Jan 2005 Posts: 5,561 Rep Power: 62	I wondered that too, but (as you said) I could not think of any reason for the front to bleed into any of those channels (but if it is somehow bleeding into both side channels, then the rear jack (Line Out 2) may have similar problem). Last edited by Russ; Nov 25, 2007 at 01:46 PM.

Nov 25, 2007, 01:41 PM	#10
Russ HardwareHeaven Extreme Member Join Date: Jan 2005 Posts: 5,561 Rep Power: 62	If you get some cables with 4 pole connectors, you could utilize the other outputs in both jacks and maybe you can find 4 channels (out of the 6) that will work for 5.1 (together with the fronts) without the bleeding. BTW: (out of curiosity) Does the swap front and rear option make any difference (with the original problem)? Last edited by Russ; Nov 25, 2007 at 01:46 PM. Reason: spelling

Nov 25, 2007, 08:14 AM	Thread Starter #5
svenjohan DriverHeaven Newbie Join Date: Nov 2007 Posts: 7 Rep Power: 0	I've now tried resetting AC97 and setting send levels to 0, no change in results. Also downgraded to 3538m, still no luck.