| MOTU problem - ideas? [message #85170] |
Thu, 24 May 2007 16:26  |
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dc[3]
Messages: 895
Registered: September 2005
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Senior Member |
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So, I am helping a friend get his studio monitors and sub dialed
in. We spend a couple of hours with the analyzer straight into
the powered speakers and move things around, play with
crossover points, etc, and get it pretty decent. Because of his
placing the monitors on the console he had the usual 100hz.
bump from the baffle extension. I got a brainstorm... Why not
develop a 2 channel EQ template in Logic that he could put across
the stereo masters and correct the speaker bump?
So, I put the pink noise into Logic via a MOTU 2408 and dang!
there is an even bigger bump at 100... About 5db worse than
straight to the speakers... Quit out of Logic and run the signal
throught the MOTU PC424 virtual mixer only. No difference...
Where is this bass bump coming from? Anyone seen this?
MOTU tech support has so far been zero help on this issue.
Ideas?
thanks
DC
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| Re: MOTU problem - ideas? [message #85180 is a reply to message #85179] |
Thu, 24 May 2007 18:10  |
dc[3]
Messages: 895
Registered: September 2005
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Senior Member |
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Yes, or something in the 2408 hardware...
I can't get MOTU to take this issue seriously. The guy actually
sent me audio files of 1K and 100hz. sinewaves to play back from
inside Logic....
I don't know what he is thinking other than trying to find
somewhere else to point a finger. Maybe if the files playback
at equal levels he can say "no problem found" and go get some
coffee...
I'm trying to get him to understand that it even happens on
the 424 mixer, but he keeps coming back with the files to
play back... So I am supposed to drive for two hours to see if
the problem exists in a totally different set of conditions.
Pass pink noise through the 2408 and back out and you get a
bass hump... What the hell is going on?
Very annoying.
DC
"Neil" <IUOIU@OI.com> wrote:
>
>Well then it's gotta be a bump that's built into the Virtual
>Mixer software, innit?
>
>Neil
>
>
>"DC" <dc@spammersinhell.com> wrote:
>>
>>Exactly! But even with a speaker off, the bump is still there...
>>
>>very strange huh?
>>
>>DC
>>
>>
>>"Neil" <IUOIU@OIU.com> wrote:
>>>
>>>"DC" <dc@spammersinhell.com> wrote:
>>>>So, I put the pink noise into Logic via a MOTU 2408 and dang!
>>>>there is an even bigger bump at 100... About 5db worse than
>>>>straight to the speakers... Quit out of Logic and run the signal
>>>>throught the MOTU PC424 virtual mixer only. No difference...
>>>>
>>>>Where is this bass bump coming from? Anyone seen this?
>>>
>>>I'll betcha it has something to do with the Panning Law in the
>>>virtual mixer... going straight into the speakers is giving you
>>>a fixed-source spectrum on each speaker, and the panning law of
>>>whatever it's set to in the virtual mixer is affecting
>>>something somewhere.
>>>
>>>Are you using a single mic for the spectrum analysis? If so,
>>>try disconnecting the right speaker, then taking a reading on
>>>the left speaker only with the noise source pumped straight in
>>>vs the same speaker with the noise going through the virtual
>>>mixer & see if there's a difference then. Then switch speakers
>>>& disconnect the left, etc. That method could also rule out
>>>phasing anomalies.
>>>
>>>Neil
>>
>
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| Re: MOTU problem - ideas? [message #85236 is a reply to message #85180] |
Fri, 25 May 2007 08:57 |
Chris Ludwig
Messages: 868
Registered: May 2006
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Senior Member |
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HI DC,
Do you have a external AD/DA? You can probably confirm that way if it is
a in the MOTU hardware. Won't surprise me if they mess with the AD/DA
stage to make it "sound" better.
You could also try using the digital I/O looped back to see if there is
a bump but I'm not sure what your using to do the measurements with.
If it happens on the digital I/O also and you are sure the pan law
between the Motu and Logic are the same then it is either Logic or Motu.
Is there a way to change the the Pan law in the MOTU stuff or in Logic.
I've never seen either option in them.
It will be easy to rule out logic by just using another program to test.
Chris
DC wrote:
> Yes, or something in the 2408 hardware...
>
> I can't get MOTU to take this issue seriously. The guy actually
> sent me audio files of 1K and 100hz. sinewaves to play back from
> inside Logic....
>
> I don't know what he is thinking other than trying to find
> somewhere else to point a finger. Maybe if the files playback
> at equal levels he can say "no problem found" and go get some
> coffee...
>
> I'm trying to get him to understand that it even happens on
> the 424 mixer, but he keeps coming back with the files to
> play back... So I am supposed to drive for two hours to see if
> the problem exists in a totally different set of conditions.
>
> Pass pink noise through the 2408 and back out and you get a
> bass hump... What the hell is going on?
>
> Very annoying.
>
> DC
>
>
> "Neil" <IUOIU@OI.com> wrote:
>> Well then it's gotta be a bump that's built into the Virtual
>> Mixer software, innit?
>>
>> Neil
>>
>>
>> "DC" <dc@spammersinhell.com> wrote:
>>> Exactly! But even with a speaker off, the bump is still there...
>>>
>>> very strange huh?
>>>
>>> DC
>>>
>>>
>>> "Neil" <IUOIU@OIU.com> wrote:
>>>> "DC" <dc@spammersinhell.com> wrote:
>>>>> So, I put the pink noise into Logic via a MOTU 2408 and dang!
>>>>> there is an even bigger bump at 100... About 5db worse than
>>>>> straight to the speakers... Quit out of Logic and run the signal
>>>>> throught the MOTU PC424 virtual mixer only. No difference...
>>>>>
>>>>> Where is this bass bump coming from? Anyone seen this?
>>>> I'll betcha it has something to do with the Panning Law in the
>>>> virtual mixer... going straight into the speakers is giving you
>>>> a fixed-source spectrum on each speaker, and the panning law of
>>>> whatever it's set to in the virtual mixer is affecting
>>>> something somewhere.
>>>>
>>>> Are you using a single mic for the spectrum analysis? If so,
>>>> try disconnecting the right speaker, then taking a reading on
>>>> the left speaker only with the noise source pumped straight in
>>>> vs the same speaker with the noise going through the virtual
>>>> mixer & see if there's a difference then. Then switch speakers
>>>> & disconnect the left, etc. That method could also rule out
>>>> phasing anomalies.
>>>>
>>>> Neil
>
--
Chris Ludwig
ADK Pro Audio
(859) 635-5762
www.adkproaudio.com
chrisl@adkproaudio.com
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