[SlimDevices: Audiophiles] Inches to DB???

[rgro]

Hello,

My amplifier/dac combo does not have any balance controls. Something on
the squeezelite thread got me to thinking and I got my SPL meter out and
measured the db, with pink noise, coming out of my left vs. right
speakers at my listening position. There is a 2-3 db difference with
the right being a bit less than the left. I realize that this is
probably just on the edge of audibility. Currently, and measured with a
laser measuring device, the speakers are almost precisely equidistant
from my listening position. I suspect the cause is likely due to room
and furniture layout----something that leaves me very little room to
adjust the speaker placement. Also, in their current position--to my
ears---voices, etc.. that are supposed to be centered do seem to be.

I suspect the easy solution is to simply move the right speaker a bit
closer. However, my anal-retentive side is interested in precision and
am wondering if, somewhere (can't find anything using a google search)
there is a conversion table that would tell me how many inches closer
the right speaker needs to be to my listening spot in order to increase
its SPL by either 2 or 3 db. Any physics or audio acoustics folks know
of this??

Cheers,



Rg

System information
------------------------
Main: Vortexbox/Squeezelite > USB> Benchmark DAC2 D > LFD LE IV
Signature amp > Revel Performa R208 speakers.

Home Theatre: Touch (Wired) > Pioneer VSX 919 > Energy Take 5 Classic
5.1, Touch FW 7.8.0-r16754.

LMS 7.9.0 - 1415789670 on a 1TB Vortexbox Appliance, V 2.3.
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[Apesbrain]

I suppose you could use SoX via a custom-convert.conf to attenuate the
left channel. But then again...

... in their current position--to my ears---voices, etc.. that are
supposed to be centered do seem to be.

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[rgro]

Post by Apesbrain
I suppose you could use SoX via a custom-convert.conf to attenuate the
left channel. But then again...

You're probably right. It would appear that, using the SPL meter and
just moving towards the speaker, it's several feet and not inches that
would actually increase the db on r.h. speaker to equal the left. And I
suspect that'd screw things up with centering the stereo image more than
just leaving as is---not to mention the speaker would be out in the
middle of the room thus making Mrs. rgro VERY unhappy ;>).



Rg

System information
------------------------
Main: Vortexbox/Squeezelite > USB> Benchmark DAC2 D > LFD LE IV
Signature amp > Revel Performa R208 speakers.

Home Theatre: Touch (Wired) > Pioneer VSX 919 > Energy Take 5 Classic
5.1, Touch FW 7.8.0-r16754.

LMS 7.9.0 - 1415789670 on a 1TB Vortexbox Appliance, V 2.3.
------------------------------------------------------------------------
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[Mnyb]

Yes is esential to keep the speaker distance to listening position the
same for stereo .

A speaker arrangement with such a big flaw is not really usable ?
Headphones is an idea .

Or can the room be rearranged ? Use another wall for the hifi .

Use a home theater reciever or processor , they can often set speaker
levels separately .

But speakers are not linear ,they would sound different anyway by
loading one harder , but maybe that's peanuts compared to the very
different acoustics for Left vs rigth speaker .

Maybe some hardware with built in digital room compensation would be a
possible solution ?

Just tossing some ideas your direction ....



--------------------------------------------------------------------
Main hifi: Touch + CIA PS +MeridianG68J MeridianHD621 MeridianG98DH 2 x
MeridianDSP5200 MeridianDSP5200HC 2 xMeridianDSP3100 +Rel Stadium 3
sub.
Bedroom/Office: Boom
Kitchen: Touch + powered Fostex PM0.4
Misc use: Radio (with battery)
iPad1 with iPengHD & SqueezePad
(in storage SB3, reciever ,controller )
server HP proliant micro server N36L with ClearOS Linux

http://people.xiph.org/~xiphmont/demo/neil-young.html
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[rgro]

Post by Mnyb
Yes is esential to keep the speaker distance to listening position the
same for stereo .
A speaker arrangement with such a big flaw is not really usable ?
Headphones is an idea .
Or can the room be rearranged ? Use another wall for the hifi .
Use a home theater reciever or processor , they can often set speaker
levels separately .
But speakers are not linear ,they would sound different anyway by
loading one harder , but maybe that's peanuts compared to the very
different acoustics for Left vs rigth speaker .
Maybe some hardware with built in digital room compensation would be a
possible solution ?
Just tossing some ideas your direction ....

Much appreciated, Michael. The Revels actually sound terrific in the
configuration I have them where they are equidistant....just the usual
"nervosa" that maybe that extra 2 db to balance the right speaker would
make things sound even better! I think the room compensation hardware
is, indeed, probably the ultimate answer, but I'm not quite ready to
take that leap in terms of complexity and expense.



Rg

System information
------------------------
Main: Vortexbox/Squeezelite > USB> Benchmark DAC2 D > LFD LE IV
Signature amp > Revel Performa R208 speakers.

Home Theatre: Touch (Wired) > Pioneer VSX 919 > Energy Take 5 Classic
5.1, Touch FW 7.8.0-r16754.

LMS 7.9.0 - 1415789670 on a 1TB Vortexbox Appliance, V 2.3.
------------------------------------------------------------------------
rgro's Profile: http://forums.slimdevices.com/member.php?userid=34348
View this thread: http://forums.slimdevices.com/showthread.php?t=102960

[Mnyb]

Post by rgro
Much appreciated, Michael. The Revels actually sound terrific in the
configuration I have them where they are equidistant....just the usual
"nervosa" that maybe that extra 2 db to balance the right speaker would
make things sound even better! I think the room compensation hardware
is, indeed, probably the ultimate answer, but I'm not quite ready to
take that leap in terms of complexity and expense.

There is a way to manipulate a Touch to do this I answered you in the
squeezelite tread about it ..

But as Julf said you fixing the symptoms not the problem ..



--------------------------------------------------------------------
Main hifi: Touch + CIA PS +MeridianG68J MeridianHD621 MeridianG98DH 2 x
MeridianDSP5200 MeridianDSP5200HC 2 xMeridianDSP3100 +Rel Stadium 3
sub.
Bedroom/Office: Boom
Kitchen: Touch + powered Fostex PM0.4
Misc use: Radio (with battery)
iPad1 with iPengHD & SqueezePad
(in storage SB3, reciever ,controller )
server HP proliant micro server N36L with ClearOS Linux

http://people.xiph.org/~xiphmont/demo/neil-young.html
------------------------------------------------------------------------
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[darrenyeats]

Using an SPL meter like this, the measurement is a combination of direct
and reflected sound. These are processed differently by the brain; it's
not at all clear to me that correcting for the 2-3db discrepancy you
measured will lead to a better result. I'd be more inclined to look at
speaker positioning and acoustics.

For example, is the room more reflective to one side? I'd try to address
the root cause.



Check it, add to it! http://www.dr.loudness-war.info/

SB Touch
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[rgro]

Post by darrenyeats
Using an SPL meter like this, the measurement is a combination of direct
and reflected sound. These are processed differently by the brain; I'm
not sure correcting (either with EQ or distance) for the 2-3db
discrepancy you measured will lead to a better result. I'd be more
inclined to look at speaker positioning and acoustics.
For example, is the room more reflective to one side? I'd try to address
the root cause.

Yeah, Darren, the room is quite problematic. The LH speaker is on the
back open side of the room with the nearest side wall about 10' away.
Big picture window behind both speakers. There is a side wall about 3'
to the right of the RH speaker plus there's a sofa about 3' ahead of the
speaker along that same wall. I've toed the RH speaker in to direct the
sound away from the sofa as much as possible, but it's a rather delicate
balancing act. It is what it is, as they say, and due to any number of
factors, marital bliss being at the top of the list, things aren't going
to change. I actually find it a bit remarkable that everything sounds
as good as it does.

And, of course, it's also quite possible that the db readings are within
the error range of the Radio Shack spl meter, heh.



Rg

System information
------------------------
Main: Vortexbox/Squeezelite > USB> Benchmark DAC2 D > LFD LE IV
Signature amp > Revel Performa R208 speakers.

Home Theatre: Touch (Wired) > Pioneer VSX 919 > Energy Take 5 Classic
5.1, Touch FW 7.8.0-r16754.

LMS 7.9.0 - 1415789670 on a 1TB Vortexbox Appliance, V 2.3.
------------------------------------------------------------------------
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[Julf]

And the human ear-brain chain is pretty good at compensating for room
oddities...



"To try to judge the real from the false will always be hard. In this
fast-growing art of 'high fidelity' the quackery will bear a solid gilt
edge that will fool many people" - Paul W Klipsch, 1953
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[rgro]

Post by Julf
And the human ear-brain chain is pretty good at compensating for room
oddities...

A devilish combination...master of both elegant compensation and
subliminal deceit!!



Rg

System information
------------------------
Main: Vortexbox/Squeezelite > USB> Benchmark DAC2 D > LFD LE IV
Signature amp > Revel Performa R208 speakers.

Home Theatre: Touch (Wired) > Pioneer VSX 919 > Energy Take 5 Classic
5.1, Touch FW 7.8.0-r16754.

LMS 7.9.0 - 1415789670 on a 1TB Vortexbox Appliance, V 2.3.
------------------------------------------------------------------------
rgro's Profile: http://forums.slimdevices.com/member.php?userid=34348
View this thread: http://forums.slimdevices.com/showthread.php?t=102960

[Julf]

Post by rgro
A devilish combination...master of both elegant compensation and
subliminal deceit!!

That doesn't of course apply to people who *know* what they hear... :)



"To try to judge the real from the false will always be hard. In this
fast-growing art of 'high fidelity' the quackery will bear a solid gilt
edge that will fool many people" - Paul W Klipsch, 1953
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[Julf]

Post by rgro
I suspect the easy solution is to simply move the right speaker a bit
closer. However, my anal-retentive side is interested in precision and
am wondering if, somewhere (can't find anything using a google search)
there is a conversion table that would tell me how many inches closer
the right speaker needs to be to my listening spot in order to increase
its SPL by either 2 or 3 db. Any physics or audio acoustics folks know
of this??

Unfortunately there is no simple formula or table, as it depends on the
directivity (and size) of your speakers as well as the reflections from
floor and walls. 2 or 3 db doesn't feel like a big difference, but in
terms of actual acoustic energy it is, so the distance you would need to
move the speaker will be significant. It will also disturb the temporal
arrangement of the channels - sound from the speaker closer to you will
arrive earlier, confusing/distorting the stereo image.



"To try to judge the real from the false will always be hard. In this
fast-growing art of 'high fidelity' the quackery will bear a solid gilt
edge that will fool many people" - Paul W Klipsch, 1953
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