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Old 18th March 2010, 07:58 PM   #781
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Quote:
Originally Posted by gedlee View Post
Flat in room LF response spatially averaged is the key, and only multiple LF sources can do this in a small room.
Sometimes one single subwoofer and a good EQ is all you need:

Click the image to open in full size.

Best, Markus
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Old 18th March 2010, 08:34 PM   #782
gedlee is offline gedlee  United States
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Quote:
Originally Posted by markus76 View Post
Sometimes one single subwoofer and a good EQ is all you need:

Click the image to open in full size.

Best, Markus
Markus

There are no hard and fast rules when one is tal;king about LF in small rooms. Every situation is unique.
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Old 18th March 2010, 09:01 PM   #783
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Quote:
Originally Posted by gedlee View Post
Markus

There are no hard and fast rules when one is tal;king about LF in small rooms. Every situation is unique.
Yes, that's probably the only valid rule. Nonetheless it shows that measurments are indispensable. This is the frequency response with the subwoofer in a corner, downfiring (could be worse):

Click the image to open in full size.

In corner at ear level:

Click the image to open in full size.

After EQing:

Click the image to open in full size.

Lift at 25Hz:

Click the image to open in full size.
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Old 18th March 2010, 09:13 PM   #784
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Default Small (average german) living rooms

Categorization of frequency ranges in room acoustics:

A from 'lower frequency limit of hearing' to
B '1st room mode' to
C 'Schröder frequency' to
D 'Schröder frequency x 4' to 'Upper frequency limit of hearing'

Categories based on:
Michael, Dickreiter: Handbuch der Tonstudiotechnik, Band 1, 6. Auflage,
München: K.G. Saur Verlag, 1997
-----------------

A: Room pressurization, no wave propagation
B: Modal range
C: Transition range between 'modal' and 'statistical' range
D: Statistical range

Example (self constructed):

Typical Ranges for an average german living room of

Area : 22 m^2
Height : 2,55 m
Volume : 56 m^3
T60 : 0,7 s (lightly to medium damped)

Fs=2000 x (T/V)^0.5 = 223Hz (Schroeder frequency)


Approximate ranges [Hz]:

(lowest mode depending on proportions, here: 5.5m x 4m)

A: _20____62
B: _62___223
C: 223___892
D: 892___20000


892 Hz converts to a subjective pitch of 926 mel
20000 Hz converts to a subjective pitch of 3817 mel


Bark Scale:
http://www.phonetik.uni-muenchen.de/..._5_reichel.pdf

Calculator for auditory units:
Conversion between Hz, semitones, bark, ERB, etc.
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Last edited by LineArray; 18th March 2010 at 09:16 PM.
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Old 18th March 2010, 09:24 PM   #785
gedlee is offline gedlee  United States
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Markus

If you think about it, if every situation is unique, then measurements are an absolute requirement to know what you have. Otherwise its just guessing.

Oliver

Those frequencies are all way too high. In my room, and I've measure this, pressurization occurs to about 38 Hz. Then the modal region goes to about 120 Hz and to 200 Hz the modal density is a bit sparse. But 200 - 20,000 is completely statistical. SO in terms of decades, the first decade is mostly modal, then the next two are completly statistical. Thats the way I think about it.
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Old 18th March 2010, 09:33 PM   #786
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Quote:
Originally Posted by gedlee View Post
If you think about it, if every situation is unique, then measurements are an absolute requirement to know what you have. Otherwise its just guessing.
Which is unfortunately what most people do. The difference is like day and night and still they argue about cables...
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Old 18th March 2010, 09:48 PM   #787
gedlee is offline gedlee  United States
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Some people would argue about the sun coming up if you respond to them.
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Old 18th March 2010, 09:48 PM   #788
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Dear Mr. Geddes,

i know that those frequencies are quite high and this is
for sure not the ideal room for listening.

But it is a kind of room which has to be expected, when
an average consumer sets up his equipment.

Maybe not the average 'high end' consumers listening room of course.

I have observed modal behaviour even in a larger than average
room up to about 360 Hz, there were pronounced local pressure maxima
which could be influenced by changing the position of the speaker.

That room was not too far from cubical unfortunately and
hat rather 'naked' walls on three sides.

Your listening room might be somewhat larger than 'german average'
i suppose and might be treated/damped professionally for its purpose.
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Last edited by LineArray; 18th March 2010 at 09:56 PM.
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Old 18th March 2010, 10:12 PM   #789
graaf is offline graaf  Poland
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so measurements and equalizers are indispensable

Can anybody recommend any consumer or semi-pro measurement gear?
Are there any consumer or semi-pro equalizers worth buying?
Behringer perhaps?

Or rather there is no escape from computer audio?
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Old 18th March 2010, 10:20 PM   #790
el`Ol is offline el`Ol  Germany
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The Behringer DEQ2496 has built-in measurement capabilities. An other alternative worth considering (not as flexible however) is a Sony digital amplifier with room correction.
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