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how can spinorama csv data show with zoom possible to see diffrences in bass range better ?

bennybbbx

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I think the best speaker is the speaker that have in bass and low mid smallest directivity to avoid as much as possible room reflections, because bass room reflections sound not nice and give mud. in bass is directivity always wide, Iin the spinorama text data i can see some speakers have at 90 degree 1 db less or more level in compare 90 degree to on axis to other speakers. So i like a spinorama viewer that can zoom the data to see more details how much db at 90 degree level is lower as on axis. is there a viewer that can do this ?
 

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bennybbbx

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I have threated my room with 5 cm basotec and have basstraps too. it does help alot above 300 hz but the problem with the bass and low mid upto 200 hz stay in and is now more hearable that the bass and low mids sound wider as the rest. a good test is hear mono and compare with headphones how wide low bass notes sound in compare to high bass notes

so every speaker that output less level at 90 degree should make the sound better. zoom for the spinorama display is very usefull to find speaker with smallest directivity in bass and test this how much it enhance sound
 
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bennybbbx

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a polar display or a plot Figure 2 – Frequency Response vs. Off-Axis Angle is usefull too. there can see on this speaker at 160 hz the level at 90 degree measure is 2 db lower as the on axis measure. but better it can zoom more https://www.ravepubs.com/a-deeper-dive-into-loudspeaker-directivity/ is something as this here for spinorama data ?
 

dfuller

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I have threated my room with 5 cm basotec and have basstraps too. it does help alot above 300 hz but the problem with the bass and low mid upto 200 hz stay in and is now more hearable that the bass and low mids sound wider as the rest. a good test is hear mono and compare with headphones how wide low bass notes sound in compare to high bass notes

so every speaker that output less level at 90 degree should make the sound better. zoom for the spinorama display is very usefull to find speaker with smallest directivity in bass and test this how much it enhance sound
Then you don't have bass traps. You have broadband absorbers. 5cm is not enough for broadband, especially without an airgap behind.
 
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bennybbbx

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I have written
I have threated my room with 5 cm basotec and have basstraps too

AND have basstraps. this mean i have basstraps and not 5cm basotec. My basstraps are 20 cm thick and i have 6 pieces. it is only cheap foam 6 pack cost ~60 $ no basotec. I measure the damping. put it before speaker 5 cm basotec give damping at 50 hz as 20 cm cheap foam. the treatening i have most done to reduce heat costs. so basotec is also in corner of back wall. so can say in corner i have damping as 10 cm basotec.

there need more precise spinorama display because when look at the text values. I get for

focal alpha 65 evo

79 hz on axis 100,092 db at 100 degreee 99.82 db (100 degree seem last value on first row) thats - 0.27 db.

magnepan LRS

81 hz on axis 77.49 at 100 degree 74.06 db . thats -3.43 db . sure the measure level is huge diffrent but logical the room reflections should be at same % . question is also wy the magnepan have on bass a good high directivity(so less room reflections db happen) and if there other speakers that have it.
 
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Curvature

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You need to read some acoustics books.

Bass is modal, meaning the room is in control of the response. The speaker provides the output energy that is transformed by the room. The spin data provides plenty of detail and no more is necessary.

Foam is a velocity based absorber. True bass traps are pressure based, like membrane or Helmholtz.

Before you argue, acknowledge that your current knowledge is deficient and work on that.
 
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bennybbbx

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You need to read some acoustics books.

The spin data provides plenty of detail and no more is necessary.

for the directivity sure. but there need a viewer that show better diffrences(and do averaging). look into the spinorama .txt file there are diffrence even on 82 hz between on axis and 100 degree value. i mark it with a arrow and post the screenshot maybe it is not clear what i mean. this thread is not about roomacoustics. all spinorama are done in same room the klippel stand i guess.


neumann kh 420.jpg


on the other screenshots i have no arrows draw hope its clear which values i mean. top left after the frequency is on axis db. then come pairs (frequency db)in 10 degree step.

magnepan LRS.jpg


on the Yamaha HS5 off axis have more level as on axis

yamaha hs 5.jpg
 

Curvature

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You are mistaken about the context. It is all about room acoustics. Speakers + room is one system.

LF directivity below the Schroeder frequency has limited relevance in small rooms.
 

ahofer

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LF directivity below the Schroeder frequency has limited relevance in small rooms.
That doesn't mean the new cardioid models are pointless, does it?
 

voodooless

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As for a viewer, REW should be just fine.
 
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bennybbbx

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voodooless

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ahofer

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Few noncardoid speakers have significant directivity control into the transitional region.
Right, my question was about cardioid. Isn't that beneficial directivity control?
 
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bennybbbx

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You are mistaken about the context. It is all about room acoustics. Speakers + room is one system.

LF directivity below the Schroeder frequency has limited relevance in small rooms.

speaker + room is one system is right. so i can influence the sound with less directivity of the speaker or damp the room more. its logical when a speaker do less energy send to side direction it is better. theory say there is no diffrence in bass. but when the air of the bass move more in front (because case do less resonate maybe) and measures show there are diffrences. in test when level of reverb reduce 0.5 db can hear good

that the magnepan have a very small bass directivity is maybe because it have no case that can resonate.
 

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There are multiple reasons for the bass response to not be 100% omni polar. First is there is no truly omni polar loudspeaker. However, you also need to be aware of the spinorama measurement precisions, which affect the measurement numbers too.

For example, the determination of the acoustic center of the loudspeaker is only approximate. The driver is not a point (and it is not even flat), so its acoustic center is not well defined. The ANSI/CTA-2034 standard allows for a 5 cm shift of the vertical spin axis, with its offset to the true acoustic center being unknown.

cta_2034.png


Let's see how much a 5 cm shift of the spin axis will affect the results.

In far field, the sound pressure is proportional to 1/r, i.e. p(r) = k/r. At 1 m, if we have a perfectly aligned measurement, p(r=1) = k. If the spin axis is offset by 0.05 m, p(r=1.05) = k/(1.05).

The ratio of the measurements is: p(r=1)/p(r=1.05) = 1.05. In dB, it is 20 log10(1.05) = 0.42 dB. Therefore, within the CTA-2034 spin axis positioning tolerance, we can already expect a 0.42 dB shift without considering other sources of error.

In reality, since we don't know where the true acoustic center is, the offset can be more than 5 cm. Adding to it the other measurement errors, comparing to directivity numbers to less than 1 dB is highly problematic.

Below is my simulation of a simple front firing boxed loudspeaker at 75 Hz. (The simulation is 2D, and represents the radiation pattern of a line source.) From this simulation the acoustic center is actually in front and outside of the speaker cabinet.

front_radiating.png
 
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bennybbbx

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Curvature

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Right, my question was about cardioid. Isn't that beneficial directivity control?
Well, if you extrapolate from my post, if few noncardioid speakers have significant directivity control to the transitional region of 300-400Hz, then many cardioid speakers do. In other words cardioid speakers control MF directivity better than regular speakers given the same size enclosure, but both lose effectiveness below a certain frequency in small rooms.

In large rooms (stadiums, music halls), even LF have directivity and cardoid arrays can be used beneficially as well, although for different reasons.
 
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