What does the number of speakers have to do with it all?

[rsf1977]

ok so what does the number of speakers really mean at the end of the day? Whats the difference when standing in front of (4) 12" speakers and (1) 12" speaker if they are producing the same volume?

 

[Matt_B]

With the same amount of power (wattage), doubling the number of speakers increases their SPL (sound pressure level, or apparent volume) by 3 dB. Simply put, more speakers push more air so they are louder.

 

[Jay Mitchell]

With the same amount of power (wattage), doubling the number of speakers increases their SPL (sound pressure level, or apparent volume) by 3 dB. Simply put, more speakers push more air so they are louder.

The question contained the conditional "if they are producing the same volume," however.

The answer is that a 4x12 cab is a 2x2 array. As such, its reponse behavior is very complex and directionally dependent. Directly on axis, its response is very similar to that of a 1x12 with the same transducer. Off axis (where you almost always hear it), however, the response becomes very detailed and varied. The general off-axis sound quality tends to retain an additive effect at the lowest frequencies - but with no added low-frequency bandwidth over a 1x12 - while frequencies as low as 250 Hz and up will have large peaks and notches ("comb filtering"). This multisource interference tends to reduce the relative level of high frequencies compared to lows, imparting an impression of "more bass."

 

[<MACHINE>]

The question contained the conditional "if they are producing the same volume," however.

The answer is that a 4x12 cab is a 2x2 array. As such, its reponse behavior is very complex and directionally dependent. Directly on axis, its response is very similar to that of a 1x12 with the same transducer. Off axis (where you almost always hear it), however, the response becomes very detailed and varied. The general off-axis sound quality tends to retain an additive effect at the lowest frequencies - but with no added low-frequency bandwidth over a 1x12 - while frequencies as low as 250 Hz and up will have large peaks and notches ("comb filtering"). This multisource interference tends to reduce the relative level of high frequencies compared to lows, imparting an impression of "more bass."

So flipping the coin...how does a 1X12 react off axis compared to a 4X12?

 

[Jay Mitchell]

how does a 1X12 react off axis compared to a 4X12?

In a more orderly manner. There is a dropoff in high frequency content compared to on axis, but it is less dramatic and more continuous than with a 4x12. There is little or no comb filtering, since there is no multi-source interference.

The curves at the top of the following page show the response of a 1x12 at various angles, from on axis to about 60 degrees off axis: http://www.tgpwebzine.com/?page_id=443 .

A 4x12 would show huge differences below 1k that are not present with the 1x12, and the off-axis HF response would be much more ragged.

 

[Lopp]

Interesting stuff. It helps explain why I perceive my 4x12 to sound better than my 1x12 or HPR122i. Thanks Jay.

 

[Sixstring]

ok so what does the number of speakers really mean at the end of the day? Whats the difference when standing in front of (4) 12" speakers and (1) 12" speaker if they are producing the same volume?

Standing in front of a 412 is like being kicked in the balls by a horse . Standing in front of a 112 is like being kicked in the shin by a midget :roll: . You will feel them both but you will rember one a lot more than the other.

 

[Scott Peterson]

ok so what does the number of speakers really mean at the end of the day? Whats the difference when standing in front of (4) 12" speakers and (1) 12" speaker if they are producing the same volume?

Standing in front of a 412 is like being kicked in the balls by a horse . Standing in front of a 112 is like being kicked in the shin by a midget :roll: . You will feel them both but you will rember one a lot more than the other.

:lol:

 

[paulmapp8306]

Taking this further,

With a 2x12 cab, there is presumable a similay "comb" and aded "bass" effect off axis when compared to 1x12.

now how will this change with the orientation of the 2x12? i.e. vertical or horizontal array.

Which is better?

Ive never really though about it , but my initial thought is that actually a vertical array'd 2x12 should be better for the audience than a horixontal. The Bass and comb effects would still be there but in the vertical plane (so the higher you are the more pronounced the effect) where as the stereo L/R spread will be effected less.

Comments - or just put me right here.

 

[Sixstring]

Taking this further,

With a 2x12 cab, there is presumable a similay "comb" and aded "bass" effect off axis when compared to 1x12.

now how will this change with the orientation of the 2x12? i.e. vertical or horizontal array.

Which is better?

Ive never really though about it , but my initial thought is that actually a vertical array'd 2x12 should be better for the audience than a horixontal. The Bass and comb effects would still be there but in the vertical plane (so the higher you are the more pronounced the effect) where as the stereo L/R spread will be effected less.

Comments - or just put me right here.

I always felt that a horizontal 212 sitting on the floor had a better sounding bass response.

 

[GM Arts]

Interesting stuff. It helps explain why I perceive my 4x12 to sound better than my 1x12 or HPR122i. Thanks Jay.

It also explains why I like 1x12 better

 

[nobbi]

A new question: what happens, when I mic a 112 or a 412 cabinet into a PA, only one microphone in front of one speaker? Is there any influence of the larger cab and the other 3 speakers of a 412 in contrast to a 112 cab? - nobbi.

 

[Jay Mitchell]

when I mic a 112 or a 412 cabinet into a PA, only one microphone in front of one speaker? Is there any influence of the larger cab and the other 3 speakers of a 412 in contrast to a 112 cab?

There is an influence, but it is very small. The "more bass" sound of a 4x12 is not evident in the response that a mic placed directly in front of one transducer will "hear," and the complex off-axis response that forms an essential part of the character of a 4x12 will also be missing.

 

[rsf1977]

when I mic a 112 or a 412 cabinet into a PA, only one microphone in front of one speaker? Is there any influence of the larger cab and the other 3 speakers of a 412 in contrast to a 112 cab?

There is an influence, but it is very small. The "more bass" sound of a 4x12 is not evident in the response that a mic placed directly in front of one transducer will "hear," and the complex off-axis response that forms an essential part of the character of a 4x12 will also be missing.

is it possible to get close to the feel of a real 4x12 by blending a close mic and far mic IR of the same cab?

 

[Jay Mitchell]

is it possible to get close to the feel of a real 4x12 by blending a close mic and far mic IR of the same cab?

Why bother with the close mic at all? It's not capturing anything that will help you get the feel of a 4x12.

 

[hunter]

when I mic a 112 or a 412 cabinet into a PA, only one microphone in front of one speaker? Is there any influence of the larger cab and the other 3 speakers of a 412 in contrast to a 112 cab?

There is an influence, but it is very small. The "more bass" sound of a 4x12 is not evident in the response that a mic placed directly in front of one transducer will "hear," and the complex off-axis response that forms an essential part of the character of a 4x12 will also be missing.

I suggest you check out this video. Vast difference between recording top left or bottom right speakers of a 4x12!

http://www.premierguitar.com/Video/2008 ... iques.aspx

 

[Jay Mitchell]

I suggest you check out this video. Vast difference between recording top left or bottom right speakers of a 4x12!

Which has absolutely nothing to do with whether it is a 4x12. I can demonstrate the same effect by recording a 1x12 elevated off the floor vs. placed directly on the floor. I can get additional sounds by placing the 1x12 at an edge between wall and floor or in a corner of the room.

This effect is due to local acoustics, not loudspeaker behavior.