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I have a Miller and Kriesel (M&K) V125 subwoofer with a 12 inch woofer. For a 11 x 15 room, is a 12 inch woofer too big? I thought I read some where (orbaudio.com?) that certain size woofers were too big - either for the room (too boomy?) or as it is too big to keep up with fast musical passages.


Am I dreaming all of this stuff up or does size matter?
 

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You can wake up now.


Generating high spl at low frequencies has alot to do with moving large amounts of air. With all else being equal, bigger drivers will move more air than smaller drivers. However, there are tradeoffs - the larger driver will generally not do as well in the upper bass region, and the larger mass means it needs good engineering design for the driver, enclosure and amp to work well together and not be sloppy. With all that said - 12" is really not all that large for a subwoofer driver. Woofer drivers are commonly 8-12", and 15" is becoming more popular in the mainstream HT. Over 15" is usually considered "big" (at least by most folks outside of some of the overacheivers on this forum :D ). It figures that Orb would tell you smaller is better - that is their whole shtick. I suspect Dayton or Adire would tell you otherwise...
 

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Size doesn't matter, don't let your girl tell you any differently! :D


Basically buy the sub that sounds the best and preforms the best. If you calibrate it properly, it shouldn't be too much.


Also, there is NO such thing as a FAST or SLOW subwoofer. That is a myth.
 

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Quote:
Originally Posted by UNICRON-WMD
Size doesn't matter, don't let your girl tell you any differently! :D


Basically buy the sub that sounds the best and preforms the best. If you calibrate it properly, it shouldn't be too much.


Also, there is NO such thing as a FAST or SLOW subwoofer. That is a myth.



Then how do you account for the differences in group delay at different bass frequencies when you compare various subwoofers??? If all subwoofers had the SAME "speed", then they all would have the same group delay at every bass frequency!



NOTE: "SPEED" is a bad word to use, but so is FAST and SLOW!
 

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Size DOES matter, but it's not the ONLY thing that matters. Power, excursion, cone mass, Qts, Resistance of the mechanical suspension (Rms), etc... All of that (and more) matters.


And no, 12" isn't too big for your room. Many 12" subs are still considered pretty musical. Now I wouldn't run an Adire Audio Maelstrom (18", though new models for 12"/15" are coming) for music.
 

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It's all about moving air.You move air by two factors.The square inch surface of the cone is one.The second is how far that cone moves.


Now if the cone moves and is faithful to the signal it is being fed you are in luck.If the movement replicates what you see on the silver screen you have magic.


If you live in a small space it will take less to produce.That does not mean you go out and pick up the first 8" subwoofer you see.A nice big driver or multiple drivers even in a smallish room are a sure bet you will meet the demands of todays movies.They are making it more difficult as the years go on.


Good luck and believe me if you ask for advice on what sub to get these boys will give you lotz to look at.



KG
 

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Quote:
Good luck and believe me if you ask for advice on what sub to get these boys will give you lotz to look at.
Just stay away from KLH!


Ian :D
 

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Quote:
Originally Posted by J_Palmer_Cass
Then how do you account for the differences in group delay at different bass frequencies when you compare various subwoofers???
Speaker drivers are minimum phase devices meaning their group delay is a function of their frequency response. Sub woofers with shallower roll-offs have less group delay. For the same F3 point a sealed sub-woofer will have less group delay than a ported design (less than half). Sub woofers with lower bass extension have less group delay. With the same Q a sealed box which is -3dB @ 20 Hz will have half the group delay of one that's -3dB @ 40Hz.


This has no relationship to the driver size. A 18" driver with the same frequency response as an 8" driver will share its group delay.


I also don't think that low group delay is perceived as fast bass.


1. A paucity of low bass and extra mid/upper bass seem faster. Conversely excess low bass is slow and bloated.


2. A lower Q woofer sounds faster.


For the same F3 point a lower Q design does have less group delay. Since Q is half the ratio of stored to disipitated energy the lower Q design also stores less energy which is radiated later. I think the better bass comes from less ringiing - the low group delay is just a side effect of the frequency response.


Then there's the room which stores a lot more energy than the sub-woofer....
 

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Quote:
Originally Posted by Drew Eckhardt
Speaker drivers are minimum phase devices meaning their group delay is a function of their frequency response. Sub woofers with shallower roll-offs have less group delay. For the same F3 point a sealed sub-woofer will have less group delay than a ported design (less than half). Sub woofers with lower bass extension have less group delay. With the same Q a sealed box which is -3dB @ 20 Hz will have half the group delay of one that's -3dB @ 40Hz.


This has no relationship to the driver size. A 18" driver with the same frequency response as an 8" driver will share its group delay.


I also don't think that low group delay is perceived as fast bass.


1. A paucity of low bass and extra mid/upper bass seem faster. Conversely excess low bass is slow and bloated.


2. A lower Q woofer sounds faster.


For the same F3 point a lower Q design does have less group delay. Since Q is half the ratio of stored to disipitated energy the lower Q design also stores less energy which is radiated later. I think the better bass comes from less ringiing - the low group delay is just a side effect of the frequency response.


Then there's the room which stores a lot more energy than the sub-woofer....
Bravo!

Well put.
 

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Quote:
Originally Posted by Drew Eckhardt
Speaker drivers are minimum phase devices meaning their group delay is a function of their frequency response. Sub woofers with shallower roll-offs have less group delay. For the same F3 point a sealed sub-woofer will have less group delay than a ported design (less than half). Sub woofers with lower bass extension have less group delay. With the same Q a sealed box which is -3dB @ 20 Hz will have half the group delay of one that's -3dB @ 40Hz.


This has no relationship to the driver size. A 18" driver with the same frequency response as an 8" driver will share its group delay.


I also don't think that low group delay is perceived as fast bass.


1. A paucity of low bass and extra mid/upper bass seem faster. Conversely excess low bass is slow and bloated.


2. A lower Q woofer sounds faster.


For the same F3 point a lower Q design does have less group delay. Since Q is half the ratio of stored to disipitated energy the lower Q design also stores less energy which is radiated later. I think the better bass comes from less ringiing - the low group delay is just a side effect of the frequency response.


Then there's the room which stores a lot more energy than the sub-woofer....


http://www.soundstage.com/maxdb/maxdb061999.htm



When I talk "fast or slow", I am talking about time integration between my main speakers and my subwoofer.


The only difference that I look at is group delay related. So I adjust my subwoofer speaker distance to adjust for differences in the group delay between my mains and my subwoofer.


The subwoofer is typically firing "late" due to additional group delay so I call that "slow" bass. So, I make the subwoofer fire early to time align the two speakers.


Yes, changing time changes phase, so let's not get into that!
 

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How bad is your group delay from your sub that you have to make your sub fire early so that it isn't late in respect to your mains? I believe group delay is measured in milliseconds (ms?), and in most quality subs it doesn't get over 25ms until below 35hz. If you can percieve a delay in the thousandths in information below 35hz, more power to you.
 

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Quote:
Originally Posted by SteveCallas
How bad is your group delay from your sub that you have to make your sub fire early so that it isn't late in respect to your mains? I believe group delay is measured in milliseconds (ms?), and in most quality subs it doesn't get over 25ms until below 35hz. If you can percieve a delay in the thousandths in information below 35hz, more power to you.



How about if you run you mains as large and have a subwoofer to integrate and use a low filter freqeuncy (50hz)?


How about if your subwoofer is located futher away from the listener than the mains?


Get a little bit out of time, and integration is not as crisp and clean at the overlap frequencies. In addition, you can measure the difference in SPL output!
 

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Don't get me wrong, I'm not saying the distance setting shouldn't be used at all, I'm just saying if your adjusting it only because you think the group delay on your sub is high, you stand the chance of making it worse by firing too early. I guess it would depend on how small the time increments of delay are in relation to each foot of distance on the receiver or pre/pro.
 

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Quote:
Originally Posted by SteveCallas
Don't get me wrong, I'm not saying the distance setting shouldn't be used at all, I'm just saying if your adjusting it only because you think the group delay on your sub is high, you stand the chance of making it worse by firing too early. I guess it would depend on how small the time increments of delay are in relation to each foot of distance on the receiver or pre/pro.



One "early" electrical signal may result in a "same time" signal output from two different speaker circuits.


What I am saying is that difference in group delays between your main speakers and your subwoofer is one reason that the CORRECT speaker distance settings MAY vary from the ACTUAL measured distances!


I run LARGE mains, so this TIMING ISSUE is a major concern with my configuration. The frequency overlap range is an equal concern. As a matter of fact, any frequency above 80HZ from the subwoofer causes an integration problem at certain freqencies above 80HZ in my system if the low bass is time matched properly.


A low pass filter setting of 60HZ at the subwoofer amplifer cures this above 80HZ integration problem. The speaker distance setting is used for the fine tuning to match group delay in the 40 to 60HZ frequency range.


If you run SMALL mains, you probably can not hear the difference in sound.
 
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