Which provides more bass, 1 12" woofer or 2 6" woofers?

therockman

From a theoretical perspective, if all other factors were equal, which speaker design would provide a better, deeper bass output; a speaker with one 12" woofer or a design with two 6 1/2" dynamic drivers (i.e. Polk RTi 70). This is a question that I have been wondering about.

Rocky Bennett

Tour2ma

With adequate power for either case, I gotta go with the single 12" there. Just based on radiating area. Over 70% more of it with the 12".

Issue with the 12" becomes whatcha gonna do for mid-range.

therockman

They are going to be driven by the same amplifier, so that really shouldn't be an issue. The speaker that I am compareing to the Polk is a pair of vintage KLH 6's, which is a 3 way desingn that includes a 5" midrange.

PolkThug

A 12" woofer should have deeper bass by far. What's the frequency response specs for it?

steveinaz

There are other issues to address----distortion. I believe a dual-6" setup would probably render lower distortion due to the smaller, stiffer cones sharing the bass "load." Though a a single 12" would probably reach a little deeper, I'm not convinced that the bass response would be "better."

RuSsMaN

In a perfect world, the 12 will have a lower resonant frequency and displace more air. You want bass, you have to move air.

As a general rule, and 'all things equal' (which is rare), two 8 inch woofs are more the the equal of one 12 inch.

In your case, the KLH's are 3db down in the upper 20's (I believe) and the 70's drop like a waterfall in the low 40's.

Cheers,
Russ

Tour2ma

Yup, twin 8" are 90% there...

Steve,
I think "better" can boil down to how good trhe control of a driver is. With 6" the throw has to increase to generate the air movement and that can make control more difficult. Part of better in bass is tactile as well as auditory.

rocky,
Ahhhh 6's.... Heard the 6's at Audiocraft in Cleveland, OH. Old college roomie had 5's.

disneyjoe7

Would an 2 woofers 6" in a larger box give lower bass?

sowen010599

I have an Altec Lansing 5.1 THX setup in my computer-room. In my 2nd living-room is a Velodyne 12. The Altecs use a dual 6 1/2 sub setup. The Velodyne would blow those Altec's into the neighbors back yard.

George Grand

While I know it is rumored that early KLH Model 6's were supplied with 12" woofers, and later switched to 10" (mine), it was always considered to be Henry Kloss' best TWO-WAY design. No mid-range.

Plenty of deep bass though.

George Grand (of the Jersey Grands)

therockman

I'm thinking that just maybe there may be other factors to consider here. What about the size of the cabinet, I mean the actual volume of air in the cabinet. One other factor might be cone excursion. My KLH is a very old design (refurbished in 1998) and the woofer might not have the same excursion as a newer design speaker. Between these factors, it might offset the bass response slightly.

Rocky Bennett

George Grand

Still wondering what kind of speaker you have there. If it is indeed a three-way, I'm going out on a limb to say it's not a KLH 6. Maybe one that was owner modified?

The KLH Model 6 was a two-way design. Maybe the most important one ever.

George Grand (of the Jersey Grands)

TechChallenged

All things being equal it seems to me that 2 6.5 speakers will produce more bass than one 12 inch speaker simply because it has more surface area.

shack

Originally posted by TechChallenged
All things being equal it seems to me that 2 6.5 speakers will produce more bass than one 12 inch speaker simply because it has more surface area.

The total area of two 6.5" drivers is 66.33 in² whereas the area of one 12" driver is 113.04 in². There goes that theory. Of course these measurements assume that the the surfaces of the drivers are flat...which of course they aren't...they are concave...but the relationship is the same.

RuSsMaN

They don't call him "Techchallenged" for nothing apparently.

Heh heh

Cheers,
Russ

George Grand

Pie Are Skwared.

George Grand (of the Jersey Grands)

therockman

Mr Grand,
To tell you the truth, I do not know for sure that I have a pair of KLH 6's, I was just told that when I bought them. They are vintage, 3 way KLH speakers with a 12" woofer. I do like them a lot but I want to move into more modern speakers, and I am pretty set on the Polk RTi 80's, and maybe some RTi 38's in the back. My rear speakers right now are some old KLH's with 8" woofers, so I guess I will sacrifice a little bass all the way around.

Thank You,
Rocky

Mazeroth

A single 12 will annihilate 2, heck, even 4 6.5" woofers. I've even experimented with quad 8" MTX Blue Thunder woofers ($150 EACH) getting 250 watts RMS off an MTX Thunder801D amplifier and a single CHEAP MTX 12" sounded louder and went probably 8-10hz. lower. Dual 10s will take out a 12", all things being equal, but not by much.

Tour2ma

Originally posted by George Grand
Pie Are Skwared.

George Grand (of the Jersey Grands)

Nuh-uh... pie are round..:D

PolkWannabie

Originally posted by Mazeroth
A single 12 will annihilate 2, heck, even 4 6.5" woofers.

3 sure, 4 I'd have to hear and measure to believe.

Originally posted by Mazeroth
Dual 10s will take out a 12", all things being equal, but not by much.

All things being equal, it should be by more than not by much.

12" = 3.14159 * 6 ^ 2 = 113 in^2
10" = 3.14159 * 5 ^ 2 * 2 = 157 in^2

Dr. Spec

You guys are missing a significant component of this discussion: Linear excursion. Don't just look at radiating surface area; look at swept volume (Vd) at xMax.

xMax is the excursion point where the suspension stiffness reaches about 4X the resting value, and BL (the motor strength) drops to about 70% of the maximum.

Drivers typically hit about 10% THD at xMax, so that's a good spot to label maximum clean output.

Get the Vd on each driver in question, and you'll have your answer.

Also, the radiating surface area really isn't the surface area of a circle of that diameter. It is typically reduced about 30% from that value. This term is Sd and represents the true radiating surface of the cone.

Doc

therockman

Dr. Spec has brought up a point that I mentioned earlier in this thread; driver excursion. I am sure that this factor alone will contribute a siginificant amount to air movement, which is the foundation of bass. I wish that I had more info regarding driver excursion.


Rocky

disneyjoe7

I don't know about all this talk about Bigger woofer to Smaller woofers stuff.

All I know there's something about the newer speaker designs.

The RTi150's I own have great low-end 3 / 6.5 inch woofers, I just don't know but if something worked lower then the 150's by a lot I don't think there's music that goes that low. So in the end I would choice the smaller slender look of RTi to some old box look. SDA maybe the exemption here. So maybe there's something about Polk's quote.

>>Three 6.5" woofers combine the large surface area benefit of a single large woofer (100 sq. inches) with that of small woofers - a high force to mass ratio - for tighter, punchier, more accurate bass response.<<

PolkWannabie

Originally posted by Dr. Spec
You guys are missing a significant component of this discussion: Linear excursion. Doc

I don't disagree, but I was only reacting to the phrase "all things being equal". This is of course a fairly sweeping assumption but it takes the rest of the factors out of consideration and a reduction of radiating surface by 30% for both 12" and 10" woofers will leave the same relationship between the two.

Dr. Spec

I missed the all things being equal, but really that only applies in theory (a for the sake of argument kind of slant).

It's really hard to build enough linear excursion into a smaller (6-1/2") driver such that two of them will equal the displaced volume of one high excursion 12".

The force to mass ratio is a bit of marketing, I'm afraid. If you really care to research it, go here for the lowdown.

http://www.adireaudio.com/tech_papers/woofer_speed.htm

Doc

PolkWannabie

Agreed ...

gatemplin

Originally posted by Dr. Spec

It's really hard to build enough linear excursion into a smaller (6-1/2") driver such that two of them will equal the displaced volume of one high excursion 12".

[/B]

Apparently the fellas at Adire can do it with just one 6 inch driver

http://www.teamxratedstl.com/Scotts/REgoodies/

click on xmx6

sowen010599

I didn't know Adire made life-support devices!?

Dr. Spec

Yes, Adire is working on some new technologies for ultra high excursion which can be applied to any diameter driver. They will be cost prohibitive (the 2004 CES prototype was about $5,000).

I'm talking regular woofers for joe consumer - like a Stryke AV-12 for $175 with a 25 Hz resonance, 23 mm xMax and a Vd of 2.3L. Try to find two 6.5" woofers than can match it in extension and displaced volume for the same price.

gatemplin

Sure Doc, I know what you meant, I just thought that little thing looked cool. The new 6.5" Adire Extremis drivers are pretty impressive too, with 11.5 mm Xmax and they should sell for less than $100.