[WC]

When looking on the Rythmik site there are the 12" rythmik drivers and a few drivers from GR research. What are the differences? It doesn't seem very clear to me what the difference is. The amps appear to be the same. Looking for a sub for 2 channel music.

[srb]

The lighter paper-cone/foam surround GR drivers can be crossed over at a higher frequency (up to 120Hz) as well as having a bit better dynamics at lower volume levels than the slightly heavier aluminum-cone/rubber surround Rythmik drivers.
 
Steve

[jtwrace]

When looking on the Rythmik site there are the 12" rythmik drivers and a few drivers from GR research. What are the differences? It doesn't seem very clear to me what the difference is. The amps appear to be the same. Looking for a sub for 2 channel music.

What are you using it for?  OB sub or sealed?  Tell us more. 

Steve is correct that they can cross higher.  I think GR says 150Hz but of course it will depend on your room.

[srb]

I think GR says 150Hz but of course it will depend on your room.

It may be.  Not sure where I thought I read 120Hz, but I can't seem to find it now.
 
At any rate, on the Rythmik F12G subwoofer page (http://www.rythmikaudio.com/F12G.html) they only say:
 
What is the difference between F12 and F12G?
The main difference is the paper-based GR research driver.
 
and just only give a link to the GR Research homepage.
 
But on Rythmik's GR Research driver page (http://www.rythmikaudio.com/GR_drivers.html), they do go on to say:
 
Driver Comparison
The GR drivers use a lower mass paper cone, which has a slightly better transient response. The result is slightly better dynamics. At higher output, due to less cone stiffness, the sound may become softer due to the pressure placed on the cone.

The GR drivers also have a more extended response, allowing a higher crossover point if desired.
 
The performance can be described as "different" rather than superior or inferior.
 
 
They are Danny's drivers, and he knows more about them than anyone, so perhaps he'll chime in if there is any additional information to add.
 
Steve

[WC]

I was going to go with a sealed sub. Will be used only for music. Room is 16' x 23', but realistically it would be a near field application since I would normally be within 7' of the speakers and the sub when listening. Room is all concrete floors and walls, so not much adsorption.

[corndog71]

I built my single servo sub and love it!  It is an excellent sub for music and will reveal details and depth that most people aren't even aware of.  Takes a few days to break in but when it does, it's awesome!  And it's very reasonably priced whether you buy Rythmik's or build one yourself.  I spent less on this than my previous B&W subwoofer which sounded terribly boomy and unrefined in comparison. 

Of course if you want even more accurate bass another option albeit more expensive is building the open baffle subs used in Danny's V-series.  I haven't heard them yet but what others have said has been pretty impressive.   One of these days I want to build a set.

[srb]

Without having multiple subs to make localization a non-issue, I'm not sure why one would want to crossover at the higher frequencies of 120Hz or 150Hz.  The majority of 2-channel users seem to crossover around 60Hz - 80Hz.
 
But if half, or even a third, of my listening was at lower volume levels (and the closer you are to your speakers, the lower the levels are going to be), I think I would personally opt for the greater detail and dynamics of the GR driver.
 
Steve

[milford3]

Also remember down firing subs sound better on hard surfaces (ie concrete, hardwood floors) whereas front firing subs sound better on carpeted floors.

[jtwrace]

Also remember down firing subs sound better on hard surfaces (ie concrete, hardwood floors) whereas front firing subs sound better on carpeted floors.

Why do you say that?

[Danny Richie]

I am a paper cone kind of guy. The paper cone is a more natural sound and offers better resolution and detail levels. And add in servo control and you will actually hear details that you might not have ever realized were there before in a low frequency range.

So if you are looking for quality over quantity then the paper cone version is the best option.

If you are using it for home theater only, aren't playing them up very high, and are planning to continually driver them to near X-Max, then the Aluminum cone might be a better option.

[jtwrace]

I am a paper cone kind of guy. The paper cone is a more natural sound and offers better resolution and detail levels. And add in servo control and you will actually hear details that you might not have ever realized were there before in a low frequency range.

So if you are looking for quality over quantity then the paper cone version is the best option.

If you are using it for home theater only, aren't playing them up very high, and are planning to continually driver them to near X-Max, then the Aluminum cone might be a better option.

At what freq range do you think the paper is "best"?  Certainly ULF stuff is fine with aluminum...

[Danny Richie]

At what freq range do you think the paper is "best"?  Certainly ULF stuff is fine with aluminum...

I'd have to say that it sounds better through it's entire range. For best quality, paper is it.

The only area better with the Aluminum cone is when pushing it to X-Max levels. It is a heavier and stiffer cone and will have less cone flex when pushed hard.

[jtwrace]

I'd have to say that it sounds better through it's entire range. For best quality, paper is it.

The only area better with the Aluminum cone is when pushing it to X-Max levels. It is a heavier and stiffer cone and will have less cone flex when pushed hard.

Hmmmmmmmm.  Since I've never heard a Servo GR cone I can't comment.  I was told by Brian that the only difference was that the paper could be crossed higher but there was no sonic difference in the low end.  In the end, if one is going to cross high, use paper, if not, aluminum will probably work just fine. 

Of course down firing or front firing made no difference to the sonic character but *can* affect the output frequency availability vs the rated. 

[Rclark]

Hmmmmmmmm.  Since I've never heard a Servo GR cone I can't comment.  I was told by Brian that the only difference was that the paper could be crossed higher but there was no sonic difference in the low end.  In the end, if one is going to cross high, use paper, if not, aluminum will probably work just fine. 

Of course down firing or front firing made no difference to the sonic character but *can* affect the output frequency availability vs the rated.

 Brian wants to sell subs too. It comes down to who's opinion you trust the most, and for me, it's Danny. He always explains things very clearly and I trust his copious experience. If I were buying box style subs, it would be his paper cones for music. If I were doing it for home theater, I would add more paper cones.

[corndog71]

For the record, Brian is a great guy too and he really supports his customers. 

[jtwrace]

For the record, Brian is a great guy too and he really supports his customers.

I agree and the servo technology is his. 

[Danny Richie]

You might get a slightly different explanation of the differences if you ask me or Brian, but we are pretty much in agreement on the whole thing.

And he sales my woofers and I sell his amps. Works pretty well for us both.

[WC]

I think I will go with the 12" GR driver for my two channel sub. I will try it out for home theater see how it works. If I need more I could always go with the 15" Rythmik sub. Danny like you said, you and Rythmik both benefit if I get a GR driver with Brian's amp.

[WC]

Danny,

Your plan is for a front mounted driver. Is there anything different that needs to be done for a bottom mounted driver? Do you recommend using bottom mounted drivers?

[jtwrace]

You might get a slightly different explanation of the differences if you ask me or Brian, but we are pretty much in agreement on the whole thing.

And he sales my woofers and I sell his amps. Works pretty well for us both.

I completely understand and I really don't think anyone can wrong with either.  Of course if one is crossing > 100 Hz it might be beneficial to use the paper GR driver. 

Danny,

Your plan is for a front mounted driver. Is there anything different that needs to be done for a bottom mounted driver? Do you recommend using bottom mounted drivers?

Again, there is no differnce for front or bottom firing from a construction standpoint or sound difference.  If you have really thick carpet you might not get as high with it but there will be more to do with the room then down firing IMO.  I've done a ton of measurements on just this.

Maybe Danny will chime in with his findings.