Best sounding subs on the market? Could be...

audioferret · « **Reply #160 on:** 10 Apr 2008, 07:52 am »

Great...just great...

Once wasn't enough for you, was it? I build one sub, everything should have been fine. Now you go and make this...

So now, I have to go and build TWO MORE subs - I hope you're happy...

sigh...

(Folks, you really need to try these subs out. You can't beat the price and the sound is to die for...even on the simple kits)

Nick77 · « **Reply #161 on:** 10 Apr 2008, 12:59 pm »

Maybe I missed this previously but is their a 15" version of this driver? IB ?

rythmik · « **Reply #162 on:** 10 Apr 2008, 02:13 pm »

Danny will put up the FR plots on his website. Here I would like to preview them.

This is measured outdoor with close-mic. Both 4ohms and 8 ohms will have the same FR. The max xover frequency is 120hz.

GR12-16 on the other hand is different. The high end roll-off is intentionally made slower. The stock version is good for 120hz xover.

For those intend to xover higher, I have made a version that can be xover at 160hz to 200hz (-3db and -6db, respectively) depending application. One needs to specify this option when ordering by writing a note. Otherwise, the default setup is 120hz xover.

It is very important to provide your baffle width so that we know where lower and upper corner frequencies of the shelving circuit (some call it 1st order integrator) to compensate for OB cancellation. The above plots assume shelving circuit compensation is perfect as in the best scenario. Since I cannot provide too many different shelving circuit designs, we need to agree on the most popular corner frequency (not frequencies, ok, we can have two of them). How about 80hz, which probably correspond to 12ft baffle width (based on quarter wavelength as half baffle width)? The lower end will always be 20hz. I don't think we need to go any further down.

One thing one can be sure about our servo subs is the accuracy of the frequency response. In this particular example, the FR of these two seemingly different drivers (16ohms vs 4/8ohms) is within +/-1db between 5hz and 60hz. As a matter of factor, as long as one uses the correct servo board, all of our models will match within that range in FR. With the servo control, we are able to clone a winner frequency response (and hence the time domain impulse characteristic) within this frequency response. Frankly, that is quite an achievement when other manufacturers "claim" to spend hundreds of hours fine tuning the frequency response and/or the T/S parameters

15" OB drivers are in the work. However, the priority is not very high.

Christof · « **Reply #163 on:** 13 Apr 2008, 02:05 pm »

Brian/Danny

I am building a few of these subs and would like to ask a couple questions regarding wiring. I was going to ask via PM but thought this these questions may be helpful to others who intend to build multiple subs. I (Marbles) will be using two subs per channel for a total of 4 individual subwoofers which will be driven by two amplifiers (one per channel). I have not yet seen the hook-up on the amps but I assume there is a single output and single servo input.

1. Driving the subs from one amp...is this a matter of shotgun wiring off the amp to both subs to parallel wire?
2. The Servo return....how is this done with two drivers and one amp, same way, parallel wired?

Last question for Brian:

Is it possible that the servo signal being sent from the drivers can be slightly different between drivers? For example, two identical subs both set up in down firing orientation with 3" risers, one sub placed on a hardwood floor and one placed on rather thick carpet. I assume the answer is no, the signal will remain the same because we are dealing with such large wavelengths but I'm curious as to what external/environmental factors, if any, can cause minor changes to the signal between two identically built subs.

Thanks guys.

rythmik · « **Reply #164 on:** 14 Apr 2008, 03:19 pm »

Quote from: Christof on 13 Apr 2008, 02:05 pm

Brian/Danny

I am building a few of these subs and would like to ask a couple questions regarding wiring. I was going to ask via PM but thought this these questions may be helpful to others who intend to build multiple subs. I (Marbles) will be using two subs per channel for a total of 4 individual subwoofers which will be driven by two amplifiers (one per channel). I have not yet seen the hook-up on the amps but I assume there is a single output and single servo input.

1. Driving the subs from one amp...is this a matter of shotgun wiring off the amp to both subs to parallel wire?
2. The Servo return....how is this done with two drivers and one amp, same way, parallel wired?

Last question for Brian:

Is it possible that the servo signal being sent from the drivers can be slightly different between drivers? For example, two identical subs both set up in down firing orientation with 3" risers, one sub placed on a hardwood floor and one placed on rather thick carpet. I assume the answer is no, the signal will remain the same because we are dealing with such large wavelengths but I'm curious as to what external/environmental factors, if any, can cause minor changes to the signal between two identically built subs.

Thanks guys.

The sensing coil should be connected in series. So driver coils in parallel and sensing coil in series. This is mainly because our servo technology uses both current feedback and sensing feedback. The parallel drivers ensure the current feedback is summing of two and series sensing coil encure the voltage feedback is summing of the two. This applies to both dual, and quad drivers.

As long as those two drivers are in close proximity to get the best coupling effect, the difference can be made as small as possible. Since the sensing feedback is summing of two, so the servo controller' objective is to control the sum of cone movement of those drivers. Even though there is slight difference between drivers, but the sum will remain the same.

rythmik · « **Reply #165 on:** 17 Apr 2008, 03:05 am »

There is a $30 discount before end of this month for those new amplifiers. Order from www.rythmikaudio.com/gr-amplifiers.html

music_love931 · « **Reply #166 on:** 27 Apr 2008, 12:15 pm »

Digital Designs and MTX don't make very good SQ subs. Of the three, Diamond would be your best bet. As Lazonby suggested, JL makes some incredible sounding subs. The W7 is one of the best sounding subs on the market IMO.

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rythmik · « **Reply #167 on:** 28 Apr 2008, 01:30 pm »

Car subs are designed with a car chamber gain in mind. So they seldom extend below 40hz in their box. I have seen several of those drivers with Vas in the range of 30L (for 12" drivers). Their natural roll-off is around 50hz (without any boost). Drivers for home use have Vas more than 100L (I will also recommend not to use drivers with low Vas for home use sealed sub). Why is Vas important? The lower the Vas, the lower the efficiency below 40hz. It has a similar effect as using an enclosure smaller than what the manufacturer recommends. In addition, low Vas means a tight spider/surround. That means the spider's distortion can be easily audible because the motor needs to deal with it. On the other hand, higher Vas driver gives the compliance control to the enclosure which has a far more linear compliance. I have received many questions regarding this. I have always recommended against it for these reasons: 1) insufficient extension, 2) low efficiency below 30hz that even an EQ cannot rescue, and 3) high spider distortion that cannot be linearized by the enclosure's compliance.

poseidonsvoice · « **Reply #168 on:** 5 May 2008, 06:29 pm »

So where would you mount the plate amp if you are building dipole sub (H-frame) with two or three of the SW12-16-FR drivers?

I'm curious why there isn't an option for a kit so that we can put the amp/crossover/servo enchilada into our own box. Then run speaker cables to the drivers.

Do you sell the Servo technology + the driver on its own? In other words, if we have our own fully configurable active crossover and amplifier, can we just purchase the Direct Servo board and driver?

Best,
Anand.

Danny Richie · « **Reply #169 on:** 5 May 2008, 08:56 pm »

Quote

So where would you mount the plate amp if you are building dipole sub (H-frame) with two or three of the SW12-16-FR drivers?

In a separate box.

Quote

I'm curious why there isn't an option for a kit so that we can put the amp/crossover/servo enchilada into our own box. Then run speaker cables to the drivers.

Yea, that's what I am going to do. I am going to put the amp and passive crossover into its own box next to the speaker. You won't need a kit for that.

Quote

Do you sell the Servo technology + the driver on its own? In other words, if we have our own fully configurable active crossover and amplifier, can we just purchase the Direct Servo board and driver?

I don't. I don't think Brian does either.

Danny Richie · « **Reply #170 on:** 17 May 2008, 05:15 pm »

The Direct Servo Amps can now be ordered straight from our web site:

http://www.gr-research.com/index.asp?PageAction=VIEWPROD&ProdID=142

All the information Brian gave us a few pages back as been copied there as well.

WerTicus · « **Reply #171 on:** 21 May 2008, 08:12 am »

I was just about to order the standard 12 inch sealed kit x 2 from rythmik when i noticed this new addition.

questions:
If I was to do an OB design using the 16 ohm driver and doing stereo OB frames with 4 drivers per side with one amp per side, What would be the best frame design to use? W, C, H? How wide should they be etc? No one has mentioned OB frame designs here and its probably very important!

I have a lynx L22 with balanced XLR stereo output, that connects to balanced nuforce 8b's.
what would be the best sound quality method to hook these two amps into my system?

Would you recommend i use the XLR amplifier and just 'double adapt' the output from my source? or use PEQ amplifier with some kind of adaptor or use high level inputs? or some other method i have not thought of.

TRADERXFAN · « **Reply #172 on:** 21 May 2008, 03:34 pm »

Quote from: WerTicus on 21 May 2008, 08:12 am

I was just about to order the standard 12 inch sealed kit x 2 from rythmik when i noticed this new addition.

questions:
If I was to do an OB design using the 16 ohm driver and doing stereo OB frames with 4 drivers per side with one amp per side, What would be the best frame design to use? W, C, H? How wide should they be etc? No one has mentioned OB frame designs here and its probably very important!

I have a lynx L22 with balanced XLR stereo output, that connects to balanced nuforce 8b's.
what would be the best sound quality method to hook these two amps into my system?

Would you recommend i use the XLR amplifier and just 'double adapt' the output from my source? or use PEQ amplifier with some kind of adaptor or use high level inputs? or some other method i have not thought of.

Just one point to add -I think they said the most drivers per amp would be 3 because they need to run in parallel for the servo control, and 4 would drop the resistance too low.

I don't know much at all about the ob speaker design, but it seems this offering isn't quite plug and play. You need to figure out what you want and how you want to integrate it, and Brian would put a corner filter on the amplifier for you at the frequency you specify...

Quote from: rythmik on 21 Feb 2008, 06:04 pm

Quote from: scorpion on 21 Feb 2008, 09:16 am
I have not read all the thread but I would be very interested to know how the Servo could compensate for Dipole-OB loss ?

/Erling

The dipole loss is a first order shelving function with a corner frequency. On the servo board, we have a place to add such shelving function. Of course, before we put in this shelving function, we set the FR to flat down to 14hz and customer can use that for IB. For me, IB and OB is same thing except one with shelving and one without. If you tell me the corner frequency, I will build it for you. The servo is a system solution. You just tell me what you want and I will build it for you, regardless if it is vented, sealed, OB, PR, blah blah blah.

Quote from: rythmik on 10 Apr 2008, 02:13 pm

It is very important to provide your baffle width so that we know where lower and upper corner frequencies of the shelving circuit (some call it 1st order integrator) to compensate for OB cancellation. The above plots assume shelving circuit compensation is perfect as in the best scenario. Since I cannot provide too many different shelving circuit designs, we need to agree on the most popular corner frequency (not frequencies, ok, we can have two of them). How about 80hz, which probably correspond to 12ft baffle width (based on quarter wavelength as half baffle width)? The lower end will always be 20hz. I don't think we need to go any further down.

Danny Richie · « **Reply #173 on:** 21 May 2008, 03:40 pm »

Quote

If I was to do an OB design using the 16 ohm driver and doing stereo OB frames with 4 drivers per side with one amp per side, What would be the best frame design to use?

First of all the 16 ohm woofers have a DCR dropping to just under 12 ohms. So you can run either two of them or three of them on each amp (Not four of them).

I have been using a pair of them in a W shaped frame and it worked out really well. You could use an H frame too and that will be fine also. It just makes it a little taller.

Quote

Would you recommend i use the XLR amplifier and just 'double adapt' the output from my source? or use PEQ amplifier with some kind of adaptor or use high level inputs? or some other method i have not thought of.

I'd use the amp with the PEQ on it. You may need it to adjust for your room gain (peaks or dips). You can then use the speaker level inputs if you need to.

WerTicus · « **Reply #174 on:** 21 May 2008, 05:08 pm »

Okay then what im wanting to do is run, 3 drivers per sub in a H frame. (would make something about the same height as my main speakers, so it would probably look better anyway

The fact that it isn't quite as plug and play and the standard rythmik kit is a bit off putting, Im sure with enough homework I could come up with a good solution

My speakers are supposed to be -6 at 35hz, -3 at 40hz and flat at 50hz, This is with a cabasse 8inch woofer and a rear firing port.
I have an equaliser that operates down to 55hz at its lowest setting, So i guess the PEQ would no doubt come in handy.

Am i correct in assuming that the XLR master slave thing isnt of interest to me since i would be running different signals to each sub?

If i were to just throw these drivers into a H frame, is it just a case of a wider baffle is better for blocking the back wave? Or will I need to do measurments and adjust the amp somehow to compensate for various things?

Anyone here got a working open baffle design for these drivers and servo amps i can borrow?

gitarretyp · « **Reply #175 on:** 21 May 2008, 08:49 pm »

You'd get better boundary re-enforcement and a larger effective baffle with the woofers placed horizontally, if such an arrangement would work in your room.

aiden · « **Reply #176 on:** 21 May 2008, 11:20 pm »

So I apologize if someone has asked this in the past, or if this is an apple to watermelon comparison, but how would a properly built Rythmik sub compare to say an SVS PB13U (http://www.svsound.com/products-sub-box-pb13ultra.cfm)? What if I wanted to build a cylinder version, like the PC13U (http://www.svsound.com/products-sub-cyl-pcultra_new.cfm)? I've been all over the usual forums reading about cylinder vs box, and it always comes down to SAF and driver responses. Has anyone done this to one of these Servo-Subs? How about just the general comparison of the two drivers themselves? Thanks for the responses.

KS · « **Reply #177 on:** 21 May 2008, 11:37 pm »

"“I have finally finished the cabinet for the DS12-sealed, and I just have to say WOW.....To make a long story short, I do not believe I have ever had this level of bass definition before. No boom, no overhang, just well defined musical notes and harmonics. "
http://www.rythmikaudio.com/reviews.html

aiden · « **Reply #178 on:** 21 May 2008, 11:43 pm »

So what you're saying is look a little closer

Thanks for the link, KS. That's exactly what I was looking for. Danny, do you have any recommendations as far as the cabinet dimensions go? Also, just curious if anyone else has done this, and if they have heard this driver in any configuration vs SVS/HSU.

Danny Richie · « **Reply #179 on:** 22 May 2008, 12:19 am »

Honestly, I have had some great subs in an out of here for years, and it doesn't matter if you have them in a Sonotube or a granite box. There is no comparison to the Direct Servo controlled system.

I am hearing detail levels in low bass regions that I didn't realize were there.

I kid you not. You don't know just how much boominess there is from a sub until you take it all a way. This is a new ball game and nothing else is even close.

You wait and see. Everyone is going to repeat the same things I just said when they get theirs up and playing.

Any shape, well braced and solidly built, sealed box in the 1.5 cubic feet range (per woofer) will work. I will try to have some easy to follow plans drawn up soon, including the sand filled box that I posted info on in another thread.

Brian (Rythmik Audio) has also had some low cost boxes built as well and they will be ready for shipping shortly.