REL vs JL AUDIO

There is nothing special about the Perlisten subs, just marketing BS. None of them include a high pass filter, a fatal mistake.

I have also been turned away from JL Labs products due to multiple reports of liability problems. I have personal experience with one failure.

There are many fine subwoofer drivers out there now and many digital processors with fine bass management capability. The best way to deal with subs is to get a processor, separate amplifiers and passive subs. The key to low distortion is using large and multiple drivers keeping the excursions short. With bass management sealed subs are best. As long as you have the power you can make the sub do anything you want. 

You would be surprised how inexpensively this can be done. Parts Express has great subwoofer kits that anyone with two hands can build.
As an example; Four Dayton Ultimax 12 sub kits + a MiniDSP DDRC 22D + 2 QSC QX7 amps = $3400.00 plus some elbow grease. 
A single JL Labs Fathom 113 is $5000.00. 

 

@james633, bigger drivers of the same caliber are always going to sound better and that is science proven. There is a simple reason for it. As the cone excursion increases the suspension becomes progressively less linear. It gets stiffer until it can't move any farther. This distorts the waveform. Larger drivers do not have to move as far to move the same amount of air resulting in less distortion for the same output level. There is a limit however. As the cone gets larger it becomes more difficult to control and in many instances starts to wobble. You can see it happen with a strobe. The largest anyone has to go in a home installation is 15" If more power is needed the go to multiple drivers which accomplishes the same thin as larger drivers, shorter excursions. With the right size drivers servos are not needed at all. It is easy to keep distortion under 0.5%.

There are issues with the use of subwoofers that manufacturers won't mention primarily because they can't deal with them or are afraid that the increase in price will knock them out of the market. 
The first is the use of a high pass filter or rather a complete two way crossover. Taking the bass out of the main speaker dramatically lowers distortion in low frequency drivers that operate well into the mid range. You can tailor the response curve of the main speakers and subwoofers to match perfectly and you can take the crossover point up higher without difficulty. Next is a critical issue that they never mention. The impulse from the subwoofers and the main speakers has to reach your ears at the same time. You want to listen to one bass drum not two bass drums. This can not easily be achieved by positioning the subs. The problem is that subwoofers are most efficient in corners and against walls, up to 6 dB more efficient requiring much less power which is vitally important if you are using DSP correction. Most people position their main speakers away from the wall placing the subwoofers 3 to5 feet behind the main speakers. That is a 0.3 to 0.5 millisecond group delay. The easiest way to fix this problem is to digitally delay the signal going to the main speakers. Phasing and time correction are impossible to do accurately by ear but you can measure them with a $300 microphone/measurement program or with a comprehensive room control system. If you want to fix the group delay by moving the subwoofers or speakers then all you need is the measurement microphone. You will just have to accept the fact that your system will not be as efficient as it could be but if you do not have digital facilities this is the only way you can do it. Comprehensive room control preamps with bass management programs are the best way to go. New units are coming along all the time and some of them are not very expensive. MiniDSP, DEQX, Anthem and Trinnov are a few. 

There is no commercially made subwoofer that will provide state of the art bass out of the box. The system I describe above will out perform any subwoofer named so far in this thread and not by a little. I will not buy any more commercially made subwoofers. There is only one that meets my requirements and it is $36,000.00. I would need four of them 🤢 Discounting my labor I can do pretty much the same thing for $15,000.00 in drivers, amps and enclosure materials. 

I have no relationship to Audio Kinesis but I think most here would be better off buying their swarm system.  

If you have one of the above subwoofers you can do your main speakers a favor by soldering capacitors in series with the inputs of your amplifier.
The value is calculated with this equation Fc = 1/2piRC or C = 1/Fc2piR Fc= cut off frequency, R=input impedance of amplifier, C= capacitance in Farads. So if your amps input impedance is 10K ohms and you want a cutoff frequency of 100 Hz  C = 160 nF.   You can get the caps from Digikey. I forgot to mention that this is a 6 dB/octave filter.

@james633 , I think you underestimate yourself. Building one of these kits is not that hard. Finishing them nicely with something like Piano Lacquer is not so easy but you can have that done by a pro for reasonable money. I tell people otherwise just to cover the enclosure with black carpet. 

The JTR woofers are very interesting. It looks like they are using a Dayton reference 18" driver which is excellent. Plywood construction is better than MDF. They are using a smaller sealed enclosure, a lot of power and DSP to force the woofer down lower. It is still a very large subwoofer. It would be impossible for me to fit four of them into the situation I have and with multiple subs a woofer that large is overkill. But using two in a point source system in a room 15 X 25' or larger would be fine if someone did not mind the look. You will also have to weight that enclosure down to keep it from shaking. I would put a granite slab on top of it. Used with digital bass management I would think it would be significantly superior to any Rel, SVS or JL sub. Here is the driver https://www.parts-express.com/Dayton-Audio-RSS460HO-4-18-Reference-HO-Subwoofer-4-ohm-295-472

manelus, I hate to be a stick in the mud (ya right) but, speed has nothing to do with it. When a driver can not move fast enough it's high frequency response rolls off. Look at the frequency response of the 18" Dayton I mention above, 20 to 500 Hz. It has no trouble putting out 500 Hz so 80 to 100 Hz is not a problem. Most 12" drivers make it to 1000 Hz without issue. It is usually not speed that cuts the drivers off either but cone breakup. So, then what are you hearing? Transients and detail are being smeared because either the subs were not well match to the main speakers or the amp driving the subwoofer was not able to control it well.
Driving big powerful subwoofers is not easy. There is a lot of back EMF.
This is a problem we noted way back in the late 70's when subwoofers were a brand new deal. Some amps made great bass others not so much. Basically you need a lot of power (big power supply) and an output stage with extremely low impedance. The class D amps that most of the Subwoofer manufacturers are using usually do an admirable job but IMHO not as good as a big class A/AB amp. But, in a small enclosed space you can't have a big amp that generates a lot of heat.
By the way, if vibration affects electronics why are we sticking amplifiers in subwoofers? Just a thought. I prefer passive subwoofers and outboard amplifiers. With outboard digital bass management there is no need to place electronics in the subs. You can then pick the amp you think makes the best bass.  As far as matching subs to main speakers is concerned, the vast majority of sub owners are not able to do it correctly because they do not have the tools. Doing it by ear is folly. It's like pinning the tail on the donkey. It is easy to do if you take off the blindfold. Using a measurement mic/program along with digital bass management allows you to dial it in perfectly every time regardless of where you place the subwoofers and boy do you get big smiles when everything is working right. 

Subwoofers are neither fast nor slow. They are either driven and integrated correctly or they are not.

Don't get me started on enclosures.

@james633 , With either the Anthem STR or Trinnov Amethyst all you have to do to completely integrate the subs is put the subs wherever you want them, set up the microphone at your listening position, tell the unit what crossover you want and tap the button. The units will ping each speaker in succession, calculate correction curves, crossovers and delays and plug them in automatically. Takes a quiet house and 15 minutes. This is a whole lot more like plug and play than crawling around the room trying to figure out what the right position for your subwoofers is. You will never be able to achieve this level of performance manually. I tried for 20 years and even though I thought I had it figured out the first cut I played after hooking up my old TacT 2.2x (Red Hot Chilli Peppers) totally blew me away.

decathalon1991, You have a fine system. I believe you are using the CR 1 crossover? While greatly superior to the low pass filter found in the vast majority of commercial subwoofers it is not near state of the art. I am also intimately familiar with the Fathom f113 and JL's drivers. I considered using them at one time, specifically the 13W7. I decided not to use it because it overs no advantage over Dayton's Ultimax drivers in home installations and I am not inclined to pay extra for cosmetics. The system I am currently working on uses 8 12" drivers. At any rate digital bass management is far superior to anything you can do in the analog world. Distortion levels are orders of magnitude lower and you can delay the signal to various speakers as needed to time aligning the whole affair. It is close to impossible to do this by analog means. You have a fine system. Please, look into the Trinnov Amethyst preamplifier. It will push your system to a whole new level. Trinnov is a French company that makes commercial systems for theaters and studios. They currently make the best audio and theater processors and that is not IMHO. I have no interest in Trinnov other than I plan to replace my aging 2.2X with an Amethyst in the near future. I probably will not use it's phono stage but everything else is top notch.

As for the efficiency of subwoofers, this is a real wild card. It depends on where you put them and how much correction they require. The beauty of digital correction is that you can get away with a much smaller enclosure as long as you have the power to do it. Adding a port or passive radiator does not necessarily make a sub more efficient. The sub will go lower before rolling off but when it rolls off it does so twice as fast making it more difficult to correct if you just happen to want to go lower. With correction like you have in your Fathom it is best to use a sealed enclosure. If done right you can push it lower with less power and avoid issues like port noise and passive radiators bottoming out. Take a strobe to any passive radiator and watch what it does!

The only commercially made subwoofers I would buy are made by Magico. They are using what is called a balanced force design. This involves putting two drivers at opposite ends of a symmetrical enclosure. The drivers operate in phase so their reactive energy cancels out and the enclosure remains stationary instead of shaking. Turn the volume up and put your hand on your subwoofer. Any vibration or shaking you feel equals distortion, a lot of distortion. Countering this requires a very stiff, heavy enclosure with a balanced force layout. This is also the main advantage of a down firing subwoofer. The driver is trapped between the floor and the weight of the enclosure. The main problem with this is how stiff the floor is.