How much faster of a sub is the REL T5X vs SVS SB12-NSD

The notion of a "fast" subwoofer is entirely inappropriate. The speed a subwoofer can vibrate at without distortion is it’s frequency response at a given volume. A smaller driver is at a distinct disadvantage because it has to travel farther (faster) to produce a given low note at a given volume than a larger driver.

I agree, but people who have never wielded a pencil in anger on a math, physics or EE test, or who are into the humanities or business side of things, like to use the term “fast” more likely to describe what is “transient response”.

And faster is also easier to spell than transient.

In this respect, sealed —> ported —> bandpass, and they sound faster as the transient response and group delay are lowest for sealed.

• sealed = 2nd order
• ported = 4th order
• bandpass = 6th or 7th order

Transmission line is likely 3rd order, so it slots in, and infinite baffle I believe is 1st order.???

["curiousjim     I also tried, Velodyne, REL(old models) and an old SVS12” and the last is a brand new SVS 2000Pro. Depending on your room, you can probably get close, but…."]

Interesting problem. Do you recall which Velodyne model you tried?

The notion of a "fast" subwoofer is entirely inappropriate. The speed a subwoofer can vibrate at without distortion is it's frequency response at a given volume. A smaller driver is at a distinct disadvantage because it has to travel farther (faster) to produce a given low note at a given volume than a larger driver. As a rule, larger drivers have less distortion than smaller ones and do not have to travel a far (faster) to produce a bass note at a given volume. Producing 18 Hz with authority requires at least four 12" or two 15" drivers in your average listening room. In a 16 X 30 foot room I use eight 12" drivers. This is a two channel system.

I just purchased a pair of REL T5x and like @Pooch2, I was very pleasantly surprised at how easy they are to set up and dial in.. The REL’s work wonderfully with either my upgraded/modded MMG’s or Sonus Faber monitors. Integration with either the little Maggies or the SF’s is seamless. I’ve had a number of subs before these, including REL T5, but the T5x’s are by far the best in my experience.

I followed REL's setup suggestions closely and am thrilled with the results.  

Sure, this is just one guy’s experience, but I do hope it helps some of you other guys and gals.

 

I have recently installed 2 REL T5/X into my system. I have been trying to integrate Mid/Base and Base response with my Wilson Benesch Square 2 Speakers as they are known for a fast base response. I wanted some additional base fill and soundstage improvements provided by a subwoofer. I have tried the SVS SB 12 sub and was not pleased with the results, just wound up with a muddy base response no matter what adjustments I tried using the app. My ear leanings are to higher frequency base so the big sub seem to sacrifice some speed that for more lower frequency. I was quite pleasantly surprised when I installed the 2 REL T5/X subs, first they were easily set up, and after some reading and trial and error on location, dialing in the frequency and volume, they were up and running. I am very pleased with their integration with with the Wilson Benesch Tactic Drivers, and while still fine tuning the subs somewhat I think I have found my solution.

This business about smaller driver being "faster" is totally and completely wrong. It is another example of lay intuition run amok. 

"fast" is a totally inappropriate term to use in regards to subwoofers. The speed at which the cone moves is determined by the frequency it is reproducing, the higher the faster. If a driver can't keep up with the frequency it rolls off. Most subs break-up before they roll off. Larger drivers or multiple drivers are always better because they produce more output with shorter excursions = lower distortion. 

A better term would be "dynamic" Some subs are more dynamic than others. This is very much dependent on the size of the driver and the amplifier used to drive them and the plate amps used in subwoofers generally stink not to mention a sub enclosure is not a great place for anything especially if it is a sealed sub due to temperature control. Amps working hard get hot so you can only use amplifier types that do not generate much heat. Passive subs with outboard amplifiers is a much more "dynamic" approach.  

If you send a signal to a well-designed sub-woofer it seems to me it will come back at you at pretty much the same time, whatever the model.

Why are you interested in 'fast'?

Glad you found a good sub that works. The Descent looks like a killer sub.

After trying or at the least seriously listening to them at shows "Either by early or late sessions to avoid possible crowding".

I auditioned them all.

And I do mean "All" of the offerings available on the higher end of the spectrum.

With the exception of that one "Krell" column. But knew I wasn't dropping ($50,000+) for a subwoofer anyway.

I decided on purchasing two for a stereo configuration from "Rythmik".

Each being servo-controlled and boasting (2 x 15") transducers. Which I then ordered and also paid for in full at that time. 

And a month later I was forced to alter my plans, as rythmik finally told me that there was no way they could provide any of the products which I had ordered!

"I'll just sum up the experience as apparently there were; (Insurmountable problems with shipping and also inventory control issues of biblical proportion)". 

"Yes", that really happened! But I believe now that it was all for the best, as things turned out!

I ended up going with the only subwoofer that had actually, "Wowed" me during my auditions. But a subwoofer which had at the time, just been taken out of production.

The "Martin Logan", "Descent".

With the three aluminum, (10") transducers in a triangular, vibration canceling cabinet. But of course, the model with the "Cherry" wood top option that I had chosen? It kept itself elusive and always, just out of my grasp.

Frustrated, and also because I had just so wanted "New".

I had then attempted to purchase the Rythmik offerings.

So finally I just found two "Descent's" all in black, which were used but with low miles. Both from the same fellow who happened to live near me for $1500 each.

Now I own (Seven) of them. All of them purchased as "used". And I could not be happier.

And I still audition subwoofers as I can. Just not at my home, most of the new offerings as they come out.

So you may wish to audition a used one of this type. And possibly save a few dollars in the process. 

One last point. And regardless of what the sales team will tell you...this is true.

There are two, quite distinctly different, servo-control systems used in subwoofers.

And either is "Far Superior" in accuracy and "IMHO", also listening pleasure. Than any sub with "No", "Servo-control" at all!

But I still feel this is a huge difference! One system which uses a "feedback loop" and an "averaging algorithm" to, "approximate" through averaging - how it controls the subwoofer/s. "Like the one utilized in the Rythmik, GR research". And most "If not all" other current subwoofers".

And then there is the "original" servo-control system. Which is much more difficult and also very expensive to manufacture by comparison. But this system stands head and shoulders above the other in both speed and quality of the results gained. This system is "Like the one in this Martin Logan model", the "Descent"

Also, the "Martin Logan", "Descent" works quite well as a side or end-tables too!

Good Luck!

 

I have 2 SVS subs.  Great for movies and good for music, but not great for music.  My buddy has a sub made for music, and it is much better then my subs.  I have not spent a ton of time messing with min.  Sorry I don't recall the brand.  I think it is REL.  

Oh, I currently have a pair of Acoustat Model X’s and they still sound great!

JD

I’ve had panel speakers since the 80’s and tried to buy or build subs to go with them and NONE are as fast as the panels. I built 7 prototypes ranging is sizes of both drivers and boxes. Used active and passive crossovers and all solid state power. Also tried every position possible. 
I also tried, Velodyne, REL(old models) and an old SVS12” and the last is a brand new SVS 2000Pro. Depending on your room, you can probably get close, but….

One thing, whatever you get, make it a sealed box, not ported.

All the best.

JD

Use a sealed box sub with Maggies,  servo controlled as well.  Much faster than a ported design.  And do not put it in a corner,  I have mine next to the electroncs rack and in between the Maggies.

All right, I was gonna leave the details of woofer "speed" to those who cared enough to watch Danny Richie’s Tech Talk 6/Fast Bass YouTube video, but in light of the akg_ca post directly above, I’ll say more.

The Vandersteen is indeed a very fine sub, one with which I am quite familiar (Brooks Berdan was one of Richard’s biggest dealers). But to say "The mass of a larger driver will not allow it to respond as quickly as the Vandersteen 8" drivers" is to over-simplify what is actually going on. Again, for a very detailed explanation, watch the video.

At one point in time, Rythmik Audio was offering sub models using 8", 12", and 15" drivers (he has discontinued the 8", and added an 18"). Contrary to common audiophile myth, an 8" woofer is not necessarily "faster" than a 15", 18", or even 24". I have an 8" sealed woofer, and my open baffle 12" and sealed 15" Rythmik subs sounds "faster" than the 8".

To understand why I used quotation marks above, I implore you: watch the video! As a simplified teaser, I’ll just say that the perceived "speed" of a (sub)woofer is not a matter of how fast a driver will respond to the signal (bass frequencies are quite slow), but in how fast it returns to rest when the signal stops. Yes, the moving mass of a driver (the cone) and its stored energy (watch the video ;) is part of that phenomenon, but so is the motor (magnet structure), it’s suspension, the cone material, and numerous other factors.

But imagine a driver which includes not just a voice coil, but a sensing coil which electronically applies the "brakes" when the signal ends, forcing the cone back to it’s rest position---faster than an uncontrolled cone, whatever it’s cone size. That’s servo-feedback, a patented form of which Brian Ding employs in his Rythmik Audio subs. Perhaps you have heard servo-feedback woofers before. I had: I owned a pair of Infinity RS-1b’s for a time, which just happened to use multiple 8" servo-feedback woofers in it’s bass towers. Not even close to the sealed-enclosure 15" Rythmik.

Now, imagine a servo-controlled driver installed not in a sealed or ported enclosure, but in an open baffle frame. Harry Pearson loved the sound of the twin bass panels of the Magneplanar Tympani T-IVa dipole planars (a pair of which I own), using them as woofers in his Tympani/IRS super speaker. I too love that kind of low frequency reproduction, which replicates the sound of upright bass, cello, the lower registers of piano, and of course drumheads like no other woofer I’ve heard. Until I built a pair of GR Research/Rythmik Audio Servo-Feedback OB/Dipole Subwoofers. THE sub for planar loudspeakers!

You might consider another contender and no pretender …VANDERSTEEN 

The VANDY is not just another subwoofer.With its internal 300-watt power amplifier, it is the perfect compliment to any sound system.

It consists of three 8″ floor-facing drivers, each with a massive motor. So why not a more typical single 12″ or 15″ design? The mass of a larger driver will not allow it to respond as quickly as the Vandersteen 8″ drivers to today’s demanding recordings. The VANDY’s  8″ drivers are designed to handle the content but be “fleet of foot” at the same time.

 

 

My recommendation:

Go onto YouTube and do a search for GR Research. Click on the GRR icon and scroll over to the Tech Talk 6/Fast Bass video. You will find the answers to all your questions, from an expert loudspeaker/subwoofer designer.

After that, I suggest you investigate what many in the planar loudspeaker fanatic community consider the ultimate (sub)woofer for use with any and all planar loudspeakers: The GR Research/Rythmik Servo-Feedback OB/Dipole Sub. The only one of its kind in the world.

on a more serious note, i would unhesitatingly recommend rel... their design and instructions (followed diligently, to the letter) will result in excellent integration and terrific sound

many many maggie owners successfully use rel's for bottom end support

ditusa, 

Great and very informative article, eye opening. I’ve always known integration played an important part of the subwoofer blending correctly with the speaker, but after reading the article it made me think maybe the T5X may blend better with my system being its a 8” cone and would give me a higher bass result being my SVS is a 12”… I’m not looking for earth shaking bass being I really use the system for 2 ch music listening.

I’m still doing my research, and thank you for the article   

OP. The punch you are looking for is often above subwoofer frequencies. The next driver up the range does that job and is backed up by the woofer. And that woofer will need real power to get it to knock your socks off.

@flasd,

Bass speed not really. Woofer and midrange integration yes.

Here is a good article on the subject See link below:

Mike

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

+1 @audiorusty 

A ton of rocks. Obviously. 

What's heaver a ton of feathers or a ton of rocks ?

😉😂

i dropped both from a 10 storey building, they hit the ground at exactly same time .... so i would say neither is faster...

sorry i couldn't resist... carry on 😆

Audiorusty,

Thank You ! That’s the info I needed …. Was not sure how to interpret that off the specs. 

Checked out the Rythmik site the other day and noted their technology but was not a fan of the return policy, especially having to ship back such a heavy item at my expense with a restocking fee. 

I did watch the YouTube video about servo subs and was very informative, so thank you for that. I also watched some other reviews and placement was more crucial with the Rythmik than the REL and being that is an issue for me could be a deciding factor  

Still waiting for more info on my actual question though from others and thank you for sharing your brand experiences.

 

Speed of a driver is determined by one thing only and that is by how high a frequency it can reproduce. The higher the frequency, the faster the driver. Tubby or boomy bass (slow decay of the bass notes in your room) is an acoustics issue. 

Not sure what you mean by slap since there is an actual slap bass technique used by some players that is heard in the upper midrange but if you are referring to chest thump, sometimes referred to as impact or impulse, that is created by the kick drum and is a matter of getting enough power to the correct frequencies in the 35 to 50 hz range.

I've owned one (and then two) SVS SB12+ which were a step up in quality from the NSD. They were nice subs but I ultimately required more headroom when I was building a system in my main system (large, open floor plan with no way to pressurize the room).

I then traded for a pair of HSU ULS-15s. These offered plenty of bass but they tended to be peaky and ultimately required the use of a sub EQ (SVS AS-EQ1). Loud, but better suited for home theater than 2-channel audio.

Both HSUs and EQ were then sold off for a single REL 212SE. The REL was the easiest to integrate and offers a seamless comparability with my mains. It's smooth when it should be, and bombastic when called for. I realize this is up the line from the T/5x, but I feel that the REL would provide some of the best quality sound if not all out quantity.

As suggested by 2psyop, the Rythmik line also has a loyal following and would be worthy of researching.


 

https://youtu.be/W5NNjEwF8Co

Look at servo subwoofer technology. Rythmik offers it but other brands may also. It's the fastest for stereo integration that I know about, but I am no expert.