Genesis Advanced Technologies SuperSub Subwoofer

[Folsom]

It’s easier to get larger drivers to play very low, like the sub 20hz you’re talking about.

You could transform a 2x2 surface into a 4x1 with the smaller drivers, changing where can position the box - an example of arrangement.

 

[Alrainbow]

Thanks for your input Gary hope all is well. Best of luck at new place. Can’t wait for things to start back up. Where ever you are with the big idea I have to go. I felt on both rooms you have the Detailed bass and seem less cross over sound.

 

[musicfirst1]

Gary

For the

The SuperSub comes with our standard ServoControl Crossover Module. The low-pass is adjustable from 80Hz to 135Hz (in 1 Hz steps), and phase from 0 to -180 degrees in 5 deg delay (phase cannot be advanced as we wouldn't know what is going to happen in the future).

So, you can use it to supplement the 8-inch woofer towers of the Quartet, or the 12-inch woofer towers of the Prime, or it can replace them.

The SuperSub sits on my usual suspension system. As the woofers are horizontally opposed, the cabinet hardly vibrates. Any vibration is generated from the internal air pressure in the cavity. To control this, the cabinet is constructed using my usual carbon-fiber/composite sandwich. So, they would stack with an additional suspension between the top and the bottom cabinet.

Gary

As I am owner of a Rel Gibraltar G1 Six-Pack (2 x 3 high 12 inch subs in sealed enclosures), you are speaking my language. The "ambient silence" you describe when present on the recording and energized by sub 25hz system response that is truly coupled to the room can be both frighteningly scary and frightenly exciting!

I have so many questions of you, but the fist that come to mind are:

How much additional performance do two SuperSubs give over one? Do you prefer them L/R in the listening room or is center stacked between the mains as effective?

You currently offer the low pass filter on the SuperSub user selectable from 80-135 Hz. Is there a reason that you don't allow the selection point to go lower for better integration with third party main speakers? My Rels for instance are selectable from 20 to 80 Hz.

Restating the question from others here, how would you expect a hypothetical 'SuperDuperSub' consisitng of two 12s, two 15s, and two 18s would compare?

 

[LL21]

It’s easier to get larger drivers to play very low, like the sub 20hz you’re talking about.

You could transform a 2x2 surface into a 4x1 with the smaller drivers, changing where can position the box - an example of arrangement.

Interesting! Thank you again for your time today!

 

[Duke LeJeune]

Certainly, having spoken off-line with a few professional sub designers, when asked to deliver subterranean signals for big standalone full range speakers, they seem consistently driven towards bigger cones rather than arrays of smaller ones.

A woofer's free-air resonance frequency plays a role in how low it can go, and in general larger and heavier cones result in a lower free-air resonance. Also the greater the cone diameter, the easier it is make a suspension system which remains linear at very long excursions. So assuming equivalent cone areas, a few big cones will probably go deeper and louder than a greater number of smaller cones. This simplified analysis doesn't account for thermal effects, which are functions of voice coil and motor thermal mass, among other things.

How much additional performance do two super subs give over one?

Obviously I can't speak for Gary, but in my experience two subs widely-spaced are significantly more effective at conveying that feeling of immersion in a large acoustic space than a single twice-as-big sub would be.

 

[LL21]

A woofer's free-air resonance frequency plays a role in how low it can go, and in general larger and heavier cones result in a lower free-air resonance. Also the greater the cone diameter, the easier it is make a suspension system which remains linear at very long excursions. So assuming equivalant cone areas, a few big cones will probably go deeper and louder than a greater number of smaller cones. This simplified analysis doesn't take thermal power handling into account, which is a function of voice coil thermal mass, among other things.

Thank you!!! Another one to put into my notes!

 

[garylkoh]

And why I am seriously trying to explore what happens if, instead of 1 x 18" servo sub...we went with 4 x 18" subs...in the same location...and NOT try to get too complicated with all the implications of a multi-sub/multi-location setup. Just take what we have...and use a bigger/badder version of a 1-sub set up which has far greater air displacement, more effortlessness, and lower distortion to see if it improves the sense of venue even better and makes it even more solid, more real.

You should!! With the Velodyne subs set at low enough a frequency, in your space location would not matter. However, I would stagger the height at which you place the subs. Four placed at different locations and different heights might sound best.

 

[garylkoh]

A woofer's free-air resonance frequency plays a role in how low it can go, and in general larger and heavier cones result in a lower free-air resonance. Also the greater the cone diameter, the easier it is make a suspension system which remains linear at very long excursions. So assuming equivalent cone areas, a few big cones will probably go deeper and louder than a greater number of smaller cones. This simplified analysis doesn't account for thermal effects, which are functions of voice coil and motor thermal mass, among other things.



Obviously I can't speak for Gary, but in my experience two subs widely-spaced are significantly more effective at conveying that feeling of immersion in a large acoustic space than a single twice-as-big sub would be.

I agree on both counts. The greater the cone diameter, the easier it is to design a suspension system but the more difficult it is to design the cone itself.

However, during my experiments, I found that with exactly the same cone surface area, and the same excursion, 8/12/15 inch cones all sound different. Or feel different. Hence, in the SuperSub I used all three sizes.

 

[garylkoh]

Gary

For the

Gary

As I am owner of a Rel Gibraltar G1 Six-Pack (2 x 3 high 12 inch subs in sealed enclosures), you are speaking my language. The "ambient silence" you describe when present on the recording and energized by sub 25hz system response that is truly coupled to the room can be both frighteningly scary and frightenly exciting!

I have so many questions of you, but the fist that come to mind are:

How much additional performance do two SuperSubs give over one? Do you prefer them L/R in the listening room or is center stacked between the mains as effective?

You currently offer the low pass filter on the SuperSub user selectable from 80-135 Hz. Is there a reason that you don't allow the selection point to go lower for better integration with third party main speakers? My Rels for instance are selectable from 20 to 80 Hz.

Restating the question from others here, how would you expect a hypothetical 'SuperDuperSub' consisitng of two 12s, two 15s, and two 18s would compare?

The SuperSub is actually the wrong name for it since it is not a sub-woofer, but it acts as a woofer for my line-source speakers. So, they will have to come in pairs, and left/right and not stacked in the center. That is also why the low pass filter only ranges from 80Hz to 135Hz.

Adding another pair of SuperSubs would increase the effortlessness but hardly make a difference in the sound. It's like when I went from twelve 12-inch woofers on the Genesis 1.2 to the twenty-four 12-inch woofers on the Dragon. Sounds the same, just that everything sounds so much more effortless..... even acoustic guitar like on Friday Night in San Francisco.

As I said earlier, 8/12/15-inch woofers all sound different. I find more of a "gap" in the sound between my 48-inch ribbon midrange and a 12-inch woofer than I do between the ribbon and 8-inch. Hence, a SuperDuperSub would have to have 8/12/15/18-inch woofers.

 

[garylkoh]

It is very interesting that in Gary's experience and experiments the "you are there"/hall ambiance effect is created not just by increasing very low frequency driver surface, but primarily by big drivers per se (two 15" woofers create the effect more fully than about the same driver surface area of eight 8" woofers).

Maybe two 18" drivers create this effect more fully than the equivalent driver surface area of 15" drivers?

But is the implication of this that to create specifically this very low frequency "you are there"/hall ambience effect we should focus on huge drivers and not worry as much as we usually do about light and "fast" drivers or about tight servo control? (In car parlance does this mean we focus on cubic inches/displacement and not so much on high RPM or "finesse"? (Dodge Hellcat, not McLaren?)

If so, Lloyd, you are on the right track with your 4 X 18" behemoth! (Although I would prefer (at least visually and psychologically) a stereo pair of whatever size boxes you can accommodate.)

Large woofers are better for the hall/ambience effect but they are harder to integrate to the midrange. In the Quartet, for example, without the wide wings of the Prime, the 8-inch woofer towers integrate far better than the 12-inch woofer towers of the Prime. The SuperSub added detail and resolution to the bass in addition to the "holodeck" effect. This may have been as a result of my spending another 6 months fine-tuning the servo control system (or not).

So, for Lloyd who already has the full-range Wilsons, you should integrate your subwoofers below the port-tuning frequency of the main speakers. Having output from the subwoofers significantly above the port frequency, you would have two conflicting signals. Since you already have 13-inch and 15-inch woofers on your main speakers, I suspect that a couple (or four) 18-inch woofers would work really well. And at such long wavelengths, a couple of degrees phase difference won't matter much. However, the subs would have to work doubly hard (that's why four might be best) as they will first need to overcome the out-of-phase port signal, before delivering the ambient sound.

 

[LL21]

Gary,

Amazing. You are busy opening up the new place and finding the time to help us audio kinder with our extravagances! Thank you! This is incredibly helpful and I will be sure to continue to pursue. Best wishes with the re-opening.

 

[LL21]

...So, for Lloyd who already has the full-range Wilsons, you should integrate your subwoofers below the port-tuning frequency of the main speakers. Having output from the subwoofers significantly above the port frequency, you would have two conflicting signals.

Since you already have 13-inch and 15-inch woofers on your main speakers, I suspect that a couple (or four) 18-inch woofers would work really well. And at such long wavelengths, a couple of degrees phase difference won't matter much. However, the subs would have to work doubly hard (that's why four might be best) as they will first need to overcome the out-of-phase port signal, before delivering the ambient sound.

Gary - I believe the port tuning frequency is around 19hz...so does that mean I cut off the subs from playing too much above this frequency?

From Stereophile: "The saddle centered at 19Hz in the impedance-magnitude trace suggests that this is the tuning frequency of the large rectangular port, which, in MF's review samples, was open to the speakers' rear rather than to the front. However, the minimum-motion notch in the woofers' summed output actually occurs at 21Hz, while the port's output, again measured in the nearfield (red trace), peaks just below 20Hz but doesn't roll off until above 70Hz."

 

[dbeau]

Gary - I believe the port tuning frequency is around 19hz...so does that mean I cut off the subs from playing too much above this frequency?

I think this is a valid issue as it might be that the port output as measured by WA (19 Hz) is different, lower, than that existing at the listening position.
If so, my question is: should the sub-bass be set to be slightly under that frequency vs. a manufacturer's measured point?

 

[LL21]

Just an observation as I've been deep diving into REL videos, etc. and they apparently agree with a lot of this as they claim 'ambiance' using their 25 model using a single 15" cone (recommend 2+) correctly 'tuned'. REL relates that first efforts were with 18" and larger cones but without good results and came back to 15" and attention to speed (filters) cone design and materials and of course always the claim of 'box' construction. i am trialing a pair of 25s and yes 'ambiance' is more 'there' although my initial settings are near 20 hz for the cross over point and I'm thinking of going lower with WA X1s and I also agree that at least my speakers are not sufficient, in my room and limitations of placement, of providing all desired.

Just saw you posting...and went back and remembered this...thanks! Very interesting. I know the vast majority of big Wilson owners I know have a tendency to cross over in the 30-38hz range. So very interesting to hear you go in around the 20hz range which is also what Gary Koh is suggesting given the port tuning frequency.

Did you try higher...30hz or 35hz? If so, what happened? Currently, I use just under 40hz with the bass set quite low...i wonder what would happen if i set the crossover lower but turned the volume UP. (Unfortunately, the Velodyne crossover internally stop at 40hz, and you can manually bring it down a little lower using EQ...i might try a little harder to do that)...but it is not so straightforward as turning a knob to 30hz...you have to suppress the signal db by db at certain frequencies.

 

[LL21]

I could 'guess' the reason it might be 'ok' to go to 30hz+, is the measurements of the overall speaker may roll off starting around the 30-35hz level in-room for some reason. Plus, I have read somewhere that some sub ports drop in output as they get to half an octave above the tuning frequency (for the big Wilsons, 30hz).

 

[LL21]

Gary - I believe the port tuning frequency is around 19hz...so does that mean I cut off the subs from playing too much above this frequency?

I think this is a valid issue as it might be that the port output as measured by WA (19 Hz) is different, lower, than that existing at the listening position.
If so, my question is: should the sub-bass be set to be slightly under that frequency vs. a manufacturer's measured point?

Interesting...If the actual measurement at listening position is HIGHER than 19hz, then would one expect to adjust the sub crossover accordingly higher? Or stick with the strict Wilson Audio output measurement?

Perhaps Metaphacts can weigh in here as a Wilson Audio person.

 

[dbeau]

Just saw you posting...and went back and remembered this...thanks! Very interesting. I know the vast majority of big Wilson owners I know have a tendency to cross over in the 30-38hz range. So very interesting to hear you go in around the 20hz range which is also what Gary Koh is suggesting given the port tuning frequency.

Did you try higher...30hz or 35hz? If so, what happened? Currently, I use just under 40hz with the bass set quite low...i wonder what would happen if i set the crossover lower but turned the volume UP. (Unfortunately, the Velodyne crossover internally stop at 40hz, and you can manually bring it down a little lower using EQ...i might try a little harder to do that)...but it is not so straightforward as turning a knob to 30hz...you have to suppress the signal db by db at certain frequencies.

ANSWER is YES. Because REL states they normally find the best setting to be from 25 > 31 Hz (WA gives 30 > 40 but probably with their subs) I moved the setting, in steps, until 28 Hz and correspondingly using lower volumes. It is much better with my wife commenting last night on how much more 'dimensional and clean' it sounds. She's spot on .
So I received the REL recommended track for setting subs (individually) and will buy a player to use for this purpose later this week.
To me, it's amazing how much better it is, even with my blundering around. As we began this, there is ambiance that surprises me.

 

[LL21]

ANSWER is YES. Because REL states they normally find the best setting to be from 25 > 31 Hz (WA gives 30 > 40 but probably with their subs) I moved the setting, in steps, until 28 Hz and correspondingly using lower volumes. It is much better with my wife commenting last night on how much more 'dimensional and clean' it sounds. She's spot on .
So I received the REL recommended track for setting subs (individually) and will buy a player to use for this purpose later this week.
To me, it's amazing how much better it is, even with my blundering around. As we began this, there is ambiance that surprises me.

Awesome...that is really, really good to know. I will DEFINITELY keep that in mind. I dont know if ultra-deep, ultra effortless bass is the final frontier or not, but it sure is cool!

 

[Duke LeJeune]

I know the vast majority of big Wilson owners I know have a tendency to cross over in the 30-38hz range.

IF you want to try overlapping the subs and mains, the phase control on your subwoofer amp can help. When the outputs of subs and mains are combining with a large amount of phase difference between them, you won't get the "peaking" that you would if they overlapped AND combined approximately in-phase.

As a supplemental or alternative technique, you might try plugging the port(s) of the mains, and/or filling the ports with open-cell foam. The net result in either case will be less bottom-end output from the mains. Plugging the ports will better protect against over-excursion, while the open-cell foam may tend to sound better once you have "dialed in" the proper amount of foam for your application. I'd try reticulated foam with about 30 pores per inch, and adjust the thickness of the "foam plug" in the port. I can't predict how much you might need - too many variables (woofer parameters & boundary reinforcement & the subwoofer's low-pass filter frequency and slope being among them).

Imo as long as your mains don't really need protection from bass excursions, you may well be better off WITHOUT a highpass filter in their signal path.

The ear is much more sensitive to frequency response peaks than it is to phase anomalies in the bass region, so focus on getting smooth in-room frequency response and you will be solving the problem that matters most. Don't let your sensibilities be offended by what looks like phase anomalies "on paper". It is not a bad thing to have multiple sources contributing in the same frequency region at low frequencies, from a room-interaction standpoint. And room interaction generally plays a very large role in the bass region.

In my opinion.

 

[musicfirst1]

Very informative stuff guys! Gary, would it be worth trying to extend the low pass filter on the SS down to, say, 20 hz to make the SuperSub more gererally applicable to other, more full range speakers? Or are the engineering challenges to difficult to overcome?