Critique my system

[ryanosaur]

Those do seem to be some questionable design choices. I get the skepticism. They are also sensitive drivers too tho, right? I guess my biggest sticking point would be how drivers not designed for infrasonics behave at those frequencies. Especially in vented cabs. They must use a crapload of dsp and bank on sensitivity and strong motors to pick up the slack.

They do have a very strong following tho, so they must be doing something right. Their aesthetic reminds me a little bit of JTR.

WARNING: TLDR

I get it... you can do a lot with a strong motor and a lot of Xmax. If you are willing to push Xmax a little and are not worried about linearity, you can even get a hair more.
Below Fs, (Resonant Frequency in Free Air), it requires Power to move that Motor. The Sensitivity of the Driver does not come in to play as one may want it to. Below Fs, it becomes a game of force moving a Motor (which in some instances actually stiffens against said force (the NSW6021 does this)) to try to create sound, hence why I say it requires "gobs of power"
As you push Extension, the output efficiency seen above Fs also drops, and can do so significantly. This creates a Mid-Bass penalty where these drivers are designed to excel.

Correcting this for any sort of linear performance, means that the less efficient extension becomes the basis for the Output. So DSP must be engaged to give as much linear extension as possible while also throttling the performance of the Driver where it is efficient.
I've see the Stereo Integrity Drivers discussed in a manner similar, but due to the nature of putting them in a small box. Nick;s Drivers have a lower Fs and are designed to play down there... But putting them in a small box limits that performance. In a Sealed box, he advises using a Linkwitz transform in DSP to boost the low end performance for flat output through the range of the Subwoofer.
Again, the same rule applies: you have to use more Power to boost that performance, and the lower you go, the more Power must be applied to maintain flat output.

I think it was Kevin, one of the owners of GSG, who told me that the shift in design is one where you have to look at the Subwoofer as a complex system. The different parts all come together to form the final product rather than just tailoring everything around what is best for the Driver. Traditional design is not quite like that... yes, the parts combine to form a whole, but in more modern practice when using a Driver with Strong Motor and Long Throw capabilities, the DSP becomes a part of that system and how it is applied plays as significant a role as the Cabinet and the Driver.

Again, I'm not saying it isn't possible, but it is done at cost somewhere else in the system. If Hoffman's Iron Law survives, then you are neutralizing the Efficiency for everything else. I think it was hisTom's/PSA's) 21" vented IPal with a 4000w Amp for almost $4K?!!?! But at what SPL and Distortion levels are we talking?

Just for kicks, that will require its own 20A circuit on 240V line... And you will blow that circuit around 3840w, well below the 6000W Peak the Amp claims to be able to deliver.
(A 30A circuit will get you safely to 5760w.)

 

[ryanosaur]

Here is an excerpt from Red Five's Devastator Index over at that other site:

Why bass physics suck:

Below is the Fat Boy Version 5 with the native 22Hz tune in gray and I tweaked the vent area down so it is now tuned to 18Hz. As you can see from the graph output takes a huge 5db hit from the lower tuning. In room that 22Hz box will probably stick with all the other Index Devastators down to 17Hz or 18Hz. That is a bit room dependent, so your mileage may vary. Also, remember 6db is the equivalent of doubling your sub system, amps, boxes and sub woofers, 3db from cone area and box displacement and 3db from the input power doubling.

Now I am going to push this further down to 15Hz tuning on the rear chamber. As you can see we are down a solid 10db on the left corner from the original 22Hz tuning and another 5db from the 18Hz tuning.

The important thing to know? Each octave (dividing a given frequency by 2) you descend in frequency will require 4 times the displacement to achieve a given level of output. Let's say when tuned 20Hz a box can hit 88db on 1 watt of power with 1mm of excursion. If we tune the box to 10Hz it would take 4mm of excursion from the woofer to hit 88db. This is an important fact when selecting a Devastator. There are three factors that will come into play. Output, Extension and Cost, those factors will always have to be balanced. You can chose 2, but you cannot get all 3 unless you are in a very small space that gains very well. A 7000 cubic foot room on a concrete slab is not a good place to chase extension. It would be better to go with higher tuned cabinets and gain the wobble effect from a BOSS platform. Unless you have the luxury of unlimited budget.

You can easily see where the Horn is taking over in output vs the Back Resonator of the Devastaor. Basically right at 50 Hz. And the lower you tune it, the worse it gets.

 

[Pogre]

Here is an excerpt from Red Five's Devastator Index over at that other site:

You can easily see where the Horn is taking over in output vs the Back Resonator of the Devastaor. Basically right at 50 Hz. And the lower you tune it, the worse it gets.

Yeah that's a trip, dropping tuning just a few hz sucks up all that sensitivity. HMM...

 

[JasonGSG]

To respect my Friend's post above, I am not suggesting that Tom does not know what he is doing, nor that he is a bad designer.
That said, you HAVE to pay the Butcher for your cut of meat, and that Butcher can't give your rack extra ribs, we can't make a Choice cut Prime...
But we can lie to you!

Yes, I did some Butchery in my day.

What does that have to do with Subwoofers?
Size, Efficiency, Extension.
Those are the traditional rules a Speaker designer has to work with. You get to pick TWO. The THIRD is OFF THE TABLE.

There are ways to game things a bit when using well designed Drivers and DSP. I don't look at this as elegance, rather it's more like putting a Shock Collar on your Doberman.

Some of these Pro Drivers can be pushed, and they can be pushed hard. The NSW 6021 can take 5000W Peak! You CAN push it into infrasonic territory, but at what cost?
The same goes for any pro Driver. These machines have some insane Motors, but they still have to obey some rules along the way.

Until I see some true measurements of those Subs, I have questions. The Cabinets aren't large enough, the Amps aren't powerful enough, and the Drivers are not designed for LF and especially Infrasonic output. Yes, these Drivers are the darling of the DIY scene, and they are getting used everywhere.
Go to GSG: they are advertising Pro Drivers for most of their product line.

@JasonGSG ... Perhaps you can shed some light on how these pro drivers really work for infrasonic content, please?

 

[ryanosaur]

View attachment 55181

Ah... A man of few words.

So Jason, how much of the behavior here is the Cabinet tune?
Do these models represent any DSP, HPF or a Voltage limit?

Curiosity: the Light Green line with the swale and slightly higher Q peak at 20Hz... which Driver?

Do you happen to have a similar comparison for Full Martys, please?

 

[bsf]

is there a big difference in the THX 15" vs THX15" v2 , $300 difference

 

[shadyJ]

is there a big difference in the THX 15" vs THX15" v2 , $300 difference

no serious difference performance wise.

 

[bsf]

no serious difference performance wise.

What about the 1000 watt 15" vs the 13" 2000 watt

 

[ryanosaur]

What about the 1000 watt 15" vs the 13" 2000 watt

This is a completely new design. Shady has reviews up IIRC. you can compare and contrast, all from the same source.

The V1 to V2 you asked above were largely just cabinet design/aesthetics I think.

 

[bsf]

This is a completely new design. Shady has reviews up IIRC. you can compare and contrast, all from the same source.

The V1 to V2 you asked above were largely just cabinet design/aesthetics I think.

which would you buy? you may have suggested already but I can't remember

 

[shadyJ]

which would you buy? you may have suggested already but I can't remember

There are some very minor improvements in the driver in the V2, but not anything that would constitute a major change. If you think the styling is worth the extra $300, go for the V2, but if not, go for the V1. As for the 13", it does offer some performance improvements, mostly in deep bass.

 

[ryanosaur]

which would you buy? you may have suggested already but I can't remember

If money is no object, you get the biggest and baddest, and you get 2 or 3 of them.

More realistically... I do not remember what your space is, volumetrically speaking.

So I would balance my choice based on cost and the ease with which the Sub can give me a clean 16Hz. I'm not looking at the reviews right now, but I recall the 15v1 and the 13 both reviewed well.
I use 16Hz as a benchmark because I want full Pipe Organ, and I want it as clean as possible.

Keep in mind, these are monster Subs. So whatever you do, make certain you pay attention to that, too.

Make friends with you Fed Ex or UPS driver if you haven't already... perhaps these ship freight, I don't know.

 

[bsf]

If money is no object, you get the biggest and baddest, and you get 2 or 3 of them.

More realistically... I do not remember what your space is, volumetrically speaking.

So I would balance my choice based on cost and the ease with which the Sub can give me a clean 16Hz. I'm not looking at the reviews right now, but I recall the 15v1 and the 13 both reviewed well.
I use 16Hz as a benchmark because I want full Pipe Organ, and I want it as clean as possible.

Keep in mind, these are monster Subs. So whatever you do, make certain you pay attention to that, too.

Make friends with you Fed Ex or UPS driver if you haven't already... perhaps these ship freight, I don't know.

I guess $2000-$3000

 

[bsf]

I am actually considered dual 13in THX Certified Ultra 2000-Watt

 

[Pogre]

There are some very minor improvements in the driver in the V2, but not anything that would constitute a major change. If you think the styling is worth the extra $300, go for the V2, but if not, go for the V1. As for the 13", it does offer some performance improvements, mostly in deep bass.

Okay, he asked about that earlier I wasn't sure. For the difference in price tho I'd still say a pair of 15s will do it. Unless the 13 is smaller and size is a factor.

 

[Pogre]

I am actually considered dual 13in THX Certified Ultra 2000-Watt

Aw hell, why not? They are great little subs and you're saving on your budget by using your avr. I say go ahead and treat yourself!

 

[Pogre]

The 15...

The 13...

That 13" does seem to pop more doesn't it!

 

[bsf]

Aw hell, why not? They are great little subs and you're saving on your budget by using your avr. I say go ahead and treat yourself!

ya and im thinking of getting the At-300 Tone Winner + TW AD-7300 7 Channel 300 watts

 

[bsf]

There are some very minor improvements in the driver in the V2, but not anything that would constitute a major change. If you think the styling is worth the extra $300, go for the V2, but if not, go for the V1. As for the 13", it does offer some performance improvements, mostly in deep bass.

will the thx 15” 1000 watt or 13” 2000 watt both out perform the ryhtmik fvhp15

 

[shadyJ]

will the thx 15” 1000 watt or 13” 2000 watt both out perform the ryhtmik fvhp15

The 15" is largely on par with the FV15HP. The 13" is similar in mid-bass but has a significant deep bass advantage.