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Discussion Starter · #1 · (Edited)
Hello People,

We all know why a lot of us are here, the ideal for a subwoofer we are striving to have. The ultimate subwoofer with punchy bass with bone shacking realism and the same time the low earth quaking power with precision and clarity from moving continental plates that the earth has ever come to live through. The ultimate flat response down to 5Hz with powerfull high output.
We know the feeling of the sound doesn’t stop by 20Hz, a lot is going on under 20Hz. That is a combination that requires a lot of technology and research. This is a task for a subwoofer which class is one of another dimension. The over 4000$ subwoofers league.

Well like a lot of the guys in the forum, which I so much adore, have built subwoofers which have gone really low down to 12 even 10Hz (Maelstroms, LMS Ultra, etc.) but we also know the cost..., something has to give. The gigantic size and the standing waves and other problems accompanying which I am not going to refer here.

Now the best subwoofers in the world I know are:

the Bowers-Wilkins B&W DB1 reaching 15Hz at -3dB with the astonishing 116dB at only 160W in only 3.2 cubic feet enclosure. Costs around 5000 USD:
http://www.bowers-wilkins.de/Lautsprecher/Heimaudio/Subwoofer/DB1.html

and the ultimate one

Paradigm Signature SUB 2 reaching 7Hz (-3dB) with the astonishing 112 dB at 10 Hz in an apprx. 23x23x23 inch enclosure. Costs around 12.000 USD at launch:
http://www.paradigm.com/products/paradigm-reference/subwoofer/signature-series/sub-2

Both use vibration-canceling designs with opposite eliminating forces, but that is not much important.

Or this one:
http://www.paradigm.com/index.php?option=com_mtree&task=viewlink&link_id=162&Itemid=2
It starts to roll of at 9Hz in only 5.2 cubic feet box outer volume! sealed box.

All are sealed designs.

I made a comparison with the results from Ilkka who tested a lot of subwoofers, here:
http://www.hometheatershack.com/for...hived/5748-cea-2010-standard-compilation.html

The closest is the TC LMS-5400 + 2 18" PRs 200L(7 cu feet) ported with 109 dB maximum clean RMS Power at 16Hz, and this is a powerful if not the best driver in the world...:unbelievable: What strucks me it even doesnt come close to B&W DB1 with its 116dB at 15Hz at only 160W...i dont know what to say :eek:

As we know how the low extension is not possible for sealed designs as they roll off very quickly, for punchy bass down to 35Hz you may be lucky with a 15” or 30 Hz with an 18” or 21” Malestrom but under 25Hz it is impossible as shown by numerous simulations, also here in the forum. Physics also has limitations

And the ultimate question is how those sealed subwoofers champions achieve those results in those miniature, really miniature enclosures and on top of that all that in sealed boxes?
What is the secret behind such extraordinary performance? Please anyone help that could be a mile stone for many of us

Yours V.
 

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Discussion Starter · #2 ·
Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

Please anyone comment how is that incredible performance in such volumes possible
 

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Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

There is no secret. It is often simply a matter of measurement method, in "average" room measuring can give significantly higher outputs, and lower response curves, as well as mic distance can have a huge impact on the numbers. Ilkka's measuring was done at 2m ground plane, not indoors at 1m as is often the case.

Also often they say for example, response to "3hz" max output "130db", notice they are not saying that it can produce 130db AT 3hz, what they are often saying is that at low level it is Eq'ed to be -3db at 3hz, and the maximum output is 130db at some other frequency often around 60hz, even that does not mean that it can produce 127db at 3hz, there is something called compression that affects subwoofers, as the output goes up to the point where the subwoofer is under stress the output stops going up evenly, and eventually output can keep going up at 60hz but not at all at 3hz once it hits its 3hz limit, and that could be 20db for all you know.

Not to say these are not great subwoofers but, bottom line, you can only compare subwoofers directly when you know all the test conditions were identical, or simmilar enough conditions to calculate the differnce but even then there can be un accounted for variables.
 

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Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

:sneeky:

You sort of answered your own question - physics has limitations.

I think you are putting in way too much credit into these manufacturer claims. First, can you show us where it says that "the B&W DB1 reaching 15Hz at -3dB with the astonishing 116dB at only 160W in only 3.2 cubic feet enclosure." The B&W product sheet claims a +/- 3db range from 17 to 145 Hz, but does not say at what dB level that was obtained at. I don't know if we've seen any good/detailed 3rd party testing of the the Sub2 either.

You are also a bit confused on subwoofer characteristics - most of the time, sealed subwoofers have the gentlest roll off (12 db) compared to ported or passive radiator designs (which are often 24 db or more). In fact, sealed are the best type of subwoofer to get those really low frequencies - you just need a lot of power and woofers to do it.
 

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Discussion Starter · #5 · (Edited)
Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

There is no secret. It is often simply a matter of measurement method, in "average" room measuring can give significantly higher outputs, and lower response curves, as well as mic distance can have a huge impact on the numbers. Ilkka's measuring was done at 2m ground plane, not indoors at 1m as is often the case.

Also often they say for example, response to "3hz" max output "130db", notice they are not saying that it can produce 130db AT 3hz, what they are often saying is that at low level it is Eq'ed to be -3db at 3hz, and the maximum output is 130db at some other frequency often around 60hz, even that does not mean that it can produce 127db at 3hz, there is something called compression that affects subwoofers, as the output goes up to the point where the subwoofer is under stress the output stops going up evenly, and eventually output can keep going up at 60hz but not at all at 3hz once it hits its 3hz limit, and that could be 20db for all you know.

Not to say these are not great subwoofers but, bottom line, you can only compare subwoofers directly when you know all the test conditions were identical, or simmilar enough conditions to calculate the differnce but even then there can be un accounted for variables.
Guys the world changes maybe it is hard to admit but in the subwoofer world some progress is made. Look all i said is based on data, measured data. Now let us look to the numbers here is the review in german language but you can see the numbers 113dB 160W:
http://audiovision.de/Test-Archiv/Tests/2010/11/Test-B-und-W-DB1-Subwoofer-fuer-4000-Euro/Seite-2

Now we are talking here about a double 12"-sub, which startrs to roll of at 17Hz in room. We are talking about a 3.2 cubic feet outer volume enclosure and 114dB output at 160W amp. Tell me how to beat that, those dimensions and low bass extension and db levels? And the magical 120dB range, look at the Ilkka's table, come on guys how many subs can top that? The TC LMS5400 with lots lots of power even at 1m distance even at 60Hz for the DB1 as you say says a lot. The LMS-5400 is a world champion as we all know. Nevertheless it is not seen in a serial production sub


:sneeky:

You sort of answered your own question - physics has limitations.

I think you are putting in way too much credit into these manufacturer claims. First, can you show us where it says that "the B&W DB1 reaching 15Hz at -3dB with the astonishing 116dB at only 160W in only 3.2 cubic feet enclosure." The B&W product sheet claims a +/- 3db range from 17 to 145 Hz, but does not say at what dB level that was obtained at. I don't know if we've seen any good/detailed 3rd party testing of the the Sub2 either.

You are also a bit confused on subwoofer characteristics - most of the time, sealed subwoofers have the gentlest roll off (12 db) compared to ported or passive radiator designs (which are often 24 db or more). In fact, sealed are the best type of subwoofer to get those really low frequencies - you just need a lot of power and woofers to do it.
@templemaners
Of course i am not confused with subwoofer characteristics, i know perfectly the sealed falls slower down than the ported which falls down like from a cliff, but but that sealed starts to roll of very soon so when a ported reaches -3dB the ported is like -20dB and remains at similar lever further down as the ported has even less than that. But -20dB contributes to absolutely nothing in the sonic picture even be it present as the case with the ported is not. Look at the design database and compare the -3dB or -6dB freqs for ported and sealed for the same driver, sealed cannot compete for a low output. If you still not believe it show me a freq response or room freq response for a sealed that beats ported for the same driver when the ported is tuned correctly (at the fs res. freq of the driver).

Again guys things change.. now to your question, of course SUB2 from Paradigm is being tested -3dB in room at 7Hz ! at 7Hz 112dB and 126dB at 60Hz with 10 inch drivers, now again here is the data not in german:):
http://www.techradar.com/reviews/au...eakers/paradigm-signature-sub-2-691179/review



How to beat that ? What a accomplishment is that? and we are talking not about a gigantic DIY 20 cu foot sub, we are talking about a 23x23x23 inch sub with 112dB at 7Hz and 126db at 60Hz again with a 7Hz -3dB LF-extension. Some people are pushing the limits out there. This is unbeatable and a world record for a serial production sub.

How about the other sub SUB 25 from paradigm, in room response down to 9Hz at -3dB in a 20x18x25-inch box with a 3000W RMS. Look at the size of it and compare it with all the gigantic subs you came across in your life that come close to the 10Hz mark and below. Look how narrow and compact it is, how to beat that response in that volume, how to even come close to it?



Again the ultimate question, what can be the secret behind such a world record performance
 

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Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

Yes, advances are being made. But your reference to Ilkka's testing is comparing apples to oranges. The stated SPL numbers from Ilkka's tests are from measurements done outdoors, the Paradigm Signature SUB 2 was tested indoors "in a typical listening room". Test a sealed TC LMS-5400 in the same environment and watch the low end numbers climb through the roof. Or test he Paradigm outdoors and watch the low end numbers fall off a cliff.
 

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Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

The closest is the TC LMS-5400 + 2 18" PRs 200L(7 cu feet) ported with 109 dB maximum clean RMS Power at 16Hz, and this is a powerful if not the best driver in the world...:unbelievable: What strucks me it even doesnt come close to B&W DB1 with its 116dB at 15Hz at only 160W...i dont know what to say :eek:
Subject all of the subs to the same test methods, you will see the TC LMS-5400 slaughter the other subs in output and extension.

As we know how the low extension is not possible for sealed designs as they roll off very quickly, for punchy bass down to 35Hz you may be lucky with a 15” or 30 Hz with an 18” or 21” Malestrom but under 25Hz it is impossible as shown by numerous simulations, also here in the forum. Physics also has limitations
Properly EQ'ed and powered sealed subs will reach well below what ported designs can. It takes a prohibitively large enclosure and port to approach the performance of sealed.
 

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Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

Don't forget most manufacturers take advantage of the MAGIC of exaggeration.
Let's test em ourselves and see what happens. We need samples!:yes:
Jet engine Engine Auto part Vehicle Aircraft engine

At a mere $1900 you know we would all have 2 of these, at least.:rofl:
 

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Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

Guys the world changes maybe it is hard to admit but in the subwoofer world some progress is made. Look all i said is based on data, measured data. Now let us look to the numbers here is the review in german language but you can see the numbers 113dB 160W:
http://audiovision.de/Test-Archiv/Tests/2010/11/Test-B-und-W-DB1-Subwoofer-fuer-4000-Euro/Seite-2
All I see in the link is a measurement at 80 dB down to 20 Hz. I see no other meaningful measurements in the article, especially none that indicate 113 dB measured.

And what professional plots the response of a subwoofer on a chart that goes to 100kHz?
 

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Discussion Starter · #10 · (Edited)
Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

All I see in the link is a measurement at 80 dB down to 20 Hz. I see no other meaningful measurements in the article, especially none that indicate 113 dB measured.
What about the review of the Paradigm SUB2 with 112dB at 7Hz and 126dB at 60Hz in 23x23x23 inch enclosure...that can not be ignored.
http://www.techradar.com/reviews/au...eakers/paradigm-signature-sub-2-691179/review
If soeone knows something that comes close to that please comment

And what professional plots the response of a subwoofer on a chart that goes to 100kHz?
This is a logarithmic scale the impoortant 20-100Hz is quite large you will see what is going on there very well.

When you look a bit down on the same page you will see a completely flat response down to 20Hz with a 80Hz X-Over Setting with a maximum sound pressure level of 113dB at 28Hz and that in a 3.2 cubic feet cube and 150W continious RMS power


Or can that be ignored too?

Can anyone comment on the Paradigm SUB 25 with a 20x18x25-inch box reaching 9Hz with -3dB be it in room...how did they do that in that little cube


Now how large are the subs that come that close to 9Hz -3dB in room response you have seen, I know what I have seen big gigantic subs with standing waves issues and s.f...

Now the truth is sometimes difficult to admit, for me as a DIY-er as well but how long can we repress that, how long can we ignore it and not giving the objective criticism and consideration the DB1, the Paradigm SUB 25 and SUB 2 so richly deserve?
And most importantly to solve the riddle of those extraordinary subs...so the next day you can be owner of a such a sub, built by your own.
 

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Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

What about the review of the Paradigm SUB2 with 112dB at 7Hz and 126dB at 60Hz in 23x23x23 inch enclosure...that can not be ignored.
http://www.techradar.com/reviews/aud...-691179/review
If someone knows something that comes close to that please comment
See post #11 and #19 in the following thread, both models so not include room gain.

http://www.hometheatershack.com/for...uld-you-try-do-diy-version-paradigm-sub2.html
 

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Discussion Starter · #12 · (Edited)
Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm




Thanks for your link Mike, i really like this but both subs SDX 10 and HiVi start to roll off at 45Hz. So my estimations were correct that if one is lucky can reach the 35Hz with a 15" or maximum 30Hz with an 18".

Now the in room response will not change the angle of that falling line rather will shift it left with 7 to 10 Hz, so the lowest freq response would be around 30-35Hz, or ....wait a minute :scratchhead: it is actually the 20Hz level now will be actually the 10Hz in room response and we have 111dB and to come equal to the plateau it should be equilized to 123dB or 12dB difference and you'll get 10Hz on a par with the 35Hz or the previous achievable without overhead 45Hz. It is feasible as long as the driver can tolerate the extra 12dB of low freq power, i see it can work...:blink: And the cone movement will be restrained cause of the sealed design..and when the driver is a good one yes, it can work even with the SDX 10 with fs 25Hz..Why bother go ported when you can...as long as the tonality of the sealed is acceptable and sounds not like chocked non breathing thing ..yes the FR down to 10Hz is possible with 4 times more power for the lowest frequencies
please comment what do you think about those 12db they should not be a problem for a high performer, it is actually 4 times power increase for the 10Hz
 

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Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

Let's establish a few things:

The Paradigm Sub2

1) Uses six 10" drivers in a very small box. natural QTC is a question mark - could be .7 and it could be all the way as high as 1.5.
2) Uses around 7kW of power to add a ton of boost in order to equalize itself flat in the so-called typical room.
3) Uses Digital Signal Processing to compress it's low end output
4) Has never been measured by a reputable source.
5) Is sold in brick and mortar stores, to people who don't know much about low end output relative to say, the people online at HTS or at AVSForum

Is the above established?

Points 1, 2 and 3 are very important above. The Sub2 requires ridiculous amounts of boost to even have "natural" sounding response at moderate listening levels. As the output levels rise, the subwoofer's transfer function alters itself significantly. It goes from looking like a flat line down to 7hz to looking, well, probably similar to those CSS SDX-10 charts you are looking at. They can EQ it flat to 7hz at low levels, but as the output rises, the digital signal processing reduces the amount of EQ being used in order to keep the sub within its limits. That is the "magic" of a flat loudspeaker.

Now let's compare the sub2 to the TC Sounds LMS-5400

six 10 inch drivers,
-each with 3" voice coils

we don't know the exact sd, but for example the CSS SDX-10 has 300cm^2, the TC Sounds Epic 10 has 330cm^2 and the JL10W7 has 386cm^2. Six 10 inch drivers would thus have an sd somewhere around 1800cm^2 to 2300 cm^2

vs

One 18 inch driver, with
-a 4" voice coil.
-38.1mm of xmax
-47.6mm of xmech

Now the sd of that one 18" driver is 1124cm^2 of surface area.

In terms of volume displacement alone, using xmax as the excursion limit (which is conservative given the world class linear performance of the LMS-5400), we get about 4282.44 cm^3

So now our assumption is that the six 10" drivers can move more than 4200 cm^3 at the very least?

okay, so we need what sort of xmax? around 18 to 24mm of xmax out of each 10 inch driver depending on its SD. The SDX-10 for reference has about 18mm of xmax and the TC/JL10w7 have 23mm of xmax. so we'll give paradigm the benefit of the doubt. 24mm xmax would be the likely upper limit of what you could pull out of the drivers in the Sub2 with everything engineered to perfection. It's optimistic, and even then the chances of having the same linearity as an LMS are pretty low.

But let's assume all of the above is in fact true. In 5.6 cu ft as with the Sub2, take a look at how

TC Epic 10
TC LMS-5400
JL 10W7s

perform with 7000 watts of available max power. Driving each to their xmax at 20hz does not even require 7000 watts (which makes you wonder about why the Sub2 needs so much power)... respectively we needed about 3300, 3500, and 6000 watts to hit respective xmax.

If you model it... notice how similar they are down low? Almost identical excursion limited displacement give or take a few db in half-space. That effectively limits the sub2 to roughly the excursion limited output of a single sealed LMS-5400 at low frequencies give or take two-three db assuming you're not amplifier limited.

about 113-115db in half space at 20hz, about 102db in half space at 10hz and about 88db at 5hz. That means the DSP for an LMS-5400 can let it be absolutely flat down to 5hz, as long as the signal is not asking for more than 88db. as soon as power rises the curve will start to look more and more like the curve for an unequalized subwoofer. Less EQ will be used because the power at 20, 10hz, 5hz is limited to keep excursion down.

So you just paid $7000 for a subwoofer hopefully on par with an LMS-5400. It needs 7kW of power which your 15a line simply cannot provide. It is still effectively a point source monopole subwoofer prone to countless room modes and room nodes with ragged in-room response.

Compared to that, you could have picked up two or three sealed LMS-5400s from Funkywaves if not six or eight DIY and spaced them around the room, for two to seven times the excursion limited output and a much more musical FLAT in-room response at multiple seating positions. You can squeeze a bit more low end naturally out of them with a box qtc closer to .5 to .7. Funkywaves and DIY also offer passive radiator options, which might not go as gut wrenchingly low but will give you more output down to around 15hz or so.

Better yet go with an efficient pair of infinite baffles using drivers that take advantage of the "large box" an infinite baffle provides, and you won't even need endless amplification..
 

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Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

I do enjoy these kinds of threads, with the theoretical DIY outputs always looking awesome. FWIW, the sub 2 is a very good sub, and not that small, at least not for us guys here in the UK. The drivers are custom built to high standards so should be very good, and they certainly do sound good at levels high enough for any UK home anyway. I do have to agree with pretty much everything GranteedEV has said though. Theoretical figures from paradigm are more selling points than rock solid bench marks. As good as the sub 2 is, there is no way I would ever pay the asking price personally. The IB I am about to install will sound better I am sure, and the entire 6 driver system will only require 200 - 300 watts max, so no power compression issues to even contemplate there.

There arent really any secrets when it comes to subs, only those with the knowledge and those with the money :D
 

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Discussion Starter · #15 · (Edited)
Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

The riddle is solved. Because of you guys, it changes its FR like a chameleon...like a scary chameleon seeing a vulture flying over to it.. and as the signal rises and it sounds like a 100 dollar PA sub from 60 Hz...well with lots of dBs, which can be accomplished by a horn PA Speaker. And that for all of them...what a shame, so it ramains SVS or DIY.. I told you i have a bad feeling about the sealed enclosures :T. Cheer up, everything's good..it is good to be here

Greets
 

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Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

Sealed enclosures are my preferred option, but value for money they really arent in comparison with other options. Larger cabinets lead to less colouration of the sound the driver produces as well, and given many sealed subs are aimed at keeping size minimal (more commercially viable), it can be difficult to achieve your goals if your standards are high. Personally, I have always favoured the extra cost and the sealed route to any ported efforts ive ever heard.
 

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Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

if you have the money, virtually nothing will beat six to eight sealed 18 inch high excursion drivers plus EQ and natural room gain in a box that gives a natural qtc = .45 to. 6

I just think the paradigm specifically is overpriced. dollar for dollar multiples of the sealed offerings from SVS, HSU, Funkywaves, Rythmik, Seaton, Acoustic Elegance and Epik will likely wipe the floor with a single Sub2 in all its over engineered but still physics limited glory. The sub2 is closer to competing with velodyne and JL than with the above brands.
 

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Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

What about the review of the Paradigm SUB2 with 112dB at 7Hz and 126dB at 60Hz in 23x23x23 inch enclosure...that can not be ignored.
neither can the simple phrase "in room". You do realize this factors room gain into the equation. and at low frequency room gain goes up, so if there hittin 112 db at 10hz, its because chances are theres AT LEAST 9db of room gain down there. Now 103, doesn't sound quite so hot. But that's marketing.

Ilkka's testing was outdoor, 2m ground plane, which eliminates the room gain from the measurement.

The plain and simple reason is that we are honest. And manufacturers are not. Its not nice to say, but its the truth.
 

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Re: THE SECRET BEHIND the BEST 2 Subs in The WORLD - B&W and Paradigm

The plain and simple reason is that we are honest. And manufacturers are not. Its not nice to say, but its the truth.
It amazes me that we still read stuff like this in 2011. Some manufacturers (read: the ones on the cusp of DIY-wanna-be-business) skirt the truth. You really can't say that about B&W and Paradigm with any semblance of believability.
 
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