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Title: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on March 20, 2013, 02:00:51 PM
You heard it here first....  :-)

What does that mean?

A couple of years ago I did single ended measurements of various EDM genres using SysTune.  I merely set the averaging to infinite, put the analyzer in RTA mode, and let it run for hours sampling internet streams of trance, house, bass music (drum and bass and dubstep), etc.

One thing that's clear is that there are two frequency bands that dominate the bass region.  50-60 Hz is the norm for for trance, techno, etc., while mid to high 40s seems to dominate dubstep (for sure) and probably drum and bass.  It's not _all_ in these specific regions, but a great deal is.

My theory (and it's just that, nothing "proven") is that 50 Hz has been traditionally chosen because of practical low frequency limits of common subwoofer systems in the past.  They will all do 50 Hz (hopefully :-), and anything below that would be considered gravy.  So to get max oomph out of your average system DJs played on, and presumably home hi-fi setups as well, the bass was focused in an area in which solid reproduction could be guaranteed.

This goes for car systems as well.  I think we're all familiar with the "one note trunk rattler".  I believe it's a fairly simple matter to design a car subwoofer that reproduces one note really well.  I leave it to the reader to speculate what that note may be ;-)

But times are a' changing.

40 Hz is common, 30 Hz is now possible, and in some cases usable sub-30 Hz performance is available, but still fairly rare.  Please don't comment with published manufacturers' specs.  What I heard last weekend at ULTRA confirms this.  There were three systems there that could do 30 Hz, and two for sure that were only a few dB down below that.

1. db audiotechnik J Infra.  Quite expensive, prodigious low frequency output down to 30 Hz, and according to my measurements two years ago, about -4 dB @ 26 Hz.  It definitely delivers the goods.  Beachsound used a different setup, with J subs stacked on top of Infras and it solved the problem of high bass being lost in the crowd when Js are on the ground.  Nice job, Beachsound.

2.  JBL VTX sub, sorry I don't know the model.  I didn't measure this system.  Raul Gonzalez was the system tech and he had it sounding great when I arrived, so we just listened.  The midrange was very clear to my ear, and nothing hurt when pushing test tracks.  It did seem to bark when poorly ripped tracks were played through it.  Subs - lots of extension and the grunt to go with it.  It really came alive when Raul put a + 3dB filter in at 26 Hz.  Very solid subbass sound, I liked it.

3.  BASSMAXX ZV28 -  David Lee has been working on this design for several years now and has improved every iteration.  He used 16x of these beasts on the UMF Worldwide Stage (the "street party" stage), with some uppper bass boxes on top.  We could hear things in tracks that would have not been present with "normal" subs, meaning usable response only down to the mid 40s.  This thing would blur your vision and modulate your voice, no problem.  I have been told this is the weakest of the 2x18 line, with lower power drivers.  I am keen to hear the high power version, this thing is sick.  I have a SysTune measurement of this sub array, attached.  Measurement mic is a Josephson C550H.

So, the low frequency extension is available.  We'll see who actually leverages it in the future. 

Edit: Marker #2 is 24.9 Hz, 12.6 dB

Edit # 2:

Dear DJs - please make better sounding tracks.  We can hear the difference between MP3 and .wav on these systems.  Your audience deserves better.

Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Ivan Feder on March 20, 2013, 03:26:14 PM
#1!!  ;D


Dear DJs - please make better sounding tracks.  We can hear the difference between MP3 and .wav on these systems.  Your audience deserves better.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Ivan Beaver on March 20, 2013, 07:05:59 PM
Some of us have realized the need for solid bass down that low for awhile :).

One thing that is often overlooked is actually LISTENING to the subs.  What happens to a lot of subs that "claim" low freq reproduction-is that at those low freq-the distortion is so hig-as is is actually louder and masks the low fundamentals.

Delivering bass that low-loud is not an easy thing to do-and also do it without sounding "flubby".

It is very important to LISTEN to the loudspeakers-not just read the spec sheets-as they don't tell the whole story.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on March 20, 2013, 07:39:24 PM
Some of us have realized the need for solid bass down that low for awhile :).

One thing that is often overlooked is actually LISTENING to the subs.  What happens to a lot of subs that "claim" low freq reproduction-is that at those low freq-the distortion is so hig-as is is actually louder and masks the low fundamentals.

Delivering bass that low-loud is not an easy thing to do-and also do it without sounding "flubby".

It is very important to LISTEN to the loudspeakers-not just read the spec sheets-as they don't tell the whole story.

All that, and the fact that if you have that super deep LF extension, the stuff that is an octave higher is being reproduced almost effortlessly. 
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: John Heinz on March 20, 2013, 09:16:20 PM
You've hit the nail on the head about the resolution of modern PA systems. I'm always amazed at guys who tune a PA with an Ipod and then complain about not having a Big Ben wordclock. The trick is the boxes can go that low, but can the amps hold up over time. Think there is going to be a new category of power amps for sale, the Bass Pump. I'd love to see someone do a shootout of big amps holding low tones at full power over time.

John Heinz
Concert Quality
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: David Sturzenbecher on March 20, 2013, 09:26:46 PM
I'd love to see someone do a shootout of big amps holding low tones at full power over time.



See link
http://www.speakerpower.net/comparative-performance.html

I believe the long term power ratings are "forever" ratings. 
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on March 20, 2013, 09:51:23 PM
You've hit the nail on the head about the resolution of modern PA systems. I'm always amazed at guys who tune a PA with an Ipod and then complain about not having a Big Ben wordclock. The trick is the boxes can go that low, but can the amps hold up over time. Think there is going to be a new category of power amps for sale, the Bass Pump. I'd love to see someone do a shootout of big amps holding low tones at full power over time.

John Heinz
Concert Quality

In fairness, I have .wav on my iPod for test tracks and a Send Station line level output device, so it's pretty good.

Point taken, though.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on March 20, 2013, 11:04:26 PM
I'm thinking Speaker Power is what's being used in the BASSMAXX speakers.

Interesting thread, thanks Doug for posting up the info.

I too have a selection of WAV files in my phone.

And I agree with Ivan about listening, many subs today get loud & go low but how's their sound quality ?
Title: AW: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Christian Tepfer on March 21, 2013, 02:59:23 AM
I'm thinking Speaker Power is what's being used in the BASSMAXX speakers.

Interesting thread, thanks Doug for posting up the info.

I too have a selection of WAV files in my phone.

And I agree with Ivan about listening, many subs today get loud & go low but how's their sound quality ?
I agree that subs can reach lower end frequencies nowadays. We should not forget the time domain, how do they reproduce the audio material? Is a bass note really just a note or do we end up with a bass "carpet"? There is still a long way to go imho.

Gesendet von meinem HTC Vision mit Tapatalk 2

Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: David Sturzenbecher on March 21, 2013, 08:40:50 AM
Doug,
Could you detail the deployment of the subs at the three systems you identified? Flown, L-R under an array hang, center clustered?

Thanks!
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: John Heinz on March 21, 2013, 11:26:04 AM
See link
http://www.speakerpower.net/comparative-performance.html

Thanks for the link. Was hoping to see a Powersoft K10 on the list. Interesting comments about the IT12000HD, kinda what we have known all along. Never paid much attention to the Speakerpower Amps, but maybe I should.

Doug, my apologies, the Ipod comment was not directed towards you, just my experience with a lot of touring enginners that are to focused on the wrong end of the horse. The speaker system and it's deployment are still the weakest link.

John Heinz
Concert Quality


Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on March 21, 2013, 11:46:22 AM
See link
http://www.speakerpower.net/comparative-performance.html

Thanks for the link. Was hoping to see a Powersoft K10 on the list. Interesting comments about the IT12000HD, kinda what we have known all along. Never paid much attention to the Speakerpower Amps, but maybe I should.

Doug, my apologies, the Ipod comment was not directed towards you, just my experience with a lot of touring enginners that are to focused on the wrong end of the horse. The speaker system and it's deployment are still the weakest link.

John Heinz
Concert Quality

John, no worries, I didn't take it that way.  I just wanted to point out it is possible to use a portable if the "proper" precautions are taken. 

It is becoming increasingly difficult to find CD players in system drive racks nowadays :-)
Title: Re: AW: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on March 21, 2013, 11:52:59 AM
I agree that subs can reach lower end frequencies nowadays. We should not forget the time domain, how do they reproduce the audio material? Is a bass note really just a note or do we end up with a bass "carpet"? There is still a long way to go imho.

Gesendet von meinem HTC Vision mit Tapatalk 2

Particularly for large systems, the amount of delay required to make the electronic arc and spread the signal is detrimental. This, combined with the width of the sub array, puts us squarely in compromise territory.

Imagine, audio compromises. Who knew? ;

I would like to see impulse responses and phase / group delay data for subs. 
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on March 21, 2013, 12:01:36 PM
Doug,
Could you detail the deployment of the subs at the three systems you identified? Flown, L-R under an array hang, center clustered?

Thanks!

db audiotechnik: 24x Infras, 24 J stretched out across the downstage edge. Js stacked on Infras.  It had to easily be 100' wide

JBL: 3x subs at top of each flown array, 8 in the center, maybe 6 arrayed together out on the sides.  This stage has to contend with a 5' deep moat in front of the arced stage, with subs standing on platforms in the moat.  Acoustically, this one is a crap shoot each year.   Search for Klipsch Amphitheater or Bayfront Park in your map application, I think you should be able to see the moat.

BASSMAXX: block of 8 wide, 2 high, with some Z5D upper bass boxes, making this on a split sub system, as was the db audiotechnik solution.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Art Welter on March 21, 2013, 12:28:10 PM
All that, and the fact that if you have that super deep LF extension, the stuff that is an octave higher is being reproduced almost effortlessly.
In most sub designs other than sealed (which are too inefficient for loud live low frequency production) excursion is least near the low corner and around an octave above, but somewhere in the middle, usually about 1/3 to half octave up, excursion is at maximum.

A sub with a 30 Hz Fb/Fc will often produce the most distortion around 40 Hz, second harmonic is 80, third, 120 Hz.

If the Fb/Fc is around 50 Hz, the worst "gack" will be 60 and 180 Hz, high enough to be easily noticed even if high passed at around 45 Hz.

Best to choose the subs for the genre, going loud an octave lower can double to quadruple the power and cabinet size requirements.

Things have not been the same since just about every bassist went from having a Low E (41Hz), to a low B (31 Hz).
Now digital recording allow frequencies down to a few Hz, back in the days of vinyl, DJs were hard pressed to get anything very loud below 50 Hz due to the medium's limitation and feedback.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on March 21, 2013, 12:41:42 PM
In most sub designs other than sealed (which are too inefficient for loud live low frequency production) excursion is least near the low corner and around an octave above, but somewhere in the middle, usually about 1/3 to half octave up, excursion is at maximum.

A sub with a 30 Hz Fb/Fc will often produce the most distortion around 40 Hz, second harmonic is 80, third, 120 Hz.

If the Fb/Fc is around 50 Hz, the worst "gack" will be 60 and 180 Hz, high enough to be easily noticed even if high passed at around 45 Hz.

Best to choose the subs for the genre, going loud an octave lower can double to quadruple the power and cabinet size requirements.

Things have not been the same since just about every bassist went from having a Low E (41Hz), to a low B (31 Hz).
Now digital recording allow frequencies down to a few Hz, back in the days of vinyl, DJs were hard pressed to get anything very loud below 50 Hz due to the medium's limitation and feedback.

Good point about vinyl, and no doubt a significant contributor to the 50 Hz thing.
Title: Re: AW: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Ivan Beaver on March 21, 2013, 01:03:02 PM
Particularly for large systems, the amount of delay required to make the electronic arc and spread the signal is detrimental. This, combined with the width of the sub array, puts us squarely in compromise territory.

Imagine, audio compromises. Who knew? ;

I would like to see impulse responses and phase / group delay data for subs.
This is something that is very often overlooked.

SURE-you can do "fancy" sub setups with physical layouts-electronic delays and such to get a nice smooth bass coverage pattern.

But at some point you are going to have to have to match up the subs with the full range cabinets.  That is where the delay associated with getting nice bass coverage is going to start screwing with you.  NOW you are all out of whack with the  mains. 

So you try to get it right on the areas on the outside of the subs and the mains-but because of the wide stage-you need to get fills in for the middle-and that becomes a problem and so forth and so on.

You are correct-at this level it is all about compromise-and what is good for somebody is bad for somebody else.

So you figure what is best for either the majority of the people-OR the person paying you or some other reason.

Whenever you have multiple loudspeakers it is about compromise.  And not everybody agrees on the compromise.

It goes from being in the "scientific" realm and into the "art" realm.
Title: Re: AW: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on March 21, 2013, 06:49:15 PM
Maybe we're finally on the way to satisfying those 70's & 80's tech riders that required "sound system capable or reproducing 20 to 20 KHz at all listening locations in the venue"
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Ivan Beaver on March 21, 2013, 07:22:07 PM
Good point about vinyl, and no doubt a significant contributor to the 50 Hz thing.
Another thing with vinyl is that often songs with deeper bass were put on the outside tracks.  That is because the arm would track straighter on the larger circles.  The needle had a better chance of staying in the groove.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Marjan Milosevic on March 21, 2013, 08:43:39 PM
No mentioning on the Void rig there.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on March 21, 2013, 08:52:51 PM
No mentioning on the Void rig there.

I don't have the sub measurements, I did the alignment on Nathan's SysTune rig.

The line array sounded great, low distortion with no listening fatigue, to my ears. 
Good tracks really sounded great.  It was a split sub system.  If Nathan will measure the new sub, I'll post it. 

Good job by Void and AIS Chicago. 
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on March 21, 2013, 09:34:08 PM
David Lee of BASSMAXX had nothing but good things to report about Nathan's line array.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Stu McDoniel on March 21, 2013, 10:26:36 PM
Some of us have realized the need for solid bass down that low for awhile :).

One thing that is often overlooked is actually LISTENING to the subs.  What happens to a lot of subs that "claim" low freq reproduction-is that at those low freq-the distortion is so hig-as is is actually louder and masks the low fundamentals.

Delivering bass that low-loud is not an easy thing to do-and also do it without sounding "flubby".

It is very important to LISTEN to the loudspeakers-not just read the spec sheets-as they don't tell the whole story.
Ivan...just curious.  Some of the most impressive sub bass I have ever heard is subs designed with servo feedback.  Accelerometer on the cone itself.  The design is a close looped system with
a comparator circuit.  The input is compared to the actual cone motion which is monitored by the accelerometer and thus the correction of cone motion takes place.
I do not understand why I am not seeing this in the pro these subwoofer designs?
This design reduces distortion in a huge way, and talk about "tight" impressive sub bass!


Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Lee Buckalew on March 21, 2013, 10:49:13 PM
Ivan...just curious.  Some of the most impressive sub bass I have ever heard is subs designed with servo feedback.  Accelerometer on the cone itself.  The design is a close looped system with
a comparator circuit.  The input is compared to the actual cone motion which is monitored by the accelerometer and thus the correction of cone motion takes place.
I do not understand why I am not seeing this in the pro these subwoofer designs?
This design reduces distortion in a huge way, and talk about "tight" impressive sub bass!

There are definitely some pro subs with servo feedback as well as other correction such as monitoring of magnetic variation due to heat build up and other factors involved in power compression.  Both the Martin MLX and the DSX are phenomenal subs.  They also have an ASX install model that's really designed more for dance club use.

Lee
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on March 21, 2013, 10:52:09 PM
There are definitely some pro subs with servo feedback as well as other correction such as monitoring of magnetic variation due to heat build up and other factors involved in power compression.  Both the Martin MLX and the DSX are phenomenal subs.  They also have an ASX install model that's really designed more for dance club use.

Lee

The B&C IPAL drivers are soon to be out there with the appropriate amplification modules.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Marjan Milosevic on March 21, 2013, 11:07:19 PM
They are out for quite some time and used in few subs already. Like the Fohnn PS9.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Craig Hauber on March 22, 2013, 01:17:12 AM
Why don't they quit messing around with large piles of cabinets and just contract with Danley for some Matterhorns  :)
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Caleb Dueck on March 22, 2013, 08:04:26 AM
Is there a large enough market for "super subs"?  Should they be tapped or folded horns?  What about sheer SPL vs LF extension? 

If someone(s) got together with a healthy sized purchase order, tapped horn, 25Hz -3dB point, maybe even a few RU for Powersoft K20's or similar - I'm happy to help coordinate and iron out capabilities, and work with Danley to oversee it coming to fruition.  From past experience, they are happy to do this.  They just need someone to spearhead the project, dollars promised, and a clear target to hit. 

Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on March 22, 2013, 10:30:54 AM
To get down to 25Hz or so, a horn cabinet would need to have a ridiculously large horn mouth. The D&B Infra's are a band pass design that gets that low but doesn't do much more-a one note wonder. Front loaded vented cabinets are the way to go for this frequency range but the cabinet needs to be pretty big.

Overall, front loaded is the viable option-for now.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on March 22, 2013, 10:34:33 AM
D&B J-Infra sub and BASSMAXX SP218 sub. The BASSMAXX MLM218 sub is what Doug heard at UMF and it's pretty flat to about 23Hz.
(http://i171.photobucket.com/albums/u316/pbellsound/J-Infragraph_zpsa881a235.jpg)

(http://i171.photobucket.com/albums/u316/pbellsound/SP218grapg_zps218f9f50.jpg)
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Art Welter on March 22, 2013, 12:17:02 PM
To get down to 25Hz or so, a horn cabinet would need to have a ridiculously large horn mouth. The D&B Infra's are a band pass design that gets that low but doesn't do much more-a one note wonder. Front loaded vented cabinets are the way to go for this frequency range but the cabinet needs to be pretty big.

Overall, front loaded is the viable option-for now.
Using conventional FLH large mouths are required for ultimate efficiency, but in multiples the requirement is relaxed.
Tapped horns don't need large mouths, Josh Ricci's single 18 TH Gjallerhorn (45 x 45 x 24 inches) proves that.
http://www.diyaudio.com/forums/subwoofers/189784-gjallerhorn.html
At 2 meters, ground plane, outdoors it measures (with reasonable distortion figures):
10hz 90.2db
12.5hz 105.2db
16hz 118.3db
20hz 122db
25hz 124.9db
31.5hz 125.8db
40hz 128.4db
50hz 127.2db
63hz 130.2db
80hz 130.9db
100hz 131.1db
125hz 123.6db

Add 6 dB for a one meter equivalency.
It uses an expensive driver, but so do any vented cabinets that move much air at 16 Hz.

Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on March 22, 2013, 12:33:53 PM
Very interesting! I'll have a better look later when I'm on a real computer.

Thanks for showing it!
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Ivan Beaver on March 22, 2013, 12:54:12 PM
D&B J-Infra sub and BASSMAXX SP218 sub. The BASSMAXX MLM218 sub is what Doug heard at UMF and it's pretty flat to about 23Hz.
(http://i171.photobucket.com/albums/u316/pbellsound/J-Infragraph_zpsa881a235.jpg)

(http://i171.photobucket.com/albums/u316/pbellsound/SP218grapg_zps218f9f50.jpg)
If "flat" is 10dB down.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on March 22, 2013, 12:58:58 PM
I think it's about five down. I'll try to get a graph of the new boxes that was at UMF.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Marjan Milosevic on March 22, 2013, 01:13:37 PM
Going to the low 20s with a vented box means you wont get huge spl out of it. It will take two quite expensive 18 inches to get flat (meaning to the point where the cure actually start declining, not the -3db point) to 30Hz and a box of about 600lit.
Going flat down to 25hz can be done in a same size box but with 4 drivers in an isobaric loading.
6th order bandpass can be done too but then i ma not a big fan of bandpass boxes.
But the spl out of this boxes wont be huge, about 97db for the double 18, and about 95db for the quad 18.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on March 22, 2013, 01:36:20 PM
I think it's about five down. I'll try to get a graph of the new boxes that was at UMF.

You don't need a graph, I already posted a field measurement.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on March 22, 2013, 01:43:38 PM
Here is a SysTune measurement of Void Acoustics new sub (Psycho X), provided by Nathan Short from the show site.  I did the alignment on his ST rig.

Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Marjan Milosevic on March 22, 2013, 01:51:36 PM
You don't need a graph, I already posted a field measurement.

Doug, you have measured 16 boxes, not one. So it surely will go lower then one box.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on March 22, 2013, 01:58:07 PM
Doug, you have measured 16 boxes, not one. So it surely will go lower then one box.

They are not horns, they are direct radiators.  The BASSMAXX documentation refers to these as a Helmholtz resonator design.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on March 22, 2013, 02:24:44 PM
The Void Acoustics system is not BASSMAXX.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on March 22, 2013, 02:43:52 PM
The Void Acoustics system is not BASSMAXX.

???

In the first post in this thread, I posted the field measurement of BASSMAXX ZV28.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Marjan Milosevic on March 22, 2013, 02:55:59 PM
Yes i know they are not horns, but in that number of boxes they will still gain a bit low extension and they will gain a lot in directivity.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on March 22, 2013, 03:03:08 PM
I posted the graphs to illustrate the difference between band pass ans front loaded/vented.

With the front loaded, you could use them without a mid-bass box on top of them as you would need to with a band pass design.

David adds upper bass boxes for these events to get that mid-bass slam.

Although there's no graph yet for the MLM box, David says one box's -3db point is at 24Hz. -3db comes in at 21Hz for two boxes.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Uwe Riemer on March 22, 2013, 04:16:59 PM
I posted the graphs to illustrate the difference between band pass ans front loaded/vented.

With the front loaded, you could use them without a mid-bass box on top of them as you would need to with a band pass design.

David adds upper bass boxes for these events to get that mid-bass slam.

Although there's no graph yet for the MLM box, David says one box's -3db point is at 24Hz. -3db comes in at 21Hz for two boxes.

The J-Infra is a direct radiating, front loaded, vented design, NOT a bandpass.
It is stated in the manual.
It covers roughly one octave, which is typical for a cardioid design.
The low crossover to the J-Sub is useful when aligning flown J-Subs to ground stacked Infras
and comparing the two provided graphs ( which is problematic anyways because one box is already processed and the other not ), the J-Infra seems to go lower

Uwe
 
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Craig Hauber on March 22, 2013, 05:29:16 PM
To get down to 25Hz or so, a horn cabinet would need to have a ridiculously large horn mouth. The D&B Infra's are a band pass design that gets that low but doesn't do much more-a one note wonder. Front loaded vented cabinets are the way to go for this frequency range but the cabinet needs to be pretty big.

Overall, front loaded is the viable option-for now.

Yes the matterhorn mouth is huge, but you only need 1 -and it's mouth is smaller than the frontal-size of the wall of direct-radiators it would be equivalent to (If you can get a stack of direct radiators that will do 100dB of 15Hz at 800ft  :)
And you don't even need to unload it from the truck if you want (It is the truck)
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Marjan Milosevic on March 22, 2013, 05:40:18 PM
Lugging two trucks just for the subs is not very practical. And it can be used on a very limited gigs. It will work for sure but not very versatile solution.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on March 22, 2013, 09:05:57 PM
Uwe, thank you for pointing that out, I stand corrected. I've worked with these subs a few times and do recall seeing the front loaded drivers. I think it was the graph that threw me off.

I recall a thread from about 2011 that discussed this sub and it was described as a band pass.

Regardless, it's published response graph certainly makes it look like a band pass cabinet.

These are great cabinets when used with the system and processed amplifiers they're designed to go with.

It's rated down to 27Hz so with the crop of other sub-bass cabinets coming to market, it's got some pretty solid competition.

Something else about D&B: You can't go purchase a bunch of these to supplement what you already have. You'd need to purchase a complete system, tops, amps, etc. It's costly stuff!

JBL, Danley Sound Labs, BASSMAXX and even Void would be happy to sell you just a bunch of their subs.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Kevin McDonough on March 23, 2013, 07:38:03 AM
hey

yeah I think this discussion of 30Hz has been the case for a little while now in the UK.

40Hz-45Hz has always suited fine for live music, but dance music and anything electronic is where you really start to notice the need for a little more.

Dance music in the US, from what I've seen, was still mostly based in "House". Where as over in the UK, while we do have a lot of that and also other dance genres like Trance that are more about kick and punch than deep deep bass, we've also had a big influence on our dance music from the reggae and dub scene and the scoop-based soundmen of those genres, and so have several genres that take insperation from these lower, deeper bass frequencies. Notting Hill carnival in the centre of London every year is probably the best example of this, where a large immigrant population has brought their culture with them and it's had a huge influence on the dance music of the UK.

Dubstep in particular started in the UK in the late 90's and is predominantly all deep, synth generated bass lines with quite sparse instrumentation on top and really pushed the boat out in this direction, and so we've had very low synth bass lines in the 30's and high 20's for a while.

Though "real" dubstep is very different from the Skrillex-type music that has sprung up recently and that you call dubstep, or "Brostep" in the US (lol love these names! ;D ), to us that's much more what we'd categorise as Drum & Bass.

Smaller companies like Void, Bassmaxx, EM acoustics with their Quake subs and others have addressed this with their various horn subs as well as the DIY crowd with their scoops and DIY horns, and now with dubstep and dance music in general having a bit of a revival in the US the bigger pro manufacturers are starting to take notice.

Obviously Ultra festival being predominantly based in these genres is a perfect example.

k
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Elliot Thompson on March 23, 2013, 09:57:30 AM
hey

yeah I think this discussion of 30Hz has been the case for a little while now in the UK.

40Hz-45Hz has always suited fine for live music, but dance music and anything electronic is where you really start to notice the need for a little more.

Dance music in the US, from what I've seen, was still mostly based in "House".


Hip Hop music offers a lot of energy within the 30 – 25 Hz range. However, there aren’t many here that are hired to cover such events. The graph below shows the low frequency response of a Rihanna track that offers a significant amount of energy around 27 Hz continuous.


(http://i.imgur.com/Qhnmghu.png)

I also measured the continuous average levels of the track crossed @ 100 Hz two years ago.

http://www.youtube.com/watch?v=Gkuk-fNG95Q (http://www.youtube.com/watch?v=Gkuk-fNG95Q)

You will need to have your HPF (if you choose to use one) set below 20 Hz (XTA offers such an option) if, you want to take advantage of the low frequency extension that many tracks offer nowadays.

 



Best Regards,
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on March 24, 2013, 07:48:30 AM
Elliot, the youtube video will not start for me, in two different browsers. Other videos work fine.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Roger Talkov on March 24, 2013, 08:41:18 AM
For those living in the Northeast US: you can hear the d&b Infras in action at MGM/Foxwoods. Its an impressive installation and the sound is really a treat for us sound guys. When you walk in there, you know you're going to have a good night at FOH mixing.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Elliot Thompson on March 24, 2013, 11:26:18 AM
Elliot, the youtube video will not start for me, in two different browsers. Other videos work fine.

Hello Paul.

I have no idea why it is not working for you. I re-recorded the video directly from You tube. Hopefully, the video will be viewable on your browser(s).

http://www.youtube.com/watch?v=VOX9Out8G00&feature=youtu.be

Best Regards, 
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on March 24, 2013, 11:38:34 AM
Thanks Elliot. It works on my Droid!
I'm pretty sure I've seen that from you over on Wave.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Elliot Thompson on March 24, 2013, 03:11:20 PM
Thanks Elliot. It works on my Droid!
I'm pretty sure I've seen that from you over on Wave.

I remember making it for a thread on speakerplans two years ago however I may have posted it on wave as well. From my analysis, most commercial Dance/Pop/Hip Hop recordings are offering a significant amount of sub lows within the 10 Hz Ė 20 Hz regions today, than 10 years ago. Movies have always offered such frequencies so it was only a matter of time before music producers embraced the idea.

Best Regards,
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Jeff Bankston on March 24, 2013, 09:07:18 PM
i'v ben tuning my tom toms low for 40+ years. i tune them to the lowest c-b-e-f on an 88 key keyboard. the frequencies are > 32.703 , 36.708 , 41.203 , 43.653. the tom sizes are > 12x15 , 12x16 , 16x18 , 18x20. thems some big drums Larry !
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Brian Oppegaard on March 24, 2013, 09:38:11 PM
See link
http://www.speakerpower.net/comparative-performance.html

Thanks for the link. Was hoping to see a Powersoft K10 on the list. Interesting comments about the IT12000HD, kinda what we have known all along. Never paid much attention to the Speakerpower Amps, but maybe I should.

I would be glad to test a K10 and any other amp under the same conditions. Send it to the factory and I'll have it back to you in a week or so.

Some amps will do high power, some will do low frequencies, some will hold power for a longer time. It is hard and expensive to build an amp that will do all three with high efficiency. And it is not always needed. But Doug's point about electronic dance music pushing the envelope is well taken.

Brian Oppegaard
Speakerpower Inc.
www.speakerpower.net
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Nathanshort on March 24, 2013, 10:19:06 PM
Here is the preliminary info on the new Void Psycho X from Rog Mogale, the designer.  It has been in the works for some time coming from our need for more truck pack friendly rather than boxes just optimized for installs and not so much tour and hire service.

Psyco X

Psyco X is the latest addition to Voids line up of
high performance low frequency enclosures.
Being the latest has meant itís got to be special
and have some extraordinary specs. A quick
glance at its specifications will confirm this.

The design features a horn with a length of just
over 3.1 meters (10.2 ft), which is about as long
as anyone has ever managed to cram into an
enclosure with a total volume of just 604 litres.
This gives a stack of four enclosures an f3 point
of 27Hz with a sensitivity of 112.5dB 1w/1m.
Power handling is 6400 watts AES, which
equates to a peak output of 154.3dB at 1 meter.

The use of such a long horn has given extreme efficiency, a very low f3 with well-behaved transient response and a predictable dispersion pattern when arrayed. Both the predictability and far field projection capabilities of a Psyco X Array are what have made it the perfect partner for Arcline 12.

These superlative performance specs have only been made possible by a recent development in transducer chassis design that has allowed a sophisticated cooling system to be implemented. All the internal metal chassis parts and magnet structure are bolted to transfer plates and cables that connect to an external heatsink. The transference of heat form the core of the transducer to the outside of the enclosure has led to a world breaking level of power compression. Measurements taken after a 2 hour test with continuous full power 90% duty cycle source material have confirmed a power compression level of only 1.8dB.

Sprayed in our new "TourCoat," polyurea finish, the Stasys X V2 also features new truck pack friendly dimensions and universal location receptors that allow interlocking and mating with adjacent enclosures regardless of their orientation.

 
Frequency Response    27 Hz - 190 Hz -3dB (4 enclosures)
Sensitivity    1 enclosure : 106.0 dB 1w/1m
   2 enclosures : 108.5 dB 1w/1m
   4 enclosures : 112.5 dB 1w/1m
Impedance    1 enclosure : 8 ohms
Power Handling    1 enclosure : 1600 watts AES 2-1984 Rev. 2003
   2 enclosures : 3200 watts AES 2-1984 Rev. 2003
   4 enclosures : 6400 watts AES 2-1984 Rev. 2003
Maximum Output    Measured to IEC61672 and ANSI S1.4 specifications
   1 enclosure : 136.8 dB cont : 141.1 dB peak
   2 enclosures : 142.5 dB cont : 148.2 dB peak
   4 enclosures : 148.6 dB cont : 154.3 dB peak
Horn Length    3.1 (meters) 10.2 ft
Dispersion    Array Dependent
Crossover Point    Hi Pass : 27 Hz - 24 dB/oct
   Lo pass : 80 - 130 Hz - 24 dB/oct
Driver Config    1 x 18" neo - 100 (mm) 4" voice coil
Construction    18 mm - 13 laminate birch plywood
Finish    Textured polyurea
Grill    Perforated steel - foam filter
Connectors    2 x 4 pole Speakon
Dimensions    1218 (mm) 48.0" widep
   554 (mm) 21.8" high
   896 (mm) 35.3" deep
Weight    96.0 (Kg) 211.6 lbs net
   115.5 (Kg) 254.7 lbs shipping
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on March 25, 2013, 01:38:37 AM
Here is the preliminary info on the new Void Psycho X from Rog Mogale, the designer.  It has been in the works for some time coming from our need for more truck pack friendly rather than boxes just optimized for installs and not so much tour and hire service.

You are the US distributor, right?

;-)
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Jeff Bankston on March 25, 2013, 03:02:06 AM
Here is the preliminary info on the new Void Psycho X from Rog Mogale, the designer.  It has been in the works for some time coming from our need for more truck pack friendly rather than boxes just optimized for installs and not so much tour and hire service.

Psyco X

Psyco X is the latest addition to Voids line up of
high performance low frequency enclosures.
Being the latest has meant itís got to be special
and have some extraordinary specs. A quick
glance at its specifications will confirm this.

The design features a horn with a length of just
over 3.1 meters (10.2 ft), which is about as long
as anyone has ever managed to cram into an
enclosure with a total volume of just 604 litres.
This gives a stack of four enclosures an f3 point
of 27Hz with a sensitivity of 112.5dB 1w/1m.
Power handling is 6400 watts AES, which
equates to a peak output of 154.3dB at 1 meter.

The use of such a long horn has given extreme efficiency, a very low f3 with well-behaved transient response and a predictable dispersion pattern when arrayed. Both the predictability and far field projection capabilities of a Psyco X Array are what have made it the perfect partner for Arcline 12.

These superlative performance specs have only been made possible by a recent development in transducer chassis design that has allowed a sophisticated cooling system to be implemented. All the internal metal chassis parts and magnet structure are bolted to transfer plates and cables that connect to an external heatsink. The transference of heat form the core of the transducer to the outside of the enclosure has led to a world breaking level of power compression. Measurements taken after a 2 hour test with continuous full power 90% duty cycle source material have confirmed a power compression level of only 1.8dB.

Sprayed in our new "TourCoat," polyurea finish, the Stasys X V2 also features new truck pack friendly dimensions and universal location receptors that allow interlocking and mating with adjacent enclosures regardless of their orientation.

 
Frequency Response    27 Hz - 190 Hz -3dB (4 enclosures)
Sensitivity    1 enclosure : 106.0 dB 1w/1m
   2 enclosures : 108.5 dB 1w/1m
   4 enclosures : 112.5 dB 1w/1m
Impedance    1 enclosure : 8 ohms
Power Handling    1 enclosure : 1600 watts AES 2-1984 Rev. 2003
   2 enclosures : 3200 watts AES 2-1984 Rev. 2003
   4 enclosures : 6400 watts AES 2-1984 Rev. 2003
Maximum Output    Measured to IEC61672 and ANSI S1.4 specifications
   1 enclosure : 136.8 dB cont : 141.1 dB peak
   2 enclosures : 142.5 dB cont : 148.2 dB peak
   4 enclosures : 148.6 dB cont : 154.3 dB peak
Horn Length    3.1 (meters) 10.2 ft
Dispersion    Array Dependent
Crossover Point    Hi Pass : 27 Hz - 24 dB/oct
   Lo pass : 80 - 130 Hz - 24 dB/oct
Driver Config    1 x 18" neo - 100 (mm) 4" voice coil
Construction    18 mm - 13 laminate birch plywood
Finish    Textured polyurea
Grill    Perforated steel - foam filter
Connectors    2 x 4 pole Speakon
Dimensions    1218 (mm) 48.0" widep
   554 (mm) 21.8" high
   896 (mm) 35.3" deep
Weight    96.0 (Kg) 211.6 lbs net
   115.5 (Kg) 254.7 lbs shipping
it looks like your using the FaitalPro 18XL1600 18" woofer. am i correct ?
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Victor Pruitt on April 29, 2013, 01:07:58 AM
i love that this topic exists
 
we run these systems out of LA. people tell me all the time that music dosent go that low generally or people aren't writing bass lines in that range, true to a point and i reply with unless you have the Danley"s your not really able to have much of an opinion on that. flat to 20 and 500 lbs... theres more to bass than the bass line there is more info down there than people realize effortless low end is where its at..
I would buy a box twice the size if it went to 10hz

at these frequencies with electronic music especially you really need to go all out went through 3 different amps all of wich just were incapable of 20hz performance

th221's with k10 the only way to experience true sub bass

when people start to understand what these frequencies will do to a dance floor there will be a shift in the production of music
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on April 29, 2013, 01:59:05 PM
i love that this topic exists
 
we run these systems out of LA. people tell me all the time that music dosent go that low generally or people aren't writing bass lines in that range, true to a point and i reply with unless you have the Danley"s your not really able to have much of an opinion on that. flat to 20 and 500 lbs... theres more to bass than the bass line there is more info down there than people realize effortless low end is where its at..
I would buy a box twice the size if it went to 10hz

at these frequencies with electronic music especially you really need to go all out went through 3 different amps all of wich just were incapable of 20hz performance

th221's with k10 the only way to experience true sub bass

when people start to understand what these frequencies will do to a dance floor there will be a shift in the production of music

Only one way, then?

You have used everything else, I presume?

Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Elliot Thompson on April 29, 2013, 03:44:53 PM
i love that this topic exists
 
we run these systems out of LA. people tell me all the time that music dosent go that low generally or people aren't writing bass lines in that range, true to a point and i reply with unless you have the Danley"s your not really able to have much of an opinion on that. flat to 20 and 500 lbs... theres more to bass than the bass line there is more info down there than people realize effortless low end is where its at..
I would buy a box twice the size if it went to 10hz




Rest assure within 10 years we will all be searching for 10 Hz subs. :)

This is the bass frequency response of a current (2013) popular American Pop track.

(http://i.imgur.com/jSHBvBO.png)

I have configured my subs HPF settings to 10 Hz five years ago.

Best Regards,
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Doug Fowler on April 29, 2013, 04:17:53 PM

Rest assure within 10 years we will all be searching for 10 Hz subs. :)

This is the bass frequency response of a current (2013) popular American Pop track.

(http://i.imgur.com/jSHBvBO.png)

I have configured my subs HPF settings to 10 Hz five years ago.

Best Regards,

Which subs, Elliott?  I forgot what you are running. 
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Elliot Thompson on April 29, 2013, 04:59:44 PM
Which subs, Elliott?  I forgot what you are running.

I’m using my own custom-designed Double Eighteen reflex subs. They should be a little bit larger in terms of cubic feet than David Lee’s Dub-ill box and loaded with the old Beyma 18 G 550s. There is an impedance rise in the cabinet around 20 Hz which allows me to HPF the subs @ 10 Hz  (6 dB per octave) without worrying about x-mechanical damage from the loudspeakers getting 20 Hz.

Best Regards,
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Terry McNeil on May 14, 2013, 10:39:40 PM
db audiotechnik: 24x Infras, 24 J stretched out across the downstage edge. Js stacked on Infras.  It had to easily be 100' wide

JBL: 3x subs at top of each flown array, 8 in the center, maybe 6 arrayed together out on the sides.  This stage has to contend with a 5' deep moat in front of the arced stage, with subs standing on platforms in the moat.  Acoustically, this one is a crap shoot each year.   Search for Klipsch Amphitheater or Bayfront Park in your map application, I think you should be able to see the moat.

BASSMAXX: block of 8 wide, 2 high, with some Z5D upper bass boxes, making this on a split sub system, as was the db audiotechnik solution.


Hey Doug. There were 2 J-subs per Infra making that 48 J-subs and 72 subs total for the d&b rig.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Jeff Bailie on July 15, 2013, 05:17:04 PM


th221's with k10 the only way to experience true sub bass

when people start to understand what these frequencies will do to a dance floor there will be a shift in the production of music

I still have not had the chance to hear TH221's...   They are most efficient at like 78 hertz though right?    I think I would prefer infra style bass out of an encloser that was tuned a little lower.  Does anyone know the peak efficiency of Labhorns?   I still have yet to hear as solid of a 35 hertz as a big group of Labs myself. 
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Lee Buckalew on July 15, 2013, 05:37:30 PM
Here is the preliminary info on the new Void Psycho X from Rog Mogale, the designer.  It has been in the works for some time coming from our need for more truck pack friendly rather than boxes just optimized for installs and not so much tour and hire service.

Psyco X

Psyco X is the latest addition to Voids line up of
high performance low frequency enclosures.
Being the latest has meant itís got to be special
and have some extraordinary specs. A quick
glance at its specifications will confirm this.

The design features a horn with a length of just
over 3.1 meters (10.2 ft), which is about as long
as anyone has ever managed to cram into an
enclosure with a total volume of just 604 litres.
This gives a stack of four enclosures an f3 point
of 27Hz with a sensitivity of 112.5dB 1w/1m.
Power handling is 6400 watts AES, which
equates to a peak output of 154.3dB at 1 meter.

The use of such a long horn has given extreme efficiency, a very low f3 with well-behaved transient response and a predictable dispersion pattern when arrayed. Both the predictability and far field projection capabilities of a Psyco X Array are what have made it the perfect partner for Arcline 12.

These superlative performance specs have only been made possible by a recent development in transducer chassis design that has allowed a sophisticated cooling system to be implemented. All the internal metal chassis parts and magnet structure are bolted to transfer plates and cables that connect to an external heatsink. The transference of heat form the core of the transducer to the outside of the enclosure has led to a world breaking level of power compression. Measurements taken after a 2 hour test with continuous full power 90% duty cycle source material have confirmed a power compression level of only 1.8dB.

Sprayed in our new "TourCoat," polyurea finish, the Stasys X V2 also features new truck pack friendly dimensions and universal location receptors that allow interlocking and mating with adjacent enclosures regardless of their orientation.

 
Frequency Response    27 Hz - 190 Hz -3dB (4 enclosures)
Sensitivity    1 enclosure : 106.0 dB 1w/1m
   2 enclosures : 108.5 dB 1w/1m
   4 enclosures : 112.5 dB 1w/1m
Impedance    1 enclosure : 8 ohms
Power Handling    1 enclosure : 1600 watts AES 2-1984 Rev. 2003
   2 enclosures : 3200 watts AES 2-1984 Rev. 2003
   4 enclosures : 6400 watts AES 2-1984 Rev. 2003
Maximum Output    Measured to IEC61672 and ANSI S1.4 specifications
   1 enclosure : 136.8 dB cont : 141.1 dB peak
   2 enclosures : 142.5 dB cont : 148.2 dB peak
   4 enclosures : 148.6 dB cont : 154.3 dB peak
Horn Length    3.1 (meters) 10.2 ft
Dispersion    Array Dependent
Crossover Point    Hi Pass : 27 Hz - 24 dB/oct
   Lo pass : 80 - 130 Hz - 24 dB/oct
Driver Config    1 x 18" neo - 100 (mm) 4" voice coil
Construction    18 mm - 13 laminate birch plywood
Finish    Textured polyurea
Grill    Perforated steel - foam filter
Connectors    2 x 4 pole Speakon
Dimensions    1218 (mm) 48.0" widep
   554 (mm) 21.8" high
   896 (mm) 35.3" deep
Weight    96.0 (Kg) 211.6 lbs net
   115.5 (Kg) 254.7 lbs shipping

A single Martin ASX wil output a measured (not calculated) 152 dB/SPL at 1m.  Rated response is 30Hz - 150Hz +- 3dB.  All DSP and mplifcation built in.  It is an install box though.

Lee
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on July 15, 2013, 10:03:42 PM
Hey Lee, as you've measured it, do you have a graph you can post?
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Sean Hennessey on July 15, 2013, 10:24:00 PM
so,  25hz is the new 50hz?  post ya tracks!!! 

http://www.youtube.com/watch?v=TVFvWkCXhAM

http://www.youtube.com/watch?v=TVFvWkCXhAM

http://www.youtube.com/watch?v=IZXDvzTkPsg

i doubt any of these have 25 hz (asteroids gets close) but they all have mid/low30s content in sustained notes.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Lee Buckalew on July 15, 2013, 10:30:38 PM
Hey Lee, as you've measured it, do you have a graph you can post?

Paul, i have not measured this myself so i dont have a graph. 

Lee
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: paul bell on July 15, 2013, 10:48:47 PM
Paul, i have not measured this myself so i dont have a graph. 

Lee

OK, if somebody has a graph, I'd like to see it.

Doing the math backwards from 8,500 watts at 152dB, it would need to have a sensitivity of 114dB at one watt. It has a one Ohm driver. Although it's kinda big, kinda heavy at 353 pounds, it does have wheels and handles so it could be portable.

What's this thing cost?
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Lee Buckalew on July 16, 2013, 12:32:12 AM
OK, if somebody has a graph, I'd like to see it.

Doing the math backwards from 8,500 watts at 152dB, it would need to have a sensitivity of 114dB at one watt. It has a one Ohm driver. Although it's kinda big, kinda heavy at 353 pounds, it does have wheels and handles so it could be portable.

What's this thing cost?

Retail is $15,550.00 although street price would be lower.  The dealer that i use would sell these for about $12,600 - $13,000.  I have jusy emailed one of the guys who does a lot of testing and tuning with MLA/MLX to see if he has any stored graphs of the ASX.  I'll let you know.

Here's a link to a PSW blurb about the Ministry of Sound upgrade that used these.
http://www.prosoundweb.com/article/award_winning_martin_audio_system_helps_ministry_of_sound_celebrate_20th_bi/


Lee

Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Ivan Beaver on July 16, 2013, 07:38:55 AM
OK, if somebody has a graph, I'd like to see it.

Doing the math backwards from 8,500 watts at 152dB, it would need to have a sensitivity of 114dB at one watt.
There you go putting SENSE AND THOUGHT into the issue.  Shame on you ;)

Without a measurement (without processing or at least show the processing curve) there is no way to know where the numbers (for any product) come from.  It takes multiple number to back up a single number claim.

It is amazing what a little bit of THOUGHT and simple MATH can do when looking at specs.

DOES IT MAKE SENSE?  If not-then more explanation is needed------------------------------------
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Lee Buckalew on July 16, 2013, 06:10:51 PM
There you go putting SENSE AND THOUGHT into the issue.  Shame on you ;)

Without a measurement (without processing or at least show the processing curve) there is no way to know where the numbers (for any product) come from.  It takes multiple number to back up a single number claim.

It is amazing what a little bit of THOUGHT and simple MATH can do when looking at specs.

DOES IT MAKE SENSE?  If not-then more explanation is needed------------------------------------

I have not seen other manufacturers of powered speakers list efficiency.  I always supposed this was because the amp is already included so why would anybody care. 
In this case an efficiency of 114dB/SPL 1w/1m does not seem unreasonable or unlikely given that their unpowered single 18 of similar design  (but much smaller cabinet) has an efficiency of 108 dB/SPL 1w/1m. 
I know the horn is 7' long and the port loading takes over below about 40Hz.

I will post a trace if I can find someone with one.  Most of my contacts are concert guys and these are not exactly out on tours.

Lee
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Ivan Beaver on July 16, 2013, 07:52:24 PM
I have not seen other manufacturers of powered speakers list efficiency.  I always supposed this was because the amp is already included so why would anybody care. 
In this case an efficiency of 114dB/SPL 1w/1m does not seem unreasonable or unlikely given that their unpowered single 18 of similar design  (but much smaller cabinet) has an efficiency of 108 dB/SPL 1w/1m. 
I know the horn is 7' long and the port loading takes over below about 40Hz.

I will post a trace if I can find someone with one.  Most of my contacts are concert guys and these are not exactly out on tours.

Lee
It can get quite interesting is you simply use the dB gain of the amp (wattage wise) and then subtract (back calculate) from the rated max output and see what the sensitivity would have to be to get that output with a given amp size.

And when doing this-you DO NOT get to "automatically add" 6dB for peaks.  Since most modern amps are already rated in burst power- you don't get to add any more.

But that requires a bit of reasoning when looking at specs.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Art Welter on July 16, 2013, 08:37:20 PM
 
In this case an efficiency of 114dB/SPL 1w/1m does not seem unreasonable or unlikely given that their unpowered single 18 of similar design  (but much smaller cabinet) has an efficiency of 108 dB/SPL 1w/1m. 
Lee,

The B&C IPal 21" used in the Martin ASX is a monster, but it is only 90 dB one watt one meter (1 ohm, 99dB at 2.83 volts, which is 8 watts).

Not too unusual to see a relatively large bass horn provide a sensitivity gain of around 10-15 dB, but a gain of 24 dB seems neither reasonable or likely to me, and if it were, it would not be in the usable pass band of a "sub".

Of course, Martin's specs don't mention what frequency or duration they "measured" 152 dB at, so at some tiny portion of a millisecond  given the nature of the IPAL system I don't doubt it is possible, but given the speaker's displacement and 2500 watt AES rating that level would be unsustainable for EDM.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Lee Buckalew on July 16, 2013, 09:38:49 PM
Lee,

The B&C IPal 21" used in the Martin ASX is a monster, but it is only 90 dB one watt one meter (1 ohm, 99dB at 2.83 volts, which is 8 watts).

Not too unusual to see a relatively large bass horn provide a sensitivity gain of around 10-15 dB, but a gain of 24 dB seems neither reasonable or likely to me, and if it were, it would not be in the usable pass band of a "sub".

Of course, Martin's specs don't mention what frequency or duration they "measured" 152 dB at, so at some tiny portion of a millisecond  given the nature of the IPAL system I don't doubt it is possible, but given the speaker's displacement and 2500 watt AES rating that level would be unsustainable for EDM.

Art,
The IPAL21 has an efficiency of 99dB 1w/1m according to the B&C spec for the OEM only driver.  This would make the possibility of an efficiency of 114dB 1w/1m achievable.  The graphs thatI have seen show peak output at approximately 60Hz. 
Where were you seeing 90dB 1w/1m?

Lee
Title: 1W or 2.83V
Post by: Mac Kerr on July 16, 2013, 09:56:49 PM
The B&C IPal 21" used in the Martin ASX is a monster, but it is only 90 dB one watt one meter (1 ohm, 99dB at 2.83 volts, which is 8 watts).

Art, where are you seeing the 2.83V spec? The 2 spec sheets I looked at both said 1W/1m.

Mac
Title: Re: 1W or 2.83V
Post by: paul bell on July 17, 2013, 02:57:06 AM
Art, where are you seeing the 2.83V spec? The 2 spec sheets I looked at both said 1W/1m.

Mac

The sensitivity shows note 3.

"3. Applied RMS Voltage is set to 2.83 V for 8 ohms Nominal Impedance."
Title: Re: 1W or 2.83V
Post by: Lee Buckalew on July 17, 2013, 06:23:32 AM
The sensitivity shows note 3.

"3. Applied RMS Voltage is set to 2.83 V for 8 ohms Nominal Impedance."

I did find that on the B&C site.  I thought that 2.83 v was used as a standard and refererenced back to 1w/1m for the driver parameters.  If we calculate out peak SPL using your assumption then we only achieve a theoretical 130 dB/SPL.   Unless I'm dong the math incorrectly.  This theoretical limit does not seem possible if you have used this speaker.  A single enclosure is putting out peaks far beyond this when measured in the room during tuning so something here must be incorrect.
I have a graph of the ASX showing a measured peak output of 152dB/SPL at approximately 58Hz.  It does not have all of the various specifications associated with it so i don't know, measured at what distance and referenced to 1m, band limited pink noise, measured in 1/2 space, etc.

I forgot to add the potential increase in output for the horn loading.  Still, this only calculates to a theoretical peak of approximately 144 dB/SPL.  It doesn't match the graph.  It's about 8 dB/SPL short.

Now I've got to find out what's going on with this seeming discrepancy.

Lee

Title: Re: 1W or 2.83V
Post by: Art Welter on July 17, 2013, 11:27:21 AM

Quote from: paul bell on Today at 02:57:06 am

    The sensitivity shows note 3.

    "3. Applied RMS Voltage is set to 2.83 V for 8 ohms Nominal Impedance."
[/i]
I did find that on the B&C site.  I thought that 2.83 v was used as a standard and refererenced back to 1w/1m for the driver parameters. 
[/quote]
The footnote makes it rather confusing, but comparing the  η0 of 3.2% does support a 99 dB one watt one meter sensitivity.

The 21 IPAL is rather different, 22mm Xmax, 15mm Xvar, all the other B&C have slightly longer Xvar than Xmax.

At any rate, the IPAL amp and speaker are tied together more closely than in "normal" powered subs allowing for more peak power than the amp itself could normally produce.
Title: Re: 1W or 2.83V
Post by: paul bell on July 18, 2013, 08:44:25 AM
I'm just having a difficult time accepting that a single cabinet with a single driver can achieve an output of 152 Db. While the IPAL woofer/amplifier is a step ahead of driver design as we know it, it's not leaps and bounds ahead.

As the driver itself appears to have a sensitivity of 90 Db, the cabinet design would need to add 24 Db of sensitivity to reach 152 Db with a maximum amplifier power of 8,500 watts (Ivan, did I get that right?)

I know what it takes to hit 150 Db with bass cabinets, we managed it with two BASSMAX TRIP cabinets at The LAB Sub Shootout NYC a few years ago-some of you were there.

I know Martin Audio is a respectable company and wouldn't fludge the numbers (and I'm certain this cabinet has stunning output) but I want-nay, NEED to see a graph derived from a measured output of the cabinet-and not from Martin Audio.

It was stated above that this 152 Db output was at 58Hz. This is kinda the usual peak output range of most horn loaded subs. What's it's maximum output at 30Hz?

I do wish that ALL manufacturers list the sensitivity of their cabinets with a true one watt input-regardless of driver load. For example, if it's a two Ohm cabinet, adjust the test input voltage to apply an actual one watt as input to determine sensitivity.
Title: Re: 1W or 2.83V
Post by: Brad Weber on July 18, 2013, 10:22:02 AM
I do wish that ALL manufacturers list the sensitivity of their cabinets with a true one watt input-regardless of driver load. For example, if it's a two Ohm cabinet, adjust the test input voltage to apply an actual one watt as input to determine sensitivity.
I'm the opposite, it's all about voltage, current and impedance.  That's especially applicable with speakers where their impedance varies with frequency.  But then I'd also like to see a power rating for speakers that represents when any audible change in response occurs and not just some type of failure or major issue.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Marjan Milosevic on July 18, 2013, 11:33:36 AM
As i am aware of all the active ASX that Martin have sold including the Ministry of sound) has been downgraded to passive due to very poor reliability of the Ipal combo. And as i have heard the active ASX has been discontinued till further notice.
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Lee Buckalew on July 18, 2013, 11:44:04 AM
As i am aware of all the active ASX that Martin have sold including the Ministry of sound) has been downgraded to passive due to very poor reliability of the Ipal combo. And as i have heard the active ASX has been discontinued till further notice.

Interesting, I had not heard this.  I thought that IPAL was also being used on the MLX which have not been having any issues.  Is this correct?

Lee

Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Jens Palm Bacher on July 18, 2013, 08:58:28 PM
As i am aware of all the active ASX that Martin have sold including the Ministry of sound) has been downgraded to passive due to very poor reliability of the Ipal combo. And as i have heard the active ASX has been discontinued till further notice.
http://translate.google.com/translate?hl=da&sl=ru&tl=en&u=http%3A%2F%2Fshowtalks.ru%2Findex.php%3Ftopic%3D311.0

I have heard of Martin MLX subs having problems with electronic music...
Title: Re: 1W or 2.83V
Post by: paul bell on July 18, 2013, 09:20:09 PM
I'm the opposite, it's all about voltage, current and impedance.

While I can't disagree with you Brad, making the industry standard sensitivity rating one watt into it's rated Ohms would level the playing field when it comes to comparing apples to apples.

Imagine if a car wasn't rated in maximum miles per hour but instead fast, faster or plaid. How do you compare?
Title: Re: 1W or 2.83V
Post by: Tim McCulloch on July 18, 2013, 09:53:38 PM

Imagine if a car wasn't rated in maximum miles per hour but instead fast, faster or plaid. How do you compare?

Plaid is fastest.  Nobody wants to be caught in it.
Title: Re: 1W or 2.83V
Post by: g'bye, Dick Rees on July 18, 2013, 09:58:11 PM
Plaid is fastest.  Nobody wants to be caught in it.

"They've gone to plaid!!!"
...Barf, Spaceballs
Title: Re: 1W or 2.83V
Post by: paul bell on July 18, 2013, 09:59:23 PM
I knew that would get some chuckles!
Title: Re: 1W or 2.83V
Post by: Ivan Beaver on July 19, 2013, 06:10:20 AM
While I can't disagree with you Brad, making the industry standard sensitivity rating one watt into it's rated Ohms would level the playing field when it comes to comparing apples to apples.

Imagine if a car wasn't rated in maximum miles per hour but instead fast, faster or plaid. How do you compare?
The problem is that you CANNOT put 1 Watt into a loudspeaker-but you CAN put 2.83V.

Because the impedance of a loudspeaker is all over the map-if you did put 1watt (at all freq) then the freq response would be all over the place.

The best that you can do is to apply a voltage that is equal to 1 watt at some impedance-usually the rated impedance.

HOWEVER- the actual impedance is going to be higher and lower-meaning that depending on freq there will more or less than 1 watt actually being dissapted by the loudspeaker.

But if you apply a standard voltage (say 2.84V) then that will remain constant.  And since we do not apply wattage to a loudspeaker-but rather voltae-to me it just makes more sense to use a standard voltage as the test input.

Yes the user has to do A LITTLE BIT OF THOUGHT (which sadly seems to be lacking these days ;(  ) to get comparative numbers.  HOWEVER in many cases you can't even begin to compare-because of the lack of USABLE data-such as a simple freq response WITHOUT eq. 

Without that=you have NO IDEA where the 'sensitivity" number came from-or if it was even in the intended passband of the device.

And once you start to add "manufacturer suggested eq" it all starts to fall apart-ESPECIALLY on subs where it seems popular to simply add a boost on the low freq to make it appear to go lower.

HOWEVER this not only increases the input voltage-but also the wattage-so the whole idea of "1 watt" or a constant voltage falls apart.

This can work at low levels-but when you start to push a sub that has a low freq boost-it will quickly "run out of gas" when it gets loud-and at the freq where the boost was added-it simply won't get as loud.

But hey-let's just ignore that fact and look at the simple number and try to make a "rational" decision-based on some unknown facts.

Just like a court case in which a lawyer simply makes up "facts" until somebody challenges him-he can make the case go his way-----------------
Title: Re: 1W or 2.83V
Post by: paul bell on July 19, 2013, 07:48:35 AM
Good morning Ivan!

I understand what is being said here. Yes, different speakers will consume one watt at different frequencies.

So then how can the discerning buyer compare speakers on a level playing field?

Perhaps our friends at McCauley have it right, they list 2.83 volts AND the current drawn at the cabinet's nominal Ohm rating.

Here is a McCauley cabinet (the SA288 dual 18 sub) that can be had in 2 or 4 Ohms and the watts drawn are listed. Stating the watts drawn tells the buyer how to compare it to other cabinets.
(http://i171.photobucket.com/albums/u316/pbellsound/McCauleyspec_zps97b9e739.jpg)
Title: Re: 1W or 2.83V
Post by: Brad Weber on July 19, 2013, 08:13:04 AM
While I can't disagree with you Brad, making the industry standard sensitivity rating one watt into it's rated Ohms would level the playing field when it comes to comparing apples to apples.
As Ivan explained, the 1 Watt sensitivity ratings and responses do not actually represent the speaker being driven with 1 Watt but rather with the voltage equivalent to 1 Watt at some stated nominal impedance, which is itself typically a 'normalized' value of 16 Ohms, 8 Ohms, 4 Ohms or maybe 6 Ohms rather than the actual, and varying with frequency, impedance of the speaker.  Thus a sensitivity specified for 1 Watt is not actually related to 1 Watt into the speaker, it is instead related to a defined drive voltage (4V for 16 Ohms, 2.83V for 8 Ohms, 2.45V for 6 Ohms and 2V for 4 Ohms).
Title: Re: 1W or 2.83V
Post by: paul bell on July 19, 2013, 08:30:19 AM
As Ivan explained, the 1 Watt sensitivity ratings and responses do not actually represent the speaker being driven with 1 Watt but rather with the voltage equivalent to 1 Watt at some stated nominal impedance, which is itself typically a 'normalized' value of 16 Ohms, 8 Ohms, 4 Ohms or maybe 6 Ohms rather than the actual, and varying with frequency, impedance of the speaker.  Thus a sensitivity specified for 1 Watt is not actually related to 1 Watt into the speaker, it is instead related to a defined drive voltage (4V for 16 Ohms, 2.83V for 8 Ohms, 2.45V for 6 Ohms and 2V for 4 Ohms).

YES MY POINT EXACTLY!

This is why a speaker's specified sensitivity should be rated using a input test voltage relative to it's rated Ohms.

A cabinet with a nominal 4 Ohms should be tested with an input voltage of 2 Volts, not 2.83 Volts.

Example: A guy goes shopping for a subwoofer. It has two 4 Ohm woofers resulting in it being a 2 Ohm cabinet. A salesman reading the specifications tells him this cabinet has a sensitivity of 104 Db. Then there's another cabinet shown that's a single 8 Ohm woofer cabinet with a sensitivity of 101 Db. How does the buyer know that the dual woofer cabinet is actually less sensitive than the single woofer cabinet?
Title: Re: 1W or 2.83V
Post by: Ivan Beaver on July 19, 2013, 01:11:30 PM
YES MY POINT EXACTLY!

This is why a speaker's specified sensitivity should be rated using a input test voltage relative to it's rated Ohms.

A cabinet with a nominal 4 Ohms should be tested with an input voltage of 2 Volts, not 2.83 Volts.

Example: A guy goes shopping for a subwoofer. It has two 4 Ohm woofers resulting in it being a 2 Ohm cabinet. A salesman reading the specifications tells him this cabinet has a sensitivity of 104 Db. Then there's another cabinet shown that's a single 8 Ohm woofer cabinet with a sensitivity of 101 Db. How does the buyer know that the dual woofer cabinet is actually less sensitive than the single woofer cabinet?
So exactly how do you determine what the impedance really is?

Is it the lowest point (even if it is only a couple of Hz wide)? or an average (exactly how is that determined-over what freq range-linear or log freq? or is it the nearest standard value?

Many loudspeakers are rated as either 4-8-16 ohms-even though the load the present to the amp may not be that. Those are just the nearest standard values. 

You could come up with sorts of different "ideas" on the impedance and use they varying ideas to state a particular voltage (that would come out to 1 watt) and still provide very unrealistic sensitivity numbers.

lets say a speaker is rated for 8 ohm-which would be 2.83V.  But it has a peak in the impedance curve around 32 ohms-not uncommon.  So if you use that value to determine the voltage required for 1 watt you get 5.6V or a difference of 6dB.  So the "rating" would actually be 6dB higher than what the average person could get out of the speaker-if they applied a normal voltage.

You can "work" the numbers in all sorts of different ways-and they are not lying-but they are far from telling the truth or at least giving an idea of what the average person could reasonably expect out of a product.  But that doesn't stop some manufacturers--------------------------------

And believe me-if a manufacturer gives a number that is REALISTIC-but not a standard-it is the source for a lot of confusion.  just rate a speaker for 6 ohms and see what happens-----------------Many people have no idea what amp to buy since they don't see a 6 ohm rating.------------------------

A slightly educated person can read the sensitivity graphs and the impedance graph (assuming that it is provided-which is becoming less and less-as I feel manufacturers are trying to "hide" things) and get an idea if the loudspeaker will do the job for them.  They also need to see the "presets" curve it presets are part of the spec sheet.

EAW has done a good job of this-showing the raw response-preset curve and a final curve.



Title: Re: 1W or 2.83V
Post by: Ivan Beaver on July 19, 2013, 01:24:02 PM
And just to "further complicate" things without a measured freq response GRAPH-there is no way to know where the stated sensitivity )be it voltage or power) is coming from.

I know a number of cases in which the sensitivity  (max output) is stated as 10dB (or more) higher than a normal person could get out of the cabinet-because there is a peak in the response that makes it really loud.

So the "casual" person would see this and say-OH that cabinet can do 140dB-it is much louder than the other one that can only do 135dB.

But if you look at the response-that 140dB number comes from a single peak that has to be eqed down to match the rest of the cabinet-and NOW the AVERAGE response is 130dB-so it is really not as loud-but they made a sale from it.

Is the manufacturer lying-NO-it will produce that SPL at "SOME" freq-but not across the usable freq range.  But the number is VERY misleading to people who either don't know better-or because the manufacturer did not provide a response graph to look at.
 
SO KNOW WHERE THE NUMBERS COME FROM-and DON'T just look at the single simple numbers on a spec sheet.

If you want a real answer-you have to dig a little deeper.

But sadly it seems that the current trend of some very expensive loudspeakers give no specs at all.  I guess this means that nobody can say it doesn't meet spec-because there are none------------------------------------
Title: Re: 1W or 2.83V
Post by: Keith Broughton on July 19, 2013, 04:04:27 PM
Quote
But sadly it seems that the current trend of some very expensive loudspeakers give no specs at all.  I guess this means that nobody can say it doesn't meet spec-because there are none------------------------------------
Like the customer who asked the Rolls Royce salesman "how much power does this engine produce?"
"Sufficient" was the answer.
It seems these days that more manufacturers want to use the black-box-it-will-work-fine concept and keep  consumers away from those pesky facts!
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Anton Tumas on October 15, 2013, 09:13:24 PM
I have heard those Danley TH221s at an outdoor event, and they give a big round bottom to the sound, with a very full feeling. The other most impressive subs I have heard have been d&b B2 ground stacked 3 per side. That was gut wrenching.
Title: Posting Rules
Post by: Mac Kerr on October 15, 2013, 09:17:22 PM
I have heard those Danley TH221s

Please go to your profile and change the "Name" field to your real first and last name as required by the posting rules displayed in the header at the top of the section, and in the Site Rules and Suggestions (http://forums.prosoundweb.com/index.php/board,36.0.html) in the Forum Announcements section, and on the registration page when you registered.

Mac
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Lee Buckalew on November 18, 2013, 02:26:48 PM
As i am aware of all the active ASX that Martin have sold including the Ministry of sound) has been downgraded to passive due to very poor reliability of the Ipal combo. And as i have heard the active ASX has been discontinued till further notice.

Wanted to reply to this and set the record straight as I am working on a project where I am investigating the ASX as an option. 
I checked with Martin and was told that not only have none of the ASX at the MoS been changed to passive but all remain as originally designed.  There has recently been a design change to the BC drivers, all at MoS have been upgraded.  They were just upgraded within the last two weeks.  Since the install MoS has had one ASX with an amplifier issue, this was 3 years ago.  They have had no problems before or since with amp modules.

MoS has also won the award for "Best Global Club Sound" 4 years running.  During this time the ASX have all been actively powered, as designed.

Lee
Title: Re: 25 Hz is the new 50 Hz - ULTRA Music Festival
Post by: Josh Hana on December 31, 2013, 09:47:40 AM
Just found out yesterday that we are likely getting a stage or two at Ultra this year. Going to be bringing out the KUDO rig, and a boatload of SB28s. I've only heard the J subs, not the infras, would SB28s at 1:1 to tops be comparable? Thinking maybe 8 a side Kudo and 16 subs, just need to figure out the best layout for them