Journey resumes - Line source VS Point source

[ronildoq]

Ok I thought we deserved to have a topic on line source woofers vs point source.

 

As usual, the journey resumes again....

 

After my various experiments with placement, MSO, stacking, time alignment, etc etc, I found the biggest benefits among all the theories is time alignment for subwoofers , placed at trihedral corners boundary loaded, in line source formation

 

Of which, Two of the points I’ve clarified and verified with actual listening experience, I’m now after the third, Line source.

 

What is line source ?

 

Whole lot of stuff to read here, otherwise known as line array

 

https://en.m.wikipedia.org/wiki/Line_array

 

But the ones above, are for stadium, concert stuff. So doesn’t really apply for my case

 

Mine will be in a small listening room, at home, in the hall that measures 6x8m

 

So I shipped in 8 more 10” Seas L26roy XM001-04 woofers, to make it a total of 6 woofers on the left, 6 woofers on the right as stereo woofers that will handle re-directed bass and LFE

 

The choice for amplifier is critical, I got in the speakerpower amps from USA, SP1-6000 HT model. (6000w into 2ohm) each to power 6 woofers and they are very good for HT application. I got it custom made (filters) to meet my requirements

 

“SpeakerPower subwoofer amplifiers are uniquely designed for long term high power output at extremely low frequencies to meet the demands of synthesized bass and explosive special effects for cinema and music, and they are really good, clean sounding “

 

The Class D amplifier has a 1ms delay, similar to my seatons pair, the customise controls allow for

 

0 = no filters, 1 knob 29hz HP filter to 10th knob 45hz (24db oct)

 

Low pass filter from 80-800hz

 

2ms delay on each knob

 

The rest are the norm, gain , trigger, xlr , rca, pass through etc etc

 

The above set up is quite rare, something u won’t see Everyday, probably haven’t come across. The difference between 3 years ago and now is, I know what I’m after, why and how to do it to bring the entire system up to the next level. I hope I’m right this time, so far all the theory is pointing in the right direction.

 

At the end of this exercise, what I’m after, really.... is not the SPLs , just to be clear. I’m after the headroom. Clean, fast, superb transient Attack with 3D definition is what I’m after, in short, Bass articulation. I’ve been observing along my journey, and I have a strong feeling this is the way forward. Having said that, the song “ head & shoulders knees and toes” come to mind.

 

I believe in order to achieve Superb tactile feedback from head down to toe, it lies with the height placement of the woofers(when it is stacked), a line source formation that will provide tactility evenly across from head to toe. This is what I’m after! Especially satisfying for dolby Atmos with BEQ. The other thing with heights, is it fills the entire AT screen, tracks all the online action seen on screen, very immersive indeed , I have no doubts here.

 

So here goes again, woofers arrived from Norway !

 

 

The Drivers 10” below.

 

Choice for 10” is because the line source is good from 140hz upwards to 400hz, due to the heights stacked, 2.4m heights. 2.4m is one wavelength of 140hz, so it will start to show directionality and below this point 140hz, omnidirectional . Choice for the seas is because of the Low voice coil inductance and they are extremely efficient 50hz upwards , upper midbass region

 

 

Actual pics of the Drivers

 

 

 

 

The cabinets

 

 

Stay tuned, I’ll share more info along the way... lotsa reading... but enjoy!

 

I’ll post my findings along the way

[Boxerfan88]

Wow, an interesting project indeed.

 

I think your theory makes sense, in that mid-sized woofers would perform much faster & less distortion compared to a huge 15” or 18” woofer; and stringing so many together as a line source can help you achieve the desired ULF output.

 

 

Sent from my iPhone using Tapatalk

[rock123]

wow another endless journey. Enjoy bro.

 

Good read up :)

[ronildoq]

Wow, an interesting project indeed.

 

I think your theory makes sense, in that mid-sized woofers would perform much faster & less distortion compared to a huge 15” or 18” woofer; and stringing so many together as a line source can help you achieve the desired ULF output.

 

 

Sent from my iPhone using Tapatalk

 

 

Actually the line up is to take advantage of the room modes, on the height aspect, since I have the space

 

Not really true that 15, 18” woofers are “slow”. They are not slow . The difference is they handle much longer wavelengths down lower frequencies, this longer wavelength take more time to decay, dissipate in energy, hence giving the feeling that it’s slower.

 

U can take a similar 18” vs 12” , play the same frequency range down to 30hz and cut it off thereafter, I’ll assure u they sound equally fast

 

The other factor which we already know, is the voice coil inductance, the lower the inductance, the faster it sounds

 

10” sounds faster than an 18” is a myth, I assure you

[kennyluck2000]

 

Actually the line up is to take advantage of the room modes, on the height aspect, since I have the space

 

Not really true that 15, 18” woofers are “slow”. They are not slow . The difference is they handle much longer wavelengths down lower frequencies, this longer wavelength take more time to decay, dissipate in energy, hence giving the feeling that it’s slower.

 

U can take a similar 18” vs 12” , play the same frequency range down to 30hz and cut it off thereafter, I’ll assure u they sound equally fast

 

The other factor which we already know, is the voice coil inductance, the lower the inductance, the faster it sounds

 

10” sounds faster than an 18” is a myth, I assure you

 

Different size driver, they are best in a certain range of frequency.  An 18" definitely can't play well at a higher frequency like a small driver. And a small driver can't play low very well like a bigger driver. That is why you use 10" driver for line source instead of 18". Of course 18" still can play 100 Hz but the 10" can do a much better job than the 18".... both tonality and feel are different. 18" can be like Mike Tyson punch feel where 10" is like Bruce Lee punch... in certain scenes from Bruce Lee is the best to use the 10".

End of the day we don't use a bass driver to play like a tweeter or use a tweeter to play ULF...

 

Remember the Dolby Atmos Leaf demo? When the leaf drop from the tree panning from the front right to left then to back go one round and drop on the water. You can clearly hear 'pop pop pop pop' from behind all the way until the leaf drop in the water. That scene I feel is not natural. Maybe your Xover point from the sub is too high or too much damping in the room that causes to sound 'pop pop pop pop'? Maybe your tweaking to make your 18" to sound clean and fast with not much bass extension that causes it to sound 'pop pop pop pop'.

Maybe using some ported sub may help you to 'smooth' out the panning?

 

From my first visit til today. Your system really improves a lot... but the most obvious improvement in the sound quality change in your system is when the day you start treating your room... :) :) :)

[ronildoq]

Actually that is incorrect. How efficient has nothing to do with the size, be it 10” or 18”

 

An 18” or 15” woofer can be made to be very efficient along the 50-100hz range and sound fast. But a 12 or 10” definitely cant be as efficient down 20hz-10hz. It’s more of design choice.

 

 

If u zoom in to the above, u will realise these woofers are efficient above 50hz straight to 800hz

 

The main purpose I picked these woofers was because I wanted to do something the Lyngdorf processor offers that none of the other processor can do. It’s called physchoacoustic bass steering . To achieve this effect, one would need to use something called” boundary woofers”

 

The crossover for these woofers, range from 400-800hz, over the mains. Not the typical 60-100hz xo u use from normal 3 way speakers to subwoofer. Hence the choice for these 10” woofers with Low voice coil inductance. Fortunately these Drivers are very efficient down to 40hz as can be seen from the graph , so the choice for using to handle upper midbass as well. They are not designed to handle LFE type of content, they are more for stereo bass. But I’m using it anyway for LfE (sunbian)

 

Maybe I wasn’t clear enough, the reason why it’s placed behind the mains, all the way up to the ceiling, is because according to Lyngdorf, a line source placement of the Drivers, offers far superior timing response , that eliminates most of the axial modes in the room . (Floor to ceiling), and when the woofers are stacked high, they offer directionality (depending on the height) in my case, 2.4m, so directionality down to 140hz , that’s the size of the wavelength for 2.4m. Below this point, they become omnidirectional

 

Now there is a difference between directionality and localisation. Directionality, is something u feel, things moving around and u can pin point it’s image as sound moves around in the room, that 3D effect. Localisation on the other hand, is every scene u watch, u feel the bass coming from a certain area only where the subwoofer is placed. It doesn’t spread, like the leaf scene around u. Actually The tok Tok sound moving around u heard is actually the door sound and the wooden structure resonating. ( that’s much better now with decoupling) initially the guys thought the subs bottom up, lol [emoji23]

 

Ok so again, it’s really incorrect and it’s a myth that 18” is slower than a 10”. It depends on the choice of design and characteristics of the driver. I was in that camp before, after moving away to 18”, I noticed that’s not the case at all

 

There are many others who have successfully implemented using 18” as midbass Drivers, they are really fast and punchy. I wanted to clear the myth that 18” is slower than 10”. Here is one article below. Hope that helps clear the doubt.

 

 

[ronildoq]

Here is the article

 

Source

 

https://data-bass.com/#/articles/5cbf5e7357f7140004d6d0ec?_k=vjt2v7

 

Myth: Bass Speed

 

Subwoofers are Fast / Slow

 

It is a common misconception that sound quality is related to the woofers speed or quickness, but in fact the woofer's speed is related to the frequency it is producing and the SPL. There are two ways to change a woofer's speed. 1. Change the frequency of the signal it is reproducing or 2. increase the output / excursion. It may sound counter-intuitive, but it is true. There are many other factors that go into making a subwoofer sound fast, or slow, or boomy, tight, airy, or whatever subjective terminology is applied, but that divulges into system design and room acoustics primarily, rather the driver itself. Bass wavelengths by definition are slow to develop. Try listening to a subwoofer operating by itself sometime.

 

Another important concept along this line of thinking is that a subwoofer with deeper extension will tend to sound slower than a unit with less extension. This should not be surprising. The deepest frequencies are the longest and slowest to develop. If you are not used to very deep frequencies being reproduced it may sound less accurate or slow, but in reality the sub with deeper extension is reproducing content that the less extended unit is simply not producing well or at all. The fastest sounding bass is when there is no bass.

 

The concepts of overshoot, difficulties overcoming inertia, or ringing after the note ends also fall into this category. These terms indicate smearing in time of the signal. Fortunately it is relatively simple to look at a few things to determine if there is a problem. The driver or system "Q" or damping is one way. There is also group delay, energy decay, etc. Most studies show that the people are insensitive to even moderate amounts of energy delay in the bass range. Generally what causes these types of subjective terms to be used are differences in frequency response, rapid changes in response vs frequency and issues due to room or vehicle acoustics. In most cases the effect that the room has on the subwoofer response and energy decay rates dwarf those inherent to the design, unless the sub exhibits some truly bad issues. What's most important about this myth is that speed is an inappropriate concept of sound quality.

 

Smaller woofers sound faster than larger woofers

 

One of the biggest myths about woofers is that smaller units like 8's and 10's sound "tighter" and "faster" than 15's or 18's. Even bigger drivers such as 21's and 24's are supposedly worse than 15's or 18's. This can be true in some specific cases, but as a blanket statement of all drivers this is factually incorrect.

 

This subjective impression is often caused by factors other than the simple size of the driver. What tends to happen is that the smaller drivers have a lower Qts because manufacturers tend to share one motor design across many different sizes of drivers in the series. They may have the same motor on the 10" driver that they have on the 15 or 18". Unless the motor can compensate for the extra mass it has to push, then the Qts will not be the same as the smaller drivers. Ultimately the larger driver may not be suited for the same kinds of alignments as the smaller driver and ends up requiring a much larger air volume for the same system "Q" and response shape. Typically the larger driver will end up in a higher "Q" undersized system with a less linear response shape that may cause it to sound more uneven or "one note". It may also end up being tuned much deeper in frequency and the increased low frequency output may also cause it to sound "slower" or "heavier". Smaller subs and those using smaller driver sizes are often not asked to go as low and will not have the same low frequency extension in their design. When comparing subs the one with more low frequency extension and output will sound quite different. Having said that, high Qts drivers are not inherently inferior sounding when compared to more efficient, highly damped drivers, but they require larger boxes and less internal pressure to prevent response peaking and increased group delay.

 

Large sub drivers can be made to have the same motor to cone ratio as smaller drivers. The larger woofers also have more room for bigger suspension components and voice coils which can allow higher power handling, more excursion capability and larger mechanical clearances that simply cannot fit on an 8 or 10" driver frame. It is more expensive to make larger driver sizes in this way, but not impossible. There are a number of good examples on the market. It's just a matter of picking the right driver for the job.

 

Impulse Response Indicates Subwoofer Speed or Tightness

 

This goes back to the myth that some subs are fast / slow. An impulse response represents a ton of condensed information. Too much to compare them directly against each other at a glance and make determinations about performance. The quickest way to make a very short, abrupt, impulse response graph, is to remove all of the bass from the speaker being measured. Bass frequencies require a long time to develop and will extend out the impulse response by their very presence. Simply changing the frequency response balance of the system, or changing the frequency range covered by the measurement will change the way the impulse response looks. For these reasons it is almost impossible to eyeball a pair of impulse responses from units having dissimilar frequency response shapes, or measurement bandwidths and make a direct comparison.

 

 

[ronildoq]

Ok some pictures on the cabinets.

 

Getting ready, hopefully we can get this up soon next week, perfect time to stay home and complete the job, can’t go outdoors as much due to covid-19

 

 

Amplifiers from speakerpower arrives this week

 

Stack stack stack the way to go....

[ronildoq]

More articles and videos on Line source, here is one from REL

 

https://rel.net/taking-bass-to-new-heights-with-the-serie-s-line-array/

 

 

[embed=425,349]

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Here is another very good article on beam subwoofer array

 

http://www.synaudcon.com/site/wp-content/uploads/2010/09/Simulation-and-Application-of-Beam-shaped-subwoofer-arrays.PDF

 

Enjoy the reading if u love bass

[wizardofoz]

lots of home time now to apply theory and test...

[kennyluck2000]

lots of home time now to apply theory and test...

 

;) :)

[ronildoq]

I’ll share my findings here for everyone, these will include measurements that show, before the line source (existing historical measurements), and after the line source , decay times etc

 

The woofers remains in their position, no shifting. The back of it will be mounted and secured against a solid wall, using L Long bracket. Thank god  for behind that wall, is not my neighbour ;), it’s an open space behind that wall, so thankfully this should not disturb the neighbours. Above the ceiling, is rockwool stuffed, 10mm 40kg density x 3 pieces , so that’s effectively 30mm, with some air GAP

 

Beneath the woofers, will be a 4cm thick granite base, isolated by cork and sorbothane beneath it, in between will be segregated by an anti slip yoga mat from diy store, to couple the stacked pair’s onto one another, to let it firmly sit above it without moving

 

Finally how it feels having a stacked x6 woofers all the way to ceiling , will share all these findings, be it good or bad

[ronildoq]

Alright amplifiers have arrived, straight from USA, speakerpower, the absolute best for HT. Having experienced the crown amplifiers for subs, they are not in the same league as the speakerpower. Price range is of course different.

 

Quick zoom , 6000w into 2ohms

 

 

Bubble wrapped! The first thing when unboxing, both the kids come running, cheong ahhhh... fighting to pop the bubbles ! Lol [emoji23]

 

 

 

18cm in width , together with the controls, customised EQ design to suit the requirements for my place on the line source woofers. Allows for HP filters from 29hz to 45hz, pass through with no HP, and Low pass options from 80hz to 800hz through its controls

 

 

40cm in height

 

 

7cm in depth

 

 

Cables to connect

 

 

It will be connected to a 15a like socket, more than enough juice and headroom.

 

These connect directly to the MCB

 

To be continued... as far as I know, this amp is the right amp for HT use, and I love the sound signature from this amplifier, so that’s a good start, it’s the same amplifier used by seatons F18

[kopidilo]

Quick zoom , 6000w into 2ohms

 

:o :o

[Boxerfan88]

240V @ 15A works out to 3.6kW.

If instantaneous 6kW demanded means fuse blow?

 

[emoji15]

 

Sent from my iPhone using Tapatalk

[ronildoq]

The 6 pieces 4ohm woofers will be wired series to 8ohm then 3 parallel for final impedence of 2.666ohm load

 

My goal is not to blast the entire system to its limits, the goal is to let all Drivers handle the respective frequencies with relative ease, in cruising mode , hence the decision for 6 woofers for the line source.

 

At the moment, 4 Drivers 2 each handling left and right, is being pushed to the limits to cope with the f18”, and its struggling to cope... many a times I noticed red light blinking on the crown amplifier (volume is at max) but driver excursion still solid doesn’t pop. Signal clips first

[ronildoq]

Here ate the specs for the SP1-6000HT, 4000w 4ohms

 

 

Out of the 6 pieces 4ohm woofers, wiring

 

3 parallel 4 ohm = 1.33 ohm

 

Another 3 parallel 4 ohm = 1.33 ohm

 

Combined the two in series 1.33+1.33 = 2.66ohm

 

Suddenly I don’t feel like an accountant, I feel like I’m an engineer ! Lol

 

4ohm Drivers at peak 500watts x 6 woofers = max 3000w into 4 ohms, more than enough juice, should be alright with ample headroom. This is what I want, cruising mode....

 

Here is the picture of the base where the woofers sit, they will sit on a 4cm thick granite

 

 

Observe closely the design of the base, is with an air GAP, this should stop transmission of energy to my neighbour below. They have been painted black thereafter to mirror the fabric of the baffle wall, absorbing light spill over from the projector

 

We know from previous exercise that having an “air GAP “ greatly improves  bass response, especially on the vertical axial mode.

 

TOP covered with rockwool, bottom covered with isolation. 6 woofers will now be centralised 1/4 from ground, 1/4 from ceiling , they will be equidistant in line source. Woofers floating, seats and MLP also floating, im gonna call my theatre hall now, “ Roni’s Floating Paradise”

 

Having further discussion with chief designer, bro synthesis on the salient points

 

I highly recommend bro synthesis for any DIY subwoofer job u need, he is very professional & experienced ! (Provides he is free) Coming from my personal experience working with him , great job!

 

More to follow as and when I have updates, I’m very keen to look at the measurements and the feeling using line source woofers

[ronildoq]

Here is a close up pic of the base, after painting works

 

 

Above it is an anti slip yoga mat from decathlon, thanks again bro NGSK! I’m getting lotsa help from bro NGSK and members , it cost $10 from decathlon. Very good and effective

 

 

They will be sandwiched in between when stacked to the ceiling .

 

Getting everything cut out, ready for the work . Use this if you want to stack, good and effective ! We have tested, firmly couples to the one it sits on

 

 

Multiple sheets, ready , cut to size for the upcoming stack work . The logic for the line source is to have all 3 pairs coupled as 1. The isolation beneath uses granite, with cork and sorbothane. That’s done and dusted

 

 

Check out the neat cabinet builds from synthesis, very nice indeed , precision cut, looks great ! Doesn’t look diy at all to me,looks so professional. Even the speaker grills look so good, same material with my baffle wall, pitch black cloth. I’ll share more pics when the amp plates are flushed into the cabinets

 

Entering war zone again......

 

 

Messy messy messy because of ....

 

Stack stack stack

 

Very exciting days ahead... can’t wait. Now planning out target curves and EQ strategy

 

[kennyluck2000]

Enjoy Byran...with your Line source array....  :) :) :)

Also good to see more people going into DIY  8) 8) 8)

[ronildoq]

Yea bro, can’t wait. Actually not my DIY skills. I open mouth and wallet only. . Talk easy, do very challenging. Purely synthesis, hats off to him ! Very neat work.

 

I’ll probably spend 1/2 day cutting 1 piece of wood , honestly this will not be possible without synthesis . Big thank you to synthesis for willing to take up this project. Nice experience for me and him too. Line source is a very interesting concept. It works very effectively from what I have seen

 

Honestly If we don’t have the manpower plus time and  skills, it’s better to buy off self, ready made. Actually DIY also not cheap really, gotta buy amp and Drivers, time spent cutting wood etc, working out the numbers, all requires time. Plus warranty stuff etc. Pros and cons

 

But the experience along the way is the fun part . Very good learning experience for me, that’s Priceless, I’ve been learning non stop for the past 3 years. So many things to absorb

[kennyluck2000]

Yea bro, can’t wait. Actually not my DIY skills. I open mouth and wallet only. . Talk easy, do very challenging. Purely synthesis, hats off to him ! Very neat work.

 

I’ll probably spend 1/2 day cutting 1 piece of wood , honestly this will not be possible without synthesis . Big thank you to synthesis for willing to take up this project. Nice experience for me and him too. Line source is a very interesting concept. It works very effectively from what I have seen

 

Honestly If we don’t have the manpower plus time and  skills, it’s better to buy off self, ready made. Actually DIY also not cheap really, gotta buy amp and Drivers, time spent cutting wood etc, working out the numbers, all requires time. Plus warranty stuff etc. Pros and cons

 

But the experience along the way is the fun part . Very good learning experience for me, that’s Priceless, I’ve been learning non stop for the past 3 years. So many things to absorb

 

Ya I have to thank Synthesis for a few projects he had done for me...also he is very helpful and humble. I also get a lot advise from him when it come to diy... :) :) :)

[ronildoq]

Ok more pics as promised

 

Quick zoom in on the Class D SP1-6000HT speakerpower amplifier

 

 

Using Sealant to prevent any chance of air leak from the amplifier

 

 

 

Bi-wired, directly soldered onto the connectors. I had some spare 14awg, kabel direkt speaker cables, left over from crowsons amp

 

 

 

[ronildoq]

So very neat work by synthesis again, really TOP notch carpentry skills

 

The cut out for the amplifiers

 

 

How they will be mounted inside the cabinets, very nice

 

 

Peek-A-Boo, dual Drivers in one cabinet, amplifiers flushed in

 

 

Gasket all around the amplifier! No chance taken to prevent any air leak

 

 

Quick view of how it’s gonna look, with the amplifier on the cabinets

 

 

The completed middle cabinet of the dual Drivers, this will sit in between another two pairs. So we can save on speaker cables, neater too. The ones with the amplifier, sits in the middle

 

 

There was some consideration to have the amplifier located outside the cabinet, due to volume. But measuring 66cmx30 x33.5cm returns 47 litres in volume. It will have a difference in the cabinet with the amplifier, but I believe it should not matter much, adding volume, increases extension of the frequency. Which is not required as these woofers,  will be high passed to handle higher frequency range

 

Very excited !

 

 

[kopidilo]

wow very nice...

[ronildoq]

The middle dual 10” section with the amplifier, ready !!

 

 

One cable for the TOP, another for the bottom pair

 

One more pair to go, then starting the stack stack stack session

 

 

 

They look gorgeous ! These Drivers